xref: /petsc/src/mat/impls/aij/mpi/mpiaij.c (revision a78d8160b5625c877aec4ce5a6db0c05a701febe)
1 
2 
3 #include <../src/mat/impls/aij/mpi/mpiaij.h>   /*I "petscmat.h" I*/
4 #include <petsc/private/vecimpl.h>
5 #include <petsc/private/isimpl.h>
6 #include <petscblaslapack.h>
7 #include <petscsf.h>
8 
9 /*MC
10    MATAIJ - MATAIJ = "aij" - A matrix type to be used for sparse matrices.
11 
12    This matrix type is identical to MATSEQAIJ when constructed with a single process communicator,
13    and MATMPIAIJ otherwise.  As a result, for single process communicators,
14   MatSeqAIJSetPreallocation is supported, and similarly MatMPIAIJSetPreallocation is supported
15   for communicators controlling multiple processes.  It is recommended that you call both of
16   the above preallocation routines for simplicity.
17 
18    Options Database Keys:
19 . -mat_type aij - sets the matrix type to "aij" during a call to MatSetFromOptions()
20 
21   Developer Notes: Subclasses include MATAIJCUSP, MATAIJCUSPARSE, MATAIJPERM, MATAIJMKL, MATAIJCRL, and also automatically switches over to use inodes when
22    enough exist.
23 
24   Level: beginner
25 
26 .seealso: MatCreateAIJ(), MatCreateSeqAIJ(), MATSEQAIJ, MATMPIAIJ
27 M*/
28 
29 /*MC
30    MATAIJCRL - MATAIJCRL = "aijcrl" - A matrix type to be used for sparse matrices.
31 
32    This matrix type is identical to MATSEQAIJCRL when constructed with a single process communicator,
33    and MATMPIAIJCRL otherwise.  As a result, for single process communicators,
34    MatSeqAIJSetPreallocation() is supported, and similarly MatMPIAIJSetPreallocation() is supported
35   for communicators controlling multiple processes.  It is recommended that you call both of
36   the above preallocation routines for simplicity.
37 
38    Options Database Keys:
39 . -mat_type aijcrl - sets the matrix type to "aijcrl" during a call to MatSetFromOptions()
40 
41   Level: beginner
42 
43 .seealso: MatCreateMPIAIJCRL,MATSEQAIJCRL,MATMPIAIJCRL, MATSEQAIJCRL, MATMPIAIJCRL
44 M*/
45 
46 PetscErrorCode MatSetBlockSizes_MPIAIJ(Mat M, PetscInt rbs, PetscInt cbs)
47 {
48   PetscErrorCode ierr;
49   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)M->data;
50 
51   PetscFunctionBegin;
52   if (mat->A) {
53     ierr = MatSetBlockSizes(mat->A,rbs,cbs);CHKERRQ(ierr);
54     ierr = MatSetBlockSizes(mat->B,rbs,1);CHKERRQ(ierr);
55   }
56   PetscFunctionReturn(0);
57 }
58 
59 PetscErrorCode MatFindNonzeroRows_MPIAIJ(Mat M,IS *keptrows)
60 {
61   PetscErrorCode  ierr;
62   Mat_MPIAIJ      *mat = (Mat_MPIAIJ*)M->data;
63   Mat_SeqAIJ      *a   = (Mat_SeqAIJ*)mat->A->data;
64   Mat_SeqAIJ      *b   = (Mat_SeqAIJ*)mat->B->data;
65   const PetscInt  *ia,*ib;
66   const MatScalar *aa,*bb;
67   PetscInt        na,nb,i,j,*rows,cnt=0,n0rows;
68   PetscInt        m = M->rmap->n,rstart = M->rmap->rstart;
69 
70   PetscFunctionBegin;
71   *keptrows = 0;
72   ia        = a->i;
73   ib        = b->i;
74   for (i=0; i<m; i++) {
75     na = ia[i+1] - ia[i];
76     nb = ib[i+1] - ib[i];
77     if (!na && !nb) {
78       cnt++;
79       goto ok1;
80     }
81     aa = a->a + ia[i];
82     for (j=0; j<na; j++) {
83       if (aa[j] != 0.0) goto ok1;
84     }
85     bb = b->a + ib[i];
86     for (j=0; j <nb; j++) {
87       if (bb[j] != 0.0) goto ok1;
88     }
89     cnt++;
90 ok1:;
91   }
92   ierr = MPIU_Allreduce(&cnt,&n0rows,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)M));CHKERRQ(ierr);
93   if (!n0rows) PetscFunctionReturn(0);
94   ierr = PetscMalloc1(M->rmap->n-cnt,&rows);CHKERRQ(ierr);
95   cnt  = 0;
96   for (i=0; i<m; i++) {
97     na = ia[i+1] - ia[i];
98     nb = ib[i+1] - ib[i];
99     if (!na && !nb) continue;
100     aa = a->a + ia[i];
101     for (j=0; j<na;j++) {
102       if (aa[j] != 0.0) {
103         rows[cnt++] = rstart + i;
104         goto ok2;
105       }
106     }
107     bb = b->a + ib[i];
108     for (j=0; j<nb; j++) {
109       if (bb[j] != 0.0) {
110         rows[cnt++] = rstart + i;
111         goto ok2;
112       }
113     }
114 ok2:;
115   }
116   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)M),cnt,rows,PETSC_OWN_POINTER,keptrows);CHKERRQ(ierr);
117   PetscFunctionReturn(0);
118 }
119 
120 PetscErrorCode  MatDiagonalSet_MPIAIJ(Mat Y,Vec D,InsertMode is)
121 {
122   PetscErrorCode    ierr;
123   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*) Y->data;
124 
125   PetscFunctionBegin;
126   if (Y->assembled && Y->rmap->rstart == Y->cmap->rstart && Y->rmap->rend == Y->cmap->rend) {
127     ierr = MatDiagonalSet(aij->A,D,is);CHKERRQ(ierr);
128   } else {
129     ierr = MatDiagonalSet_Default(Y,D,is);CHKERRQ(ierr);
130   }
131   PetscFunctionReturn(0);
132 }
133 
134 PetscErrorCode MatFindZeroDiagonals_MPIAIJ(Mat M,IS *zrows)
135 {
136   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)M->data;
137   PetscErrorCode ierr;
138   PetscInt       i,rstart,nrows,*rows;
139 
140   PetscFunctionBegin;
141   *zrows = NULL;
142   ierr   = MatFindZeroDiagonals_SeqAIJ_Private(aij->A,&nrows,&rows);CHKERRQ(ierr);
143   ierr   = MatGetOwnershipRange(M,&rstart,NULL);CHKERRQ(ierr);
144   for (i=0; i<nrows; i++) rows[i] += rstart;
145   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)M),nrows,rows,PETSC_OWN_POINTER,zrows);CHKERRQ(ierr);
146   PetscFunctionReturn(0);
147 }
148 
149 PetscErrorCode MatGetColumnNorms_MPIAIJ(Mat A,NormType type,PetscReal *norms)
150 {
151   PetscErrorCode ierr;
152   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)A->data;
153   PetscInt       i,n,*garray = aij->garray;
154   Mat_SeqAIJ     *a_aij = (Mat_SeqAIJ*) aij->A->data;
155   Mat_SeqAIJ     *b_aij = (Mat_SeqAIJ*) aij->B->data;
156   PetscReal      *work;
157 
158   PetscFunctionBegin;
159   ierr = MatGetSize(A,NULL,&n);CHKERRQ(ierr);
160   ierr = PetscCalloc1(n,&work);CHKERRQ(ierr);
161   if (type == NORM_2) {
162     for (i=0; i<a_aij->i[aij->A->rmap->n]; i++) {
163       work[A->cmap->rstart + a_aij->j[i]] += PetscAbsScalar(a_aij->a[i]*a_aij->a[i]);
164     }
165     for (i=0; i<b_aij->i[aij->B->rmap->n]; i++) {
166       work[garray[b_aij->j[i]]] += PetscAbsScalar(b_aij->a[i]*b_aij->a[i]);
167     }
168   } else if (type == NORM_1) {
169     for (i=0; i<a_aij->i[aij->A->rmap->n]; i++) {
170       work[A->cmap->rstart + a_aij->j[i]] += PetscAbsScalar(a_aij->a[i]);
171     }
172     for (i=0; i<b_aij->i[aij->B->rmap->n]; i++) {
173       work[garray[b_aij->j[i]]] += PetscAbsScalar(b_aij->a[i]);
174     }
175   } else if (type == NORM_INFINITY) {
176     for (i=0; i<a_aij->i[aij->A->rmap->n]; i++) {
177       work[A->cmap->rstart + a_aij->j[i]] = PetscMax(PetscAbsScalar(a_aij->a[i]), work[A->cmap->rstart + a_aij->j[i]]);
178     }
179     for (i=0; i<b_aij->i[aij->B->rmap->n]; i++) {
180       work[garray[b_aij->j[i]]] = PetscMax(PetscAbsScalar(b_aij->a[i]),work[garray[b_aij->j[i]]]);
181     }
182 
183   } else SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_WRONG,"Unknown NormType");
184   if (type == NORM_INFINITY) {
185     ierr = MPIU_Allreduce(work,norms,n,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
186   } else {
187     ierr = MPIU_Allreduce(work,norms,n,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
188   }
189   ierr = PetscFree(work);CHKERRQ(ierr);
190   if (type == NORM_2) {
191     for (i=0; i<n; i++) norms[i] = PetscSqrtReal(norms[i]);
192   }
193   PetscFunctionReturn(0);
194 }
195 
196 PetscErrorCode MatFindOffBlockDiagonalEntries_MPIAIJ(Mat A,IS *is)
197 {
198   Mat_MPIAIJ      *a  = (Mat_MPIAIJ*)A->data;
199   IS              sis,gis;
200   PetscErrorCode  ierr;
201   const PetscInt  *isis,*igis;
202   PetscInt        n,*iis,nsis,ngis,rstart,i;
203 
204   PetscFunctionBegin;
205   ierr = MatFindOffBlockDiagonalEntries(a->A,&sis);CHKERRQ(ierr);
206   ierr = MatFindNonzeroRows(a->B,&gis);CHKERRQ(ierr);
207   ierr = ISGetSize(gis,&ngis);CHKERRQ(ierr);
208   ierr = ISGetSize(sis,&nsis);CHKERRQ(ierr);
209   ierr = ISGetIndices(sis,&isis);CHKERRQ(ierr);
210   ierr = ISGetIndices(gis,&igis);CHKERRQ(ierr);
211 
212   ierr = PetscMalloc1(ngis+nsis,&iis);CHKERRQ(ierr);
213   ierr = PetscMemcpy(iis,igis,ngis*sizeof(PetscInt));CHKERRQ(ierr);
214   ierr = PetscMemcpy(iis+ngis,isis,nsis*sizeof(PetscInt));CHKERRQ(ierr);
215   n    = ngis + nsis;
216   ierr = PetscSortRemoveDupsInt(&n,iis);CHKERRQ(ierr);
217   ierr = MatGetOwnershipRange(A,&rstart,NULL);CHKERRQ(ierr);
218   for (i=0; i<n; i++) iis[i] += rstart;
219   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)A),n,iis,PETSC_OWN_POINTER,is);CHKERRQ(ierr);
220 
221   ierr = ISRestoreIndices(sis,&isis);CHKERRQ(ierr);
222   ierr = ISRestoreIndices(gis,&igis);CHKERRQ(ierr);
223   ierr = ISDestroy(&sis);CHKERRQ(ierr);
224   ierr = ISDestroy(&gis);CHKERRQ(ierr);
225   PetscFunctionReturn(0);
226 }
227 
228 /*
229     Distributes a SeqAIJ matrix across a set of processes. Code stolen from
230     MatLoad_MPIAIJ(). Horrible lack of reuse. Should be a routine for each matrix type.
231 
232     Only for square matrices
233 
234     Used by a preconditioner, hence PETSC_EXTERN
235 */
236 PETSC_EXTERN PetscErrorCode MatDistribute_MPIAIJ(MPI_Comm comm,Mat gmat,PetscInt m,MatReuse reuse,Mat *inmat)
237 {
238   PetscMPIInt    rank,size;
239   PetscInt       *rowners,*dlens,*olens,i,rstart,rend,j,jj,nz = 0,*gmataj,cnt,row,*ld,bses[2];
240   PetscErrorCode ierr;
241   Mat            mat;
242   Mat_SeqAIJ     *gmata;
243   PetscMPIInt    tag;
244   MPI_Status     status;
245   PetscBool      aij;
246   MatScalar      *gmataa,*ao,*ad,*gmataarestore=0;
247 
248   PetscFunctionBegin;
249   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
250   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
251   if (!rank) {
252     ierr = PetscObjectTypeCompare((PetscObject)gmat,MATSEQAIJ,&aij);CHKERRQ(ierr);
253     if (!aij) SETERRQ1(PetscObjectComm((PetscObject)gmat),PETSC_ERR_SUP,"Currently no support for input matrix of type %s\n",((PetscObject)gmat)->type_name);
254   }
255   if (reuse == MAT_INITIAL_MATRIX) {
256     ierr = MatCreate(comm,&mat);CHKERRQ(ierr);
257     ierr = MatSetSizes(mat,m,m,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
258     ierr = MatGetBlockSizes(gmat,&bses[0],&bses[1]);CHKERRQ(ierr);
259     ierr = MPI_Bcast(bses,2,MPIU_INT,0,comm);CHKERRQ(ierr);
260     ierr = MatSetBlockSizes(mat,bses[0],bses[1]);CHKERRQ(ierr);
261     ierr = MatSetType(mat,MATAIJ);CHKERRQ(ierr);
262     ierr = PetscMalloc1(size+1,&rowners);CHKERRQ(ierr);
263     ierr = PetscMalloc2(m,&dlens,m,&olens);CHKERRQ(ierr);
264     ierr = MPI_Allgather(&m,1,MPIU_INT,rowners+1,1,MPIU_INT,comm);CHKERRQ(ierr);
265 
266     rowners[0] = 0;
267     for (i=2; i<=size; i++) rowners[i] += rowners[i-1];
268     rstart = rowners[rank];
269     rend   = rowners[rank+1];
270     ierr   = PetscObjectGetNewTag((PetscObject)mat,&tag);CHKERRQ(ierr);
271     if (!rank) {
272       gmata = (Mat_SeqAIJ*) gmat->data;
273       /* send row lengths to all processors */
274       for (i=0; i<m; i++) dlens[i] = gmata->ilen[i];
275       for (i=1; i<size; i++) {
276         ierr = MPI_Send(gmata->ilen + rowners[i],rowners[i+1]-rowners[i],MPIU_INT,i,tag,comm);CHKERRQ(ierr);
277       }
278       /* determine number diagonal and off-diagonal counts */
279       ierr = PetscMemzero(olens,m*sizeof(PetscInt));CHKERRQ(ierr);
280       ierr = PetscCalloc1(m,&ld);CHKERRQ(ierr);
281       jj   = 0;
282       for (i=0; i<m; i++) {
283         for (j=0; j<dlens[i]; j++) {
284           if (gmata->j[jj] < rstart) ld[i]++;
285           if (gmata->j[jj] < rstart || gmata->j[jj] >= rend) olens[i]++;
286           jj++;
287         }
288       }
289       /* send column indices to other processes */
290       for (i=1; i<size; i++) {
291         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
292         ierr = MPI_Send(&nz,1,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
293         ierr = MPI_Send(gmata->j + gmata->i[rowners[i]],nz,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
294       }
295 
296       /* send numerical values to other processes */
297       for (i=1; i<size; i++) {
298         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
299         ierr = MPI_Send(gmata->a + gmata->i[rowners[i]],nz,MPIU_SCALAR,i,tag,comm);CHKERRQ(ierr);
300       }
301       gmataa = gmata->a;
302       gmataj = gmata->j;
303 
304     } else {
305       /* receive row lengths */
306       ierr = MPI_Recv(dlens,m,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
307       /* receive column indices */
308       ierr = MPI_Recv(&nz,1,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
309       ierr = PetscMalloc2(nz,&gmataa,nz,&gmataj);CHKERRQ(ierr);
310       ierr = MPI_Recv(gmataj,nz,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
311       /* determine number diagonal and off-diagonal counts */
312       ierr = PetscMemzero(olens,m*sizeof(PetscInt));CHKERRQ(ierr);
313       ierr = PetscCalloc1(m,&ld);CHKERRQ(ierr);
314       jj   = 0;
315       for (i=0; i<m; i++) {
316         for (j=0; j<dlens[i]; j++) {
317           if (gmataj[jj] < rstart) ld[i]++;
318           if (gmataj[jj] < rstart || gmataj[jj] >= rend) olens[i]++;
319           jj++;
320         }
321       }
322       /* receive numerical values */
323       ierr = PetscMemzero(gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr);
324       ierr = MPI_Recv(gmataa,nz,MPIU_SCALAR,0,tag,comm,&status);CHKERRQ(ierr);
325     }
326     /* set preallocation */
327     for (i=0; i<m; i++) {
328       dlens[i] -= olens[i];
329     }
330     ierr = MatSeqAIJSetPreallocation(mat,0,dlens);CHKERRQ(ierr);
331     ierr = MatMPIAIJSetPreallocation(mat,0,dlens,0,olens);CHKERRQ(ierr);
332 
333     for (i=0; i<m; i++) {
334       dlens[i] += olens[i];
335     }
336     cnt = 0;
337     for (i=0; i<m; i++) {
338       row  = rstart + i;
339       ierr = MatSetValues(mat,1,&row,dlens[i],gmataj+cnt,gmataa+cnt,INSERT_VALUES);CHKERRQ(ierr);
340       cnt += dlens[i];
341     }
342     if (rank) {
343       ierr = PetscFree2(gmataa,gmataj);CHKERRQ(ierr);
344     }
345     ierr = PetscFree2(dlens,olens);CHKERRQ(ierr);
346     ierr = PetscFree(rowners);CHKERRQ(ierr);
347 
348     ((Mat_MPIAIJ*)(mat->data))->ld = ld;
349 
350     *inmat = mat;
351   } else {   /* column indices are already set; only need to move over numerical values from process 0 */
352     Mat_SeqAIJ *Ad = (Mat_SeqAIJ*)((Mat_MPIAIJ*)((*inmat)->data))->A->data;
353     Mat_SeqAIJ *Ao = (Mat_SeqAIJ*)((Mat_MPIAIJ*)((*inmat)->data))->B->data;
354     mat  = *inmat;
355     ierr = PetscObjectGetNewTag((PetscObject)mat,&tag);CHKERRQ(ierr);
356     if (!rank) {
357       /* send numerical values to other processes */
358       gmata  = (Mat_SeqAIJ*) gmat->data;
359       ierr   = MatGetOwnershipRanges(mat,(const PetscInt**)&rowners);CHKERRQ(ierr);
360       gmataa = gmata->a;
361       for (i=1; i<size; i++) {
362         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
363         ierr = MPI_Send(gmataa + gmata->i[rowners[i]],nz,MPIU_SCALAR,i,tag,comm);CHKERRQ(ierr);
364       }
365       nz = gmata->i[rowners[1]]-gmata->i[rowners[0]];
366     } else {
367       /* receive numerical values from process 0*/
368       nz   = Ad->nz + Ao->nz;
369       ierr = PetscMalloc1(nz,&gmataa);CHKERRQ(ierr); gmataarestore = gmataa;
370       ierr = MPI_Recv(gmataa,nz,MPIU_SCALAR,0,tag,comm,&status);CHKERRQ(ierr);
371     }
372     /* transfer numerical values into the diagonal A and off diagonal B parts of mat */
373     ld = ((Mat_MPIAIJ*)(mat->data))->ld;
374     ad = Ad->a;
375     ao = Ao->a;
376     if (mat->rmap->n) {
377       i  = 0;
378       nz = ld[i];                                   ierr = PetscMemcpy(ao,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ao += nz; gmataa += nz;
379       nz = Ad->i[i+1] - Ad->i[i];                   ierr = PetscMemcpy(ad,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ad += nz; gmataa += nz;
380     }
381     for (i=1; i<mat->rmap->n; i++) {
382       nz = Ao->i[i] - Ao->i[i-1] - ld[i-1] + ld[i]; ierr = PetscMemcpy(ao,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ao += nz; gmataa += nz;
383       nz = Ad->i[i+1] - Ad->i[i];                   ierr = PetscMemcpy(ad,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ad += nz; gmataa += nz;
384     }
385     i--;
386     if (mat->rmap->n) {
387       nz = Ao->i[i+1] - Ao->i[i] - ld[i];           ierr = PetscMemcpy(ao,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr);
388     }
389     if (rank) {
390       ierr = PetscFree(gmataarestore);CHKERRQ(ierr);
391     }
392   }
393   ierr = MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
394   ierr = MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
395   PetscFunctionReturn(0);
396 }
397 
398 /*
399   Local utility routine that creates a mapping from the global column
400 number to the local number in the off-diagonal part of the local
401 storage of the matrix.  When PETSC_USE_CTABLE is used this is scalable at
402 a slightly higher hash table cost; without it it is not scalable (each processor
403 has an order N integer array but is fast to acess.
404 */
405 PetscErrorCode MatCreateColmap_MPIAIJ_Private(Mat mat)
406 {
407   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
408   PetscErrorCode ierr;
409   PetscInt       n = aij->B->cmap->n,i;
410 
411   PetscFunctionBegin;
412   if (!aij->garray) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"MPIAIJ Matrix was assembled but is missing garray");
413 #if defined(PETSC_USE_CTABLE)
414   ierr = PetscTableCreate(n,mat->cmap->N+1,&aij->colmap);CHKERRQ(ierr);
415   for (i=0; i<n; i++) {
416     ierr = PetscTableAdd(aij->colmap,aij->garray[i]+1,i+1,INSERT_VALUES);CHKERRQ(ierr);
417   }
418 #else
419   ierr = PetscCalloc1(mat->cmap->N+1,&aij->colmap);CHKERRQ(ierr);
420   ierr = PetscLogObjectMemory((PetscObject)mat,(mat->cmap->N+1)*sizeof(PetscInt));CHKERRQ(ierr);
421   for (i=0; i<n; i++) aij->colmap[aij->garray[i]] = i+1;
422 #endif
423   PetscFunctionReturn(0);
424 }
425 
426 #define MatSetValues_SeqAIJ_A_Private(row,col,value,addv,orow,ocol)     \
427 { \
428     if (col <= lastcol1)  low1 = 0;     \
429     else                 high1 = nrow1; \
430     lastcol1 = col;\
431     while (high1-low1 > 5) { \
432       t = (low1+high1)/2; \
433       if (rp1[t] > col) high1 = t; \
434       else              low1  = t; \
435     } \
436       for (_i=low1; _i<high1; _i++) { \
437         if (rp1[_i] > col) break; \
438         if (rp1[_i] == col) { \
439           if (addv == ADD_VALUES) ap1[_i] += value;   \
440           else                    ap1[_i] = value; \
441           goto a_noinsert; \
442         } \
443       }  \
444       if (value == 0.0 && ignorezeroentries && row != col) {low1 = 0; high1 = nrow1;goto a_noinsert;} \
445       if (nonew == 1) {low1 = 0; high1 = nrow1; goto a_noinsert;}                \
446       if (nonew == -1) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero at global row/column (%D, %D) into matrix", orow, ocol); \
447       MatSeqXAIJReallocateAIJ(A,am,1,nrow1,row,col,rmax1,aa,ai,aj,rp1,ap1,aimax,nonew,MatScalar); \
448       N = nrow1++ - 1; a->nz++; high1++; \
449       /* shift up all the later entries in this row */ \
450       for (ii=N; ii>=_i; ii--) { \
451         rp1[ii+1] = rp1[ii]; \
452         ap1[ii+1] = ap1[ii]; \
453       } \
454       rp1[_i] = col;  \
455       ap1[_i] = value;  \
456       A->nonzerostate++;\
457       a_noinsert: ; \
458       ailen[row] = nrow1; \
459 }
460 
461 #define MatSetValues_SeqAIJ_B_Private(row,col,value,addv,orow,ocol) \
462   { \
463     if (col <= lastcol2) low2 = 0;                        \
464     else high2 = nrow2;                                   \
465     lastcol2 = col;                                       \
466     while (high2-low2 > 5) {                              \
467       t = (low2+high2)/2;                                 \
468       if (rp2[t] > col) high2 = t;                        \
469       else             low2  = t;                         \
470     }                                                     \
471     for (_i=low2; _i<high2; _i++) {                       \
472       if (rp2[_i] > col) break;                           \
473       if (rp2[_i] == col) {                               \
474         if (addv == ADD_VALUES) ap2[_i] += value;         \
475         else                    ap2[_i] = value;          \
476         goto b_noinsert;                                  \
477       }                                                   \
478     }                                                     \
479     if (value == 0.0 && ignorezeroentries) {low2 = 0; high2 = nrow2; goto b_noinsert;} \
480     if (nonew == 1) {low2 = 0; high2 = nrow2; goto b_noinsert;}                        \
481     if (nonew == -1) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero at global row/column (%D, %D) into matrix", orow, ocol); \
482     MatSeqXAIJReallocateAIJ(B,bm,1,nrow2,row,col,rmax2,ba,bi,bj,rp2,ap2,bimax,nonew,MatScalar); \
483     N = nrow2++ - 1; b->nz++; high2++;                    \
484     /* shift up all the later entries in this row */      \
485     for (ii=N; ii>=_i; ii--) {                            \
486       rp2[ii+1] = rp2[ii];                                \
487       ap2[ii+1] = ap2[ii];                                \
488     }                                                     \
489     rp2[_i] = col;                                        \
490     ap2[_i] = value;                                      \
491     B->nonzerostate++;                                    \
492     b_noinsert: ;                                         \
493     bilen[row] = nrow2;                                   \
494   }
495 
496 PetscErrorCode MatSetValuesRow_MPIAIJ(Mat A,PetscInt row,const PetscScalar v[])
497 {
498   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)A->data;
499   Mat_SeqAIJ     *a   = (Mat_SeqAIJ*)mat->A->data,*b = (Mat_SeqAIJ*)mat->B->data;
500   PetscErrorCode ierr;
501   PetscInt       l,*garray = mat->garray,diag;
502 
503   PetscFunctionBegin;
504   /* code only works for square matrices A */
505 
506   /* find size of row to the left of the diagonal part */
507   ierr = MatGetOwnershipRange(A,&diag,0);CHKERRQ(ierr);
508   row  = row - diag;
509   for (l=0; l<b->i[row+1]-b->i[row]; l++) {
510     if (garray[b->j[b->i[row]+l]] > diag) break;
511   }
512   ierr = PetscMemcpy(b->a+b->i[row],v,l*sizeof(PetscScalar));CHKERRQ(ierr);
513 
514   /* diagonal part */
515   ierr = PetscMemcpy(a->a+a->i[row],v+l,(a->i[row+1]-a->i[row])*sizeof(PetscScalar));CHKERRQ(ierr);
516 
517   /* right of diagonal part */
518   ierr = PetscMemcpy(b->a+b->i[row]+l,v+l+a->i[row+1]-a->i[row],(b->i[row+1]-b->i[row]-l)*sizeof(PetscScalar));CHKERRQ(ierr);
519   PetscFunctionReturn(0);
520 }
521 
522 PetscErrorCode MatSetValues_MPIAIJ(Mat mat,PetscInt m,const PetscInt im[],PetscInt n,const PetscInt in[],const PetscScalar v[],InsertMode addv)
523 {
524   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
525   PetscScalar    value;
526   PetscErrorCode ierr;
527   PetscInt       i,j,rstart  = mat->rmap->rstart,rend = mat->rmap->rend;
528   PetscInt       cstart      = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
529   PetscBool      roworiented = aij->roworiented;
530 
531   /* Some Variables required in the macro */
532   Mat        A                 = aij->A;
533   Mat_SeqAIJ *a                = (Mat_SeqAIJ*)A->data;
534   PetscInt   *aimax            = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
535   MatScalar  *aa               = a->a;
536   PetscBool  ignorezeroentries = a->ignorezeroentries;
537   Mat        B                 = aij->B;
538   Mat_SeqAIJ *b                = (Mat_SeqAIJ*)B->data;
539   PetscInt   *bimax            = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->rmap->n,am = aij->A->rmap->n;
540   MatScalar  *ba               = b->a;
541 
542   PetscInt  *rp1,*rp2,ii,nrow1,nrow2,_i,rmax1,rmax2,N,low1,high1,low2,high2,t,lastcol1,lastcol2;
543   PetscInt  nonew;
544   MatScalar *ap1,*ap2;
545 
546   PetscFunctionBegin;
547   for (i=0; i<m; i++) {
548     if (im[i] < 0) continue;
549 #if defined(PETSC_USE_DEBUG)
550     if (im[i] >= mat->rmap->N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %D max %D",im[i],mat->rmap->N-1);
551 #endif
552     if (im[i] >= rstart && im[i] < rend) {
553       row      = im[i] - rstart;
554       lastcol1 = -1;
555       rp1      = aj + ai[row];
556       ap1      = aa + ai[row];
557       rmax1    = aimax[row];
558       nrow1    = ailen[row];
559       low1     = 0;
560       high1    = nrow1;
561       lastcol2 = -1;
562       rp2      = bj + bi[row];
563       ap2      = ba + bi[row];
564       rmax2    = bimax[row];
565       nrow2    = bilen[row];
566       low2     = 0;
567       high2    = nrow2;
568 
569       for (j=0; j<n; j++) {
570         if (roworiented) value = v[i*n+j];
571         else             value = v[i+j*m];
572         if (in[j] >= cstart && in[j] < cend) {
573           col   = in[j] - cstart;
574           nonew = a->nonew;
575           if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES) && row != col) continue;
576           MatSetValues_SeqAIJ_A_Private(row,col,value,addv,im[i],in[j]);
577         } else if (in[j] < 0) continue;
578 #if defined(PETSC_USE_DEBUG)
579         else if (in[j] >= mat->cmap->N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %D max %D",in[j],mat->cmap->N-1);
580 #endif
581         else {
582           if (mat->was_assembled) {
583             if (!aij->colmap) {
584               ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
585             }
586 #if defined(PETSC_USE_CTABLE)
587             ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
588             col--;
589 #else
590             col = aij->colmap[in[j]] - 1;
591 #endif
592             if (col < 0 && !((Mat_SeqAIJ*)(aij->B->data))->nonew) {
593               ierr = MatDisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
594               col  =  in[j];
595               /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
596               B     = aij->B;
597               b     = (Mat_SeqAIJ*)B->data;
598               bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j; ba = b->a;
599               rp2   = bj + bi[row];
600               ap2   = ba + bi[row];
601               rmax2 = bimax[row];
602               nrow2 = bilen[row];
603               low2  = 0;
604               high2 = nrow2;
605               bm    = aij->B->rmap->n;
606               ba    = b->a;
607             } else if (col < 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero at global row/column (%D, %D) into matrix", im[i], in[j]);
608           } else col = in[j];
609           nonew = b->nonew;
610           MatSetValues_SeqAIJ_B_Private(row,col,value,addv,im[i],in[j]);
611         }
612       }
613     } else {
614       if (mat->nooffprocentries) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Setting off process row %D even though MatSetOption(,MAT_NO_OFF_PROC_ENTRIES,PETSC_TRUE) was set",im[i]);
615       if (!aij->donotstash) {
616         mat->assembled = PETSC_FALSE;
617         if (roworiented) {
618           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
619         } else {
620           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
621         }
622       }
623     }
624   }
625   PetscFunctionReturn(0);
626 }
627 
628 PetscErrorCode MatGetValues_MPIAIJ(Mat mat,PetscInt m,const PetscInt idxm[],PetscInt n,const PetscInt idxn[],PetscScalar v[])
629 {
630   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
631   PetscErrorCode ierr;
632   PetscInt       i,j,rstart = mat->rmap->rstart,rend = mat->rmap->rend;
633   PetscInt       cstart = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
634 
635   PetscFunctionBegin;
636   for (i=0; i<m; i++) {
637     if (idxm[i] < 0) continue; /* SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative row: %D",idxm[i]);*/
638     if (idxm[i] >= mat->rmap->N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %D max %D",idxm[i],mat->rmap->N-1);
639     if (idxm[i] >= rstart && idxm[i] < rend) {
640       row = idxm[i] - rstart;
641       for (j=0; j<n; j++) {
642         if (idxn[j] < 0) continue; /* SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative column: %D",idxn[j]); */
643         if (idxn[j] >= mat->cmap->N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %D max %D",idxn[j],mat->cmap->N-1);
644         if (idxn[j] >= cstart && idxn[j] < cend) {
645           col  = idxn[j] - cstart;
646           ierr = MatGetValues(aij->A,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
647         } else {
648           if (!aij->colmap) {
649             ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
650           }
651 #if defined(PETSC_USE_CTABLE)
652           ierr = PetscTableFind(aij->colmap,idxn[j]+1,&col);CHKERRQ(ierr);
653           col--;
654 #else
655           col = aij->colmap[idxn[j]] - 1;
656 #endif
657           if ((col < 0) || (aij->garray[col] != idxn[j])) *(v+i*n+j) = 0.0;
658           else {
659             ierr = MatGetValues(aij->B,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
660           }
661         }
662       }
663     } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Only local values currently supported");
664   }
665   PetscFunctionReturn(0);
666 }
667 
668 extern PetscErrorCode MatMultDiagonalBlock_MPIAIJ(Mat,Vec,Vec);
669 
670 PetscErrorCode MatAssemblyBegin_MPIAIJ(Mat mat,MatAssemblyType mode)
671 {
672   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
673   PetscErrorCode ierr;
674   PetscInt       nstash,reallocs;
675 
676   PetscFunctionBegin;
677   if (aij->donotstash || mat->nooffprocentries) PetscFunctionReturn(0);
678 
679   ierr = MatStashScatterBegin_Private(mat,&mat->stash,mat->rmap->range);CHKERRQ(ierr);
680   ierr = MatStashGetInfo_Private(&mat->stash,&nstash,&reallocs);CHKERRQ(ierr);
681   ierr = PetscInfo2(aij->A,"Stash has %D entries, uses %D mallocs.\n",nstash,reallocs);CHKERRQ(ierr);
682   PetscFunctionReturn(0);
683 }
684 
685 PetscErrorCode MatAssemblyEnd_MPIAIJ(Mat mat,MatAssemblyType mode)
686 {
687   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
688   Mat_SeqAIJ     *a   = (Mat_SeqAIJ*)aij->A->data;
689   PetscErrorCode ierr;
690   PetscMPIInt    n;
691   PetscInt       i,j,rstart,ncols,flg;
692   PetscInt       *row,*col;
693   PetscBool      other_disassembled;
694   PetscScalar    *val;
695 
696   /* do not use 'b = (Mat_SeqAIJ*)aij->B->data' as B can be reset in disassembly */
697 
698   PetscFunctionBegin;
699   if (!aij->donotstash && !mat->nooffprocentries) {
700     while (1) {
701       ierr = MatStashScatterGetMesg_Private(&mat->stash,&n,&row,&col,&val,&flg);CHKERRQ(ierr);
702       if (!flg) break;
703 
704       for (i=0; i<n; ) {
705         /* Now identify the consecutive vals belonging to the same row */
706         for (j=i,rstart=row[j]; j<n; j++) {
707           if (row[j] != rstart) break;
708         }
709         if (j < n) ncols = j-i;
710         else       ncols = n-i;
711         /* Now assemble all these values with a single function call */
712         ierr = MatSetValues_MPIAIJ(mat,1,row+i,ncols,col+i,val+i,mat->insertmode);CHKERRQ(ierr);
713 
714         i = j;
715       }
716     }
717     ierr = MatStashScatterEnd_Private(&mat->stash);CHKERRQ(ierr);
718   }
719   ierr = MatAssemblyBegin(aij->A,mode);CHKERRQ(ierr);
720   ierr = MatAssemblyEnd(aij->A,mode);CHKERRQ(ierr);
721 
722   /* determine if any processor has disassembled, if so we must
723      also disassemble ourselfs, in order that we may reassemble. */
724   /*
725      if nonzero structure of submatrix B cannot change then we know that
726      no processor disassembled thus we can skip this stuff
727   */
728   if (!((Mat_SeqAIJ*)aij->B->data)->nonew) {
729     ierr = MPIU_Allreduce(&mat->was_assembled,&other_disassembled,1,MPIU_BOOL,MPI_PROD,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
730     if (mat->was_assembled && !other_disassembled) {
731       ierr = MatDisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
732     }
733   }
734   if (!mat->was_assembled && mode == MAT_FINAL_ASSEMBLY) {
735     ierr = MatSetUpMultiply_MPIAIJ(mat);CHKERRQ(ierr);
736   }
737   ierr = MatSetOption(aij->B,MAT_USE_INODES,PETSC_FALSE);CHKERRQ(ierr);
738   ierr = MatAssemblyBegin(aij->B,mode);CHKERRQ(ierr);
739   ierr = MatAssemblyEnd(aij->B,mode);CHKERRQ(ierr);
740 
741   ierr = PetscFree2(aij->rowvalues,aij->rowindices);CHKERRQ(ierr);
742 
743   aij->rowvalues = 0;
744 
745   ierr = VecDestroy(&aij->diag);CHKERRQ(ierr);
746   if (a->inode.size) mat->ops->multdiagonalblock = MatMultDiagonalBlock_MPIAIJ;
747 
748   /* if no new nonzero locations are allowed in matrix then only set the matrix state the first time through */
749   if ((!mat->was_assembled && mode == MAT_FINAL_ASSEMBLY) || !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
750     PetscObjectState state = aij->A->nonzerostate + aij->B->nonzerostate;
751     ierr = MPIU_Allreduce(&state,&mat->nonzerostate,1,MPIU_INT64,MPI_SUM,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
752   }
753   PetscFunctionReturn(0);
754 }
755 
756 PetscErrorCode MatZeroEntries_MPIAIJ(Mat A)
757 {
758   Mat_MPIAIJ     *l = (Mat_MPIAIJ*)A->data;
759   PetscErrorCode ierr;
760 
761   PetscFunctionBegin;
762   ierr = MatZeroEntries(l->A);CHKERRQ(ierr);
763   ierr = MatZeroEntries(l->B);CHKERRQ(ierr);
764   PetscFunctionReturn(0);
765 }
766 
767 PetscErrorCode MatZeroRows_MPIAIJ(Mat A,PetscInt N,const PetscInt rows[],PetscScalar diag,Vec x,Vec b)
768 {
769   Mat_MPIAIJ    *mat    = (Mat_MPIAIJ *) A->data;
770   PetscInt      *lrows;
771   PetscInt       r, len;
772   PetscErrorCode ierr;
773 
774   PetscFunctionBegin;
775   /* get locally owned rows */
776   ierr = MatZeroRowsMapLocal_Private(A,N,rows,&len,&lrows);CHKERRQ(ierr);
777   /* fix right hand side if needed */
778   if (x && b) {
779     const PetscScalar *xx;
780     PetscScalar       *bb;
781 
782     ierr = VecGetArrayRead(x, &xx);CHKERRQ(ierr);
783     ierr = VecGetArray(b, &bb);CHKERRQ(ierr);
784     for (r = 0; r < len; ++r) bb[lrows[r]] = diag*xx[lrows[r]];
785     ierr = VecRestoreArrayRead(x, &xx);CHKERRQ(ierr);
786     ierr = VecRestoreArray(b, &bb);CHKERRQ(ierr);
787   }
788   /* Must zero l->B before l->A because the (diag) case below may put values into l->B*/
789   ierr = MatZeroRows(mat->B, len, lrows, 0.0, NULL, NULL);CHKERRQ(ierr);
790   if (A->congruentlayouts == -1) { /* first time we compare rows and cols layouts */
791     PetscBool cong;
792     ierr = PetscLayoutCompare(A->rmap,A->cmap,&cong);CHKERRQ(ierr);
793     if (cong) A->congruentlayouts = 1;
794     else      A->congruentlayouts = 0;
795   }
796   if ((diag != 0.0) && A->congruentlayouts) {
797     ierr = MatZeroRows(mat->A, len, lrows, diag, NULL, NULL);CHKERRQ(ierr);
798   } else if (diag != 0.0) {
799     ierr = MatZeroRows(mat->A, len, lrows, 0.0, NULL, NULL);CHKERRQ(ierr);
800     if (((Mat_SeqAIJ *) mat->A->data)->nonew) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "MatZeroRows() on rectangular matrices cannot be used with the Mat options\nMAT_NEW_NONZERO_LOCATIONS,MAT_NEW_NONZERO_LOCATION_ERR,MAT_NEW_NONZERO_ALLOCATION_ERR");
801     for (r = 0; r < len; ++r) {
802       const PetscInt row = lrows[r] + A->rmap->rstart;
803       ierr = MatSetValues(A, 1, &row, 1, &row, &diag, INSERT_VALUES);CHKERRQ(ierr);
804     }
805     ierr = MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
806     ierr = MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
807   } else {
808     ierr = MatZeroRows(mat->A, len, lrows, 0.0, NULL, NULL);CHKERRQ(ierr);
809   }
810   ierr = PetscFree(lrows);CHKERRQ(ierr);
811 
812   /* only change matrix nonzero state if pattern was allowed to be changed */
813   if (!((Mat_SeqAIJ*)(mat->A->data))->keepnonzeropattern) {
814     PetscObjectState state = mat->A->nonzerostate + mat->B->nonzerostate;
815     ierr = MPIU_Allreduce(&state,&A->nonzerostate,1,MPIU_INT64,MPI_SUM,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
816   }
817   PetscFunctionReturn(0);
818 }
819 
820 PetscErrorCode MatZeroRowsColumns_MPIAIJ(Mat A,PetscInt N,const PetscInt rows[],PetscScalar diag,Vec x,Vec b)
821 {
822   Mat_MPIAIJ        *l = (Mat_MPIAIJ*)A->data;
823   PetscErrorCode    ierr;
824   PetscMPIInt       n = A->rmap->n;
825   PetscInt          i,j,r,m,p = 0,len = 0;
826   PetscInt          *lrows,*owners = A->rmap->range;
827   PetscSFNode       *rrows;
828   PetscSF           sf;
829   const PetscScalar *xx;
830   PetscScalar       *bb,*mask;
831   Vec               xmask,lmask;
832   Mat_SeqAIJ        *aij = (Mat_SeqAIJ*)l->B->data;
833   const PetscInt    *aj, *ii,*ridx;
834   PetscScalar       *aa;
835 
836   PetscFunctionBegin;
837   /* Create SF where leaves are input rows and roots are owned rows */
838   ierr = PetscMalloc1(n, &lrows);CHKERRQ(ierr);
839   for (r = 0; r < n; ++r) lrows[r] = -1;
840   ierr = PetscMalloc1(N, &rrows);CHKERRQ(ierr);
841   for (r = 0; r < N; ++r) {
842     const PetscInt idx   = rows[r];
843     if (idx < 0 || A->rmap->N <= idx) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Row %D out of range [0,%D)",idx,A->rmap->N);
844     if (idx < owners[p] || owners[p+1] <= idx) { /* short-circuit the search if the last p owns this row too */
845       ierr = PetscLayoutFindOwner(A->rmap,idx,&p);CHKERRQ(ierr);
846     }
847     rrows[r].rank  = p;
848     rrows[r].index = rows[r] - owners[p];
849   }
850   ierr = PetscSFCreate(PetscObjectComm((PetscObject) A), &sf);CHKERRQ(ierr);
851   ierr = PetscSFSetGraph(sf, n, N, NULL, PETSC_OWN_POINTER, rrows, PETSC_OWN_POINTER);CHKERRQ(ierr);
852   /* Collect flags for rows to be zeroed */
853   ierr = PetscSFReduceBegin(sf, MPIU_INT, (PetscInt *) rows, lrows, MPI_LOR);CHKERRQ(ierr);
854   ierr = PetscSFReduceEnd(sf, MPIU_INT, (PetscInt *) rows, lrows, MPI_LOR);CHKERRQ(ierr);
855   ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
856   /* Compress and put in row numbers */
857   for (r = 0; r < n; ++r) if (lrows[r] >= 0) lrows[len++] = r;
858   /* zero diagonal part of matrix */
859   ierr = MatZeroRowsColumns(l->A,len,lrows,diag,x,b);CHKERRQ(ierr);
860   /* handle off diagonal part of matrix */
861   ierr = MatCreateVecs(A,&xmask,NULL);CHKERRQ(ierr);
862   ierr = VecDuplicate(l->lvec,&lmask);CHKERRQ(ierr);
863   ierr = VecGetArray(xmask,&bb);CHKERRQ(ierr);
864   for (i=0; i<len; i++) bb[lrows[i]] = 1;
865   ierr = VecRestoreArray(xmask,&bb);CHKERRQ(ierr);
866   ierr = VecScatterBegin(l->Mvctx,xmask,lmask,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
867   ierr = VecScatterEnd(l->Mvctx,xmask,lmask,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
868   ierr = VecDestroy(&xmask);CHKERRQ(ierr);
869   if (x) {
870     ierr = VecScatterBegin(l->Mvctx,x,l->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
871     ierr = VecScatterEnd(l->Mvctx,x,l->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
872     ierr = VecGetArrayRead(l->lvec,&xx);CHKERRQ(ierr);
873     ierr = VecGetArray(b,&bb);CHKERRQ(ierr);
874   }
875   ierr = VecGetArray(lmask,&mask);CHKERRQ(ierr);
876   /* remove zeroed rows of off diagonal matrix */
877   ii = aij->i;
878   for (i=0; i<len; i++) {
879     ierr = PetscMemzero(aij->a + ii[lrows[i]],(ii[lrows[i]+1] - ii[lrows[i]])*sizeof(PetscScalar));CHKERRQ(ierr);
880   }
881   /* loop over all elements of off process part of matrix zeroing removed columns*/
882   if (aij->compressedrow.use) {
883     m    = aij->compressedrow.nrows;
884     ii   = aij->compressedrow.i;
885     ridx = aij->compressedrow.rindex;
886     for (i=0; i<m; i++) {
887       n  = ii[i+1] - ii[i];
888       aj = aij->j + ii[i];
889       aa = aij->a + ii[i];
890 
891       for (j=0; j<n; j++) {
892         if (PetscAbsScalar(mask[*aj])) {
893           if (b) bb[*ridx] -= *aa*xx[*aj];
894           *aa = 0.0;
895         }
896         aa++;
897         aj++;
898       }
899       ridx++;
900     }
901   } else { /* do not use compressed row format */
902     m = l->B->rmap->n;
903     for (i=0; i<m; i++) {
904       n  = ii[i+1] - ii[i];
905       aj = aij->j + ii[i];
906       aa = aij->a + ii[i];
907       for (j=0; j<n; j++) {
908         if (PetscAbsScalar(mask[*aj])) {
909           if (b) bb[i] -= *aa*xx[*aj];
910           *aa = 0.0;
911         }
912         aa++;
913         aj++;
914       }
915     }
916   }
917   if (x) {
918     ierr = VecRestoreArray(b,&bb);CHKERRQ(ierr);
919     ierr = VecRestoreArrayRead(l->lvec,&xx);CHKERRQ(ierr);
920   }
921   ierr = VecRestoreArray(lmask,&mask);CHKERRQ(ierr);
922   ierr = VecDestroy(&lmask);CHKERRQ(ierr);
923   ierr = PetscFree(lrows);CHKERRQ(ierr);
924 
925   /* only change matrix nonzero state if pattern was allowed to be changed */
926   if (!((Mat_SeqAIJ*)(l->A->data))->keepnonzeropattern) {
927     PetscObjectState state = l->A->nonzerostate + l->B->nonzerostate;
928     ierr = MPIU_Allreduce(&state,&A->nonzerostate,1,MPIU_INT64,MPI_SUM,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
929   }
930   PetscFunctionReturn(0);
931 }
932 
933 PetscErrorCode MatMult_MPIAIJ(Mat A,Vec xx,Vec yy)
934 {
935   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
936   PetscErrorCode ierr;
937   PetscInt       nt;
938   VecScatter     Mvctx = a->Mvctx;
939 
940   PetscFunctionBegin;
941   ierr = VecGetLocalSize(xx,&nt);CHKERRQ(ierr);
942   if (nt != A->cmap->n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Incompatible partition of A (%D) and xx (%D)",A->cmap->n,nt);
943 
944   ierr = VecScatterBegin(Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
945   ierr = (*a->A->ops->mult)(a->A,xx,yy);CHKERRQ(ierr);
946   ierr = VecScatterEnd(Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
947   ierr = (*a->B->ops->multadd)(a->B,a->lvec,yy,yy);CHKERRQ(ierr);
948   PetscFunctionReturn(0);
949 }
950 
951 PetscErrorCode MatMultDiagonalBlock_MPIAIJ(Mat A,Vec bb,Vec xx)
952 {
953   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
954   PetscErrorCode ierr;
955 
956   PetscFunctionBegin;
957   ierr = MatMultDiagonalBlock(a->A,bb,xx);CHKERRQ(ierr);
958   PetscFunctionReturn(0);
959 }
960 
961 PetscErrorCode MatMultAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
962 {
963   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
964   PetscErrorCode ierr;
965   VecScatter     Mvctx = a->Mvctx;
966 
967   PetscFunctionBegin;
968   if (a->Mvctx_mpi1_flg) Mvctx = a->Mvctx_mpi1;
969   ierr = VecScatterBegin(Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
970   ierr = (*a->A->ops->multadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
971   ierr = VecScatterEnd(Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
972   ierr = (*a->B->ops->multadd)(a->B,a->lvec,zz,zz);CHKERRQ(ierr);
973   PetscFunctionReturn(0);
974 }
975 
976 PetscErrorCode MatMultTranspose_MPIAIJ(Mat A,Vec xx,Vec yy)
977 {
978   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
979   PetscErrorCode ierr;
980   PetscBool      merged;
981 
982   PetscFunctionBegin;
983   ierr = VecScatterGetMerged(a->Mvctx,&merged);CHKERRQ(ierr);
984   /* do nondiagonal part */
985   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
986   if (!merged) {
987     /* send it on its way */
988     ierr = VecScatterBegin(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
989     /* do local part */
990     ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
991     /* receive remote parts: note this assumes the values are not actually */
992     /* added in yy until the next line, */
993     ierr = VecScatterEnd(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
994   } else {
995     /* do local part */
996     ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
997     /* send it on its way */
998     ierr = VecScatterBegin(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
999     /* values actually were received in the Begin() but we need to call this nop */
1000     ierr = VecScatterEnd(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1001   }
1002   PetscFunctionReturn(0);
1003 }
1004 
1005 PetscErrorCode MatIsTranspose_MPIAIJ(Mat Amat,Mat Bmat,PetscReal tol,PetscBool  *f)
1006 {
1007   MPI_Comm       comm;
1008   Mat_MPIAIJ     *Aij = (Mat_MPIAIJ*) Amat->data, *Bij;
1009   Mat            Adia = Aij->A, Bdia, Aoff,Boff,*Aoffs,*Boffs;
1010   IS             Me,Notme;
1011   PetscErrorCode ierr;
1012   PetscInt       M,N,first,last,*notme,i;
1013   PetscMPIInt    size;
1014 
1015   PetscFunctionBegin;
1016   /* Easy test: symmetric diagonal block */
1017   Bij  = (Mat_MPIAIJ*) Bmat->data; Bdia = Bij->A;
1018   ierr = MatIsTranspose(Adia,Bdia,tol,f);CHKERRQ(ierr);
1019   if (!*f) PetscFunctionReturn(0);
1020   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
1021   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
1022   if (size == 1) PetscFunctionReturn(0);
1023 
1024   /* Hard test: off-diagonal block. This takes a MatCreateSubMatrix. */
1025   ierr = MatGetSize(Amat,&M,&N);CHKERRQ(ierr);
1026   ierr = MatGetOwnershipRange(Amat,&first,&last);CHKERRQ(ierr);
1027   ierr = PetscMalloc1(N-last+first,&notme);CHKERRQ(ierr);
1028   for (i=0; i<first; i++) notme[i] = i;
1029   for (i=last; i<M; i++) notme[i-last+first] = i;
1030   ierr = ISCreateGeneral(MPI_COMM_SELF,N-last+first,notme,PETSC_COPY_VALUES,&Notme);CHKERRQ(ierr);
1031   ierr = ISCreateStride(MPI_COMM_SELF,last-first,first,1,&Me);CHKERRQ(ierr);
1032   ierr = MatCreateSubMatrices(Amat,1,&Me,&Notme,MAT_INITIAL_MATRIX,&Aoffs);CHKERRQ(ierr);
1033   Aoff = Aoffs[0];
1034   ierr = MatCreateSubMatrices(Bmat,1,&Notme,&Me,MAT_INITIAL_MATRIX,&Boffs);CHKERRQ(ierr);
1035   Boff = Boffs[0];
1036   ierr = MatIsTranspose(Aoff,Boff,tol,f);CHKERRQ(ierr);
1037   ierr = MatDestroyMatrices(1,&Aoffs);CHKERRQ(ierr);
1038   ierr = MatDestroyMatrices(1,&Boffs);CHKERRQ(ierr);
1039   ierr = ISDestroy(&Me);CHKERRQ(ierr);
1040   ierr = ISDestroy(&Notme);CHKERRQ(ierr);
1041   ierr = PetscFree(notme);CHKERRQ(ierr);
1042   PetscFunctionReturn(0);
1043 }
1044 
1045 PetscErrorCode MatIsSymmetric_MPIAIJ(Mat A,PetscReal tol,PetscBool  *f)
1046 {
1047   PetscErrorCode ierr;
1048 
1049   PetscFunctionBegin;
1050   ierr = MatIsTranspose_MPIAIJ(A,A,tol,f);CHKERRQ(ierr);
1051   PetscFunctionReturn(0);
1052 }
1053 
1054 PetscErrorCode MatMultTransposeAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
1055 {
1056   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1057   PetscErrorCode ierr;
1058 
1059   PetscFunctionBegin;
1060   /* do nondiagonal part */
1061   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
1062   /* send it on its way */
1063   ierr = VecScatterBegin(a->Mvctx,a->lvec,zz,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1064   /* do local part */
1065   ierr = (*a->A->ops->multtransposeadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
1066   /* receive remote parts */
1067   ierr = VecScatterEnd(a->Mvctx,a->lvec,zz,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1068   PetscFunctionReturn(0);
1069 }
1070 
1071 /*
1072   This only works correctly for square matrices where the subblock A->A is the
1073    diagonal block
1074 */
1075 PetscErrorCode MatGetDiagonal_MPIAIJ(Mat A,Vec v)
1076 {
1077   PetscErrorCode ierr;
1078   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1079 
1080   PetscFunctionBegin;
1081   if (A->rmap->N != A->cmap->N) SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_SUP,"Supports only square matrix where A->A is diag block");
1082   if (A->rmap->rstart != A->cmap->rstart || A->rmap->rend != A->cmap->rend) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"row partition must equal col partition");
1083   ierr = MatGetDiagonal(a->A,v);CHKERRQ(ierr);
1084   PetscFunctionReturn(0);
1085 }
1086 
1087 PetscErrorCode MatScale_MPIAIJ(Mat A,PetscScalar aa)
1088 {
1089   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1090   PetscErrorCode ierr;
1091 
1092   PetscFunctionBegin;
1093   ierr = MatScale(a->A,aa);CHKERRQ(ierr);
1094   ierr = MatScale(a->B,aa);CHKERRQ(ierr);
1095   PetscFunctionReturn(0);
1096 }
1097 
1098 PetscErrorCode MatDestroy_MPIAIJ(Mat mat)
1099 {
1100   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1101   PetscErrorCode ierr;
1102 
1103   PetscFunctionBegin;
1104 #if defined(PETSC_USE_LOG)
1105   PetscLogObjectState((PetscObject)mat,"Rows=%D, Cols=%D",mat->rmap->N,mat->cmap->N);
1106 #endif
1107   ierr = MatStashDestroy_Private(&mat->stash);CHKERRQ(ierr);
1108   ierr = VecDestroy(&aij->diag);CHKERRQ(ierr);
1109   ierr = MatDestroy(&aij->A);CHKERRQ(ierr);
1110   ierr = MatDestroy(&aij->B);CHKERRQ(ierr);
1111 #if defined(PETSC_USE_CTABLE)
1112   ierr = PetscTableDestroy(&aij->colmap);CHKERRQ(ierr);
1113 #else
1114   ierr = PetscFree(aij->colmap);CHKERRQ(ierr);
1115 #endif
1116   ierr = PetscFree(aij->garray);CHKERRQ(ierr);
1117   ierr = VecDestroy(&aij->lvec);CHKERRQ(ierr);
1118   ierr = VecScatterDestroy(&aij->Mvctx);CHKERRQ(ierr);
1119   if (aij->Mvctx_mpi1) {ierr = VecScatterDestroy(&aij->Mvctx_mpi1);CHKERRQ(ierr);}
1120   ierr = PetscFree2(aij->rowvalues,aij->rowindices);CHKERRQ(ierr);
1121   ierr = PetscFree(aij->ld);CHKERRQ(ierr);
1122   ierr = PetscFree(mat->data);CHKERRQ(ierr);
1123 
1124   ierr = PetscObjectChangeTypeName((PetscObject)mat,0);CHKERRQ(ierr);
1125   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatStoreValues_C",NULL);CHKERRQ(ierr);
1126   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatRetrieveValues_C",NULL);CHKERRQ(ierr);
1127   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatIsTranspose_C",NULL);CHKERRQ(ierr);
1128   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMPIAIJSetPreallocation_C",NULL);CHKERRQ(ierr);
1129   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatResetPreallocation_C",NULL);CHKERRQ(ierr);
1130   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMPIAIJSetPreallocationCSR_C",NULL);CHKERRQ(ierr);
1131   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatDiagonalScaleLocal_C",NULL);CHKERRQ(ierr);
1132   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatConvert_mpiaij_mpisbaij_C",NULL);CHKERRQ(ierr);
1133 #if defined(PETSC_HAVE_ELEMENTAL)
1134   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatConvert_mpiaij_elemental_C",NULL);CHKERRQ(ierr);
1135 #endif
1136 #if defined(PETSC_HAVE_HYPRE)
1137   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatConvert_mpiaij_hypre_C",NULL);CHKERRQ(ierr);
1138   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMatMatMult_transpose_mpiaij_mpiaij_C",NULL);CHKERRQ(ierr);
1139 #endif
1140   PetscFunctionReturn(0);
1141 }
1142 
1143 PetscErrorCode MatView_MPIAIJ_Binary(Mat mat,PetscViewer viewer)
1144 {
1145   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1146   Mat_SeqAIJ     *A   = (Mat_SeqAIJ*)aij->A->data;
1147   Mat_SeqAIJ     *B   = (Mat_SeqAIJ*)aij->B->data;
1148   PetscErrorCode ierr;
1149   PetscMPIInt    rank,size,tag = ((PetscObject)viewer)->tag;
1150   int            fd;
1151   PetscInt       nz,header[4],*row_lengths,*range=0,rlen,i;
1152   PetscInt       nzmax,*column_indices,j,k,col,*garray = aij->garray,cnt,cstart = mat->cmap->rstart,rnz = 0;
1153   PetscScalar    *column_values;
1154   PetscInt       message_count,flowcontrolcount;
1155   FILE           *file;
1156 
1157   PetscFunctionBegin;
1158   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)mat),&rank);CHKERRQ(ierr);
1159   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)mat),&size);CHKERRQ(ierr);
1160   nz   = A->nz + B->nz;
1161   ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
1162   if (!rank) {
1163     header[0] = MAT_FILE_CLASSID;
1164     header[1] = mat->rmap->N;
1165     header[2] = mat->cmap->N;
1166 
1167     ierr = MPI_Reduce(&nz,&header[3],1,MPIU_INT,MPI_SUM,0,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1168     ierr = PetscBinaryWrite(fd,header,4,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1169     /* get largest number of rows any processor has */
1170     rlen  = mat->rmap->n;
1171     range = mat->rmap->range;
1172     for (i=1; i<size; i++) rlen = PetscMax(rlen,range[i+1] - range[i]);
1173   } else {
1174     ierr = MPI_Reduce(&nz,0,1,MPIU_INT,MPI_SUM,0,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1175     rlen = mat->rmap->n;
1176   }
1177 
1178   /* load up the local row counts */
1179   ierr = PetscMalloc1(rlen+1,&row_lengths);CHKERRQ(ierr);
1180   for (i=0; i<mat->rmap->n; i++) row_lengths[i] = A->i[i+1] - A->i[i] + B->i[i+1] - B->i[i];
1181 
1182   /* store the row lengths to the file */
1183   ierr = PetscViewerFlowControlStart(viewer,&message_count,&flowcontrolcount);CHKERRQ(ierr);
1184   if (!rank) {
1185     ierr = PetscBinaryWrite(fd,row_lengths,mat->rmap->n,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1186     for (i=1; i<size; i++) {
1187       ierr = PetscViewerFlowControlStepMaster(viewer,i,&message_count,flowcontrolcount);CHKERRQ(ierr);
1188       rlen = range[i+1] - range[i];
1189       ierr = MPIULong_Recv(row_lengths,rlen,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1190       ierr = PetscBinaryWrite(fd,row_lengths,rlen,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1191     }
1192     ierr = PetscViewerFlowControlEndMaster(viewer,&message_count);CHKERRQ(ierr);
1193   } else {
1194     ierr = PetscViewerFlowControlStepWorker(viewer,rank,&message_count);CHKERRQ(ierr);
1195     ierr = MPIULong_Send(row_lengths,mat->rmap->n,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1196     ierr = PetscViewerFlowControlEndWorker(viewer,&message_count);CHKERRQ(ierr);
1197   }
1198   ierr = PetscFree(row_lengths);CHKERRQ(ierr);
1199 
1200   /* load up the local column indices */
1201   nzmax = nz; /* th processor needs space a largest processor needs */
1202   ierr  = MPI_Reduce(&nz,&nzmax,1,MPIU_INT,MPI_MAX,0,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1203   ierr  = PetscMalloc1(nzmax+1,&column_indices);CHKERRQ(ierr);
1204   cnt   = 0;
1205   for (i=0; i<mat->rmap->n; i++) {
1206     for (j=B->i[i]; j<B->i[i+1]; j++) {
1207       if ((col = garray[B->j[j]]) > cstart) break;
1208       column_indices[cnt++] = col;
1209     }
1210     for (k=A->i[i]; k<A->i[i+1]; k++) column_indices[cnt++] = A->j[k] + cstart;
1211     for (; j<B->i[i+1]; j++) column_indices[cnt++] = garray[B->j[j]];
1212   }
1213   if (cnt != A->nz + B->nz) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_LIB,"Internal PETSc error: cnt = %D nz = %D",cnt,A->nz+B->nz);
1214 
1215   /* store the column indices to the file */
1216   ierr = PetscViewerFlowControlStart(viewer,&message_count,&flowcontrolcount);CHKERRQ(ierr);
1217   if (!rank) {
1218     MPI_Status status;
1219     ierr = PetscBinaryWrite(fd,column_indices,nz,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1220     for (i=1; i<size; i++) {
1221       ierr = PetscViewerFlowControlStepMaster(viewer,i,&message_count,flowcontrolcount);CHKERRQ(ierr);
1222       ierr = MPI_Recv(&rnz,1,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat),&status);CHKERRQ(ierr);
1223       if (rnz > nzmax) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_LIB,"Internal PETSc error: nz = %D nzmax = %D",nz,nzmax);
1224       ierr = MPIULong_Recv(column_indices,rnz,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1225       ierr = PetscBinaryWrite(fd,column_indices,rnz,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1226     }
1227     ierr = PetscViewerFlowControlEndMaster(viewer,&message_count);CHKERRQ(ierr);
1228   } else {
1229     ierr = PetscViewerFlowControlStepWorker(viewer,rank,&message_count);CHKERRQ(ierr);
1230     ierr = MPI_Send(&nz,1,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1231     ierr = MPIULong_Send(column_indices,nz,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1232     ierr = PetscViewerFlowControlEndWorker(viewer,&message_count);CHKERRQ(ierr);
1233   }
1234   ierr = PetscFree(column_indices);CHKERRQ(ierr);
1235 
1236   /* load up the local column values */
1237   ierr = PetscMalloc1(nzmax+1,&column_values);CHKERRQ(ierr);
1238   cnt  = 0;
1239   for (i=0; i<mat->rmap->n; i++) {
1240     for (j=B->i[i]; j<B->i[i+1]; j++) {
1241       if (garray[B->j[j]] > cstart) break;
1242       column_values[cnt++] = B->a[j];
1243     }
1244     for (k=A->i[i]; k<A->i[i+1]; k++) column_values[cnt++] = A->a[k];
1245     for (; j<B->i[i+1]; j++) column_values[cnt++] = B->a[j];
1246   }
1247   if (cnt != A->nz + B->nz) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Internal PETSc error: cnt = %D nz = %D",cnt,A->nz+B->nz);
1248 
1249   /* store the column values to the file */
1250   ierr = PetscViewerFlowControlStart(viewer,&message_count,&flowcontrolcount);CHKERRQ(ierr);
1251   if (!rank) {
1252     MPI_Status status;
1253     ierr = PetscBinaryWrite(fd,column_values,nz,PETSC_SCALAR,PETSC_TRUE);CHKERRQ(ierr);
1254     for (i=1; i<size; i++) {
1255       ierr = PetscViewerFlowControlStepMaster(viewer,i,&message_count,flowcontrolcount);CHKERRQ(ierr);
1256       ierr = MPI_Recv(&rnz,1,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat),&status);CHKERRQ(ierr);
1257       if (rnz > nzmax) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_LIB,"Internal PETSc error: nz = %D nzmax = %D",nz,nzmax);
1258       ierr = MPIULong_Recv(column_values,rnz,MPIU_SCALAR,i,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1259       ierr = PetscBinaryWrite(fd,column_values,rnz,PETSC_SCALAR,PETSC_TRUE);CHKERRQ(ierr);
1260     }
1261     ierr = PetscViewerFlowControlEndMaster(viewer,&message_count);CHKERRQ(ierr);
1262   } else {
1263     ierr = PetscViewerFlowControlStepWorker(viewer,rank,&message_count);CHKERRQ(ierr);
1264     ierr = MPI_Send(&nz,1,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1265     ierr = MPIULong_Send(column_values,nz,MPIU_SCALAR,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1266     ierr = PetscViewerFlowControlEndWorker(viewer,&message_count);CHKERRQ(ierr);
1267   }
1268   ierr = PetscFree(column_values);CHKERRQ(ierr);
1269 
1270   ierr = PetscViewerBinaryGetInfoPointer(viewer,&file);CHKERRQ(ierr);
1271   if (file) fprintf(file,"-matload_block_size %d\n",(int)PetscAbs(mat->rmap->bs));
1272   PetscFunctionReturn(0);
1273 }
1274 
1275 #include <petscdraw.h>
1276 PetscErrorCode MatView_MPIAIJ_ASCIIorDraworSocket(Mat mat,PetscViewer viewer)
1277 {
1278   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
1279   PetscErrorCode    ierr;
1280   PetscMPIInt       rank = aij->rank,size = aij->size;
1281   PetscBool         isdraw,iascii,isbinary;
1282   PetscViewer       sviewer;
1283   PetscViewerFormat format;
1284 
1285   PetscFunctionBegin;
1286   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr);
1287   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
1288   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1289   if (iascii) {
1290     ierr = PetscViewerGetFormat(viewer,&format);CHKERRQ(ierr);
1291     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
1292       MatInfo   info;
1293       PetscBool inodes;
1294 
1295       ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)mat),&rank);CHKERRQ(ierr);
1296       ierr = MatGetInfo(mat,MAT_LOCAL,&info);CHKERRQ(ierr);
1297       ierr = MatInodeGetInodeSizes(aij->A,NULL,(PetscInt**)&inodes,NULL);CHKERRQ(ierr);
1298       ierr = PetscViewerASCIIPushSynchronized(viewer);CHKERRQ(ierr);
1299       if (!inodes) {
1300         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %D nz %D nz alloced %D mem %D, not using I-node routines\n",
1301                                                   rank,mat->rmap->n,(PetscInt)info.nz_used,(PetscInt)info.nz_allocated,(PetscInt)info.memory);CHKERRQ(ierr);
1302       } else {
1303         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %D nz %D nz alloced %D mem %D, using I-node routines\n",
1304                                                   rank,mat->rmap->n,(PetscInt)info.nz_used,(PetscInt)info.nz_allocated,(PetscInt)info.memory);CHKERRQ(ierr);
1305       }
1306       ierr = MatGetInfo(aij->A,MAT_LOCAL,&info);CHKERRQ(ierr);
1307       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] on-diagonal part: nz %D \n",rank,(PetscInt)info.nz_used);CHKERRQ(ierr);
1308       ierr = MatGetInfo(aij->B,MAT_LOCAL,&info);CHKERRQ(ierr);
1309       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] off-diagonal part: nz %D \n",rank,(PetscInt)info.nz_used);CHKERRQ(ierr);
1310       ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
1311       ierr = PetscViewerASCIIPopSynchronized(viewer);CHKERRQ(ierr);
1312       ierr = PetscViewerASCIIPrintf(viewer,"Information on VecScatter used in matrix-vector product: \n");CHKERRQ(ierr);
1313       ierr = VecScatterView(aij->Mvctx,viewer);CHKERRQ(ierr);
1314       PetscFunctionReturn(0);
1315     } else if (format == PETSC_VIEWER_ASCII_INFO) {
1316       PetscInt inodecount,inodelimit,*inodes;
1317       ierr = MatInodeGetInodeSizes(aij->A,&inodecount,&inodes,&inodelimit);CHKERRQ(ierr);
1318       if (inodes) {
1319         ierr = PetscViewerASCIIPrintf(viewer,"using I-node (on process 0) routines: found %D nodes, limit used is %D\n",inodecount,inodelimit);CHKERRQ(ierr);
1320       } else {
1321         ierr = PetscViewerASCIIPrintf(viewer,"not using I-node (on process 0) routines\n");CHKERRQ(ierr);
1322       }
1323       PetscFunctionReturn(0);
1324     } else if (format == PETSC_VIEWER_ASCII_FACTOR_INFO) {
1325       PetscFunctionReturn(0);
1326     }
1327   } else if (isbinary) {
1328     if (size == 1) {
1329       ierr = PetscObjectSetName((PetscObject)aij->A,((PetscObject)mat)->name);CHKERRQ(ierr);
1330       ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
1331     } else {
1332       ierr = MatView_MPIAIJ_Binary(mat,viewer);CHKERRQ(ierr);
1333     }
1334     PetscFunctionReturn(0);
1335   } else if (isdraw) {
1336     PetscDraw draw;
1337     PetscBool isnull;
1338     ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
1339     ierr = PetscDrawIsNull(draw,&isnull);CHKERRQ(ierr);
1340     if (isnull) PetscFunctionReturn(0);
1341   }
1342 
1343   {
1344     /* assemble the entire matrix onto first processor. */
1345     Mat        A;
1346     Mat_SeqAIJ *Aloc;
1347     PetscInt   M = mat->rmap->N,N = mat->cmap->N,m,*ai,*aj,row,*cols,i,*ct;
1348     MatScalar  *a;
1349 
1350     ierr = MatCreate(PetscObjectComm((PetscObject)mat),&A);CHKERRQ(ierr);
1351     if (!rank) {
1352       ierr = MatSetSizes(A,M,N,M,N);CHKERRQ(ierr);
1353     } else {
1354       ierr = MatSetSizes(A,0,0,M,N);CHKERRQ(ierr);
1355     }
1356     /* This is just a temporary matrix, so explicitly using MATMPIAIJ is probably best */
1357     ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
1358     ierr = MatMPIAIJSetPreallocation(A,0,NULL,0,NULL);CHKERRQ(ierr);
1359     ierr = MatSetOption(A,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr);
1360     ierr = PetscLogObjectParent((PetscObject)mat,(PetscObject)A);CHKERRQ(ierr);
1361 
1362     /* copy over the A part */
1363     Aloc = (Mat_SeqAIJ*)aij->A->data;
1364     m    = aij->A->rmap->n; ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
1365     row  = mat->rmap->rstart;
1366     for (i=0; i<ai[m]; i++) aj[i] += mat->cmap->rstart;
1367     for (i=0; i<m; i++) {
1368       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],aj,a,INSERT_VALUES);CHKERRQ(ierr);
1369       row++;
1370       a += ai[i+1]-ai[i]; aj += ai[i+1]-ai[i];
1371     }
1372     aj = Aloc->j;
1373     for (i=0; i<ai[m]; i++) aj[i] -= mat->cmap->rstart;
1374 
1375     /* copy over the B part */
1376     Aloc = (Mat_SeqAIJ*)aij->B->data;
1377     m    = aij->B->rmap->n;  ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
1378     row  = mat->rmap->rstart;
1379     ierr = PetscMalloc1(ai[m]+1,&cols);CHKERRQ(ierr);
1380     ct   = cols;
1381     for (i=0; i<ai[m]; i++) cols[i] = aij->garray[aj[i]];
1382     for (i=0; i<m; i++) {
1383       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],cols,a,INSERT_VALUES);CHKERRQ(ierr);
1384       row++;
1385       a += ai[i+1]-ai[i]; cols += ai[i+1]-ai[i];
1386     }
1387     ierr = PetscFree(ct);CHKERRQ(ierr);
1388     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1389     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1390     /*
1391        Everyone has to call to draw the matrix since the graphics waits are
1392        synchronized across all processors that share the PetscDraw object
1393     */
1394     ierr = PetscViewerGetSubViewer(viewer,PETSC_COMM_SELF,&sviewer);CHKERRQ(ierr);
1395     if (!rank) {
1396       ierr = PetscObjectSetName((PetscObject)((Mat_MPIAIJ*)(A->data))->A,((PetscObject)mat)->name);CHKERRQ(ierr);
1397       ierr = MatView_SeqAIJ(((Mat_MPIAIJ*)(A->data))->A,sviewer);CHKERRQ(ierr);
1398     }
1399     ierr = PetscViewerRestoreSubViewer(viewer,PETSC_COMM_SELF,&sviewer);CHKERRQ(ierr);
1400     ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
1401     ierr = MatDestroy(&A);CHKERRQ(ierr);
1402   }
1403   PetscFunctionReturn(0);
1404 }
1405 
1406 PetscErrorCode MatView_MPIAIJ(Mat mat,PetscViewer viewer)
1407 {
1408   PetscErrorCode ierr;
1409   PetscBool      iascii,isdraw,issocket,isbinary;
1410 
1411   PetscFunctionBegin;
1412   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
1413   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr);
1414   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1415   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSOCKET,&issocket);CHKERRQ(ierr);
1416   if (iascii || isdraw || isbinary || issocket) {
1417     ierr = MatView_MPIAIJ_ASCIIorDraworSocket(mat,viewer);CHKERRQ(ierr);
1418   }
1419   PetscFunctionReturn(0);
1420 }
1421 
1422 PetscErrorCode MatSOR_MPIAIJ(Mat matin,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
1423 {
1424   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1425   PetscErrorCode ierr;
1426   Vec            bb1 = 0;
1427   PetscBool      hasop;
1428 
1429   PetscFunctionBegin;
1430   if (flag == SOR_APPLY_UPPER) {
1431     ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1432     PetscFunctionReturn(0);
1433   }
1434 
1435   if (its > 1 || ~flag & SOR_ZERO_INITIAL_GUESS || flag & SOR_EISENSTAT) {
1436     ierr = VecDuplicate(bb,&bb1);CHKERRQ(ierr);
1437   }
1438 
1439   if ((flag & SOR_LOCAL_SYMMETRIC_SWEEP) == SOR_LOCAL_SYMMETRIC_SWEEP) {
1440     if (flag & SOR_ZERO_INITIAL_GUESS) {
1441       ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1442       its--;
1443     }
1444 
1445     while (its--) {
1446       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1447       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1448 
1449       /* update rhs: bb1 = bb - B*x */
1450       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1451       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1452 
1453       /* local sweep */
1454       ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,SOR_SYMMETRIC_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1455     }
1456   } else if (flag & SOR_LOCAL_FORWARD_SWEEP) {
1457     if (flag & SOR_ZERO_INITIAL_GUESS) {
1458       ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1459       its--;
1460     }
1461     while (its--) {
1462       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1463       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1464 
1465       /* update rhs: bb1 = bb - B*x */
1466       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1467       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1468 
1469       /* local sweep */
1470       ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,SOR_FORWARD_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1471     }
1472   } else if (flag & SOR_LOCAL_BACKWARD_SWEEP) {
1473     if (flag & SOR_ZERO_INITIAL_GUESS) {
1474       ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1475       its--;
1476     }
1477     while (its--) {
1478       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1479       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1480 
1481       /* update rhs: bb1 = bb - B*x */
1482       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1483       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1484 
1485       /* local sweep */
1486       ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,SOR_BACKWARD_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1487     }
1488   } else if (flag & SOR_EISENSTAT) {
1489     Vec xx1;
1490 
1491     ierr = VecDuplicate(bb,&xx1);CHKERRQ(ierr);
1492     ierr = (*mat->A->ops->sor)(mat->A,bb,omega,(MatSORType)(SOR_ZERO_INITIAL_GUESS | SOR_LOCAL_BACKWARD_SWEEP),fshift,lits,1,xx);CHKERRQ(ierr);
1493 
1494     ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1495     ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1496     if (!mat->diag) {
1497       ierr = MatCreateVecs(matin,&mat->diag,NULL);CHKERRQ(ierr);
1498       ierr = MatGetDiagonal(matin,mat->diag);CHKERRQ(ierr);
1499     }
1500     ierr = MatHasOperation(matin,MATOP_MULT_DIAGONAL_BLOCK,&hasop);CHKERRQ(ierr);
1501     if (hasop) {
1502       ierr = MatMultDiagonalBlock(matin,xx,bb1);CHKERRQ(ierr);
1503     } else {
1504       ierr = VecPointwiseMult(bb1,mat->diag,xx);CHKERRQ(ierr);
1505     }
1506     ierr = VecAYPX(bb1,(omega-2.0)/omega,bb);CHKERRQ(ierr);
1507 
1508     ierr = MatMultAdd(mat->B,mat->lvec,bb1,bb1);CHKERRQ(ierr);
1509 
1510     /* local sweep */
1511     ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,(MatSORType)(SOR_ZERO_INITIAL_GUESS | SOR_LOCAL_FORWARD_SWEEP),fshift,lits,1,xx1);CHKERRQ(ierr);
1512     ierr = VecAXPY(xx,1.0,xx1);CHKERRQ(ierr);
1513     ierr = VecDestroy(&xx1);CHKERRQ(ierr);
1514   } else SETERRQ(PetscObjectComm((PetscObject)matin),PETSC_ERR_SUP,"Parallel SOR not supported");
1515 
1516   ierr = VecDestroy(&bb1);CHKERRQ(ierr);
1517 
1518   matin->factorerrortype = mat->A->factorerrortype;
1519   PetscFunctionReturn(0);
1520 }
1521 
1522 PetscErrorCode MatPermute_MPIAIJ(Mat A,IS rowp,IS colp,Mat *B)
1523 {
1524   Mat            aA,aB,Aperm;
1525   const PetscInt *rwant,*cwant,*gcols,*ai,*bi,*aj,*bj;
1526   PetscScalar    *aa,*ba;
1527   PetscInt       i,j,m,n,ng,anz,bnz,*dnnz,*onnz,*tdnnz,*tonnz,*rdest,*cdest,*work,*gcdest;
1528   PetscSF        rowsf,sf;
1529   IS             parcolp = NULL;
1530   PetscBool      done;
1531   PetscErrorCode ierr;
1532 
1533   PetscFunctionBegin;
1534   ierr = MatGetLocalSize(A,&m,&n);CHKERRQ(ierr);
1535   ierr = ISGetIndices(rowp,&rwant);CHKERRQ(ierr);
1536   ierr = ISGetIndices(colp,&cwant);CHKERRQ(ierr);
1537   ierr = PetscMalloc3(PetscMax(m,n),&work,m,&rdest,n,&cdest);CHKERRQ(ierr);
1538 
1539   /* Invert row permutation to find out where my rows should go */
1540   ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&rowsf);CHKERRQ(ierr);
1541   ierr = PetscSFSetGraphLayout(rowsf,A->rmap,A->rmap->n,NULL,PETSC_OWN_POINTER,rwant);CHKERRQ(ierr);
1542   ierr = PetscSFSetFromOptions(rowsf);CHKERRQ(ierr);
1543   for (i=0; i<m; i++) work[i] = A->rmap->rstart + i;
1544   ierr = PetscSFReduceBegin(rowsf,MPIU_INT,work,rdest,MPIU_REPLACE);CHKERRQ(ierr);
1545   ierr = PetscSFReduceEnd(rowsf,MPIU_INT,work,rdest,MPIU_REPLACE);CHKERRQ(ierr);
1546 
1547   /* Invert column permutation to find out where my columns should go */
1548   ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&sf);CHKERRQ(ierr);
1549   ierr = PetscSFSetGraphLayout(sf,A->cmap,A->cmap->n,NULL,PETSC_OWN_POINTER,cwant);CHKERRQ(ierr);
1550   ierr = PetscSFSetFromOptions(sf);CHKERRQ(ierr);
1551   for (i=0; i<n; i++) work[i] = A->cmap->rstart + i;
1552   ierr = PetscSFReduceBegin(sf,MPIU_INT,work,cdest,MPIU_REPLACE);CHKERRQ(ierr);
1553   ierr = PetscSFReduceEnd(sf,MPIU_INT,work,cdest,MPIU_REPLACE);CHKERRQ(ierr);
1554   ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
1555 
1556   ierr = ISRestoreIndices(rowp,&rwant);CHKERRQ(ierr);
1557   ierr = ISRestoreIndices(colp,&cwant);CHKERRQ(ierr);
1558   ierr = MatMPIAIJGetSeqAIJ(A,&aA,&aB,&gcols);CHKERRQ(ierr);
1559 
1560   /* Find out where my gcols should go */
1561   ierr = MatGetSize(aB,NULL,&ng);CHKERRQ(ierr);
1562   ierr = PetscMalloc1(ng,&gcdest);CHKERRQ(ierr);
1563   ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&sf);CHKERRQ(ierr);
1564   ierr = PetscSFSetGraphLayout(sf,A->cmap,ng,NULL,PETSC_OWN_POINTER,gcols);CHKERRQ(ierr);
1565   ierr = PetscSFSetFromOptions(sf);CHKERRQ(ierr);
1566   ierr = PetscSFBcastBegin(sf,MPIU_INT,cdest,gcdest);CHKERRQ(ierr);
1567   ierr = PetscSFBcastEnd(sf,MPIU_INT,cdest,gcdest);CHKERRQ(ierr);
1568   ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
1569 
1570   ierr = PetscCalloc4(m,&dnnz,m,&onnz,m,&tdnnz,m,&tonnz);CHKERRQ(ierr);
1571   ierr = MatGetRowIJ(aA,0,PETSC_FALSE,PETSC_FALSE,&anz,&ai,&aj,&done);CHKERRQ(ierr);
1572   ierr = MatGetRowIJ(aB,0,PETSC_FALSE,PETSC_FALSE,&bnz,&bi,&bj,&done);CHKERRQ(ierr);
1573   for (i=0; i<m; i++) {
1574     PetscInt row = rdest[i],rowner;
1575     ierr = PetscLayoutFindOwner(A->rmap,row,&rowner);CHKERRQ(ierr);
1576     for (j=ai[i]; j<ai[i+1]; j++) {
1577       PetscInt cowner,col = cdest[aj[j]];
1578       ierr = PetscLayoutFindOwner(A->cmap,col,&cowner);CHKERRQ(ierr); /* Could build an index for the columns to eliminate this search */
1579       if (rowner == cowner) dnnz[i]++;
1580       else onnz[i]++;
1581     }
1582     for (j=bi[i]; j<bi[i+1]; j++) {
1583       PetscInt cowner,col = gcdest[bj[j]];
1584       ierr = PetscLayoutFindOwner(A->cmap,col,&cowner);CHKERRQ(ierr);
1585       if (rowner == cowner) dnnz[i]++;
1586       else onnz[i]++;
1587     }
1588   }
1589   ierr = PetscSFBcastBegin(rowsf,MPIU_INT,dnnz,tdnnz);CHKERRQ(ierr);
1590   ierr = PetscSFBcastEnd(rowsf,MPIU_INT,dnnz,tdnnz);CHKERRQ(ierr);
1591   ierr = PetscSFBcastBegin(rowsf,MPIU_INT,onnz,tonnz);CHKERRQ(ierr);
1592   ierr = PetscSFBcastEnd(rowsf,MPIU_INT,onnz,tonnz);CHKERRQ(ierr);
1593   ierr = PetscSFDestroy(&rowsf);CHKERRQ(ierr);
1594 
1595   ierr = MatCreateAIJ(PetscObjectComm((PetscObject)A),A->rmap->n,A->cmap->n,A->rmap->N,A->cmap->N,0,tdnnz,0,tonnz,&Aperm);CHKERRQ(ierr);
1596   ierr = MatSeqAIJGetArray(aA,&aa);CHKERRQ(ierr);
1597   ierr = MatSeqAIJGetArray(aB,&ba);CHKERRQ(ierr);
1598   for (i=0; i<m; i++) {
1599     PetscInt *acols = dnnz,*bcols = onnz; /* Repurpose now-unneeded arrays */
1600     PetscInt j0,rowlen;
1601     rowlen = ai[i+1] - ai[i];
1602     for (j0=j=0; j<rowlen; j0=j) { /* rowlen could be larger than number of rows m, so sum in batches */
1603       for ( ; j<PetscMin(rowlen,j0+m); j++) acols[j-j0] = cdest[aj[ai[i]+j]];
1604       ierr = MatSetValues(Aperm,1,&rdest[i],j-j0,acols,aa+ai[i]+j0,INSERT_VALUES);CHKERRQ(ierr);
1605     }
1606     rowlen = bi[i+1] - bi[i];
1607     for (j0=j=0; j<rowlen; j0=j) {
1608       for ( ; j<PetscMin(rowlen,j0+m); j++) bcols[j-j0] = gcdest[bj[bi[i]+j]];
1609       ierr = MatSetValues(Aperm,1,&rdest[i],j-j0,bcols,ba+bi[i]+j0,INSERT_VALUES);CHKERRQ(ierr);
1610     }
1611   }
1612   ierr = MatAssemblyBegin(Aperm,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1613   ierr = MatAssemblyEnd(Aperm,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1614   ierr = MatRestoreRowIJ(aA,0,PETSC_FALSE,PETSC_FALSE,&anz,&ai,&aj,&done);CHKERRQ(ierr);
1615   ierr = MatRestoreRowIJ(aB,0,PETSC_FALSE,PETSC_FALSE,&bnz,&bi,&bj,&done);CHKERRQ(ierr);
1616   ierr = MatSeqAIJRestoreArray(aA,&aa);CHKERRQ(ierr);
1617   ierr = MatSeqAIJRestoreArray(aB,&ba);CHKERRQ(ierr);
1618   ierr = PetscFree4(dnnz,onnz,tdnnz,tonnz);CHKERRQ(ierr);
1619   ierr = PetscFree3(work,rdest,cdest);CHKERRQ(ierr);
1620   ierr = PetscFree(gcdest);CHKERRQ(ierr);
1621   if (parcolp) {ierr = ISDestroy(&colp);CHKERRQ(ierr);}
1622   *B = Aperm;
1623   PetscFunctionReturn(0);
1624 }
1625 
1626 PetscErrorCode  MatGetGhosts_MPIAIJ(Mat mat,PetscInt *nghosts,const PetscInt *ghosts[])
1627 {
1628   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1629   PetscErrorCode ierr;
1630 
1631   PetscFunctionBegin;
1632   ierr = MatGetSize(aij->B,NULL,nghosts);CHKERRQ(ierr);
1633   if (ghosts) *ghosts = aij->garray;
1634   PetscFunctionReturn(0);
1635 }
1636 
1637 PetscErrorCode MatGetInfo_MPIAIJ(Mat matin,MatInfoType flag,MatInfo *info)
1638 {
1639   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1640   Mat            A    = mat->A,B = mat->B;
1641   PetscErrorCode ierr;
1642   PetscReal      isend[5],irecv[5];
1643 
1644   PetscFunctionBegin;
1645   info->block_size = 1.0;
1646   ierr             = MatGetInfo(A,MAT_LOCAL,info);CHKERRQ(ierr);
1647 
1648   isend[0] = info->nz_used; isend[1] = info->nz_allocated; isend[2] = info->nz_unneeded;
1649   isend[3] = info->memory;  isend[4] = info->mallocs;
1650 
1651   ierr = MatGetInfo(B,MAT_LOCAL,info);CHKERRQ(ierr);
1652 
1653   isend[0] += info->nz_used; isend[1] += info->nz_allocated; isend[2] += info->nz_unneeded;
1654   isend[3] += info->memory;  isend[4] += info->mallocs;
1655   if (flag == MAT_LOCAL) {
1656     info->nz_used      = isend[0];
1657     info->nz_allocated = isend[1];
1658     info->nz_unneeded  = isend[2];
1659     info->memory       = isend[3];
1660     info->mallocs      = isend[4];
1661   } else if (flag == MAT_GLOBAL_MAX) {
1662     ierr = MPIU_Allreduce(isend,irecv,5,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)matin));CHKERRQ(ierr);
1663 
1664     info->nz_used      = irecv[0];
1665     info->nz_allocated = irecv[1];
1666     info->nz_unneeded  = irecv[2];
1667     info->memory       = irecv[3];
1668     info->mallocs      = irecv[4];
1669   } else if (flag == MAT_GLOBAL_SUM) {
1670     ierr = MPIU_Allreduce(isend,irecv,5,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)matin));CHKERRQ(ierr);
1671 
1672     info->nz_used      = irecv[0];
1673     info->nz_allocated = irecv[1];
1674     info->nz_unneeded  = irecv[2];
1675     info->memory       = irecv[3];
1676     info->mallocs      = irecv[4];
1677   }
1678   info->fill_ratio_given  = 0; /* no parallel LU/ILU/Cholesky */
1679   info->fill_ratio_needed = 0;
1680   info->factor_mallocs    = 0;
1681   PetscFunctionReturn(0);
1682 }
1683 
1684 PetscErrorCode MatSetOption_MPIAIJ(Mat A,MatOption op,PetscBool flg)
1685 {
1686   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1687   PetscErrorCode ierr;
1688 
1689   PetscFunctionBegin;
1690   switch (op) {
1691   case MAT_NEW_NONZERO_LOCATIONS:
1692   case MAT_NEW_NONZERO_ALLOCATION_ERR:
1693   case MAT_UNUSED_NONZERO_LOCATION_ERR:
1694   case MAT_KEEP_NONZERO_PATTERN:
1695   case MAT_NEW_NONZERO_LOCATION_ERR:
1696   case MAT_USE_INODES:
1697   case MAT_IGNORE_ZERO_ENTRIES:
1698     MatCheckPreallocated(A,1);
1699     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1700     ierr = MatSetOption(a->B,op,flg);CHKERRQ(ierr);
1701     break;
1702   case MAT_ROW_ORIENTED:
1703     MatCheckPreallocated(A,1);
1704     a->roworiented = flg;
1705 
1706     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1707     ierr = MatSetOption(a->B,op,flg);CHKERRQ(ierr);
1708     break;
1709   case MAT_NEW_DIAGONALS:
1710     ierr = PetscInfo1(A,"Option %s ignored\n",MatOptions[op]);CHKERRQ(ierr);
1711     break;
1712   case MAT_IGNORE_OFF_PROC_ENTRIES:
1713     a->donotstash = flg;
1714     break;
1715   case MAT_SPD:
1716     A->spd_set = PETSC_TRUE;
1717     A->spd     = flg;
1718     if (flg) {
1719       A->symmetric                  = PETSC_TRUE;
1720       A->structurally_symmetric     = PETSC_TRUE;
1721       A->symmetric_set              = PETSC_TRUE;
1722       A->structurally_symmetric_set = PETSC_TRUE;
1723     }
1724     break;
1725   case MAT_SYMMETRIC:
1726     MatCheckPreallocated(A,1);
1727     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1728     break;
1729   case MAT_STRUCTURALLY_SYMMETRIC:
1730     MatCheckPreallocated(A,1);
1731     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1732     break;
1733   case MAT_HERMITIAN:
1734     MatCheckPreallocated(A,1);
1735     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1736     break;
1737   case MAT_SYMMETRY_ETERNAL:
1738     MatCheckPreallocated(A,1);
1739     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1740     break;
1741   case MAT_SUBMAT_SINGLEIS:
1742     A->submat_singleis = flg;
1743     break;
1744   case MAT_STRUCTURE_ONLY:
1745     /* The option is handled directly by MatSetOption() */
1746     break;
1747   default:
1748     SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"unknown option %d",op);
1749   }
1750   PetscFunctionReturn(0);
1751 }
1752 
1753 PetscErrorCode MatGetRow_MPIAIJ(Mat matin,PetscInt row,PetscInt *nz,PetscInt **idx,PetscScalar **v)
1754 {
1755   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1756   PetscScalar    *vworkA,*vworkB,**pvA,**pvB,*v_p;
1757   PetscErrorCode ierr;
1758   PetscInt       i,*cworkA,*cworkB,**pcA,**pcB,cstart = matin->cmap->rstart;
1759   PetscInt       nztot,nzA,nzB,lrow,rstart = matin->rmap->rstart,rend = matin->rmap->rend;
1760   PetscInt       *cmap,*idx_p;
1761 
1762   PetscFunctionBegin;
1763   if (mat->getrowactive) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Already active");
1764   mat->getrowactive = PETSC_TRUE;
1765 
1766   if (!mat->rowvalues && (idx || v)) {
1767     /*
1768         allocate enough space to hold information from the longest row.
1769     */
1770     Mat_SeqAIJ *Aa = (Mat_SeqAIJ*)mat->A->data,*Ba = (Mat_SeqAIJ*)mat->B->data;
1771     PetscInt   max = 1,tmp;
1772     for (i=0; i<matin->rmap->n; i++) {
1773       tmp = Aa->i[i+1] - Aa->i[i] + Ba->i[i+1] - Ba->i[i];
1774       if (max < tmp) max = tmp;
1775     }
1776     ierr = PetscMalloc2(max,&mat->rowvalues,max,&mat->rowindices);CHKERRQ(ierr);
1777   }
1778 
1779   if (row < rstart || row >= rend) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only local rows");
1780   lrow = row - rstart;
1781 
1782   pvA = &vworkA; pcA = &cworkA; pvB = &vworkB; pcB = &cworkB;
1783   if (!v)   {pvA = 0; pvB = 0;}
1784   if (!idx) {pcA = 0; if (!v) pcB = 0;}
1785   ierr  = (*mat->A->ops->getrow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1786   ierr  = (*mat->B->ops->getrow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1787   nztot = nzA + nzB;
1788 
1789   cmap = mat->garray;
1790   if (v  || idx) {
1791     if (nztot) {
1792       /* Sort by increasing column numbers, assuming A and B already sorted */
1793       PetscInt imark = -1;
1794       if (v) {
1795         *v = v_p = mat->rowvalues;
1796         for (i=0; i<nzB; i++) {
1797           if (cmap[cworkB[i]] < cstart) v_p[i] = vworkB[i];
1798           else break;
1799         }
1800         imark = i;
1801         for (i=0; i<nzA; i++)     v_p[imark+i] = vworkA[i];
1802         for (i=imark; i<nzB; i++) v_p[nzA+i]   = vworkB[i];
1803       }
1804       if (idx) {
1805         *idx = idx_p = mat->rowindices;
1806         if (imark > -1) {
1807           for (i=0; i<imark; i++) {
1808             idx_p[i] = cmap[cworkB[i]];
1809           }
1810         } else {
1811           for (i=0; i<nzB; i++) {
1812             if (cmap[cworkB[i]] < cstart) idx_p[i] = cmap[cworkB[i]];
1813             else break;
1814           }
1815           imark = i;
1816         }
1817         for (i=0; i<nzA; i++)     idx_p[imark+i] = cstart + cworkA[i];
1818         for (i=imark; i<nzB; i++) idx_p[nzA+i]   = cmap[cworkB[i]];
1819       }
1820     } else {
1821       if (idx) *idx = 0;
1822       if (v)   *v   = 0;
1823     }
1824   }
1825   *nz  = nztot;
1826   ierr = (*mat->A->ops->restorerow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1827   ierr = (*mat->B->ops->restorerow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1828   PetscFunctionReturn(0);
1829 }
1830 
1831 PetscErrorCode MatRestoreRow_MPIAIJ(Mat mat,PetscInt row,PetscInt *nz,PetscInt **idx,PetscScalar **v)
1832 {
1833   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1834 
1835   PetscFunctionBegin;
1836   if (!aij->getrowactive) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"MatGetRow() must be called first");
1837   aij->getrowactive = PETSC_FALSE;
1838   PetscFunctionReturn(0);
1839 }
1840 
1841 PetscErrorCode MatNorm_MPIAIJ(Mat mat,NormType type,PetscReal *norm)
1842 {
1843   Mat_MPIAIJ     *aij  = (Mat_MPIAIJ*)mat->data;
1844   Mat_SeqAIJ     *amat = (Mat_SeqAIJ*)aij->A->data,*bmat = (Mat_SeqAIJ*)aij->B->data;
1845   PetscErrorCode ierr;
1846   PetscInt       i,j,cstart = mat->cmap->rstart;
1847   PetscReal      sum = 0.0;
1848   MatScalar      *v;
1849 
1850   PetscFunctionBegin;
1851   if (aij->size == 1) {
1852     ierr =  MatNorm(aij->A,type,norm);CHKERRQ(ierr);
1853   } else {
1854     if (type == NORM_FROBENIUS) {
1855       v = amat->a;
1856       for (i=0; i<amat->nz; i++) {
1857         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1858       }
1859       v = bmat->a;
1860       for (i=0; i<bmat->nz; i++) {
1861         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1862       }
1863       ierr  = MPIU_Allreduce(&sum,norm,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1864       *norm = PetscSqrtReal(*norm);
1865       ierr = PetscLogFlops(2*amat->nz+2*bmat->nz);CHKERRQ(ierr);
1866     } else if (type == NORM_1) { /* max column norm */
1867       PetscReal *tmp,*tmp2;
1868       PetscInt  *jj,*garray = aij->garray;
1869       ierr  = PetscCalloc1(mat->cmap->N+1,&tmp);CHKERRQ(ierr);
1870       ierr  = PetscMalloc1(mat->cmap->N+1,&tmp2);CHKERRQ(ierr);
1871       *norm = 0.0;
1872       v     = amat->a; jj = amat->j;
1873       for (j=0; j<amat->nz; j++) {
1874         tmp[cstart + *jj++] += PetscAbsScalar(*v);  v++;
1875       }
1876       v = bmat->a; jj = bmat->j;
1877       for (j=0; j<bmat->nz; j++) {
1878         tmp[garray[*jj++]] += PetscAbsScalar(*v); v++;
1879       }
1880       ierr = MPIU_Allreduce(tmp,tmp2,mat->cmap->N,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1881       for (j=0; j<mat->cmap->N; j++) {
1882         if (tmp2[j] > *norm) *norm = tmp2[j];
1883       }
1884       ierr = PetscFree(tmp);CHKERRQ(ierr);
1885       ierr = PetscFree(tmp2);CHKERRQ(ierr);
1886       ierr = PetscLogFlops(PetscMax(amat->nz+bmat->nz-1,0));CHKERRQ(ierr);
1887     } else if (type == NORM_INFINITY) { /* max row norm */
1888       PetscReal ntemp = 0.0;
1889       for (j=0; j<aij->A->rmap->n; j++) {
1890         v   = amat->a + amat->i[j];
1891         sum = 0.0;
1892         for (i=0; i<amat->i[j+1]-amat->i[j]; i++) {
1893           sum += PetscAbsScalar(*v); v++;
1894         }
1895         v = bmat->a + bmat->i[j];
1896         for (i=0; i<bmat->i[j+1]-bmat->i[j]; i++) {
1897           sum += PetscAbsScalar(*v); v++;
1898         }
1899         if (sum > ntemp) ntemp = sum;
1900       }
1901       ierr = MPIU_Allreduce(&ntemp,norm,1,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1902       ierr = PetscLogFlops(PetscMax(amat->nz+bmat->nz-1,0));CHKERRQ(ierr);
1903     } else SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_SUP,"No support for two norm");
1904   }
1905   PetscFunctionReturn(0);
1906 }
1907 
1908 PetscErrorCode MatTranspose_MPIAIJ(Mat A,MatReuse reuse,Mat *matout)
1909 {
1910   Mat_MPIAIJ     *a   = (Mat_MPIAIJ*)A->data;
1911   Mat_SeqAIJ     *Aloc=(Mat_SeqAIJ*)a->A->data,*Bloc=(Mat_SeqAIJ*)a->B->data;
1912   PetscErrorCode ierr;
1913   PetscInt       M      = A->rmap->N,N = A->cmap->N,ma,na,mb,nb,*ai,*aj,*bi,*bj,row,*cols,*cols_tmp,i;
1914   PetscInt       cstart = A->cmap->rstart,ncol;
1915   Mat            B;
1916   MatScalar      *array;
1917 
1918   PetscFunctionBegin;
1919   if (reuse == MAT_INPLACE_MATRIX && M != N) SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_SIZ,"Square matrix only for in-place");
1920 
1921   ma = A->rmap->n; na = A->cmap->n; mb = a->B->rmap->n; nb = a->B->cmap->n;
1922   ai = Aloc->i; aj = Aloc->j;
1923   bi = Bloc->i; bj = Bloc->j;
1924   if (reuse == MAT_INITIAL_MATRIX || *matout == A) {
1925     PetscInt             *d_nnz,*g_nnz,*o_nnz;
1926     PetscSFNode          *oloc;
1927     PETSC_UNUSED PetscSF sf;
1928 
1929     ierr = PetscMalloc4(na,&d_nnz,na,&o_nnz,nb,&g_nnz,nb,&oloc);CHKERRQ(ierr);
1930     /* compute d_nnz for preallocation */
1931     ierr = PetscMemzero(d_nnz,na*sizeof(PetscInt));CHKERRQ(ierr);
1932     for (i=0; i<ai[ma]; i++) {
1933       d_nnz[aj[i]]++;
1934       aj[i] += cstart; /* global col index to be used by MatSetValues() */
1935     }
1936     /* compute local off-diagonal contributions */
1937     ierr = PetscMemzero(g_nnz,nb*sizeof(PetscInt));CHKERRQ(ierr);
1938     for (i=0; i<bi[ma]; i++) g_nnz[bj[i]]++;
1939     /* map those to global */
1940     ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&sf);CHKERRQ(ierr);
1941     ierr = PetscSFSetGraphLayout(sf,A->cmap,nb,NULL,PETSC_USE_POINTER,a->garray);CHKERRQ(ierr);
1942     ierr = PetscSFSetFromOptions(sf);CHKERRQ(ierr);
1943     ierr = PetscMemzero(o_nnz,na*sizeof(PetscInt));CHKERRQ(ierr);
1944     ierr = PetscSFReduceBegin(sf,MPIU_INT,g_nnz,o_nnz,MPIU_SUM);CHKERRQ(ierr);
1945     ierr = PetscSFReduceEnd(sf,MPIU_INT,g_nnz,o_nnz,MPIU_SUM);CHKERRQ(ierr);
1946     ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
1947 
1948     ierr = MatCreate(PetscObjectComm((PetscObject)A),&B);CHKERRQ(ierr);
1949     ierr = MatSetSizes(B,A->cmap->n,A->rmap->n,N,M);CHKERRQ(ierr);
1950     ierr = MatSetBlockSizes(B,PetscAbs(A->cmap->bs),PetscAbs(A->rmap->bs));CHKERRQ(ierr);
1951     ierr = MatSetType(B,((PetscObject)A)->type_name);CHKERRQ(ierr);
1952     ierr = MatMPIAIJSetPreallocation(B,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
1953     ierr = PetscFree4(d_nnz,o_nnz,g_nnz,oloc);CHKERRQ(ierr);
1954   } else {
1955     B    = *matout;
1956     ierr = MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
1957     for (i=0; i<ai[ma]; i++) aj[i] += cstart; /* global col index to be used by MatSetValues() */
1958   }
1959 
1960   /* copy over the A part */
1961   array = Aloc->a;
1962   row   = A->rmap->rstart;
1963   for (i=0; i<ma; i++) {
1964     ncol = ai[i+1]-ai[i];
1965     ierr = MatSetValues(B,ncol,aj,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1966     row++;
1967     array += ncol; aj += ncol;
1968   }
1969   aj = Aloc->j;
1970   for (i=0; i<ai[ma]; i++) aj[i] -= cstart; /* resume local col index */
1971 
1972   /* copy over the B part */
1973   ierr  = PetscCalloc1(bi[mb],&cols);CHKERRQ(ierr);
1974   array = Bloc->a;
1975   row   = A->rmap->rstart;
1976   for (i=0; i<bi[mb]; i++) cols[i] = a->garray[bj[i]];
1977   cols_tmp = cols;
1978   for (i=0; i<mb; i++) {
1979     ncol = bi[i+1]-bi[i];
1980     ierr = MatSetValues(B,ncol,cols_tmp,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1981     row++;
1982     array += ncol; cols_tmp += ncol;
1983   }
1984   ierr = PetscFree(cols);CHKERRQ(ierr);
1985 
1986   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1987   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1988   if (reuse == MAT_INITIAL_MATRIX || reuse == MAT_REUSE_MATRIX) {
1989     *matout = B;
1990   } else {
1991     ierr = MatHeaderMerge(A,&B);CHKERRQ(ierr);
1992   }
1993   PetscFunctionReturn(0);
1994 }
1995 
1996 PetscErrorCode MatDiagonalScale_MPIAIJ(Mat mat,Vec ll,Vec rr)
1997 {
1998   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1999   Mat            a    = aij->A,b = aij->B;
2000   PetscErrorCode ierr;
2001   PetscInt       s1,s2,s3;
2002 
2003   PetscFunctionBegin;
2004   ierr = MatGetLocalSize(mat,&s2,&s3);CHKERRQ(ierr);
2005   if (rr) {
2006     ierr = VecGetLocalSize(rr,&s1);CHKERRQ(ierr);
2007     if (s1!=s3) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"right vector non-conforming local size");
2008     /* Overlap communication with computation. */
2009     ierr = VecScatterBegin(aij->Mvctx,rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
2010   }
2011   if (ll) {
2012     ierr = VecGetLocalSize(ll,&s1);CHKERRQ(ierr);
2013     if (s1!=s2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"left vector non-conforming local size");
2014     ierr = (*b->ops->diagonalscale)(b,ll,0);CHKERRQ(ierr);
2015   }
2016   /* scale  the diagonal block */
2017   ierr = (*a->ops->diagonalscale)(a,ll,rr);CHKERRQ(ierr);
2018 
2019   if (rr) {
2020     /* Do a scatter end and then right scale the off-diagonal block */
2021     ierr = VecScatterEnd(aij->Mvctx,rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
2022     ierr = (*b->ops->diagonalscale)(b,0,aij->lvec);CHKERRQ(ierr);
2023   }
2024   PetscFunctionReturn(0);
2025 }
2026 
2027 PetscErrorCode MatSetUnfactored_MPIAIJ(Mat A)
2028 {
2029   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2030   PetscErrorCode ierr;
2031 
2032   PetscFunctionBegin;
2033   ierr = MatSetUnfactored(a->A);CHKERRQ(ierr);
2034   PetscFunctionReturn(0);
2035 }
2036 
2037 PetscErrorCode MatEqual_MPIAIJ(Mat A,Mat B,PetscBool  *flag)
2038 {
2039   Mat_MPIAIJ     *matB = (Mat_MPIAIJ*)B->data,*matA = (Mat_MPIAIJ*)A->data;
2040   Mat            a,b,c,d;
2041   PetscBool      flg;
2042   PetscErrorCode ierr;
2043 
2044   PetscFunctionBegin;
2045   a = matA->A; b = matA->B;
2046   c = matB->A; d = matB->B;
2047 
2048   ierr = MatEqual(a,c,&flg);CHKERRQ(ierr);
2049   if (flg) {
2050     ierr = MatEqual(b,d,&flg);CHKERRQ(ierr);
2051   }
2052   ierr = MPIU_Allreduce(&flg,flag,1,MPIU_BOOL,MPI_LAND,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
2053   PetscFunctionReturn(0);
2054 }
2055 
2056 PetscErrorCode MatCopy_MPIAIJ(Mat A,Mat B,MatStructure str)
2057 {
2058   PetscErrorCode ierr;
2059   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2060   Mat_MPIAIJ     *b = (Mat_MPIAIJ*)B->data;
2061 
2062   PetscFunctionBegin;
2063   /* If the two matrices don't have the same copy implementation, they aren't compatible for fast copy. */
2064   if ((str != SAME_NONZERO_PATTERN) || (A->ops->copy != B->ops->copy)) {
2065     /* because of the column compression in the off-processor part of the matrix a->B,
2066        the number of columns in a->B and b->B may be different, hence we cannot call
2067        the MatCopy() directly on the two parts. If need be, we can provide a more
2068        efficient copy than the MatCopy_Basic() by first uncompressing the a->B matrices
2069        then copying the submatrices */
2070     ierr = MatCopy_Basic(A,B,str);CHKERRQ(ierr);
2071   } else {
2072     ierr = MatCopy(a->A,b->A,str);CHKERRQ(ierr);
2073     ierr = MatCopy(a->B,b->B,str);CHKERRQ(ierr);
2074   }
2075   ierr = PetscObjectStateIncrease((PetscObject)B);CHKERRQ(ierr);
2076   PetscFunctionReturn(0);
2077 }
2078 
2079 PetscErrorCode MatSetUp_MPIAIJ(Mat A)
2080 {
2081   PetscErrorCode ierr;
2082 
2083   PetscFunctionBegin;
2084   ierr =  MatMPIAIJSetPreallocation(A,PETSC_DEFAULT,0,PETSC_DEFAULT,0);CHKERRQ(ierr);
2085   PetscFunctionReturn(0);
2086 }
2087 
2088 /*
2089    Computes the number of nonzeros per row needed for preallocation when X and Y
2090    have different nonzero structure.
2091 */
2092 PetscErrorCode MatAXPYGetPreallocation_MPIX_private(PetscInt m,const PetscInt *xi,const PetscInt *xj,const PetscInt *xltog,const PetscInt *yi,const PetscInt *yj,const PetscInt *yltog,PetscInt *nnz)
2093 {
2094   PetscInt       i,j,k,nzx,nzy;
2095 
2096   PetscFunctionBegin;
2097   /* Set the number of nonzeros in the new matrix */
2098   for (i=0; i<m; i++) {
2099     const PetscInt *xjj = xj+xi[i],*yjj = yj+yi[i];
2100     nzx = xi[i+1] - xi[i];
2101     nzy = yi[i+1] - yi[i];
2102     nnz[i] = 0;
2103     for (j=0,k=0; j<nzx; j++) {                   /* Point in X */
2104       for (; k<nzy && yltog[yjj[k]]<xltog[xjj[j]]; k++) nnz[i]++; /* Catch up to X */
2105       if (k<nzy && yltog[yjj[k]]==xltog[xjj[j]]) k++;             /* Skip duplicate */
2106       nnz[i]++;
2107     }
2108     for (; k<nzy; k++) nnz[i]++;
2109   }
2110   PetscFunctionReturn(0);
2111 }
2112 
2113 /* This is the same as MatAXPYGetPreallocation_SeqAIJ, except that the local-to-global map is provided */
2114 static PetscErrorCode MatAXPYGetPreallocation_MPIAIJ(Mat Y,const PetscInt *yltog,Mat X,const PetscInt *xltog,PetscInt *nnz)
2115 {
2116   PetscErrorCode ierr;
2117   PetscInt       m = Y->rmap->N;
2118   Mat_SeqAIJ     *x = (Mat_SeqAIJ*)X->data;
2119   Mat_SeqAIJ     *y = (Mat_SeqAIJ*)Y->data;
2120 
2121   PetscFunctionBegin;
2122   ierr = MatAXPYGetPreallocation_MPIX_private(m,x->i,x->j,xltog,y->i,y->j,yltog,nnz);CHKERRQ(ierr);
2123   PetscFunctionReturn(0);
2124 }
2125 
2126 PetscErrorCode MatAXPY_MPIAIJ(Mat Y,PetscScalar a,Mat X,MatStructure str)
2127 {
2128   PetscErrorCode ierr;
2129   Mat_MPIAIJ     *xx = (Mat_MPIAIJ*)X->data,*yy = (Mat_MPIAIJ*)Y->data;
2130   PetscBLASInt   bnz,one=1;
2131   Mat_SeqAIJ     *x,*y;
2132 
2133   PetscFunctionBegin;
2134   if (str == SAME_NONZERO_PATTERN) {
2135     PetscScalar alpha = a;
2136     x    = (Mat_SeqAIJ*)xx->A->data;
2137     ierr = PetscBLASIntCast(x->nz,&bnz);CHKERRQ(ierr);
2138     y    = (Mat_SeqAIJ*)yy->A->data;
2139     PetscStackCallBLAS("BLASaxpy",BLASaxpy_(&bnz,&alpha,x->a,&one,y->a,&one));
2140     x    = (Mat_SeqAIJ*)xx->B->data;
2141     y    = (Mat_SeqAIJ*)yy->B->data;
2142     ierr = PetscBLASIntCast(x->nz,&bnz);CHKERRQ(ierr);
2143     PetscStackCallBLAS("BLASaxpy",BLASaxpy_(&bnz,&alpha,x->a,&one,y->a,&one));
2144     ierr = PetscObjectStateIncrease((PetscObject)Y);CHKERRQ(ierr);
2145   } else if (str == SUBSET_NONZERO_PATTERN) { /* nonzeros of X is a subset of Y's */
2146     ierr = MatAXPY_Basic(Y,a,X,str);CHKERRQ(ierr);
2147   } else {
2148     Mat      B;
2149     PetscInt *nnz_d,*nnz_o;
2150     ierr = PetscMalloc1(yy->A->rmap->N,&nnz_d);CHKERRQ(ierr);
2151     ierr = PetscMalloc1(yy->B->rmap->N,&nnz_o);CHKERRQ(ierr);
2152     ierr = MatCreate(PetscObjectComm((PetscObject)Y),&B);CHKERRQ(ierr);
2153     ierr = PetscObjectSetName((PetscObject)B,((PetscObject)Y)->name);CHKERRQ(ierr);
2154     ierr = MatSetSizes(B,Y->rmap->n,Y->cmap->n,Y->rmap->N,Y->cmap->N);CHKERRQ(ierr);
2155     ierr = MatSetBlockSizesFromMats(B,Y,Y);CHKERRQ(ierr);
2156     ierr = MatSetType(B,MATMPIAIJ);CHKERRQ(ierr);
2157     ierr = MatAXPYGetPreallocation_SeqAIJ(yy->A,xx->A,nnz_d);CHKERRQ(ierr);
2158     ierr = MatAXPYGetPreallocation_MPIAIJ(yy->B,yy->garray,xx->B,xx->garray,nnz_o);CHKERRQ(ierr);
2159     ierr = MatMPIAIJSetPreallocation(B,0,nnz_d,0,nnz_o);CHKERRQ(ierr);
2160     ierr = MatAXPY_BasicWithPreallocation(B,Y,a,X,str);CHKERRQ(ierr);
2161     ierr = MatHeaderReplace(Y,&B);CHKERRQ(ierr);
2162     ierr = PetscFree(nnz_d);CHKERRQ(ierr);
2163     ierr = PetscFree(nnz_o);CHKERRQ(ierr);
2164   }
2165   PetscFunctionReturn(0);
2166 }
2167 
2168 extern PetscErrorCode  MatConjugate_SeqAIJ(Mat);
2169 
2170 PetscErrorCode  MatConjugate_MPIAIJ(Mat mat)
2171 {
2172 #if defined(PETSC_USE_COMPLEX)
2173   PetscErrorCode ierr;
2174   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
2175 
2176   PetscFunctionBegin;
2177   ierr = MatConjugate_SeqAIJ(aij->A);CHKERRQ(ierr);
2178   ierr = MatConjugate_SeqAIJ(aij->B);CHKERRQ(ierr);
2179 #else
2180   PetscFunctionBegin;
2181 #endif
2182   PetscFunctionReturn(0);
2183 }
2184 
2185 PetscErrorCode MatRealPart_MPIAIJ(Mat A)
2186 {
2187   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2188   PetscErrorCode ierr;
2189 
2190   PetscFunctionBegin;
2191   ierr = MatRealPart(a->A);CHKERRQ(ierr);
2192   ierr = MatRealPart(a->B);CHKERRQ(ierr);
2193   PetscFunctionReturn(0);
2194 }
2195 
2196 PetscErrorCode MatImaginaryPart_MPIAIJ(Mat A)
2197 {
2198   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2199   PetscErrorCode ierr;
2200 
2201   PetscFunctionBegin;
2202   ierr = MatImaginaryPart(a->A);CHKERRQ(ierr);
2203   ierr = MatImaginaryPart(a->B);CHKERRQ(ierr);
2204   PetscFunctionReturn(0);
2205 }
2206 
2207 PetscErrorCode MatGetRowMaxAbs_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2208 {
2209   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2210   PetscErrorCode ierr;
2211   PetscInt       i,*idxb = 0;
2212   PetscScalar    *va,*vb;
2213   Vec            vtmp;
2214 
2215   PetscFunctionBegin;
2216   ierr = MatGetRowMaxAbs(a->A,v,idx);CHKERRQ(ierr);
2217   ierr = VecGetArray(v,&va);CHKERRQ(ierr);
2218   if (idx) {
2219     for (i=0; i<A->rmap->n; i++) {
2220       if (PetscAbsScalar(va[i])) idx[i] += A->cmap->rstart;
2221     }
2222   }
2223 
2224   ierr = VecCreateSeq(PETSC_COMM_SELF,A->rmap->n,&vtmp);CHKERRQ(ierr);
2225   if (idx) {
2226     ierr = PetscMalloc1(A->rmap->n,&idxb);CHKERRQ(ierr);
2227   }
2228   ierr = MatGetRowMaxAbs(a->B,vtmp,idxb);CHKERRQ(ierr);
2229   ierr = VecGetArray(vtmp,&vb);CHKERRQ(ierr);
2230 
2231   for (i=0; i<A->rmap->n; i++) {
2232     if (PetscAbsScalar(va[i]) < PetscAbsScalar(vb[i])) {
2233       va[i] = vb[i];
2234       if (idx) idx[i] = a->garray[idxb[i]];
2235     }
2236   }
2237 
2238   ierr = VecRestoreArray(v,&va);CHKERRQ(ierr);
2239   ierr = VecRestoreArray(vtmp,&vb);CHKERRQ(ierr);
2240   ierr = PetscFree(idxb);CHKERRQ(ierr);
2241   ierr = VecDestroy(&vtmp);CHKERRQ(ierr);
2242   PetscFunctionReturn(0);
2243 }
2244 
2245 PetscErrorCode MatGetRowMinAbs_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2246 {
2247   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2248   PetscErrorCode ierr;
2249   PetscInt       i,*idxb = 0;
2250   PetscScalar    *va,*vb;
2251   Vec            vtmp;
2252 
2253   PetscFunctionBegin;
2254   ierr = MatGetRowMinAbs(a->A,v,idx);CHKERRQ(ierr);
2255   ierr = VecGetArray(v,&va);CHKERRQ(ierr);
2256   if (idx) {
2257     for (i=0; i<A->cmap->n; i++) {
2258       if (PetscAbsScalar(va[i])) idx[i] += A->cmap->rstart;
2259     }
2260   }
2261 
2262   ierr = VecCreateSeq(PETSC_COMM_SELF,A->rmap->n,&vtmp);CHKERRQ(ierr);
2263   if (idx) {
2264     ierr = PetscMalloc1(A->rmap->n,&idxb);CHKERRQ(ierr);
2265   }
2266   ierr = MatGetRowMinAbs(a->B,vtmp,idxb);CHKERRQ(ierr);
2267   ierr = VecGetArray(vtmp,&vb);CHKERRQ(ierr);
2268 
2269   for (i=0; i<A->rmap->n; i++) {
2270     if (PetscAbsScalar(va[i]) > PetscAbsScalar(vb[i])) {
2271       va[i] = vb[i];
2272       if (idx) idx[i] = a->garray[idxb[i]];
2273     }
2274   }
2275 
2276   ierr = VecRestoreArray(v,&va);CHKERRQ(ierr);
2277   ierr = VecRestoreArray(vtmp,&vb);CHKERRQ(ierr);
2278   ierr = PetscFree(idxb);CHKERRQ(ierr);
2279   ierr = VecDestroy(&vtmp);CHKERRQ(ierr);
2280   PetscFunctionReturn(0);
2281 }
2282 
2283 PetscErrorCode MatGetRowMin_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2284 {
2285   Mat_MPIAIJ     *mat   = (Mat_MPIAIJ*) A->data;
2286   PetscInt       n      = A->rmap->n;
2287   PetscInt       cstart = A->cmap->rstart;
2288   PetscInt       *cmap  = mat->garray;
2289   PetscInt       *diagIdx, *offdiagIdx;
2290   Vec            diagV, offdiagV;
2291   PetscScalar    *a, *diagA, *offdiagA;
2292   PetscInt       r;
2293   PetscErrorCode ierr;
2294 
2295   PetscFunctionBegin;
2296   ierr = PetscMalloc2(n,&diagIdx,n,&offdiagIdx);CHKERRQ(ierr);
2297   ierr = VecCreateSeq(PetscObjectComm((PetscObject)A), n, &diagV);CHKERRQ(ierr);
2298   ierr = VecCreateSeq(PetscObjectComm((PetscObject)A), n, &offdiagV);CHKERRQ(ierr);
2299   ierr = MatGetRowMin(mat->A, diagV,    diagIdx);CHKERRQ(ierr);
2300   ierr = MatGetRowMin(mat->B, offdiagV, offdiagIdx);CHKERRQ(ierr);
2301   ierr = VecGetArray(v,        &a);CHKERRQ(ierr);
2302   ierr = VecGetArray(diagV,    &diagA);CHKERRQ(ierr);
2303   ierr = VecGetArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2304   for (r = 0; r < n; ++r) {
2305     if (PetscAbsScalar(diagA[r]) <= PetscAbsScalar(offdiagA[r])) {
2306       a[r]   = diagA[r];
2307       idx[r] = cstart + diagIdx[r];
2308     } else {
2309       a[r]   = offdiagA[r];
2310       idx[r] = cmap[offdiagIdx[r]];
2311     }
2312   }
2313   ierr = VecRestoreArray(v,        &a);CHKERRQ(ierr);
2314   ierr = VecRestoreArray(diagV,    &diagA);CHKERRQ(ierr);
2315   ierr = VecRestoreArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2316   ierr = VecDestroy(&diagV);CHKERRQ(ierr);
2317   ierr = VecDestroy(&offdiagV);CHKERRQ(ierr);
2318   ierr = PetscFree2(diagIdx, offdiagIdx);CHKERRQ(ierr);
2319   PetscFunctionReturn(0);
2320 }
2321 
2322 PetscErrorCode MatGetRowMax_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2323 {
2324   Mat_MPIAIJ     *mat   = (Mat_MPIAIJ*) A->data;
2325   PetscInt       n      = A->rmap->n;
2326   PetscInt       cstart = A->cmap->rstart;
2327   PetscInt       *cmap  = mat->garray;
2328   PetscInt       *diagIdx, *offdiagIdx;
2329   Vec            diagV, offdiagV;
2330   PetscScalar    *a, *diagA, *offdiagA;
2331   PetscInt       r;
2332   PetscErrorCode ierr;
2333 
2334   PetscFunctionBegin;
2335   ierr = PetscMalloc2(n,&diagIdx,n,&offdiagIdx);CHKERRQ(ierr);
2336   ierr = VecCreateSeq(PETSC_COMM_SELF, n, &diagV);CHKERRQ(ierr);
2337   ierr = VecCreateSeq(PETSC_COMM_SELF, n, &offdiagV);CHKERRQ(ierr);
2338   ierr = MatGetRowMax(mat->A, diagV,    diagIdx);CHKERRQ(ierr);
2339   ierr = MatGetRowMax(mat->B, offdiagV, offdiagIdx);CHKERRQ(ierr);
2340   ierr = VecGetArray(v,        &a);CHKERRQ(ierr);
2341   ierr = VecGetArray(diagV,    &diagA);CHKERRQ(ierr);
2342   ierr = VecGetArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2343   for (r = 0; r < n; ++r) {
2344     if (PetscAbsScalar(diagA[r]) >= PetscAbsScalar(offdiagA[r])) {
2345       a[r]   = diagA[r];
2346       idx[r] = cstart + diagIdx[r];
2347     } else {
2348       a[r]   = offdiagA[r];
2349       idx[r] = cmap[offdiagIdx[r]];
2350     }
2351   }
2352   ierr = VecRestoreArray(v,        &a);CHKERRQ(ierr);
2353   ierr = VecRestoreArray(diagV,    &diagA);CHKERRQ(ierr);
2354   ierr = VecRestoreArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2355   ierr = VecDestroy(&diagV);CHKERRQ(ierr);
2356   ierr = VecDestroy(&offdiagV);CHKERRQ(ierr);
2357   ierr = PetscFree2(diagIdx, offdiagIdx);CHKERRQ(ierr);
2358   PetscFunctionReturn(0);
2359 }
2360 
2361 PetscErrorCode MatGetSeqNonzeroStructure_MPIAIJ(Mat mat,Mat *newmat)
2362 {
2363   PetscErrorCode ierr;
2364   Mat            *dummy;
2365 
2366   PetscFunctionBegin;
2367   ierr    = MatCreateSubMatrix_MPIAIJ_All(mat,MAT_DO_NOT_GET_VALUES,MAT_INITIAL_MATRIX,&dummy);CHKERRQ(ierr);
2368   *newmat = *dummy;
2369   ierr    = PetscFree(dummy);CHKERRQ(ierr);
2370   PetscFunctionReturn(0);
2371 }
2372 
2373 PetscErrorCode  MatInvertBlockDiagonal_MPIAIJ(Mat A,const PetscScalar **values)
2374 {
2375   Mat_MPIAIJ     *a = (Mat_MPIAIJ*) A->data;
2376   PetscErrorCode ierr;
2377 
2378   PetscFunctionBegin;
2379   ierr = MatInvertBlockDiagonal(a->A,values);CHKERRQ(ierr);
2380   A->factorerrortype = a->A->factorerrortype;
2381   PetscFunctionReturn(0);
2382 }
2383 
2384 static PetscErrorCode  MatSetRandom_MPIAIJ(Mat x,PetscRandom rctx)
2385 {
2386   PetscErrorCode ierr;
2387   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)x->data;
2388 
2389   PetscFunctionBegin;
2390   ierr = MatSetRandom(aij->A,rctx);CHKERRQ(ierr);
2391   ierr = MatSetRandom(aij->B,rctx);CHKERRQ(ierr);
2392   ierr = MatAssemblyBegin(x,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2393   ierr = MatAssemblyEnd(x,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2394   PetscFunctionReturn(0);
2395 }
2396 
2397 PetscErrorCode MatMPIAIJSetUseScalableIncreaseOverlap_MPIAIJ(Mat A,PetscBool sc)
2398 {
2399   PetscFunctionBegin;
2400   if (sc) A->ops->increaseoverlap = MatIncreaseOverlap_MPIAIJ_Scalable;
2401   else A->ops->increaseoverlap    = MatIncreaseOverlap_MPIAIJ;
2402   PetscFunctionReturn(0);
2403 }
2404 
2405 /*@
2406    MatMPIAIJSetUseScalableIncreaseOverlap - Determine if the matrix uses a scalable algorithm to compute the overlap
2407 
2408    Collective on Mat
2409 
2410    Input Parameters:
2411 +    A - the matrix
2412 -    sc - PETSC_TRUE indicates use the scalable algorithm (default is not to use the scalable algorithm)
2413 
2414  Level: advanced
2415 
2416 @*/
2417 PetscErrorCode MatMPIAIJSetUseScalableIncreaseOverlap(Mat A,PetscBool sc)
2418 {
2419   PetscErrorCode       ierr;
2420 
2421   PetscFunctionBegin;
2422   ierr = PetscTryMethod(A,"MatMPIAIJSetUseScalableIncreaseOverlap_C",(Mat,PetscBool),(A,sc));CHKERRQ(ierr);
2423   PetscFunctionReturn(0);
2424 }
2425 
2426 PetscErrorCode MatSetFromOptions_MPIAIJ(PetscOptionItems *PetscOptionsObject,Mat A)
2427 {
2428   PetscErrorCode       ierr;
2429   PetscBool            sc = PETSC_FALSE,flg;
2430 
2431   PetscFunctionBegin;
2432   ierr = PetscOptionsHead(PetscOptionsObject,"MPIAIJ options");CHKERRQ(ierr);
2433   ierr = PetscObjectOptionsBegin((PetscObject)A);
2434     if (A->ops->increaseoverlap == MatIncreaseOverlap_MPIAIJ_Scalable) sc = PETSC_TRUE;
2435     ierr = PetscOptionsBool("-mat_increase_overlap_scalable","Use a scalable algorithm to compute the overlap","MatIncreaseOverlap",sc,&sc,&flg);CHKERRQ(ierr);
2436     if (flg) {
2437       ierr = MatMPIAIJSetUseScalableIncreaseOverlap(A,sc);CHKERRQ(ierr);
2438     }
2439   ierr = PetscOptionsEnd();CHKERRQ(ierr);
2440   PetscFunctionReturn(0);
2441 }
2442 
2443 PetscErrorCode MatShift_MPIAIJ(Mat Y,PetscScalar a)
2444 {
2445   PetscErrorCode ierr;
2446   Mat_MPIAIJ     *maij = (Mat_MPIAIJ*)Y->data;
2447   Mat_SeqAIJ     *aij = (Mat_SeqAIJ*)maij->A->data;
2448 
2449   PetscFunctionBegin;
2450   if (!Y->preallocated) {
2451     ierr = MatMPIAIJSetPreallocation(Y,1,NULL,0,NULL);CHKERRQ(ierr);
2452   } else if (!aij->nz) {
2453     PetscInt nonew = aij->nonew;
2454     ierr = MatSeqAIJSetPreallocation(maij->A,1,NULL);CHKERRQ(ierr);
2455     aij->nonew = nonew;
2456   }
2457   ierr = MatShift_Basic(Y,a);CHKERRQ(ierr);
2458   PetscFunctionReturn(0);
2459 }
2460 
2461 PetscErrorCode MatMissingDiagonal_MPIAIJ(Mat A,PetscBool  *missing,PetscInt *d)
2462 {
2463   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2464   PetscErrorCode ierr;
2465 
2466   PetscFunctionBegin;
2467   if (A->rmap->n != A->cmap->n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Only works for square matrices");
2468   ierr = MatMissingDiagonal(a->A,missing,d);CHKERRQ(ierr);
2469   if (d) {
2470     PetscInt rstart;
2471     ierr = MatGetOwnershipRange(A,&rstart,NULL);CHKERRQ(ierr);
2472     *d += rstart;
2473 
2474   }
2475   PetscFunctionReturn(0);
2476 }
2477 
2478 
2479 /* -------------------------------------------------------------------*/
2480 static struct _MatOps MatOps_Values = {MatSetValues_MPIAIJ,
2481                                        MatGetRow_MPIAIJ,
2482                                        MatRestoreRow_MPIAIJ,
2483                                        MatMult_MPIAIJ,
2484                                 /* 4*/ MatMultAdd_MPIAIJ,
2485                                        MatMultTranspose_MPIAIJ,
2486                                        MatMultTransposeAdd_MPIAIJ,
2487                                        0,
2488                                        0,
2489                                        0,
2490                                 /*10*/ 0,
2491                                        0,
2492                                        0,
2493                                        MatSOR_MPIAIJ,
2494                                        MatTranspose_MPIAIJ,
2495                                 /*15*/ MatGetInfo_MPIAIJ,
2496                                        MatEqual_MPIAIJ,
2497                                        MatGetDiagonal_MPIAIJ,
2498                                        MatDiagonalScale_MPIAIJ,
2499                                        MatNorm_MPIAIJ,
2500                                 /*20*/ MatAssemblyBegin_MPIAIJ,
2501                                        MatAssemblyEnd_MPIAIJ,
2502                                        MatSetOption_MPIAIJ,
2503                                        MatZeroEntries_MPIAIJ,
2504                                 /*24*/ MatZeroRows_MPIAIJ,
2505                                        0,
2506                                        0,
2507                                        0,
2508                                        0,
2509                                 /*29*/ MatSetUp_MPIAIJ,
2510                                        0,
2511                                        0,
2512                                        MatGetDiagonalBlock_MPIAIJ,
2513                                        0,
2514                                 /*34*/ MatDuplicate_MPIAIJ,
2515                                        0,
2516                                        0,
2517                                        0,
2518                                        0,
2519                                 /*39*/ MatAXPY_MPIAIJ,
2520                                        MatCreateSubMatrices_MPIAIJ,
2521                                        MatIncreaseOverlap_MPIAIJ,
2522                                        MatGetValues_MPIAIJ,
2523                                        MatCopy_MPIAIJ,
2524                                 /*44*/ MatGetRowMax_MPIAIJ,
2525                                        MatScale_MPIAIJ,
2526                                        MatShift_MPIAIJ,
2527                                        MatDiagonalSet_MPIAIJ,
2528                                        MatZeroRowsColumns_MPIAIJ,
2529                                 /*49*/ MatSetRandom_MPIAIJ,
2530                                        0,
2531                                        0,
2532                                        0,
2533                                        0,
2534                                 /*54*/ MatFDColoringCreate_MPIXAIJ,
2535                                        0,
2536                                        MatSetUnfactored_MPIAIJ,
2537                                        MatPermute_MPIAIJ,
2538                                        0,
2539                                 /*59*/ MatCreateSubMatrix_MPIAIJ,
2540                                        MatDestroy_MPIAIJ,
2541                                        MatView_MPIAIJ,
2542                                        0,
2543                                        MatMatMatMult_MPIAIJ_MPIAIJ_MPIAIJ,
2544                                 /*64*/ MatMatMatMultSymbolic_MPIAIJ_MPIAIJ_MPIAIJ,
2545                                        MatMatMatMultNumeric_MPIAIJ_MPIAIJ_MPIAIJ,
2546                                        0,
2547                                        0,
2548                                        0,
2549                                 /*69*/ MatGetRowMaxAbs_MPIAIJ,
2550                                        MatGetRowMinAbs_MPIAIJ,
2551                                        0,
2552                                        0,
2553                                        0,
2554                                        0,
2555                                 /*75*/ MatFDColoringApply_AIJ,
2556                                        MatSetFromOptions_MPIAIJ,
2557                                        0,
2558                                        0,
2559                                        MatFindZeroDiagonals_MPIAIJ,
2560                                 /*80*/ 0,
2561                                        0,
2562                                        0,
2563                                 /*83*/ MatLoad_MPIAIJ,
2564                                        MatIsSymmetric_MPIAIJ,
2565                                        0,
2566                                        0,
2567                                        0,
2568                                        0,
2569                                 /*89*/ MatMatMult_MPIAIJ_MPIAIJ,
2570                                        MatMatMultSymbolic_MPIAIJ_MPIAIJ,
2571                                        MatMatMultNumeric_MPIAIJ_MPIAIJ,
2572                                        MatPtAP_MPIAIJ_MPIAIJ,
2573                                        MatPtAPSymbolic_MPIAIJ_MPIAIJ,
2574                                 /*94*/ MatPtAPNumeric_MPIAIJ_MPIAIJ,
2575                                        0,
2576                                        0,
2577                                        0,
2578                                        0,
2579                                 /*99*/ 0,
2580                                        0,
2581                                        0,
2582                                        MatConjugate_MPIAIJ,
2583                                        0,
2584                                 /*104*/MatSetValuesRow_MPIAIJ,
2585                                        MatRealPart_MPIAIJ,
2586                                        MatImaginaryPart_MPIAIJ,
2587                                        0,
2588                                        0,
2589                                 /*109*/0,
2590                                        0,
2591                                        MatGetRowMin_MPIAIJ,
2592                                        0,
2593                                        MatMissingDiagonal_MPIAIJ,
2594                                 /*114*/MatGetSeqNonzeroStructure_MPIAIJ,
2595                                        0,
2596                                        MatGetGhosts_MPIAIJ,
2597                                        0,
2598                                        0,
2599                                 /*119*/0,
2600                                        0,
2601                                        0,
2602                                        0,
2603                                        MatGetMultiProcBlock_MPIAIJ,
2604                                 /*124*/MatFindNonzeroRows_MPIAIJ,
2605                                        MatGetColumnNorms_MPIAIJ,
2606                                        MatInvertBlockDiagonal_MPIAIJ,
2607                                        0,
2608                                        MatCreateSubMatricesMPI_MPIAIJ,
2609                                 /*129*/0,
2610                                        MatTransposeMatMult_MPIAIJ_MPIAIJ,
2611                                        MatTransposeMatMultSymbolic_MPIAIJ_MPIAIJ,
2612                                        MatTransposeMatMultNumeric_MPIAIJ_MPIAIJ,
2613                                        0,
2614                                 /*134*/0,
2615                                        0,
2616                                        MatRARt_MPIAIJ_MPIAIJ,
2617                                        0,
2618                                        0,
2619                                 /*139*/MatSetBlockSizes_MPIAIJ,
2620                                        0,
2621                                        0,
2622                                        MatFDColoringSetUp_MPIXAIJ,
2623                                        MatFindOffBlockDiagonalEntries_MPIAIJ,
2624                                 /*144*/MatCreateMPIMatConcatenateSeqMat_MPIAIJ
2625 };
2626 
2627 /* ----------------------------------------------------------------------------------------*/
2628 
2629 PetscErrorCode  MatStoreValues_MPIAIJ(Mat mat)
2630 {
2631   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
2632   PetscErrorCode ierr;
2633 
2634   PetscFunctionBegin;
2635   ierr = MatStoreValues(aij->A);CHKERRQ(ierr);
2636   ierr = MatStoreValues(aij->B);CHKERRQ(ierr);
2637   PetscFunctionReturn(0);
2638 }
2639 
2640 PetscErrorCode  MatRetrieveValues_MPIAIJ(Mat mat)
2641 {
2642   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
2643   PetscErrorCode ierr;
2644 
2645   PetscFunctionBegin;
2646   ierr = MatRetrieveValues(aij->A);CHKERRQ(ierr);
2647   ierr = MatRetrieveValues(aij->B);CHKERRQ(ierr);
2648   PetscFunctionReturn(0);
2649 }
2650 
2651 PetscErrorCode  MatMPIAIJSetPreallocation_MPIAIJ(Mat B,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[])
2652 {
2653   Mat_MPIAIJ     *b;
2654   PetscErrorCode ierr;
2655 
2656   PetscFunctionBegin;
2657   ierr = PetscLayoutSetUp(B->rmap);CHKERRQ(ierr);
2658   ierr = PetscLayoutSetUp(B->cmap);CHKERRQ(ierr);
2659   b = (Mat_MPIAIJ*)B->data;
2660 
2661 #if defined(PETSC_USE_CTABLE)
2662   ierr = PetscTableDestroy(&b->colmap);CHKERRQ(ierr);
2663 #else
2664   ierr = PetscFree(b->colmap);CHKERRQ(ierr);
2665 #endif
2666   ierr = PetscFree(b->garray);CHKERRQ(ierr);
2667   ierr = VecDestroy(&b->lvec);CHKERRQ(ierr);
2668   ierr = VecScatterDestroy(&b->Mvctx);CHKERRQ(ierr);
2669 
2670   /* Because the B will have been resized we simply destroy it and create a new one each time */
2671   ierr = MatDestroy(&b->B);CHKERRQ(ierr);
2672   ierr = MatCreate(PETSC_COMM_SELF,&b->B);CHKERRQ(ierr);
2673   ierr = MatSetSizes(b->B,B->rmap->n,B->cmap->N,B->rmap->n,B->cmap->N);CHKERRQ(ierr);
2674   ierr = MatSetBlockSizesFromMats(b->B,B,B);CHKERRQ(ierr);
2675   ierr = MatSetType(b->B,MATSEQAIJ);CHKERRQ(ierr);
2676   ierr = PetscLogObjectParent((PetscObject)B,(PetscObject)b->B);CHKERRQ(ierr);
2677 
2678   if (!B->preallocated) {
2679     ierr = MatCreate(PETSC_COMM_SELF,&b->A);CHKERRQ(ierr);
2680     ierr = MatSetSizes(b->A,B->rmap->n,B->cmap->n,B->rmap->n,B->cmap->n);CHKERRQ(ierr);
2681     ierr = MatSetBlockSizesFromMats(b->A,B,B);CHKERRQ(ierr);
2682     ierr = MatSetType(b->A,MATSEQAIJ);CHKERRQ(ierr);
2683     ierr = PetscLogObjectParent((PetscObject)B,(PetscObject)b->A);CHKERRQ(ierr);
2684   }
2685 
2686   ierr = MatSeqAIJSetPreallocation(b->A,d_nz,d_nnz);CHKERRQ(ierr);
2687   ierr = MatSeqAIJSetPreallocation(b->B,o_nz,o_nnz);CHKERRQ(ierr);
2688   B->preallocated  = PETSC_TRUE;
2689   B->was_assembled = PETSC_FALSE;
2690   B->assembled     = PETSC_FALSE;;
2691   PetscFunctionReturn(0);
2692 }
2693 
2694 PetscErrorCode MatResetPreallocation_MPIAIJ(Mat B)
2695 {
2696   Mat_MPIAIJ     *b;
2697   PetscErrorCode ierr;
2698 
2699   PetscFunctionBegin;
2700   PetscValidHeaderSpecific(B,MAT_CLASSID,1);
2701   ierr = PetscLayoutSetUp(B->rmap);CHKERRQ(ierr);
2702   ierr = PetscLayoutSetUp(B->cmap);CHKERRQ(ierr);
2703   b = (Mat_MPIAIJ*)B->data;
2704 
2705 #if defined(PETSC_USE_CTABLE)
2706   ierr = PetscTableDestroy(&b->colmap);CHKERRQ(ierr);
2707 #else
2708   ierr = PetscFree(b->colmap);CHKERRQ(ierr);
2709 #endif
2710   ierr = PetscFree(b->garray);CHKERRQ(ierr);
2711   ierr = VecDestroy(&b->lvec);CHKERRQ(ierr);
2712   ierr = VecScatterDestroy(&b->Mvctx);CHKERRQ(ierr);
2713 
2714   ierr = MatResetPreallocation(b->A);CHKERRQ(ierr);
2715   ierr = MatResetPreallocation(b->B);CHKERRQ(ierr);
2716   B->preallocated  = PETSC_TRUE;
2717   B->was_assembled = PETSC_FALSE;
2718   B->assembled = PETSC_FALSE;
2719   PetscFunctionReturn(0);
2720 }
2721 
2722 PetscErrorCode MatDuplicate_MPIAIJ(Mat matin,MatDuplicateOption cpvalues,Mat *newmat)
2723 {
2724   Mat            mat;
2725   Mat_MPIAIJ     *a,*oldmat = (Mat_MPIAIJ*)matin->data;
2726   PetscErrorCode ierr;
2727 
2728   PetscFunctionBegin;
2729   *newmat = 0;
2730   ierr    = MatCreate(PetscObjectComm((PetscObject)matin),&mat);CHKERRQ(ierr);
2731   ierr    = MatSetSizes(mat,matin->rmap->n,matin->cmap->n,matin->rmap->N,matin->cmap->N);CHKERRQ(ierr);
2732   ierr    = MatSetBlockSizesFromMats(mat,matin,matin);CHKERRQ(ierr);
2733   ierr    = MatSetType(mat,((PetscObject)matin)->type_name);CHKERRQ(ierr);
2734   ierr    = PetscMemcpy(mat->ops,matin->ops,sizeof(struct _MatOps));CHKERRQ(ierr);
2735   a       = (Mat_MPIAIJ*)mat->data;
2736 
2737   mat->factortype   = matin->factortype;
2738   mat->assembled    = PETSC_TRUE;
2739   mat->insertmode   = NOT_SET_VALUES;
2740   mat->preallocated = PETSC_TRUE;
2741 
2742   a->size         = oldmat->size;
2743   a->rank         = oldmat->rank;
2744   a->donotstash   = oldmat->donotstash;
2745   a->roworiented  = oldmat->roworiented;
2746   a->rowindices   = 0;
2747   a->rowvalues    = 0;
2748   a->getrowactive = PETSC_FALSE;
2749 
2750   ierr = PetscLayoutReference(matin->rmap,&mat->rmap);CHKERRQ(ierr);
2751   ierr = PetscLayoutReference(matin->cmap,&mat->cmap);CHKERRQ(ierr);
2752 
2753   if (oldmat->colmap) {
2754 #if defined(PETSC_USE_CTABLE)
2755     ierr = PetscTableCreateCopy(oldmat->colmap,&a->colmap);CHKERRQ(ierr);
2756 #else
2757     ierr = PetscMalloc1(mat->cmap->N,&a->colmap);CHKERRQ(ierr);
2758     ierr = PetscLogObjectMemory((PetscObject)mat,(mat->cmap->N)*sizeof(PetscInt));CHKERRQ(ierr);
2759     ierr = PetscMemcpy(a->colmap,oldmat->colmap,(mat->cmap->N)*sizeof(PetscInt));CHKERRQ(ierr);
2760 #endif
2761   } else a->colmap = 0;
2762   if (oldmat->garray) {
2763     PetscInt len;
2764     len  = oldmat->B->cmap->n;
2765     ierr = PetscMalloc1(len+1,&a->garray);CHKERRQ(ierr);
2766     ierr = PetscLogObjectMemory((PetscObject)mat,len*sizeof(PetscInt));CHKERRQ(ierr);
2767     if (len) { ierr = PetscMemcpy(a->garray,oldmat->garray,len*sizeof(PetscInt));CHKERRQ(ierr); }
2768   } else a->garray = 0;
2769 
2770   ierr    = VecDuplicate(oldmat->lvec,&a->lvec);CHKERRQ(ierr);
2771   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->lvec);CHKERRQ(ierr);
2772   ierr    = VecScatterCopy(oldmat->Mvctx,&a->Mvctx);CHKERRQ(ierr);
2773   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->Mvctx);CHKERRQ(ierr);
2774   ierr    = MatDuplicate(oldmat->A,cpvalues,&a->A);CHKERRQ(ierr);
2775   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->A);CHKERRQ(ierr);
2776   ierr    = MatDuplicate(oldmat->B,cpvalues,&a->B);CHKERRQ(ierr);
2777   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->B);CHKERRQ(ierr);
2778   ierr    = PetscFunctionListDuplicate(((PetscObject)matin)->qlist,&((PetscObject)mat)->qlist);CHKERRQ(ierr);
2779   *newmat = mat;
2780   PetscFunctionReturn(0);
2781 }
2782 
2783 PetscErrorCode MatLoad_MPIAIJ(Mat newMat, PetscViewer viewer)
2784 {
2785   PetscScalar    *vals,*svals;
2786   MPI_Comm       comm;
2787   PetscErrorCode ierr;
2788   PetscMPIInt    rank,size,tag = ((PetscObject)viewer)->tag;
2789   PetscInt       i,nz,j,rstart,rend,mmax,maxnz = 0;
2790   PetscInt       header[4],*rowlengths = 0,M,N,m,*cols;
2791   PetscInt       *ourlens = NULL,*procsnz = NULL,*offlens = NULL,jj,*mycols,*smycols;
2792   PetscInt       cend,cstart,n,*rowners;
2793   int            fd;
2794   PetscInt       bs = newMat->rmap->bs;
2795 
2796   PetscFunctionBegin;
2797   /* force binary viewer to load .info file if it has not yet done so */
2798   ierr = PetscViewerSetUp(viewer);CHKERRQ(ierr);
2799   ierr = PetscObjectGetComm((PetscObject)viewer,&comm);CHKERRQ(ierr);
2800   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2801   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
2802   ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
2803   if (!rank) {
2804     ierr = PetscBinaryRead(fd,(char*)header,4,PETSC_INT);CHKERRQ(ierr);
2805     if (header[0] != MAT_FILE_CLASSID) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FILE_UNEXPECTED,"not matrix object");
2806     if (header[3] < 0) SETERRQ(PetscObjectComm((PetscObject)newMat),PETSC_ERR_FILE_UNEXPECTED,"Matrix stored in special format on disk,cannot load as MATMPIAIJ");
2807   }
2808 
2809   ierr = PetscOptionsBegin(comm,NULL,"Options for loading MATMPIAIJ matrix","Mat");CHKERRQ(ierr);
2810   ierr = PetscOptionsInt("-matload_block_size","Set the blocksize used to store the matrix","MatLoad",bs,&bs,NULL);CHKERRQ(ierr);
2811   ierr = PetscOptionsEnd();CHKERRQ(ierr);
2812   if (bs < 0) bs = 1;
2813 
2814   ierr = MPI_Bcast(header+1,3,MPIU_INT,0,comm);CHKERRQ(ierr);
2815   M    = header[1]; N = header[2];
2816 
2817   /* If global sizes are set, check if they are consistent with that given in the file */
2818   if (newMat->rmap->N >= 0 && newMat->rmap->N != M) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_FILE_UNEXPECTED,"Inconsistent # of rows:Matrix in file has (%D) and input matrix has (%D)",newMat->rmap->N,M);
2819   if (newMat->cmap->N >=0 && newMat->cmap->N != N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_FILE_UNEXPECTED,"Inconsistent # of cols:Matrix in file has (%D) and input matrix has (%D)",newMat->cmap->N,N);
2820 
2821   /* determine ownership of all (block) rows */
2822   if (M%bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_FILE_UNEXPECTED, "Inconsistent # of rows (%d) and block size (%d)",M,bs);
2823   if (newMat->rmap->n < 0) m = bs*((M/bs)/size + (((M/bs) % size) > rank));    /* PETSC_DECIDE */
2824   else m = newMat->rmap->n; /* Set by user */
2825 
2826   ierr = PetscMalloc1(size+1,&rowners);CHKERRQ(ierr);
2827   ierr = MPI_Allgather(&m,1,MPIU_INT,rowners+1,1,MPIU_INT,comm);CHKERRQ(ierr);
2828 
2829   /* First process needs enough room for process with most rows */
2830   if (!rank) {
2831     mmax = rowners[1];
2832     for (i=2; i<=size; i++) {
2833       mmax = PetscMax(mmax, rowners[i]);
2834     }
2835   } else mmax = -1;             /* unused, but compilers complain */
2836 
2837   rowners[0] = 0;
2838   for (i=2; i<=size; i++) {
2839     rowners[i] += rowners[i-1];
2840   }
2841   rstart = rowners[rank];
2842   rend   = rowners[rank+1];
2843 
2844   /* distribute row lengths to all processors */
2845   ierr = PetscMalloc2(m,&ourlens,m,&offlens);CHKERRQ(ierr);
2846   if (!rank) {
2847     ierr = PetscBinaryRead(fd,ourlens,m,PETSC_INT);CHKERRQ(ierr);
2848     ierr = PetscMalloc1(mmax,&rowlengths);CHKERRQ(ierr);
2849     ierr = PetscCalloc1(size,&procsnz);CHKERRQ(ierr);
2850     for (j=0; j<m; j++) {
2851       procsnz[0] += ourlens[j];
2852     }
2853     for (i=1; i<size; i++) {
2854       ierr = PetscBinaryRead(fd,rowlengths,rowners[i+1]-rowners[i],PETSC_INT);CHKERRQ(ierr);
2855       /* calculate the number of nonzeros on each processor */
2856       for (j=0; j<rowners[i+1]-rowners[i]; j++) {
2857         procsnz[i] += rowlengths[j];
2858       }
2859       ierr = MPIULong_Send(rowlengths,rowners[i+1]-rowners[i],MPIU_INT,i,tag,comm);CHKERRQ(ierr);
2860     }
2861     ierr = PetscFree(rowlengths);CHKERRQ(ierr);
2862   } else {
2863     ierr = MPIULong_Recv(ourlens,m,MPIU_INT,0,tag,comm);CHKERRQ(ierr);
2864   }
2865 
2866   if (!rank) {
2867     /* determine max buffer needed and allocate it */
2868     maxnz = 0;
2869     for (i=0; i<size; i++) {
2870       maxnz = PetscMax(maxnz,procsnz[i]);
2871     }
2872     ierr = PetscMalloc1(maxnz,&cols);CHKERRQ(ierr);
2873 
2874     /* read in my part of the matrix column indices  */
2875     nz   = procsnz[0];
2876     ierr = PetscMalloc1(nz,&mycols);CHKERRQ(ierr);
2877     ierr = PetscBinaryRead(fd,mycols,nz,PETSC_INT);CHKERRQ(ierr);
2878 
2879     /* read in every one elses and ship off */
2880     for (i=1; i<size; i++) {
2881       nz   = procsnz[i];
2882       ierr = PetscBinaryRead(fd,cols,nz,PETSC_INT);CHKERRQ(ierr);
2883       ierr = MPIULong_Send(cols,nz,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
2884     }
2885     ierr = PetscFree(cols);CHKERRQ(ierr);
2886   } else {
2887     /* determine buffer space needed for message */
2888     nz = 0;
2889     for (i=0; i<m; i++) {
2890       nz += ourlens[i];
2891     }
2892     ierr = PetscMalloc1(nz,&mycols);CHKERRQ(ierr);
2893 
2894     /* receive message of column indices*/
2895     ierr = MPIULong_Recv(mycols,nz,MPIU_INT,0,tag,comm);CHKERRQ(ierr);
2896   }
2897 
2898   /* determine column ownership if matrix is not square */
2899   if (N != M) {
2900     if (newMat->cmap->n < 0) n = N/size + ((N % size) > rank);
2901     else n = newMat->cmap->n;
2902     ierr   = MPI_Scan(&n,&cend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
2903     cstart = cend - n;
2904   } else {
2905     cstart = rstart;
2906     cend   = rend;
2907     n      = cend - cstart;
2908   }
2909 
2910   /* loop over local rows, determining number of off diagonal entries */
2911   ierr = PetscMemzero(offlens,m*sizeof(PetscInt));CHKERRQ(ierr);
2912   jj   = 0;
2913   for (i=0; i<m; i++) {
2914     for (j=0; j<ourlens[i]; j++) {
2915       if (mycols[jj] < cstart || mycols[jj] >= cend) offlens[i]++;
2916       jj++;
2917     }
2918   }
2919 
2920   for (i=0; i<m; i++) {
2921     ourlens[i] -= offlens[i];
2922   }
2923   ierr = MatSetSizes(newMat,m,n,M,N);CHKERRQ(ierr);
2924 
2925   if (bs > 1) {ierr = MatSetBlockSize(newMat,bs);CHKERRQ(ierr);}
2926 
2927   ierr = MatMPIAIJSetPreallocation(newMat,0,ourlens,0,offlens);CHKERRQ(ierr);
2928 
2929   for (i=0; i<m; i++) {
2930     ourlens[i] += offlens[i];
2931   }
2932 
2933   if (!rank) {
2934     ierr = PetscMalloc1(maxnz+1,&vals);CHKERRQ(ierr);
2935 
2936     /* read in my part of the matrix numerical values  */
2937     nz   = procsnz[0];
2938     ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2939 
2940     /* insert into matrix */
2941     jj      = rstart;
2942     smycols = mycols;
2943     svals   = vals;
2944     for (i=0; i<m; i++) {
2945       ierr     = MatSetValues_MPIAIJ(newMat,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2946       smycols += ourlens[i];
2947       svals   += ourlens[i];
2948       jj++;
2949     }
2950 
2951     /* read in other processors and ship out */
2952     for (i=1; i<size; i++) {
2953       nz   = procsnz[i];
2954       ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2955       ierr = MPIULong_Send(vals,nz,MPIU_SCALAR,i,((PetscObject)newMat)->tag,comm);CHKERRQ(ierr);
2956     }
2957     ierr = PetscFree(procsnz);CHKERRQ(ierr);
2958   } else {
2959     /* receive numeric values */
2960     ierr = PetscMalloc1(nz+1,&vals);CHKERRQ(ierr);
2961 
2962     /* receive message of values*/
2963     ierr = MPIULong_Recv(vals,nz,MPIU_SCALAR,0,((PetscObject)newMat)->tag,comm);CHKERRQ(ierr);
2964 
2965     /* insert into matrix */
2966     jj      = rstart;
2967     smycols = mycols;
2968     svals   = vals;
2969     for (i=0; i<m; i++) {
2970       ierr     = MatSetValues_MPIAIJ(newMat,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2971       smycols += ourlens[i];
2972       svals   += ourlens[i];
2973       jj++;
2974     }
2975   }
2976   ierr = PetscFree2(ourlens,offlens);CHKERRQ(ierr);
2977   ierr = PetscFree(vals);CHKERRQ(ierr);
2978   ierr = PetscFree(mycols);CHKERRQ(ierr);
2979   ierr = PetscFree(rowners);CHKERRQ(ierr);
2980   ierr = MatAssemblyBegin(newMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2981   ierr = MatAssemblyEnd(newMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2982   PetscFunctionReturn(0);
2983 }
2984 
2985 /* Not scalable because of ISAllGather() unless getting all columns. */
2986 PetscErrorCode ISGetSeqIS_Private(Mat mat,IS iscol,IS *isseq)
2987 {
2988   PetscErrorCode ierr;
2989   IS             iscol_local;
2990   PetscBool      isstride;
2991   PetscMPIInt    lisstride=0,gisstride;
2992 
2993   PetscFunctionBegin;
2994   /* check if we are grabbing all columns*/
2995   ierr = PetscObjectTypeCompare((PetscObject)iscol,ISSTRIDE,&isstride);CHKERRQ(ierr);
2996 
2997   if (isstride) {
2998     PetscInt  start,len,mstart,mlen;
2999     ierr = ISStrideGetInfo(iscol,&start,NULL);CHKERRQ(ierr);
3000     ierr = ISGetLocalSize(iscol,&len);CHKERRQ(ierr);
3001     ierr = MatGetOwnershipRangeColumn(mat,&mstart,&mlen);CHKERRQ(ierr);
3002     if (mstart == start && mlen-mstart == len) lisstride = 1;
3003   }
3004 
3005   ierr = MPIU_Allreduce(&lisstride,&gisstride,1,MPI_INT,MPI_MIN,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
3006   if (gisstride) {
3007     PetscInt N;
3008     ierr = MatGetSize(mat,NULL,&N);CHKERRQ(ierr);
3009     ierr = ISCreateStride(PetscObjectComm((PetscObject)mat),N,0,1,&iscol_local);CHKERRQ(ierr);
3010     ierr = ISSetIdentity(iscol_local);CHKERRQ(ierr);
3011     ierr = PetscInfo(mat,"Optimizing for obtaining all columns of the matrix; skipping ISAllGather()\n");CHKERRQ(ierr);
3012   } else {
3013     PetscInt cbs;
3014     ierr = ISGetBlockSize(iscol,&cbs);CHKERRQ(ierr);
3015     ierr = ISAllGather(iscol,&iscol_local);CHKERRQ(ierr);
3016     ierr = ISSetBlockSize(iscol_local,cbs);CHKERRQ(ierr);
3017   }
3018 
3019   *isseq = iscol_local;
3020   PetscFunctionReturn(0);
3021 }
3022 
3023 /*
3024  Used by MatCreateSubMatrix_MPIAIJ_SameRowColDist() to avoid ISAllGather() and global size of iscol_local
3025  (see MatCreateSubMatrix_MPIAIJ_nonscalable)
3026 
3027  Input Parameters:
3028    mat - matrix
3029    isrow - parallel row index set; its local indices are a subset of local columns of mat,
3030            i.e., mat->rstart <= isrow[i] < mat->rend
3031    iscol - parallel column index set; its local indices are a subset of local columns of mat,
3032            i.e., mat->cstart <= iscol[i] < mat->cend
3033  Output Parameter:
3034    isrow_d,iscol_d - sequential row and column index sets for retrieving mat->A
3035    iscol_o - sequential column index set for retrieving mat->B
3036    garray - column map; garray[i] indicates global location of iscol_o[i] in iscol
3037  */
3038 PetscErrorCode ISGetSeqIS_SameColDist_Private(Mat mat,IS isrow,IS iscol,IS *isrow_d,IS *iscol_d,IS *iscol_o,const PetscInt *garray[])
3039 {
3040   PetscErrorCode ierr;
3041   Vec            x,cmap;
3042   const PetscInt *is_idx;
3043   PetscScalar    *xarray,*cmaparray;
3044   PetscInt       ncols,isstart,*idx,m,rstart,*cmap1,count;
3045   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)mat->data;
3046   Mat            B=a->B;
3047   Vec            lvec=a->lvec,lcmap;
3048   PetscInt       i,cstart,cend,Bn=B->cmap->N;
3049   MPI_Comm       comm;
3050   VecScatter     Mvctx=a->Mvctx;
3051 
3052   PetscFunctionBegin;
3053   ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3054   ierr = ISGetLocalSize(iscol,&ncols);CHKERRQ(ierr);
3055 
3056   /* (1) iscol is a sub-column vector of mat, pad it with '-1.' to form a full vector x */
3057   ierr = MatCreateVecs(mat,&x,NULL);CHKERRQ(ierr);
3058   ierr = VecSet(x,-1.0);CHKERRQ(ierr);
3059   ierr = VecDuplicate(x,&cmap);CHKERRQ(ierr);
3060   ierr = VecSet(cmap,-1.0);CHKERRQ(ierr);
3061 
3062   /* Get start indices */
3063   ierr = MPI_Scan(&ncols,&isstart,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3064   isstart -= ncols;
3065   ierr = MatGetOwnershipRangeColumn(mat,&cstart,&cend);CHKERRQ(ierr);
3066 
3067   ierr = ISGetIndices(iscol,&is_idx);CHKERRQ(ierr);
3068   ierr = VecGetArray(x,&xarray);CHKERRQ(ierr);
3069   ierr = VecGetArray(cmap,&cmaparray);CHKERRQ(ierr);
3070   ierr = PetscMalloc1(ncols,&idx);CHKERRQ(ierr);
3071   for (i=0; i<ncols; i++) {
3072     xarray[is_idx[i]-cstart]    = (PetscScalar)is_idx[i];
3073     cmaparray[is_idx[i]-cstart] = i + isstart;      /* global index of iscol[i] */
3074     idx[i]                      = is_idx[i]-cstart; /* local index of iscol[i]  */
3075   }
3076   ierr = VecRestoreArray(x,&xarray);CHKERRQ(ierr);
3077   ierr = VecRestoreArray(cmap,&cmaparray);CHKERRQ(ierr);
3078   ierr = ISRestoreIndices(iscol,&is_idx);CHKERRQ(ierr);
3079 
3080   /* Get iscol_d */
3081   ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,PETSC_OWN_POINTER,iscol_d);CHKERRQ(ierr);
3082   ierr = ISGetBlockSize(iscol,&i);CHKERRQ(ierr);
3083   ierr = ISSetBlockSize(*iscol_d,i);CHKERRQ(ierr);
3084 
3085   /* Get isrow_d */
3086   ierr = ISGetLocalSize(isrow,&m);CHKERRQ(ierr);
3087   rstart = mat->rmap->rstart;
3088   ierr = PetscMalloc1(m,&idx);CHKERRQ(ierr);
3089   ierr = ISGetIndices(isrow,&is_idx);CHKERRQ(ierr);
3090   for (i=0; i<m; i++) idx[i] = is_idx[i]-rstart;
3091   ierr = ISRestoreIndices(isrow,&is_idx);CHKERRQ(ierr);
3092 
3093   ierr = ISCreateGeneral(PETSC_COMM_SELF,m,idx,PETSC_OWN_POINTER,isrow_d);CHKERRQ(ierr);
3094   ierr = ISGetBlockSize(isrow,&i);CHKERRQ(ierr);
3095   ierr = ISSetBlockSize(*isrow_d,i);CHKERRQ(ierr);
3096 
3097   /* (2) Scatter x and cmap using aij->Mvctx to get their off-process portions (see MatMult_MPIAIJ) */
3098   ierr = VecScatterBegin(Mvctx,x,lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3099   ierr = VecScatterEnd(Mvctx,x,lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3100 
3101   ierr = VecDuplicate(lvec,&lcmap);CHKERRQ(ierr);
3102 
3103   ierr = VecScatterBegin(Mvctx,cmap,lcmap,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3104   ierr = VecScatterEnd(Mvctx,cmap,lcmap,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3105 
3106   /* (3) create sequential iscol_o (a subset of iscol) and isgarray */
3107   /* off-process column indices */
3108   count = 0;
3109   ierr = PetscMalloc1(Bn,&idx);CHKERRQ(ierr);
3110   ierr = PetscMalloc1(Bn,&cmap1);CHKERRQ(ierr);
3111 
3112   ierr = VecGetArray(lvec,&xarray);CHKERRQ(ierr);
3113   ierr = VecGetArray(lcmap,&cmaparray);CHKERRQ(ierr);
3114   for (i=0; i<Bn; i++) {
3115     if (PetscRealPart(xarray[i]) > -1.0) {
3116       idx[count]     = i;                   /* local column index in off-diagonal part B */
3117       cmap1[count] = (PetscInt)PetscRealPart(cmaparray[i]);  /* column index in submat */
3118       count++;
3119     }
3120   }
3121   ierr = VecRestoreArray(lvec,&xarray);CHKERRQ(ierr);
3122   ierr = VecRestoreArray(lcmap,&cmaparray);CHKERRQ(ierr);
3123 
3124   ierr = ISCreateGeneral(PETSC_COMM_SELF,count,idx,PETSC_COPY_VALUES,iscol_o);CHKERRQ(ierr);
3125   /* cannot ensure iscol_o has same blocksize as iscol! */
3126 
3127   ierr = PetscFree(idx);CHKERRQ(ierr);
3128   *garray = cmap1;
3129 
3130   ierr = VecDestroy(&x);CHKERRQ(ierr);
3131   ierr = VecDestroy(&cmap);CHKERRQ(ierr);
3132   ierr = VecDestroy(&lcmap);CHKERRQ(ierr);
3133   PetscFunctionReturn(0);
3134 }
3135 
3136 /* isrow and iscol have same processor distribution as mat, output *submat is a submatrix of local mat */
3137 PetscErrorCode MatCreateSubMatrix_MPIAIJ_SameRowColDist(Mat mat,IS isrow,IS iscol,MatReuse call,Mat *submat)
3138 {
3139   PetscErrorCode ierr;
3140   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)mat->data,*asub;
3141   Mat            M = NULL;
3142   MPI_Comm       comm;
3143   IS             iscol_d,isrow_d,iscol_o;
3144   Mat            Asub = NULL,Bsub = NULL;
3145   PetscInt       n;
3146 
3147   PetscFunctionBegin;
3148   ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3149 
3150   if (call == MAT_REUSE_MATRIX) {
3151     /* Retrieve isrow_d, iscol_d and iscol_o from submat */
3152     ierr = PetscObjectQuery((PetscObject)*submat,"isrow_d",(PetscObject*)&isrow_d);CHKERRQ(ierr);
3153     if (!isrow_d) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"isrow_d passed in was not used before, cannot reuse");
3154 
3155     ierr = PetscObjectQuery((PetscObject)*submat,"iscol_d",(PetscObject*)&iscol_d);CHKERRQ(ierr);
3156     if (!iscol_d) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"iscol_d passed in was not used before, cannot reuse");
3157 
3158     ierr = PetscObjectQuery((PetscObject)*submat,"iscol_o",(PetscObject*)&iscol_o);CHKERRQ(ierr);
3159     if (!iscol_o) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"iscol_o passed in was not used before, cannot reuse");
3160 
3161     /* Update diagonal and off-diagonal portions of submat */
3162     asub = (Mat_MPIAIJ*)(*submat)->data;
3163     ierr = MatCreateSubMatrix_SeqAIJ(a->A,isrow_d,iscol_d,PETSC_DECIDE,MAT_REUSE_MATRIX,&asub->A);CHKERRQ(ierr);
3164     ierr = ISGetLocalSize(iscol_o,&n);CHKERRQ(ierr);
3165     if (n) {
3166       ierr = MatCreateSubMatrix_SeqAIJ(a->B,isrow_d,iscol_o,PETSC_DECIDE,MAT_REUSE_MATRIX,&asub->B);CHKERRQ(ierr);
3167     }
3168     ierr = MatAssemblyBegin(*submat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3169     ierr = MatAssemblyEnd(*submat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3170 
3171   } else { /* call == MAT_INITIAL_MATRIX) */
3172     const PetscInt *garray;
3173     PetscInt        BsubN;
3174 
3175     /* Create isrow_d, iscol_d, iscol_o and isgarray (replace isgarray with array?) */
3176     ierr = ISGetSeqIS_SameColDist_Private(mat,isrow,iscol,&isrow_d,&iscol_d,&iscol_o,&garray);CHKERRQ(ierr);
3177 
3178     /* Create local submatrices Asub and Bsub */
3179     ierr = MatCreateSubMatrix_SeqAIJ(a->A,isrow_d,iscol_d,PETSC_DECIDE,MAT_INITIAL_MATRIX,&Asub);CHKERRQ(ierr);
3180     ierr = MatCreateSubMatrix_SeqAIJ(a->B,isrow_d,iscol_o,PETSC_DECIDE,MAT_INITIAL_MATRIX,&Bsub);CHKERRQ(ierr);
3181 
3182     /* Create submatrix M */
3183     ierr = MatCreateMPIAIJWithSeqAIJ(comm,Asub,Bsub,garray,&M);CHKERRQ(ierr);
3184 
3185     /* If Bsub has empty columns, compress iscol_o such that it will retrieve condensed Bsub from a->B during reuse */
3186     asub = (Mat_MPIAIJ*)M->data;
3187 
3188     ierr = ISGetLocalSize(iscol_o,&BsubN);CHKERRQ(ierr);
3189     n = asub->B->cmap->N;
3190     if (BsubN > n) {
3191       /* This case can be tested using ~petsc/src/tao/bound/examples/tutorials/runplate2_3 */
3192       const PetscInt *idx;
3193       PetscInt       i,j,*idx_new,*subgarray = asub->garray;
3194       ierr = PetscInfo2(M,"submatrix Bn %D != BsubN %D, update iscol_o\n",n,BsubN);CHKERRQ(ierr);
3195 
3196       ierr = PetscMalloc1(n,&idx_new);CHKERRQ(ierr);
3197       j = 0;
3198       ierr = ISGetIndices(iscol_o,&idx);CHKERRQ(ierr);
3199       for (i=0; i<n; i++) {
3200         if (j >= BsubN) break;
3201         while (subgarray[i] > garray[j]) j++;
3202 
3203         if (subgarray[i] == garray[j]) {
3204           idx_new[i] = idx[j++];
3205         } else SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"subgarray[%D]=%D cannot < garray[%D]=%D",i,subgarray[i],j,garray[j]);
3206       }
3207       ierr = ISRestoreIndices(iscol_o,&idx);CHKERRQ(ierr);
3208 
3209       ierr = ISDestroy(&iscol_o);CHKERRQ(ierr);
3210       ierr = ISCreateGeneral(PETSC_COMM_SELF,n,idx_new,PETSC_OWN_POINTER,&iscol_o);CHKERRQ(ierr);
3211 
3212     } else if (BsubN < n) {
3213       SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Columns of Bsub cannot be smaller than B's",BsubN,asub->B->cmap->N);
3214     }
3215 
3216     ierr = PetscFree(garray);CHKERRQ(ierr);
3217     *submat = M;
3218 
3219     /* Save isrow_d, iscol_d and iscol_o used in processor for next request */
3220     ierr = PetscObjectCompose((PetscObject)M,"isrow_d",(PetscObject)isrow_d);CHKERRQ(ierr);
3221     ierr = ISDestroy(&isrow_d);CHKERRQ(ierr);
3222 
3223     ierr = PetscObjectCompose((PetscObject)M,"iscol_d",(PetscObject)iscol_d);CHKERRQ(ierr);
3224     ierr = ISDestroy(&iscol_d);CHKERRQ(ierr);
3225 
3226     ierr = PetscObjectCompose((PetscObject)M,"iscol_o",(PetscObject)iscol_o);CHKERRQ(ierr);
3227     ierr = ISDestroy(&iscol_o);CHKERRQ(ierr);
3228   }
3229   PetscFunctionReturn(0);
3230 }
3231 
3232 PetscErrorCode MatCreateSubMatrix_MPIAIJ(Mat mat,IS isrow,IS iscol,MatReuse call,Mat *newmat)
3233 {
3234   PetscErrorCode ierr;
3235   IS             iscol_local=NULL,isrow_d;
3236   PetscInt       csize;
3237   PetscInt       n,i,j,start,end;
3238   PetscBool      sameRowDist=PETSC_FALSE,sameDist[2],tsameDist[2];
3239   MPI_Comm       comm;
3240 
3241   PetscFunctionBegin;
3242   /* If isrow has same processor distribution as mat,
3243      call MatCreateSubMatrix_MPIAIJ_SameRowDist() to avoid using a hash table with global size of iscol */
3244   if (call == MAT_REUSE_MATRIX) {
3245     ierr = PetscObjectQuery((PetscObject)*newmat,"isrow_d",(PetscObject*)&isrow_d);CHKERRQ(ierr);
3246     if (isrow_d) {
3247       sameRowDist  = PETSC_TRUE;
3248       tsameDist[1] = PETSC_TRUE; /* sameColDist */
3249     } else {
3250       ierr = PetscObjectQuery((PetscObject)*newmat,"SubIScol",(PetscObject*)&iscol_local);CHKERRQ(ierr);
3251       if (iscol_local) {
3252         sameRowDist  = PETSC_TRUE;
3253         tsameDist[1] = PETSC_FALSE; /* !sameColDist */
3254       }
3255     }
3256   } else {
3257     /* Check if isrow has same processor distribution as mat */
3258     sameDist[0] = PETSC_FALSE;
3259     ierr = ISGetLocalSize(isrow,&n);CHKERRQ(ierr);
3260     if (!n) {
3261       sameDist[0] = PETSC_TRUE;
3262     } else {
3263       ierr = ISGetMinMax(isrow,&i,&j);CHKERRQ(ierr);
3264       ierr = MatGetOwnershipRange(mat,&start,&end);CHKERRQ(ierr);
3265       if (i >= start && j < end) {
3266         sameDist[0] = PETSC_TRUE;
3267       }
3268     }
3269 
3270     /* Check if iscol has same processor distribution as mat */
3271     sameDist[1] = PETSC_FALSE;
3272     ierr = ISGetLocalSize(iscol,&n);CHKERRQ(ierr);
3273     if (!n) {
3274       sameDist[1] = PETSC_TRUE;
3275     } else {
3276       ierr = ISGetMinMax(iscol,&i,&j);CHKERRQ(ierr);
3277       ierr = MatGetOwnershipRangeColumn(mat,&start,&end);CHKERRQ(ierr);
3278       if (i >= start && j < end) sameDist[1] = PETSC_TRUE;
3279     }
3280 
3281     ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3282     ierr = MPIU_Allreduce(&sameDist,&tsameDist,2,MPIU_BOOL,MPI_LAND,comm);CHKERRQ(ierr);
3283     sameRowDist = tsameDist[0];
3284   }
3285 
3286   if (sameRowDist) {
3287     if (tsameDist[1]) { /* sameRowDist & sameColDist */
3288       /* isrow and iscol have same processor distribution as mat */
3289       ierr = MatCreateSubMatrix_MPIAIJ_SameRowColDist(mat,isrow,iscol,call,newmat);CHKERRQ(ierr);
3290       PetscFunctionReturn(0);
3291     } else { /* sameRowDist */
3292       /* isrow has same processor distribution as mat */
3293       if (call == MAT_INITIAL_MATRIX) {
3294         PetscBool sorted;
3295         ierr = ISGetSeqIS_Private(mat,iscol,&iscol_local);CHKERRQ(ierr);
3296         ierr = ISGetLocalSize(iscol_local,&n);CHKERRQ(ierr); /* local size of iscol_local = global columns of newmat */
3297         ierr = ISGetSize(iscol,&i);CHKERRQ(ierr);
3298         if (n != i) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"n %d != size of iscol %d",n,i);
3299 
3300         ierr = ISSorted(iscol_local,&sorted);CHKERRQ(ierr);
3301         if (sorted) {
3302           /* MatCreateSubMatrix_MPIAIJ_SameRowDist() requires iscol_local be sorted; it can have duplicate indices */
3303           ierr = MatCreateSubMatrix_MPIAIJ_SameRowDist(mat,isrow,iscol,iscol_local,MAT_INITIAL_MATRIX,newmat);CHKERRQ(ierr);
3304           PetscFunctionReturn(0);
3305         }
3306       } else { /* call == MAT_REUSE_MATRIX */
3307         IS    iscol_sub;
3308         ierr = PetscObjectQuery((PetscObject)*newmat,"SubIScol",(PetscObject*)&iscol_sub);CHKERRQ(ierr);
3309         if (iscol_sub) {
3310           ierr = MatCreateSubMatrix_MPIAIJ_SameRowDist(mat,isrow,iscol,NULL,call,newmat);CHKERRQ(ierr);
3311           PetscFunctionReturn(0);
3312         }
3313       }
3314     }
3315   }
3316 
3317   /* General case: iscol -> iscol_local which has global size of iscol */
3318   if (call == MAT_REUSE_MATRIX) {
3319     ierr = PetscObjectQuery((PetscObject)*newmat,"ISAllGather",(PetscObject*)&iscol_local);CHKERRQ(ierr);
3320     if (!iscol_local) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3321   } else {
3322     if (!iscol_local) {
3323       ierr = ISGetSeqIS_Private(mat,iscol,&iscol_local);CHKERRQ(ierr);
3324     }
3325   }
3326 
3327   ierr = ISGetLocalSize(iscol,&csize);CHKERRQ(ierr);
3328   ierr = MatCreateSubMatrix_MPIAIJ_nonscalable(mat,isrow,iscol_local,csize,call,newmat);CHKERRQ(ierr);
3329 
3330   if (call == MAT_INITIAL_MATRIX) {
3331     ierr = PetscObjectCompose((PetscObject)*newmat,"ISAllGather",(PetscObject)iscol_local);CHKERRQ(ierr);
3332     ierr = ISDestroy(&iscol_local);CHKERRQ(ierr);
3333   }
3334   PetscFunctionReturn(0);
3335 }
3336 
3337 /*@C
3338      MatCreateMPIAIJWithSeqAIJ - creates a MPIAIJ matrix using SeqAIJ matrices that contain the "diagonal"
3339          and "off-diagonal" part of the matrix in CSR format.
3340 
3341    Collective on MPI_Comm
3342 
3343    Input Parameters:
3344 +  comm - MPI communicator
3345 .  A - "diagonal" portion of matrix
3346 .  B - "off-diagonal" portion of matrix, may have empty columns, will be destroyed by this routine
3347 -  garray - global index of B columns
3348 
3349    Output Parameter:
3350 .   mat - the matrix, with input A as its local diagonal matrix
3351    Level: advanced
3352 
3353    Notes:
3354        See MatCreateAIJ() for the definition of "diagonal" and "off-diagonal" portion of the matrix.
3355        A becomes part of output mat, B is destroyed by this routine. The user cannot use A and B anymore.
3356 
3357 .seealso: MatCreateMPIAIJWithSplitArrays()
3358 @*/
3359 PetscErrorCode MatCreateMPIAIJWithSeqAIJ(MPI_Comm comm,Mat A,Mat B,const PetscInt garray[],Mat *mat)
3360 {
3361   PetscErrorCode ierr;
3362   Mat_MPIAIJ     *maij;
3363   Mat_SeqAIJ     *b=(Mat_SeqAIJ*)B->data,*bnew;
3364   PetscInt       *oi=b->i,*oj=b->j,i,nz,col;
3365   PetscScalar    *oa=b->a;
3366   Mat            Bnew;
3367   PetscInt       m,n,N;
3368 
3369   PetscFunctionBegin;
3370   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
3371   ierr = MatGetSize(A,&m,&n);CHKERRQ(ierr);
3372   if (m != B->rmap->N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Am %D != Bm %D",m,B->rmap->N);
3373   if (A->rmap->bs != B->rmap->bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"A row bs %D != B row bs %D",A->rmap->bs,B->rmap->bs);
3374   /* remove check below; When B is created using iscol_o from ISGetSeqIS_SameColDist_Private(), its bs may not be same as A */
3375   /* if (A->cmap->bs != B->cmap->bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"A column bs %D != B column bs %D",A->cmap->bs,B->cmap->bs); */
3376 
3377   /* Get global columns of mat */
3378   ierr = MPIU_Allreduce(&n,&N,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3379 
3380   ierr = MatSetSizes(*mat,m,n,PETSC_DECIDE,N);CHKERRQ(ierr);
3381   ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
3382   ierr = MatSetBlockSizes(*mat,A->rmap->bs,A->cmap->bs);CHKERRQ(ierr);
3383   maij = (Mat_MPIAIJ*)(*mat)->data;
3384 
3385   (*mat)->preallocated = PETSC_TRUE;
3386 
3387   ierr = PetscLayoutSetUp((*mat)->rmap);CHKERRQ(ierr);
3388   ierr = PetscLayoutSetUp((*mat)->cmap);CHKERRQ(ierr);
3389 
3390   /* Set A as diagonal portion of *mat */
3391   maij->A = A;
3392 
3393   nz = oi[m];
3394   for (i=0; i<nz; i++) {
3395     col   = oj[i];
3396     oj[i] = garray[col];
3397   }
3398 
3399    /* Set Bnew as off-diagonal portion of *mat */
3400   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,m,N,oi,oj,oa,&Bnew);CHKERRQ(ierr);
3401   bnew        = (Mat_SeqAIJ*)Bnew->data;
3402   bnew->maxnz = b->maxnz; /* allocated nonzeros of B */
3403   maij->B     = Bnew;
3404 
3405   if (B->rmap->N != Bnew->rmap->N) SETERRQ2(PETSC_COMM_SELF,0,"BN %d != BnewN %d",B->rmap->N,Bnew->rmap->N);
3406 
3407   b->singlemalloc = PETSC_FALSE; /* B arrays are shared by Bnew */
3408   b->free_a       = PETSC_FALSE;
3409   b->free_ij      = PETSC_FALSE;
3410   ierr = MatDestroy(&B);CHKERRQ(ierr);
3411 
3412   bnew->singlemalloc = PETSC_TRUE; /* arrays will be freed by MatDestroy(&Bnew) */
3413   bnew->free_a       = PETSC_TRUE;
3414   bnew->free_ij      = PETSC_TRUE;
3415 
3416   /* condense columns of maij->B */
3417   ierr = MatSetOption(*mat,MAT_NO_OFF_PROC_ENTRIES,PETSC_TRUE);CHKERRQ(ierr);
3418   ierr = MatAssemblyBegin(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3419   ierr = MatAssemblyEnd(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3420   ierr = MatSetOption(*mat,MAT_NO_OFF_PROC_ENTRIES,PETSC_FALSE);CHKERRQ(ierr);
3421   ierr = MatSetOption(*mat,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
3422   PetscFunctionReturn(0);
3423 }
3424 
3425 extern PetscErrorCode MatCreateSubMatrices_MPIAIJ_SingleIS_Local(Mat,PetscInt,const IS[],const IS[],MatReuse,PetscBool,Mat*);
3426 
3427 PetscErrorCode MatCreateSubMatrix_MPIAIJ_SameRowDist(Mat mat,IS isrow,IS iscol,IS iscol_local,MatReuse call,Mat *newmat)
3428 {
3429   PetscErrorCode ierr;
3430   PetscInt       i,m,n,rstart,row,rend,nz,j,bs,cbs;
3431   PetscInt       *ii,*jj,nlocal,*dlens,*olens,dlen,olen,jend,mglobal;
3432   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)mat->data;
3433   Mat            M,Msub,B=a->B;
3434   MatScalar      *aa;
3435   Mat_SeqAIJ     *aij;
3436   PetscInt       *garray = a->garray,*colsub,Ncols;
3437   PetscInt       count,Bn=B->cmap->N,cstart=mat->cmap->rstart,cend=mat->cmap->rend;
3438   IS             iscol_sub,iscmap;
3439   const PetscInt *is_idx,*cmap;
3440   PetscBool      allcolumns=PETSC_FALSE;
3441   MPI_Comm       comm;
3442 
3443   PetscFunctionBegin;
3444   ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3445 
3446   if (call == MAT_REUSE_MATRIX) {
3447     ierr = PetscObjectQuery((PetscObject)*newmat,"SubIScol",(PetscObject*)&iscol_sub);CHKERRQ(ierr);
3448     if (!iscol_sub) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SubIScol passed in was not used before, cannot reuse");
3449     ierr = ISGetLocalSize(iscol_sub,&count);CHKERRQ(ierr);
3450 
3451     ierr = PetscObjectQuery((PetscObject)*newmat,"Subcmap",(PetscObject*)&iscmap);CHKERRQ(ierr);
3452     if (!iscmap) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Subcmap passed in was not used before, cannot reuse");
3453 
3454     ierr = PetscObjectQuery((PetscObject)*newmat,"SubMatrix",(PetscObject*)&Msub);CHKERRQ(ierr);
3455     if (!Msub) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3456 
3457     ierr = MatCreateSubMatrices_MPIAIJ_SingleIS_Local(mat,1,&isrow,&iscol_sub,MAT_REUSE_MATRIX,PETSC_FALSE,&Msub);CHKERRQ(ierr);
3458 
3459   } else { /* call == MAT_INITIAL_MATRIX) */
3460     PetscBool flg;
3461 
3462     ierr = ISGetLocalSize(iscol,&n);CHKERRQ(ierr);
3463     ierr = ISGetSize(iscol,&Ncols);CHKERRQ(ierr);
3464 
3465     /* (1) iscol -> nonscalable iscol_local */
3466     /* Check for special case: each processor gets entire matrix columns */
3467     ierr = ISIdentity(iscol_local,&flg);CHKERRQ(ierr);
3468     if (flg && n == mat->cmap->N) allcolumns = PETSC_TRUE;
3469     if (allcolumns) {
3470       iscol_sub = iscol_local;
3471       ierr = PetscObjectReference((PetscObject)iscol_local);CHKERRQ(ierr);
3472       ierr = ISCreateStride(PETSC_COMM_SELF,n,0,1,&iscmap);CHKERRQ(ierr);
3473 
3474     } else {
3475       /* (2) iscol_local -> iscol_sub and iscmap. Implementation below requires iscol_local be sorted, it can have duplicate indices */
3476       PetscInt *idx,*cmap1,k;
3477       ierr = PetscMalloc1(Ncols,&idx);CHKERRQ(ierr);
3478       ierr = PetscMalloc1(Ncols,&cmap1);CHKERRQ(ierr);
3479       ierr = ISGetIndices(iscol_local,&is_idx);CHKERRQ(ierr);
3480       count = 0;
3481       k     = 0;
3482       for (i=0; i<Ncols; i++) {
3483         j = is_idx[i];
3484         if (j >= cstart && j < cend) {
3485           /* diagonal part of mat */
3486           idx[count]     = j;
3487           cmap1[count++] = i; /* column index in submat */
3488         } else if (Bn) {
3489           /* off-diagonal part of mat */
3490           if (j == garray[k]) {
3491             idx[count]     = j;
3492             cmap1[count++] = i;  /* column index in submat */
3493           } else if (j > garray[k]) {
3494             while (j > garray[k] && k < Bn-1) k++;
3495             if (j == garray[k]) {
3496               idx[count]     = j;
3497               cmap1[count++] = i; /* column index in submat */
3498             }
3499           }
3500         }
3501       }
3502       ierr = ISRestoreIndices(iscol_local,&is_idx);CHKERRQ(ierr);
3503 
3504       ierr = ISCreateGeneral(PETSC_COMM_SELF,count,idx,PETSC_OWN_POINTER,&iscol_sub);CHKERRQ(ierr);
3505       ierr = ISGetBlockSize(iscol,&cbs);CHKERRQ(ierr);
3506       ierr = ISSetBlockSize(iscol_sub,cbs);CHKERRQ(ierr);
3507 
3508       ierr = ISCreateGeneral(PetscObjectComm((PetscObject)iscol_local),count,cmap1,PETSC_OWN_POINTER,&iscmap);CHKERRQ(ierr);
3509     }
3510 
3511     /* (3) Create sequential Msub */
3512     ierr = MatCreateSubMatrices_MPIAIJ_SingleIS_Local(mat,1,&isrow,&iscol_sub,MAT_INITIAL_MATRIX,allcolumns,&Msub);CHKERRQ(ierr);
3513   }
3514 
3515   ierr = ISGetLocalSize(iscol_sub,&count);CHKERRQ(ierr);
3516   aij  = (Mat_SeqAIJ*)(Msub)->data;
3517   ii   = aij->i;
3518   ierr = ISGetIndices(iscmap,&cmap);CHKERRQ(ierr);
3519 
3520   /*
3521       m - number of local rows
3522       Ncols - number of columns (same on all processors)
3523       rstart - first row in new global matrix generated
3524   */
3525   ierr = MatGetSize(Msub,&m,NULL);CHKERRQ(ierr);
3526 
3527   if (call == MAT_INITIAL_MATRIX) {
3528     /* (4) Create parallel newmat */
3529     PetscMPIInt    rank,size;
3530     PetscInt       csize;
3531 
3532     ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3533     ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
3534 
3535     /*
3536         Determine the number of non-zeros in the diagonal and off-diagonal
3537         portions of the matrix in order to do correct preallocation
3538     */
3539 
3540     /* first get start and end of "diagonal" columns */
3541     ierr = ISGetLocalSize(iscol,&csize);CHKERRQ(ierr);
3542     if (csize == PETSC_DECIDE) {
3543       ierr = ISGetSize(isrow,&mglobal);CHKERRQ(ierr);
3544       if (mglobal == Ncols) { /* square matrix */
3545         nlocal = m;
3546       } else {
3547         nlocal = Ncols/size + ((Ncols % size) > rank);
3548       }
3549     } else {
3550       nlocal = csize;
3551     }
3552     ierr   = MPI_Scan(&nlocal,&rend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3553     rstart = rend - nlocal;
3554     if (rank == size - 1 && rend != Ncols) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Local column sizes %D do not add up to total number of columns %D",rend,Ncols);
3555 
3556     /* next, compute all the lengths */
3557     jj    = aij->j;
3558     ierr  = PetscMalloc1(2*m+1,&dlens);CHKERRQ(ierr);
3559     olens = dlens + m;
3560     for (i=0; i<m; i++) {
3561       jend = ii[i+1] - ii[i];
3562       olen = 0;
3563       dlen = 0;
3564       for (j=0; j<jend; j++) {
3565         if (cmap[*jj] < rstart || cmap[*jj] >= rend) olen++;
3566         else dlen++;
3567         jj++;
3568       }
3569       olens[i] = olen;
3570       dlens[i] = dlen;
3571     }
3572 
3573     ierr = ISGetBlockSize(isrow,&bs);CHKERRQ(ierr);
3574     ierr = ISGetBlockSize(iscol,&cbs);CHKERRQ(ierr);
3575 
3576     ierr = MatCreate(comm,&M);CHKERRQ(ierr);
3577     ierr = MatSetSizes(M,m,nlocal,PETSC_DECIDE,Ncols);CHKERRQ(ierr);
3578     ierr = MatSetBlockSizes(M,bs,cbs);CHKERRQ(ierr);
3579     ierr = MatSetType(M,((PetscObject)mat)->type_name);CHKERRQ(ierr);
3580     ierr = MatMPIAIJSetPreallocation(M,0,dlens,0,olens);CHKERRQ(ierr);
3581     ierr = PetscFree(dlens);CHKERRQ(ierr);
3582 
3583   } else { /* call == MAT_REUSE_MATRIX */
3584     M    = *newmat;
3585     ierr = MatGetLocalSize(M,&i,NULL);CHKERRQ(ierr);
3586     if (i != m) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Previous matrix must be same size/layout as request");
3587     ierr = MatZeroEntries(M);CHKERRQ(ierr);
3588     /*
3589          The next two lines are needed so we may call MatSetValues_MPIAIJ() below directly,
3590        rather than the slower MatSetValues().
3591     */
3592     M->was_assembled = PETSC_TRUE;
3593     M->assembled     = PETSC_FALSE;
3594   }
3595 
3596   /* (5) Set values of Msub to *newmat */
3597   ierr = PetscMalloc1(count,&colsub);CHKERRQ(ierr);
3598   ierr = MatGetOwnershipRange(M,&rstart,NULL);CHKERRQ(ierr);
3599 
3600   jj   = aij->j;
3601   aa   = aij->a;
3602   for (i=0; i<m; i++) {
3603     row = rstart + i;
3604     nz  = ii[i+1] - ii[i];
3605     for (j=0; j<nz; j++) colsub[j] = cmap[jj[j]];
3606     ierr  = MatSetValues_MPIAIJ(M,1,&row,nz,colsub,aa,INSERT_VALUES);CHKERRQ(ierr);
3607     jj += nz; aa += nz;
3608   }
3609   ierr = ISRestoreIndices(iscmap,&cmap);CHKERRQ(ierr);
3610 
3611   ierr    = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3612   ierr    = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3613 
3614   ierr = PetscFree(colsub);CHKERRQ(ierr);
3615 
3616   /* save Msub, iscol_sub and iscmap used in processor for next request */
3617   if (call ==  MAT_INITIAL_MATRIX) {
3618     *newmat = M;
3619     ierr = PetscObjectCompose((PetscObject)(*newmat),"SubMatrix",(PetscObject)Msub);CHKERRQ(ierr);
3620     ierr = MatDestroy(&Msub);CHKERRQ(ierr);
3621 
3622     ierr = PetscObjectCompose((PetscObject)(*newmat),"SubIScol",(PetscObject)iscol_sub);CHKERRQ(ierr);
3623     ierr = ISDestroy(&iscol_sub);CHKERRQ(ierr);
3624 
3625     ierr = PetscObjectCompose((PetscObject)(*newmat),"Subcmap",(PetscObject)iscmap);CHKERRQ(ierr);
3626     ierr = ISDestroy(&iscmap);CHKERRQ(ierr);
3627 
3628     if (iscol_local) {
3629       ierr = PetscObjectCompose((PetscObject)(*newmat),"ISAllGather",(PetscObject)iscol_local);CHKERRQ(ierr);
3630       ierr = ISDestroy(&iscol_local);CHKERRQ(ierr);
3631     }
3632   }
3633   PetscFunctionReturn(0);
3634 }
3635 
3636 /*
3637     Not great since it makes two copies of the submatrix, first an SeqAIJ
3638   in local and then by concatenating the local matrices the end result.
3639   Writing it directly would be much like MatCreateSubMatrices_MPIAIJ()
3640 
3641   Note: This requires a sequential iscol with all indices.
3642 */
3643 PetscErrorCode MatCreateSubMatrix_MPIAIJ_nonscalable(Mat mat,IS isrow,IS iscol,PetscInt csize,MatReuse call,Mat *newmat)
3644 {
3645   PetscErrorCode ierr;
3646   PetscMPIInt    rank,size;
3647   PetscInt       i,m,n,rstart,row,rend,nz,*cwork,j,bs,cbs;
3648   PetscInt       *ii,*jj,nlocal,*dlens,*olens,dlen,olen,jend,mglobal;
3649   Mat            M,Mreuse;
3650   MatScalar      *aa,*vwork;
3651   MPI_Comm       comm;
3652   Mat_SeqAIJ     *aij;
3653   PetscBool      colflag,allcolumns=PETSC_FALSE;
3654 
3655   PetscFunctionBegin;
3656   ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3657   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
3658   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3659 
3660   /* Check for special case: each processor gets entire matrix columns */
3661   ierr = ISIdentity(iscol,&colflag);CHKERRQ(ierr);
3662   ierr = ISGetLocalSize(iscol,&n);CHKERRQ(ierr);
3663   if (colflag && n == mat->cmap->N) allcolumns = PETSC_TRUE;
3664 
3665   if (call ==  MAT_REUSE_MATRIX) {
3666     ierr = PetscObjectQuery((PetscObject)*newmat,"SubMatrix",(PetscObject*)&Mreuse);CHKERRQ(ierr);
3667     if (!Mreuse) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3668     ierr = MatCreateSubMatrices_MPIAIJ_SingleIS_Local(mat,1,&isrow,&iscol,MAT_REUSE_MATRIX,allcolumns,&Mreuse);CHKERRQ(ierr);
3669   } else {
3670     ierr = MatCreateSubMatrices_MPIAIJ_SingleIS_Local(mat,1,&isrow,&iscol,MAT_INITIAL_MATRIX,allcolumns,&Mreuse);CHKERRQ(ierr);
3671   }
3672 
3673   /*
3674       m - number of local rows
3675       n - number of columns (same on all processors)
3676       rstart - first row in new global matrix generated
3677   */
3678   ierr = MatGetSize(Mreuse,&m,&n);CHKERRQ(ierr);
3679   ierr = MatGetBlockSizes(Mreuse,&bs,&cbs);CHKERRQ(ierr);
3680   if (call == MAT_INITIAL_MATRIX) {
3681     aij = (Mat_SeqAIJ*)(Mreuse)->data;
3682     ii  = aij->i;
3683     jj  = aij->j;
3684 
3685     /*
3686         Determine the number of non-zeros in the diagonal and off-diagonal
3687         portions of the matrix in order to do correct preallocation
3688     */
3689 
3690     /* first get start and end of "diagonal" columns */
3691     if (csize == PETSC_DECIDE) {
3692       ierr = ISGetSize(isrow,&mglobal);CHKERRQ(ierr);
3693       if (mglobal == n) { /* square matrix */
3694         nlocal = m;
3695       } else {
3696         nlocal = n/size + ((n % size) > rank);
3697       }
3698     } else {
3699       nlocal = csize;
3700     }
3701     ierr   = MPI_Scan(&nlocal,&rend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3702     rstart = rend - nlocal;
3703     if (rank == size - 1 && rend != n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Local column sizes %D do not add up to total number of columns %D",rend,n);
3704 
3705     /* next, compute all the lengths */
3706     ierr  = PetscMalloc1(2*m+1,&dlens);CHKERRQ(ierr);
3707     olens = dlens + m;
3708     for (i=0; i<m; i++) {
3709       jend = ii[i+1] - ii[i];
3710       olen = 0;
3711       dlen = 0;
3712       for (j=0; j<jend; j++) {
3713         if (*jj < rstart || *jj >= rend) olen++;
3714         else dlen++;
3715         jj++;
3716       }
3717       olens[i] = olen;
3718       dlens[i] = dlen;
3719     }
3720     ierr = MatCreate(comm,&M);CHKERRQ(ierr);
3721     ierr = MatSetSizes(M,m,nlocal,PETSC_DECIDE,n);CHKERRQ(ierr);
3722     ierr = MatSetBlockSizes(M,bs,cbs);CHKERRQ(ierr);
3723     ierr = MatSetType(M,((PetscObject)mat)->type_name);CHKERRQ(ierr);
3724     ierr = MatMPIAIJSetPreallocation(M,0,dlens,0,olens);CHKERRQ(ierr);
3725     ierr = PetscFree(dlens);CHKERRQ(ierr);
3726   } else {
3727     PetscInt ml,nl;
3728 
3729     M    = *newmat;
3730     ierr = MatGetLocalSize(M,&ml,&nl);CHKERRQ(ierr);
3731     if (ml != m) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Previous matrix must be same size/layout as request");
3732     ierr = MatZeroEntries(M);CHKERRQ(ierr);
3733     /*
3734          The next two lines are needed so we may call MatSetValues_MPIAIJ() below directly,
3735        rather than the slower MatSetValues().
3736     */
3737     M->was_assembled = PETSC_TRUE;
3738     M->assembled     = PETSC_FALSE;
3739   }
3740   ierr = MatGetOwnershipRange(M,&rstart,&rend);CHKERRQ(ierr);
3741   aij  = (Mat_SeqAIJ*)(Mreuse)->data;
3742   ii   = aij->i;
3743   jj   = aij->j;
3744   aa   = aij->a;
3745   for (i=0; i<m; i++) {
3746     row   = rstart + i;
3747     nz    = ii[i+1] - ii[i];
3748     cwork = jj;     jj += nz;
3749     vwork = aa;     aa += nz;
3750     ierr  = MatSetValues_MPIAIJ(M,1,&row,nz,cwork,vwork,INSERT_VALUES);CHKERRQ(ierr);
3751   }
3752 
3753   ierr    = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3754   ierr    = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3755   *newmat = M;
3756 
3757   /* save submatrix used in processor for next request */
3758   if (call ==  MAT_INITIAL_MATRIX) {
3759     ierr = PetscObjectCompose((PetscObject)M,"SubMatrix",(PetscObject)Mreuse);CHKERRQ(ierr);
3760     ierr = MatDestroy(&Mreuse);CHKERRQ(ierr);
3761   }
3762   PetscFunctionReturn(0);
3763 }
3764 
3765 PetscErrorCode MatMPIAIJSetPreallocationCSR_MPIAIJ(Mat B,const PetscInt Ii[],const PetscInt J[],const PetscScalar v[])
3766 {
3767   PetscInt       m,cstart, cend,j,nnz,i,d;
3768   PetscInt       *d_nnz,*o_nnz,nnz_max = 0,rstart,ii;
3769   const PetscInt *JJ;
3770   PetscScalar    *values;
3771   PetscErrorCode ierr;
3772   PetscBool      nooffprocentries;
3773 
3774   PetscFunctionBegin;
3775   if (Ii[0]) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Ii[0] must be 0 it is %D",Ii[0]);
3776 
3777   ierr   = PetscLayoutSetUp(B->rmap);CHKERRQ(ierr);
3778   ierr   = PetscLayoutSetUp(B->cmap);CHKERRQ(ierr);
3779   m      = B->rmap->n;
3780   cstart = B->cmap->rstart;
3781   cend   = B->cmap->rend;
3782   rstart = B->rmap->rstart;
3783 
3784   ierr = PetscMalloc2(m,&d_nnz,m,&o_nnz);CHKERRQ(ierr);
3785 
3786 #if defined(PETSC_USE_DEBUGGING)
3787   for (i=0; i<m; i++) {
3788     nnz = Ii[i+1]- Ii[i];
3789     JJ  = J + Ii[i];
3790     if (nnz < 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Local row %D has a negative %D number of columns",i,nnz);
3791     if (nnz && (JJ[0] < 0)) SETERRRQ1(PETSC_ERR_ARG_WRONGSTATE,"Row %D starts with negative column index",i,j);
3792     if (nnz && (JJ[nnz-1] >= B->cmap->N) SETERRRQ3(PETSC_ERR_ARG_WRONGSTATE,"Row %D ends with too large a column index %D (max allowed %D)",i,JJ[nnz-1],B->cmap->N);
3793   }
3794 #endif
3795 
3796   for (i=0; i<m; i++) {
3797     nnz     = Ii[i+1]- Ii[i];
3798     JJ      = J + Ii[i];
3799     nnz_max = PetscMax(nnz_max,nnz);
3800     d       = 0;
3801     for (j=0; j<nnz; j++) {
3802       if (cstart <= JJ[j] && JJ[j] < cend) d++;
3803     }
3804     d_nnz[i] = d;
3805     o_nnz[i] = nnz - d;
3806   }
3807   ierr = MatMPIAIJSetPreallocation(B,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
3808   ierr = PetscFree2(d_nnz,o_nnz);CHKERRQ(ierr);
3809 
3810   if (v) values = (PetscScalar*)v;
3811   else {
3812     ierr = PetscCalloc1(nnz_max+1,&values);CHKERRQ(ierr);
3813   }
3814 
3815   for (i=0; i<m; i++) {
3816     ii   = i + rstart;
3817     nnz  = Ii[i+1]- Ii[i];
3818     ierr = MatSetValues_MPIAIJ(B,1,&ii,nnz,J+Ii[i],values+(v ? Ii[i] : 0),INSERT_VALUES);CHKERRQ(ierr);
3819   }
3820   nooffprocentries    = B->nooffprocentries;
3821   B->nooffprocentries = PETSC_TRUE;
3822   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3823   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3824   B->nooffprocentries = nooffprocentries;
3825 
3826   if (!v) {
3827     ierr = PetscFree(values);CHKERRQ(ierr);
3828   }
3829   ierr = MatSetOption(B,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
3830   PetscFunctionReturn(0);
3831 }
3832 
3833 /*@
3834    MatMPIAIJSetPreallocationCSR - Allocates memory for a sparse parallel matrix in AIJ format
3835    (the default parallel PETSc format).
3836 
3837    Collective on MPI_Comm
3838 
3839    Input Parameters:
3840 +  B - the matrix
3841 .  i - the indices into j for the start of each local row (starts with zero)
3842 .  j - the column indices for each local row (starts with zero)
3843 -  v - optional values in the matrix
3844 
3845    Level: developer
3846 
3847    Notes:
3848        The i, j, and a arrays ARE copied by this routine into the internal format used by PETSc;
3849      thus you CANNOT change the matrix entries by changing the values of a[] after you have
3850      called this routine. Use MatCreateMPIAIJWithSplitArrays() to avoid needing to copy the arrays.
3851 
3852        The i and j indices are 0 based, and i indices are indices corresponding to the local j array.
3853 
3854        The format which is used for the sparse matrix input, is equivalent to a
3855     row-major ordering.. i.e for the following matrix, the input data expected is
3856     as shown
3857 
3858 $        1 0 0
3859 $        2 0 3     P0
3860 $       -------
3861 $        4 5 6     P1
3862 $
3863 $     Process0 [P0]: rows_owned=[0,1]
3864 $        i =  {0,1,3}  [size = nrow+1  = 2+1]
3865 $        j =  {0,0,2}  [size = 3]
3866 $        v =  {1,2,3}  [size = 3]
3867 $
3868 $     Process1 [P1]: rows_owned=[2]
3869 $        i =  {0,3}    [size = nrow+1  = 1+1]
3870 $        j =  {0,1,2}  [size = 3]
3871 $        v =  {4,5,6}  [size = 3]
3872 
3873 .keywords: matrix, aij, compressed row, sparse, parallel
3874 
3875 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatCreateAIJ(), MATMPIAIJ,
3876           MatCreateSeqAIJWithArrays(), MatCreateMPIAIJWithSplitArrays()
3877 @*/
3878 PetscErrorCode  MatMPIAIJSetPreallocationCSR(Mat B,const PetscInt i[],const PetscInt j[], const PetscScalar v[])
3879 {
3880   PetscErrorCode ierr;
3881 
3882   PetscFunctionBegin;
3883   ierr = PetscTryMethod(B,"MatMPIAIJSetPreallocationCSR_C",(Mat,const PetscInt[],const PetscInt[],const PetscScalar[]),(B,i,j,v));CHKERRQ(ierr);
3884   PetscFunctionReturn(0);
3885 }
3886 
3887 /*@C
3888    MatMPIAIJSetPreallocation - Preallocates memory for a sparse parallel matrix in AIJ format
3889    (the default parallel PETSc format).  For good matrix assembly performance
3890    the user should preallocate the matrix storage by setting the parameters
3891    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
3892    performance can be increased by more than a factor of 50.
3893 
3894    Collective on MPI_Comm
3895 
3896    Input Parameters:
3897 +  B - the matrix
3898 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
3899            (same value is used for all local rows)
3900 .  d_nnz - array containing the number of nonzeros in the various rows of the
3901            DIAGONAL portion of the local submatrix (possibly different for each row)
3902            or NULL (PETSC_NULL_INTEGER in Fortran), if d_nz is used to specify the nonzero structure.
3903            The size of this array is equal to the number of local rows, i.e 'm'.
3904            For matrices that will be factored, you must leave room for (and set)
3905            the diagonal entry even if it is zero.
3906 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
3907            submatrix (same value is used for all local rows).
3908 -  o_nnz - array containing the number of nonzeros in the various rows of the
3909            OFF-DIAGONAL portion of the local submatrix (possibly different for
3910            each row) or NULL (PETSC_NULL_INTEGER in Fortran), if o_nz is used to specify the nonzero
3911            structure. The size of this array is equal to the number
3912            of local rows, i.e 'm'.
3913 
3914    If the *_nnz parameter is given then the *_nz parameter is ignored
3915 
3916    The AIJ format (also called the Yale sparse matrix format or
3917    compressed row storage (CSR)), is fully compatible with standard Fortran 77
3918    storage.  The stored row and column indices begin with zero.
3919    See Users-Manual: ch_mat for details.
3920 
3921    The parallel matrix is partitioned such that the first m0 rows belong to
3922    process 0, the next m1 rows belong to process 1, the next m2 rows belong
3923    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.
3924 
3925    The DIAGONAL portion of the local submatrix of a processor can be defined
3926    as the submatrix which is obtained by extraction the part corresponding to
3927    the rows r1-r2 and columns c1-c2 of the global matrix, where r1 is the
3928    first row that belongs to the processor, r2 is the last row belonging to
3929    the this processor, and c1-c2 is range of indices of the local part of a
3930    vector suitable for applying the matrix to.  This is an mxn matrix.  In the
3931    common case of a square matrix, the row and column ranges are the same and
3932    the DIAGONAL part is also square. The remaining portion of the local
3933    submatrix (mxN) constitute the OFF-DIAGONAL portion.
3934 
3935    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
3936 
3937    You can call MatGetInfo() to get information on how effective the preallocation was;
3938    for example the fields mallocs,nz_allocated,nz_used,nz_unneeded;
3939    You can also run with the option -info and look for messages with the string
3940    malloc in them to see if additional memory allocation was needed.
3941 
3942    Example usage:
3943 
3944    Consider the following 8x8 matrix with 34 non-zero values, that is
3945    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
3946    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
3947    as follows:
3948 
3949 .vb
3950             1  2  0  |  0  3  0  |  0  4
3951     Proc0   0  5  6  |  7  0  0  |  8  0
3952             9  0 10  | 11  0  0  | 12  0
3953     -------------------------------------
3954            13  0 14  | 15 16 17  |  0  0
3955     Proc1   0 18  0  | 19 20 21  |  0  0
3956             0  0  0  | 22 23  0  | 24  0
3957     -------------------------------------
3958     Proc2  25 26 27  |  0  0 28  | 29  0
3959            30  0  0  | 31 32 33  |  0 34
3960 .ve
3961 
3962    This can be represented as a collection of submatrices as:
3963 
3964 .vb
3965       A B C
3966       D E F
3967       G H I
3968 .ve
3969 
3970    Where the submatrices A,B,C are owned by proc0, D,E,F are
3971    owned by proc1, G,H,I are owned by proc2.
3972 
3973    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3974    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3975    The 'M','N' parameters are 8,8, and have the same values on all procs.
3976 
3977    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
3978    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
3979    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
3980    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
3981    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
3982    matrix, ans [DF] as another SeqAIJ matrix.
3983 
3984    When d_nz, o_nz parameters are specified, d_nz storage elements are
3985    allocated for every row of the local diagonal submatrix, and o_nz
3986    storage locations are allocated for every row of the OFF-DIAGONAL submat.
3987    One way to choose d_nz and o_nz is to use the max nonzerors per local
3988    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
3989    In this case, the values of d_nz,o_nz are:
3990 .vb
3991      proc0 : dnz = 2, o_nz = 2
3992      proc1 : dnz = 3, o_nz = 2
3993      proc2 : dnz = 1, o_nz = 4
3994 .ve
3995    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
3996    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
3997    for proc3. i.e we are using 12+15+10=37 storage locations to store
3998    34 values.
3999 
4000    When d_nnz, o_nnz parameters are specified, the storage is specified
4001    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
4002    In the above case the values for d_nnz,o_nnz are:
4003 .vb
4004      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
4005      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
4006      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
4007 .ve
4008    Here the space allocated is sum of all the above values i.e 34, and
4009    hence pre-allocation is perfect.
4010 
4011    Level: intermediate
4012 
4013 .keywords: matrix, aij, compressed row, sparse, parallel
4014 
4015 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatCreateAIJ(), MatMPIAIJSetPreallocationCSR(),
4016           MATMPIAIJ, MatGetInfo(), PetscSplitOwnership()
4017 @*/
4018 PetscErrorCode MatMPIAIJSetPreallocation(Mat B,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[])
4019 {
4020   PetscErrorCode ierr;
4021 
4022   PetscFunctionBegin;
4023   PetscValidHeaderSpecific(B,MAT_CLASSID,1);
4024   PetscValidType(B,1);
4025   ierr = PetscTryMethod(B,"MatMPIAIJSetPreallocation_C",(Mat,PetscInt,const PetscInt[],PetscInt,const PetscInt[]),(B,d_nz,d_nnz,o_nz,o_nnz));CHKERRQ(ierr);
4026   PetscFunctionReturn(0);
4027 }
4028 
4029 /*@
4030      MatCreateMPIAIJWithArrays - creates a MPI AIJ matrix using arrays that contain in standard
4031          CSR format the local rows.
4032 
4033    Collective on MPI_Comm
4034 
4035    Input Parameters:
4036 +  comm - MPI communicator
4037 .  m - number of local rows (Cannot be PETSC_DECIDE)
4038 .  n - This value should be the same as the local size used in creating the
4039        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
4040        calculated if N is given) For square matrices n is almost always m.
4041 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
4042 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
4043 .   i - row indices
4044 .   j - column indices
4045 -   a - matrix values
4046 
4047    Output Parameter:
4048 .   mat - the matrix
4049 
4050    Level: intermediate
4051 
4052    Notes:
4053        The i, j, and a arrays ARE copied by this routine into the internal format used by PETSc;
4054      thus you CANNOT change the matrix entries by changing the values of a[] after you have
4055      called this routine. Use MatCreateMPIAIJWithSplitArrays() to avoid needing to copy the arrays.
4056 
4057        The i and j indices are 0 based, and i indices are indices corresponding to the local j array.
4058 
4059        The format which is used for the sparse matrix input, is equivalent to a
4060     row-major ordering.. i.e for the following matrix, the input data expected is
4061     as shown
4062 
4063 $        1 0 0
4064 $        2 0 3     P0
4065 $       -------
4066 $        4 5 6     P1
4067 $
4068 $     Process0 [P0]: rows_owned=[0,1]
4069 $        i =  {0,1,3}  [size = nrow+1  = 2+1]
4070 $        j =  {0,0,2}  [size = 3]
4071 $        v =  {1,2,3}  [size = 3]
4072 $
4073 $     Process1 [P1]: rows_owned=[2]
4074 $        i =  {0,3}    [size = nrow+1  = 1+1]
4075 $        j =  {0,1,2}  [size = 3]
4076 $        v =  {4,5,6}  [size = 3]
4077 
4078 .keywords: matrix, aij, compressed row, sparse, parallel
4079 
4080 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
4081           MATMPIAIJ, MatCreateAIJ(), MatCreateMPIAIJWithSplitArrays()
4082 @*/
4083 PetscErrorCode MatCreateMPIAIJWithArrays(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,const PetscInt i[],const PetscInt j[],const PetscScalar a[],Mat *mat)
4084 {
4085   PetscErrorCode ierr;
4086 
4087   PetscFunctionBegin;
4088   if (i[0]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"i (row indices) must start with 0");
4089   if (m < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"local number of rows (m) cannot be PETSC_DECIDE, or negative");
4090   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
4091   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
4092   /* ierr = MatSetBlockSizes(M,bs,cbs);CHKERRQ(ierr); */
4093   ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
4094   ierr = MatMPIAIJSetPreallocationCSR(*mat,i,j,a);CHKERRQ(ierr);
4095   PetscFunctionReturn(0);
4096 }
4097 
4098 /*@C
4099    MatCreateAIJ - Creates a sparse parallel matrix in AIJ format
4100    (the default parallel PETSc format).  For good matrix assembly performance
4101    the user should preallocate the matrix storage by setting the parameters
4102    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
4103    performance can be increased by more than a factor of 50.
4104 
4105    Collective on MPI_Comm
4106 
4107    Input Parameters:
4108 +  comm - MPI communicator
4109 .  m - number of local rows (or PETSC_DECIDE to have calculated if M is given)
4110            This value should be the same as the local size used in creating the
4111            y vector for the matrix-vector product y = Ax.
4112 .  n - This value should be the same as the local size used in creating the
4113        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
4114        calculated if N is given) For square matrices n is almost always m.
4115 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
4116 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
4117 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
4118            (same value is used for all local rows)
4119 .  d_nnz - array containing the number of nonzeros in the various rows of the
4120            DIAGONAL portion of the local submatrix (possibly different for each row)
4121            or NULL, if d_nz is used to specify the nonzero structure.
4122            The size of this array is equal to the number of local rows, i.e 'm'.
4123 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
4124            submatrix (same value is used for all local rows).
4125 -  o_nnz - array containing the number of nonzeros in the various rows of the
4126            OFF-DIAGONAL portion of the local submatrix (possibly different for
4127            each row) or NULL, if o_nz is used to specify the nonzero
4128            structure. The size of this array is equal to the number
4129            of local rows, i.e 'm'.
4130 
4131    Output Parameter:
4132 .  A - the matrix
4133 
4134    It is recommended that one use the MatCreate(), MatSetType() and/or MatSetFromOptions(),
4135    MatXXXXSetPreallocation() paradgm instead of this routine directly.
4136    [MatXXXXSetPreallocation() is, for example, MatSeqAIJSetPreallocation]
4137 
4138    Notes:
4139    If the *_nnz parameter is given then the *_nz parameter is ignored
4140 
4141    m,n,M,N parameters specify the size of the matrix, and its partitioning across
4142    processors, while d_nz,d_nnz,o_nz,o_nnz parameters specify the approximate
4143    storage requirements for this matrix.
4144 
4145    If PETSC_DECIDE or  PETSC_DETERMINE is used for a particular argument on one
4146    processor than it must be used on all processors that share the object for
4147    that argument.
4148 
4149    The user MUST specify either the local or global matrix dimensions
4150    (possibly both).
4151 
4152    The parallel matrix is partitioned across processors such that the
4153    first m0 rows belong to process 0, the next m1 rows belong to
4154    process 1, the next m2 rows belong to process 2 etc.. where
4155    m0,m1,m2,.. are the input parameter 'm'. i.e each processor stores
4156    values corresponding to [m x N] submatrix.
4157 
4158    The columns are logically partitioned with the n0 columns belonging
4159    to 0th partition, the next n1 columns belonging to the next
4160    partition etc.. where n0,n1,n2... are the input parameter 'n'.
4161 
4162    The DIAGONAL portion of the local submatrix on any given processor
4163    is the submatrix corresponding to the rows and columns m,n
4164    corresponding to the given processor. i.e diagonal matrix on
4165    process 0 is [m0 x n0], diagonal matrix on process 1 is [m1 x n1]
4166    etc. The remaining portion of the local submatrix [m x (N-n)]
4167    constitute the OFF-DIAGONAL portion. The example below better
4168    illustrates this concept.
4169 
4170    For a square global matrix we define each processor's diagonal portion
4171    to be its local rows and the corresponding columns (a square submatrix);
4172    each processor's off-diagonal portion encompasses the remainder of the
4173    local matrix (a rectangular submatrix).
4174 
4175    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
4176 
4177    When calling this routine with a single process communicator, a matrix of
4178    type SEQAIJ is returned.  If a matrix of type MPIAIJ is desired for this
4179    type of communicator, use the construction mechanism
4180 .vb
4181      MatCreate(...,&A); MatSetType(A,MATMPIAIJ); MatSetSizes(A, m,n,M,N); MatMPIAIJSetPreallocation(A,...);
4182 .ve
4183 
4184 $     MatCreate(...,&A);
4185 $     MatSetType(A,MATMPIAIJ);
4186 $     MatSetSizes(A, m,n,M,N);
4187 $     MatMPIAIJSetPreallocation(A,...);
4188 
4189    By default, this format uses inodes (identical nodes) when possible.
4190    We search for consecutive rows with the same nonzero structure, thereby
4191    reusing matrix information to achieve increased efficiency.
4192 
4193    Options Database Keys:
4194 +  -mat_no_inode  - Do not use inodes
4195 .  -mat_inode_limit <limit> - Sets inode limit (max limit=5)
4196 -  -mat_aij_oneindex - Internally use indexing starting at 1
4197         rather than 0.  Note that when calling MatSetValues(),
4198         the user still MUST index entries starting at 0!
4199 
4200 
4201    Example usage:
4202 
4203    Consider the following 8x8 matrix with 34 non-zero values, that is
4204    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
4205    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
4206    as follows
4207 
4208 .vb
4209             1  2  0  |  0  3  0  |  0  4
4210     Proc0   0  5  6  |  7  0  0  |  8  0
4211             9  0 10  | 11  0  0  | 12  0
4212     -------------------------------------
4213            13  0 14  | 15 16 17  |  0  0
4214     Proc1   0 18  0  | 19 20 21  |  0  0
4215             0  0  0  | 22 23  0  | 24  0
4216     -------------------------------------
4217     Proc2  25 26 27  |  0  0 28  | 29  0
4218            30  0  0  | 31 32 33  |  0 34
4219 .ve
4220 
4221    This can be represented as a collection of submatrices as
4222 
4223 .vb
4224       A B C
4225       D E F
4226       G H I
4227 .ve
4228 
4229    Where the submatrices A,B,C are owned by proc0, D,E,F are
4230    owned by proc1, G,H,I are owned by proc2.
4231 
4232    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
4233    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
4234    The 'M','N' parameters are 8,8, and have the same values on all procs.
4235 
4236    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
4237    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
4238    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
4239    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
4240    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
4241    matrix, ans [DF] as another SeqAIJ matrix.
4242 
4243    When d_nz, o_nz parameters are specified, d_nz storage elements are
4244    allocated for every row of the local diagonal submatrix, and o_nz
4245    storage locations are allocated for every row of the OFF-DIAGONAL submat.
4246    One way to choose d_nz and o_nz is to use the max nonzerors per local
4247    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
4248    In this case, the values of d_nz,o_nz are
4249 .vb
4250      proc0 : dnz = 2, o_nz = 2
4251      proc1 : dnz = 3, o_nz = 2
4252      proc2 : dnz = 1, o_nz = 4
4253 .ve
4254    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
4255    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
4256    for proc3. i.e we are using 12+15+10=37 storage locations to store
4257    34 values.
4258 
4259    When d_nnz, o_nnz parameters are specified, the storage is specified
4260    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
4261    In the above case the values for d_nnz,o_nnz are
4262 .vb
4263      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
4264      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
4265      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
4266 .ve
4267    Here the space allocated is sum of all the above values i.e 34, and
4268    hence pre-allocation is perfect.
4269 
4270    Level: intermediate
4271 
4272 .keywords: matrix, aij, compressed row, sparse, parallel
4273 
4274 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
4275           MATMPIAIJ, MatCreateMPIAIJWithArrays()
4276 @*/
4277 PetscErrorCode  MatCreateAIJ(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[],Mat *A)
4278 {
4279   PetscErrorCode ierr;
4280   PetscMPIInt    size;
4281 
4282   PetscFunctionBegin;
4283   ierr = MatCreate(comm,A);CHKERRQ(ierr);
4284   ierr = MatSetSizes(*A,m,n,M,N);CHKERRQ(ierr);
4285   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4286   if (size > 1) {
4287     ierr = MatSetType(*A,MATMPIAIJ);CHKERRQ(ierr);
4288     ierr = MatMPIAIJSetPreallocation(*A,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
4289   } else {
4290     ierr = MatSetType(*A,MATSEQAIJ);CHKERRQ(ierr);
4291     ierr = MatSeqAIJSetPreallocation(*A,d_nz,d_nnz);CHKERRQ(ierr);
4292   }
4293   PetscFunctionReturn(0);
4294 }
4295 
4296 PetscErrorCode MatMPIAIJGetSeqAIJ(Mat A,Mat *Ad,Mat *Ao,const PetscInt *colmap[])
4297 {
4298   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
4299   PetscBool      flg;
4300   PetscErrorCode ierr;
4301 
4302   PetscFunctionBegin;
4303   ierr = PetscObjectTypeCompare((PetscObject)A,MATMPIAIJ,&flg);CHKERRQ(ierr);
4304   if (!flg) SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_SUP,"This function requires a MATMPIAIJ matrix as input");
4305   if (Ad)     *Ad     = a->A;
4306   if (Ao)     *Ao     = a->B;
4307   if (colmap) *colmap = a->garray;
4308   PetscFunctionReturn(0);
4309 }
4310 
4311 PetscErrorCode MatCreateMPIMatConcatenateSeqMat_MPIAIJ(MPI_Comm comm,Mat inmat,PetscInt n,MatReuse scall,Mat *outmat)
4312 {
4313   PetscErrorCode ierr;
4314   PetscInt       m,N,i,rstart,nnz,Ii;
4315   PetscInt       *indx;
4316   PetscScalar    *values;
4317 
4318   PetscFunctionBegin;
4319   ierr = MatGetSize(inmat,&m,&N);CHKERRQ(ierr);
4320   if (scall == MAT_INITIAL_MATRIX) { /* symbolic phase */
4321     PetscInt       *dnz,*onz,sum,bs,cbs;
4322 
4323     if (n == PETSC_DECIDE) {
4324       ierr = PetscSplitOwnership(comm,&n,&N);CHKERRQ(ierr);
4325     }
4326     /* Check sum(n) = N */
4327     ierr = MPIU_Allreduce(&n,&sum,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
4328     if (sum != N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Sum of local columns %D != global columns %D",sum,N);
4329 
4330     ierr    = MPI_Scan(&m, &rstart,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
4331     rstart -= m;
4332 
4333     ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
4334     for (i=0; i<m; i++) {
4335       ierr = MatGetRow_SeqAIJ(inmat,i,&nnz,&indx,NULL);CHKERRQ(ierr);
4336       ierr = MatPreallocateSet(i+rstart,nnz,indx,dnz,onz);CHKERRQ(ierr);
4337       ierr = MatRestoreRow_SeqAIJ(inmat,i,&nnz,&indx,NULL);CHKERRQ(ierr);
4338     }
4339 
4340     ierr = MatCreate(comm,outmat);CHKERRQ(ierr);
4341     ierr = MatSetSizes(*outmat,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
4342     ierr = MatGetBlockSizes(inmat,&bs,&cbs);CHKERRQ(ierr);
4343     ierr = MatSetBlockSizes(*outmat,bs,cbs);CHKERRQ(ierr);
4344     ierr = MatSetType(*outmat,MATAIJ);CHKERRQ(ierr);
4345     ierr = MatSeqAIJSetPreallocation(*outmat,0,dnz);CHKERRQ(ierr);
4346     ierr = MatMPIAIJSetPreallocation(*outmat,0,dnz,0,onz);CHKERRQ(ierr);
4347     ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
4348   }
4349 
4350   /* numeric phase */
4351   ierr = MatGetOwnershipRange(*outmat,&rstart,NULL);CHKERRQ(ierr);
4352   for (i=0; i<m; i++) {
4353     ierr = MatGetRow_SeqAIJ(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
4354     Ii   = i + rstart;
4355     ierr = MatSetValues(*outmat,1,&Ii,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
4356     ierr = MatRestoreRow_SeqAIJ(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
4357   }
4358   ierr = MatAssemblyBegin(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4359   ierr = MatAssemblyEnd(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4360   PetscFunctionReturn(0);
4361 }
4362 
4363 PetscErrorCode MatFileSplit(Mat A,char *outfile)
4364 {
4365   PetscErrorCode    ierr;
4366   PetscMPIInt       rank;
4367   PetscInt          m,N,i,rstart,nnz;
4368   size_t            len;
4369   const PetscInt    *indx;
4370   PetscViewer       out;
4371   char              *name;
4372   Mat               B;
4373   const PetscScalar *values;
4374 
4375   PetscFunctionBegin;
4376   ierr = MatGetLocalSize(A,&m,0);CHKERRQ(ierr);
4377   ierr = MatGetSize(A,0,&N);CHKERRQ(ierr);
4378   /* Should this be the type of the diagonal block of A? */
4379   ierr = MatCreate(PETSC_COMM_SELF,&B);CHKERRQ(ierr);
4380   ierr = MatSetSizes(B,m,N,m,N);CHKERRQ(ierr);
4381   ierr = MatSetBlockSizesFromMats(B,A,A);CHKERRQ(ierr);
4382   ierr = MatSetType(B,MATSEQAIJ);CHKERRQ(ierr);
4383   ierr = MatSeqAIJSetPreallocation(B,0,NULL);CHKERRQ(ierr);
4384   ierr = MatGetOwnershipRange(A,&rstart,0);CHKERRQ(ierr);
4385   for (i=0; i<m; i++) {
4386     ierr = MatGetRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
4387     ierr = MatSetValues(B,1,&i,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
4388     ierr = MatRestoreRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
4389   }
4390   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4391   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4392 
4393   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)A),&rank);CHKERRQ(ierr);
4394   ierr = PetscStrlen(outfile,&len);CHKERRQ(ierr);
4395   ierr = PetscMalloc1(len+5,&name);CHKERRQ(ierr);
4396   sprintf(name,"%s.%d",outfile,rank);
4397   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,name,FILE_MODE_APPEND,&out);CHKERRQ(ierr);
4398   ierr = PetscFree(name);CHKERRQ(ierr);
4399   ierr = MatView(B,out);CHKERRQ(ierr);
4400   ierr = PetscViewerDestroy(&out);CHKERRQ(ierr);
4401   ierr = MatDestroy(&B);CHKERRQ(ierr);
4402   PetscFunctionReturn(0);
4403 }
4404 
4405 PetscErrorCode MatDestroy_MPIAIJ_SeqsToMPI(Mat A)
4406 {
4407   PetscErrorCode      ierr;
4408   Mat_Merge_SeqsToMPI *merge;
4409   PetscContainer      container;
4410 
4411   PetscFunctionBegin;
4412   ierr = PetscObjectQuery((PetscObject)A,"MatMergeSeqsToMPI",(PetscObject*)&container);CHKERRQ(ierr);
4413   if (container) {
4414     ierr = PetscContainerGetPointer(container,(void**)&merge);CHKERRQ(ierr);
4415     ierr = PetscFree(merge->id_r);CHKERRQ(ierr);
4416     ierr = PetscFree(merge->len_s);CHKERRQ(ierr);
4417     ierr = PetscFree(merge->len_r);CHKERRQ(ierr);
4418     ierr = PetscFree(merge->bi);CHKERRQ(ierr);
4419     ierr = PetscFree(merge->bj);CHKERRQ(ierr);
4420     ierr = PetscFree(merge->buf_ri[0]);CHKERRQ(ierr);
4421     ierr = PetscFree(merge->buf_ri);CHKERRQ(ierr);
4422     ierr = PetscFree(merge->buf_rj[0]);CHKERRQ(ierr);
4423     ierr = PetscFree(merge->buf_rj);CHKERRQ(ierr);
4424     ierr = PetscFree(merge->coi);CHKERRQ(ierr);
4425     ierr = PetscFree(merge->coj);CHKERRQ(ierr);
4426     ierr = PetscFree(merge->owners_co);CHKERRQ(ierr);
4427     ierr = PetscLayoutDestroy(&merge->rowmap);CHKERRQ(ierr);
4428     ierr = PetscFree(merge);CHKERRQ(ierr);
4429     ierr = PetscObjectCompose((PetscObject)A,"MatMergeSeqsToMPI",0);CHKERRQ(ierr);
4430   }
4431   ierr = MatDestroy_MPIAIJ(A);CHKERRQ(ierr);
4432   PetscFunctionReturn(0);
4433 }
4434 
4435 #include <../src/mat/utils/freespace.h>
4436 #include <petscbt.h>
4437 
4438 PetscErrorCode MatCreateMPIAIJSumSeqAIJNumeric(Mat seqmat,Mat mpimat)
4439 {
4440   PetscErrorCode      ierr;
4441   MPI_Comm            comm;
4442   Mat_SeqAIJ          *a  =(Mat_SeqAIJ*)seqmat->data;
4443   PetscMPIInt         size,rank,taga,*len_s;
4444   PetscInt            N=mpimat->cmap->N,i,j,*owners,*ai=a->i,*aj;
4445   PetscInt            proc,m;
4446   PetscInt            **buf_ri,**buf_rj;
4447   PetscInt            k,anzi,*bj_i,*bi,*bj,arow,bnzi,nextaj;
4448   PetscInt            nrows,**buf_ri_k,**nextrow,**nextai;
4449   MPI_Request         *s_waits,*r_waits;
4450   MPI_Status          *status;
4451   MatScalar           *aa=a->a;
4452   MatScalar           **abuf_r,*ba_i;
4453   Mat_Merge_SeqsToMPI *merge;
4454   PetscContainer      container;
4455 
4456   PetscFunctionBegin;
4457   ierr = PetscObjectGetComm((PetscObject)mpimat,&comm);CHKERRQ(ierr);
4458   ierr = PetscLogEventBegin(MAT_Seqstompinum,seqmat,0,0,0);CHKERRQ(ierr);
4459 
4460   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4461   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4462 
4463   ierr = PetscObjectQuery((PetscObject)mpimat,"MatMergeSeqsToMPI",(PetscObject*)&container);CHKERRQ(ierr);
4464   ierr = PetscContainerGetPointer(container,(void**)&merge);CHKERRQ(ierr);
4465 
4466   bi     = merge->bi;
4467   bj     = merge->bj;
4468   buf_ri = merge->buf_ri;
4469   buf_rj = merge->buf_rj;
4470 
4471   ierr   = PetscMalloc1(size,&status);CHKERRQ(ierr);
4472   owners = merge->rowmap->range;
4473   len_s  = merge->len_s;
4474 
4475   /* send and recv matrix values */
4476   /*-----------------------------*/
4477   ierr = PetscObjectGetNewTag((PetscObject)mpimat,&taga);CHKERRQ(ierr);
4478   ierr = PetscPostIrecvScalar(comm,taga,merge->nrecv,merge->id_r,merge->len_r,&abuf_r,&r_waits);CHKERRQ(ierr);
4479 
4480   ierr = PetscMalloc1(merge->nsend+1,&s_waits);CHKERRQ(ierr);
4481   for (proc=0,k=0; proc<size; proc++) {
4482     if (!len_s[proc]) continue;
4483     i    = owners[proc];
4484     ierr = MPI_Isend(aa+ai[i],len_s[proc],MPIU_MATSCALAR,proc,taga,comm,s_waits+k);CHKERRQ(ierr);
4485     k++;
4486   }
4487 
4488   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,r_waits,status);CHKERRQ(ierr);}
4489   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,s_waits,status);CHKERRQ(ierr);}
4490   ierr = PetscFree(status);CHKERRQ(ierr);
4491 
4492   ierr = PetscFree(s_waits);CHKERRQ(ierr);
4493   ierr = PetscFree(r_waits);CHKERRQ(ierr);
4494 
4495   /* insert mat values of mpimat */
4496   /*----------------------------*/
4497   ierr = PetscMalloc1(N,&ba_i);CHKERRQ(ierr);
4498   ierr = PetscMalloc3(merge->nrecv,&buf_ri_k,merge->nrecv,&nextrow,merge->nrecv,&nextai);CHKERRQ(ierr);
4499 
4500   for (k=0; k<merge->nrecv; k++) {
4501     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
4502     nrows       = *(buf_ri_k[k]);
4503     nextrow[k]  = buf_ri_k[k]+1;  /* next row number of k-th recved i-structure */
4504     nextai[k]   = buf_ri_k[k] + (nrows + 1); /* poins to the next i-structure of k-th recved i-structure  */
4505   }
4506 
4507   /* set values of ba */
4508   m = merge->rowmap->n;
4509   for (i=0; i<m; i++) {
4510     arow = owners[rank] + i;
4511     bj_i = bj+bi[i];  /* col indices of the i-th row of mpimat */
4512     bnzi = bi[i+1] - bi[i];
4513     ierr = PetscMemzero(ba_i,bnzi*sizeof(PetscScalar));CHKERRQ(ierr);
4514 
4515     /* add local non-zero vals of this proc's seqmat into ba */
4516     anzi   = ai[arow+1] - ai[arow];
4517     aj     = a->j + ai[arow];
4518     aa     = a->a + ai[arow];
4519     nextaj = 0;
4520     for (j=0; nextaj<anzi; j++) {
4521       if (*(bj_i + j) == aj[nextaj]) { /* bcol == acol */
4522         ba_i[j] += aa[nextaj++];
4523       }
4524     }
4525 
4526     /* add received vals into ba */
4527     for (k=0; k<merge->nrecv; k++) { /* k-th received message */
4528       /* i-th row */
4529       if (i == *nextrow[k]) {
4530         anzi   = *(nextai[k]+1) - *nextai[k];
4531         aj     = buf_rj[k] + *(nextai[k]);
4532         aa     = abuf_r[k] + *(nextai[k]);
4533         nextaj = 0;
4534         for (j=0; nextaj<anzi; j++) {
4535           if (*(bj_i + j) == aj[nextaj]) { /* bcol == acol */
4536             ba_i[j] += aa[nextaj++];
4537           }
4538         }
4539         nextrow[k]++; nextai[k]++;
4540       }
4541     }
4542     ierr = MatSetValues(mpimat,1,&arow,bnzi,bj_i,ba_i,INSERT_VALUES);CHKERRQ(ierr);
4543   }
4544   ierr = MatAssemblyBegin(mpimat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4545   ierr = MatAssemblyEnd(mpimat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4546 
4547   ierr = PetscFree(abuf_r[0]);CHKERRQ(ierr);
4548   ierr = PetscFree(abuf_r);CHKERRQ(ierr);
4549   ierr = PetscFree(ba_i);CHKERRQ(ierr);
4550   ierr = PetscFree3(buf_ri_k,nextrow,nextai);CHKERRQ(ierr);
4551   ierr = PetscLogEventEnd(MAT_Seqstompinum,seqmat,0,0,0);CHKERRQ(ierr);
4552   PetscFunctionReturn(0);
4553 }
4554 
4555 PetscErrorCode  MatCreateMPIAIJSumSeqAIJSymbolic(MPI_Comm comm,Mat seqmat,PetscInt m,PetscInt n,Mat *mpimat)
4556 {
4557   PetscErrorCode      ierr;
4558   Mat                 B_mpi;
4559   Mat_SeqAIJ          *a=(Mat_SeqAIJ*)seqmat->data;
4560   PetscMPIInt         size,rank,tagi,tagj,*len_s,*len_si,*len_ri;
4561   PetscInt            **buf_rj,**buf_ri,**buf_ri_k;
4562   PetscInt            M=seqmat->rmap->n,N=seqmat->cmap->n,i,*owners,*ai=a->i,*aj=a->j;
4563   PetscInt            len,proc,*dnz,*onz,bs,cbs;
4564   PetscInt            k,anzi,*bi,*bj,*lnk,nlnk,arow,bnzi,nspacedouble=0;
4565   PetscInt            nrows,*buf_s,*buf_si,*buf_si_i,**nextrow,**nextai;
4566   MPI_Request         *si_waits,*sj_waits,*ri_waits,*rj_waits;
4567   MPI_Status          *status;
4568   PetscFreeSpaceList  free_space=NULL,current_space=NULL;
4569   PetscBT             lnkbt;
4570   Mat_Merge_SeqsToMPI *merge;
4571   PetscContainer      container;
4572 
4573   PetscFunctionBegin;
4574   ierr = PetscLogEventBegin(MAT_Seqstompisym,seqmat,0,0,0);CHKERRQ(ierr);
4575 
4576   /* make sure it is a PETSc comm */
4577   ierr = PetscCommDuplicate(comm,&comm,NULL);CHKERRQ(ierr);
4578   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4579   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4580 
4581   ierr = PetscNew(&merge);CHKERRQ(ierr);
4582   ierr = PetscMalloc1(size,&status);CHKERRQ(ierr);
4583 
4584   /* determine row ownership */
4585   /*---------------------------------------------------------*/
4586   ierr = PetscLayoutCreate(comm,&merge->rowmap);CHKERRQ(ierr);
4587   ierr = PetscLayoutSetLocalSize(merge->rowmap,m);CHKERRQ(ierr);
4588   ierr = PetscLayoutSetSize(merge->rowmap,M);CHKERRQ(ierr);
4589   ierr = PetscLayoutSetBlockSize(merge->rowmap,1);CHKERRQ(ierr);
4590   ierr = PetscLayoutSetUp(merge->rowmap);CHKERRQ(ierr);
4591   ierr = PetscMalloc1(size,&len_si);CHKERRQ(ierr);
4592   ierr = PetscMalloc1(size,&merge->len_s);CHKERRQ(ierr);
4593 
4594   m      = merge->rowmap->n;
4595   owners = merge->rowmap->range;
4596 
4597   /* determine the number of messages to send, their lengths */
4598   /*---------------------------------------------------------*/
4599   len_s = merge->len_s;
4600 
4601   len          = 0; /* length of buf_si[] */
4602   merge->nsend = 0;
4603   for (proc=0; proc<size; proc++) {
4604     len_si[proc] = 0;
4605     if (proc == rank) {
4606       len_s[proc] = 0;
4607     } else {
4608       len_si[proc] = owners[proc+1] - owners[proc] + 1;
4609       len_s[proc]  = ai[owners[proc+1]] - ai[owners[proc]]; /* num of rows to be sent to [proc] */
4610     }
4611     if (len_s[proc]) {
4612       merge->nsend++;
4613       nrows = 0;
4614       for (i=owners[proc]; i<owners[proc+1]; i++) {
4615         if (ai[i+1] > ai[i]) nrows++;
4616       }
4617       len_si[proc] = 2*(nrows+1);
4618       len         += len_si[proc];
4619     }
4620   }
4621 
4622   /* determine the number and length of messages to receive for ij-structure */
4623   /*-------------------------------------------------------------------------*/
4624   ierr = PetscGatherNumberOfMessages(comm,NULL,len_s,&merge->nrecv);CHKERRQ(ierr);
4625   ierr = PetscGatherMessageLengths2(comm,merge->nsend,merge->nrecv,len_s,len_si,&merge->id_r,&merge->len_r,&len_ri);CHKERRQ(ierr);
4626 
4627   /* post the Irecv of j-structure */
4628   /*-------------------------------*/
4629   ierr = PetscCommGetNewTag(comm,&tagj);CHKERRQ(ierr);
4630   ierr = PetscPostIrecvInt(comm,tagj,merge->nrecv,merge->id_r,merge->len_r,&buf_rj,&rj_waits);CHKERRQ(ierr);
4631 
4632   /* post the Isend of j-structure */
4633   /*--------------------------------*/
4634   ierr = PetscMalloc2(merge->nsend,&si_waits,merge->nsend,&sj_waits);CHKERRQ(ierr);
4635 
4636   for (proc=0, k=0; proc<size; proc++) {
4637     if (!len_s[proc]) continue;
4638     i    = owners[proc];
4639     ierr = MPI_Isend(aj+ai[i],len_s[proc],MPIU_INT,proc,tagj,comm,sj_waits+k);CHKERRQ(ierr);
4640     k++;
4641   }
4642 
4643   /* receives and sends of j-structure are complete */
4644   /*------------------------------------------------*/
4645   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,rj_waits,status);CHKERRQ(ierr);}
4646   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,sj_waits,status);CHKERRQ(ierr);}
4647 
4648   /* send and recv i-structure */
4649   /*---------------------------*/
4650   ierr = PetscCommGetNewTag(comm,&tagi);CHKERRQ(ierr);
4651   ierr = PetscPostIrecvInt(comm,tagi,merge->nrecv,merge->id_r,len_ri,&buf_ri,&ri_waits);CHKERRQ(ierr);
4652 
4653   ierr   = PetscMalloc1(len+1,&buf_s);CHKERRQ(ierr);
4654   buf_si = buf_s;  /* points to the beginning of k-th msg to be sent */
4655   for (proc=0,k=0; proc<size; proc++) {
4656     if (!len_s[proc]) continue;
4657     /* form outgoing message for i-structure:
4658          buf_si[0]:                 nrows to be sent
4659                [1:nrows]:           row index (global)
4660                [nrows+1:2*nrows+1]: i-structure index
4661     */
4662     /*-------------------------------------------*/
4663     nrows       = len_si[proc]/2 - 1;
4664     buf_si_i    = buf_si + nrows+1;
4665     buf_si[0]   = nrows;
4666     buf_si_i[0] = 0;
4667     nrows       = 0;
4668     for (i=owners[proc]; i<owners[proc+1]; i++) {
4669       anzi = ai[i+1] - ai[i];
4670       if (anzi) {
4671         buf_si_i[nrows+1] = buf_si_i[nrows] + anzi; /* i-structure */
4672         buf_si[nrows+1]   = i-owners[proc]; /* local row index */
4673         nrows++;
4674       }
4675     }
4676     ierr = MPI_Isend(buf_si,len_si[proc],MPIU_INT,proc,tagi,comm,si_waits+k);CHKERRQ(ierr);
4677     k++;
4678     buf_si += len_si[proc];
4679   }
4680 
4681   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,ri_waits,status);CHKERRQ(ierr);}
4682   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,si_waits,status);CHKERRQ(ierr);}
4683 
4684   ierr = PetscInfo2(seqmat,"nsend: %D, nrecv: %D\n",merge->nsend,merge->nrecv);CHKERRQ(ierr);
4685   for (i=0; i<merge->nrecv; i++) {
4686     ierr = PetscInfo3(seqmat,"recv len_ri=%D, len_rj=%D from [%D]\n",len_ri[i],merge->len_r[i],merge->id_r[i]);CHKERRQ(ierr);
4687   }
4688 
4689   ierr = PetscFree(len_si);CHKERRQ(ierr);
4690   ierr = PetscFree(len_ri);CHKERRQ(ierr);
4691   ierr = PetscFree(rj_waits);CHKERRQ(ierr);
4692   ierr = PetscFree2(si_waits,sj_waits);CHKERRQ(ierr);
4693   ierr = PetscFree(ri_waits);CHKERRQ(ierr);
4694   ierr = PetscFree(buf_s);CHKERRQ(ierr);
4695   ierr = PetscFree(status);CHKERRQ(ierr);
4696 
4697   /* compute a local seq matrix in each processor */
4698   /*----------------------------------------------*/
4699   /* allocate bi array and free space for accumulating nonzero column info */
4700   ierr  = PetscMalloc1(m+1,&bi);CHKERRQ(ierr);
4701   bi[0] = 0;
4702 
4703   /* create and initialize a linked list */
4704   nlnk = N+1;
4705   ierr = PetscLLCreate(N,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4706 
4707   /* initial FreeSpace size is 2*(num of local nnz(seqmat)) */
4708   len  = ai[owners[rank+1]] - ai[owners[rank]];
4709   ierr = PetscFreeSpaceGet(PetscIntMultTruncate(2,len)+1,&free_space);CHKERRQ(ierr);
4710 
4711   current_space = free_space;
4712 
4713   /* determine symbolic info for each local row */
4714   ierr = PetscMalloc3(merge->nrecv,&buf_ri_k,merge->nrecv,&nextrow,merge->nrecv,&nextai);CHKERRQ(ierr);
4715 
4716   for (k=0; k<merge->nrecv; k++) {
4717     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
4718     nrows       = *buf_ri_k[k];
4719     nextrow[k]  = buf_ri_k[k] + 1;  /* next row number of k-th recved i-structure */
4720     nextai[k]   = buf_ri_k[k] + (nrows + 1); /* poins to the next i-structure of k-th recved i-structure  */
4721   }
4722 
4723   ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
4724   len  = 0;
4725   for (i=0; i<m; i++) {
4726     bnzi = 0;
4727     /* add local non-zero cols of this proc's seqmat into lnk */
4728     arow  = owners[rank] + i;
4729     anzi  = ai[arow+1] - ai[arow];
4730     aj    = a->j + ai[arow];
4731     ierr  = PetscLLAddSorted(anzi,aj,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4732     bnzi += nlnk;
4733     /* add received col data into lnk */
4734     for (k=0; k<merge->nrecv; k++) { /* k-th received message */
4735       if (i == *nextrow[k]) { /* i-th row */
4736         anzi  = *(nextai[k]+1) - *nextai[k];
4737         aj    = buf_rj[k] + *nextai[k];
4738         ierr  = PetscLLAddSorted(anzi,aj,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4739         bnzi += nlnk;
4740         nextrow[k]++; nextai[k]++;
4741       }
4742     }
4743     if (len < bnzi) len = bnzi;  /* =max(bnzi) */
4744 
4745     /* if free space is not available, make more free space */
4746     if (current_space->local_remaining<bnzi) {
4747       ierr = PetscFreeSpaceGet(PetscIntSumTruncate(bnzi,current_space->total_array_size),&current_space);CHKERRQ(ierr);
4748       nspacedouble++;
4749     }
4750     /* copy data into free space, then initialize lnk */
4751     ierr = PetscLLClean(N,N,bnzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
4752     ierr = MatPreallocateSet(i+owners[rank],bnzi,current_space->array,dnz,onz);CHKERRQ(ierr);
4753 
4754     current_space->array           += bnzi;
4755     current_space->local_used      += bnzi;
4756     current_space->local_remaining -= bnzi;
4757 
4758     bi[i+1] = bi[i] + bnzi;
4759   }
4760 
4761   ierr = PetscFree3(buf_ri_k,nextrow,nextai);CHKERRQ(ierr);
4762 
4763   ierr = PetscMalloc1(bi[m]+1,&bj);CHKERRQ(ierr);
4764   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr);
4765   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
4766 
4767   /* create symbolic parallel matrix B_mpi */
4768   /*---------------------------------------*/
4769   ierr = MatGetBlockSizes(seqmat,&bs,&cbs);CHKERRQ(ierr);
4770   ierr = MatCreate(comm,&B_mpi);CHKERRQ(ierr);
4771   if (n==PETSC_DECIDE) {
4772     ierr = MatSetSizes(B_mpi,m,n,PETSC_DETERMINE,N);CHKERRQ(ierr);
4773   } else {
4774     ierr = MatSetSizes(B_mpi,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
4775   }
4776   ierr = MatSetBlockSizes(B_mpi,bs,cbs);CHKERRQ(ierr);
4777   ierr = MatSetType(B_mpi,MATMPIAIJ);CHKERRQ(ierr);
4778   ierr = MatMPIAIJSetPreallocation(B_mpi,0,dnz,0,onz);CHKERRQ(ierr);
4779   ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
4780   ierr = MatSetOption(B_mpi,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr);
4781 
4782   /* B_mpi is not ready for use - assembly will be done by MatCreateMPIAIJSumSeqAIJNumeric() */
4783   B_mpi->assembled    = PETSC_FALSE;
4784   B_mpi->ops->destroy = MatDestroy_MPIAIJ_SeqsToMPI;
4785   merge->bi           = bi;
4786   merge->bj           = bj;
4787   merge->buf_ri       = buf_ri;
4788   merge->buf_rj       = buf_rj;
4789   merge->coi          = NULL;
4790   merge->coj          = NULL;
4791   merge->owners_co    = NULL;
4792 
4793   ierr = PetscCommDestroy(&comm);CHKERRQ(ierr);
4794 
4795   /* attach the supporting struct to B_mpi for reuse */
4796   ierr    = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
4797   ierr    = PetscContainerSetPointer(container,merge);CHKERRQ(ierr);
4798   ierr    = PetscObjectCompose((PetscObject)B_mpi,"MatMergeSeqsToMPI",(PetscObject)container);CHKERRQ(ierr);
4799   ierr    = PetscContainerDestroy(&container);CHKERRQ(ierr);
4800   *mpimat = B_mpi;
4801 
4802   ierr = PetscLogEventEnd(MAT_Seqstompisym,seqmat,0,0,0);CHKERRQ(ierr);
4803   PetscFunctionReturn(0);
4804 }
4805 
4806 /*@C
4807       MatCreateMPIAIJSumSeqAIJ - Creates a MATMPIAIJ matrix by adding sequential
4808                  matrices from each processor
4809 
4810     Collective on MPI_Comm
4811 
4812    Input Parameters:
4813 +    comm - the communicators the parallel matrix will live on
4814 .    seqmat - the input sequential matrices
4815 .    m - number of local rows (or PETSC_DECIDE)
4816 .    n - number of local columns (or PETSC_DECIDE)
4817 -    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4818 
4819    Output Parameter:
4820 .    mpimat - the parallel matrix generated
4821 
4822     Level: advanced
4823 
4824    Notes:
4825      The dimensions of the sequential matrix in each processor MUST be the same.
4826      The input seqmat is included into the container "Mat_Merge_SeqsToMPI", and will be
4827      destroyed when mpimat is destroyed. Call PetscObjectQuery() to access seqmat.
4828 @*/
4829 PetscErrorCode MatCreateMPIAIJSumSeqAIJ(MPI_Comm comm,Mat seqmat,PetscInt m,PetscInt n,MatReuse scall,Mat *mpimat)
4830 {
4831   PetscErrorCode ierr;
4832   PetscMPIInt    size;
4833 
4834   PetscFunctionBegin;
4835   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4836   if (size == 1) {
4837     ierr = PetscLogEventBegin(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4838     if (scall == MAT_INITIAL_MATRIX) {
4839       ierr = MatDuplicate(seqmat,MAT_COPY_VALUES,mpimat);CHKERRQ(ierr);
4840     } else {
4841       ierr = MatCopy(seqmat,*mpimat,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
4842     }
4843     ierr = PetscLogEventEnd(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4844     PetscFunctionReturn(0);
4845   }
4846   ierr = PetscLogEventBegin(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4847   if (scall == MAT_INITIAL_MATRIX) {
4848     ierr = MatCreateMPIAIJSumSeqAIJSymbolic(comm,seqmat,m,n,mpimat);CHKERRQ(ierr);
4849   }
4850   ierr = MatCreateMPIAIJSumSeqAIJNumeric(seqmat,*mpimat);CHKERRQ(ierr);
4851   ierr = PetscLogEventEnd(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4852   PetscFunctionReturn(0);
4853 }
4854 
4855 /*@
4856      MatMPIAIJGetLocalMat - Creates a SeqAIJ from a MATMPIAIJ matrix by taking all its local rows and putting them into a sequential matrix with
4857           mlocal rows and n columns. Where mlocal is the row count obtained with MatGetLocalSize() and n is the global column count obtained
4858           with MatGetSize()
4859 
4860     Not Collective
4861 
4862    Input Parameters:
4863 +    A - the matrix
4864 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4865 
4866    Output Parameter:
4867 .    A_loc - the local sequential matrix generated
4868 
4869     Level: developer
4870 
4871 .seealso: MatGetOwnerShipRange(), MatMPIAIJGetLocalMatCondensed()
4872 
4873 @*/
4874 PetscErrorCode MatMPIAIJGetLocalMat(Mat A,MatReuse scall,Mat *A_loc)
4875 {
4876   PetscErrorCode ierr;
4877   Mat_MPIAIJ     *mpimat=(Mat_MPIAIJ*)A->data;
4878   Mat_SeqAIJ     *mat,*a,*b;
4879   PetscInt       *ai,*aj,*bi,*bj,*cmap=mpimat->garray;
4880   MatScalar      *aa,*ba,*cam;
4881   PetscScalar    *ca;
4882   PetscInt       am=A->rmap->n,i,j,k,cstart=A->cmap->rstart;
4883   PetscInt       *ci,*cj,col,ncols_d,ncols_o,jo;
4884   PetscBool      match;
4885   MPI_Comm       comm;
4886   PetscMPIInt    size;
4887 
4888   PetscFunctionBegin;
4889   ierr = PetscObjectTypeCompare((PetscObject)A,MATMPIAIJ,&match);CHKERRQ(ierr);
4890   if (!match) SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_SUP,"Requires MATMPIAIJ matrix as input");
4891   ierr = PetscObjectGetComm((PetscObject)A,&comm);CHKERRQ(ierr);
4892   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4893   if (size == 1 && scall == MAT_REUSE_MATRIX) PetscFunctionReturn(0);
4894 
4895   ierr = PetscLogEventBegin(MAT_Getlocalmat,A,0,0,0);CHKERRQ(ierr);
4896   a = (Mat_SeqAIJ*)(mpimat->A)->data;
4897   b = (Mat_SeqAIJ*)(mpimat->B)->data;
4898   ai = a->i; aj = a->j; bi = b->i; bj = b->j;
4899   aa = a->a; ba = b->a;
4900   if (scall == MAT_INITIAL_MATRIX) {
4901     if (size == 1) {
4902       ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,am,A->cmap->N,ai,aj,aa,A_loc);CHKERRQ(ierr);
4903       PetscFunctionReturn(0);
4904     }
4905 
4906     ierr  = PetscMalloc1(1+am,&ci);CHKERRQ(ierr);
4907     ci[0] = 0;
4908     for (i=0; i<am; i++) {
4909       ci[i+1] = ci[i] + (ai[i+1] - ai[i]) + (bi[i+1] - bi[i]);
4910     }
4911     ierr = PetscMalloc1(1+ci[am],&cj);CHKERRQ(ierr);
4912     ierr = PetscMalloc1(1+ci[am],&ca);CHKERRQ(ierr);
4913     k    = 0;
4914     for (i=0; i<am; i++) {
4915       ncols_o = bi[i+1] - bi[i];
4916       ncols_d = ai[i+1] - ai[i];
4917       /* off-diagonal portion of A */
4918       for (jo=0; jo<ncols_o; jo++) {
4919         col = cmap[*bj];
4920         if (col >= cstart) break;
4921         cj[k]   = col; bj++;
4922         ca[k++] = *ba++;
4923       }
4924       /* diagonal portion of A */
4925       for (j=0; j<ncols_d; j++) {
4926         cj[k]   = cstart + *aj++;
4927         ca[k++] = *aa++;
4928       }
4929       /* off-diagonal portion of A */
4930       for (j=jo; j<ncols_o; j++) {
4931         cj[k]   = cmap[*bj++];
4932         ca[k++] = *ba++;
4933       }
4934     }
4935     /* put together the new matrix */
4936     ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,am,A->cmap->N,ci,cj,ca,A_loc);CHKERRQ(ierr);
4937     /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
4938     /* Since these are PETSc arrays, change flags to free them as necessary. */
4939     mat          = (Mat_SeqAIJ*)(*A_loc)->data;
4940     mat->free_a  = PETSC_TRUE;
4941     mat->free_ij = PETSC_TRUE;
4942     mat->nonew   = 0;
4943   } else if (scall == MAT_REUSE_MATRIX) {
4944     mat=(Mat_SeqAIJ*)(*A_loc)->data;
4945     ci = mat->i; cj = mat->j; cam = mat->a;
4946     for (i=0; i<am; i++) {
4947       /* off-diagonal portion of A */
4948       ncols_o = bi[i+1] - bi[i];
4949       for (jo=0; jo<ncols_o; jo++) {
4950         col = cmap[*bj];
4951         if (col >= cstart) break;
4952         *cam++ = *ba++; bj++;
4953       }
4954       /* diagonal portion of A */
4955       ncols_d = ai[i+1] - ai[i];
4956       for (j=0; j<ncols_d; j++) *cam++ = *aa++;
4957       /* off-diagonal portion of A */
4958       for (j=jo; j<ncols_o; j++) {
4959         *cam++ = *ba++; bj++;
4960       }
4961     }
4962   } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid MatReuse %d",(int)scall);
4963   ierr = PetscLogEventEnd(MAT_Getlocalmat,A,0,0,0);CHKERRQ(ierr);
4964   PetscFunctionReturn(0);
4965 }
4966 
4967 /*@C
4968      MatMPIAIJGetLocalMatCondensed - Creates a SeqAIJ matrix from an MATMPIAIJ matrix by taking all its local rows and NON-ZERO columns
4969 
4970     Not Collective
4971 
4972    Input Parameters:
4973 +    A - the matrix
4974 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4975 -    row, col - index sets of rows and columns to extract (or NULL)
4976 
4977    Output Parameter:
4978 .    A_loc - the local sequential matrix generated
4979 
4980     Level: developer
4981 
4982 .seealso: MatGetOwnershipRange(), MatMPIAIJGetLocalMat()
4983 
4984 @*/
4985 PetscErrorCode MatMPIAIJGetLocalMatCondensed(Mat A,MatReuse scall,IS *row,IS *col,Mat *A_loc)
4986 {
4987   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)A->data;
4988   PetscErrorCode ierr;
4989   PetscInt       i,start,end,ncols,nzA,nzB,*cmap,imark,*idx;
4990   IS             isrowa,iscola;
4991   Mat            *aloc;
4992   PetscBool      match;
4993 
4994   PetscFunctionBegin;
4995   ierr = PetscObjectTypeCompare((PetscObject)A,MATMPIAIJ,&match);CHKERRQ(ierr);
4996   if (!match) SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_SUP,"Requires MATMPIAIJ matrix as input");
4997   ierr = PetscLogEventBegin(MAT_Getlocalmatcondensed,A,0,0,0);CHKERRQ(ierr);
4998   if (!row) {
4999     start = A->rmap->rstart; end = A->rmap->rend;
5000     ierr  = ISCreateStride(PETSC_COMM_SELF,end-start,start,1,&isrowa);CHKERRQ(ierr);
5001   } else {
5002     isrowa = *row;
5003   }
5004   if (!col) {
5005     start = A->cmap->rstart;
5006     cmap  = a->garray;
5007     nzA   = a->A->cmap->n;
5008     nzB   = a->B->cmap->n;
5009     ierr  = PetscMalloc1(nzA+nzB, &idx);CHKERRQ(ierr);
5010     ncols = 0;
5011     for (i=0; i<nzB; i++) {
5012       if (cmap[i] < start) idx[ncols++] = cmap[i];
5013       else break;
5014     }
5015     imark = i;
5016     for (i=0; i<nzA; i++) idx[ncols++] = start + i;
5017     for (i=imark; i<nzB; i++) idx[ncols++] = cmap[i];
5018     ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,PETSC_OWN_POINTER,&iscola);CHKERRQ(ierr);
5019   } else {
5020     iscola = *col;
5021   }
5022   if (scall != MAT_INITIAL_MATRIX) {
5023     ierr    = PetscMalloc1(1,&aloc);CHKERRQ(ierr);
5024     aloc[0] = *A_loc;
5025   }
5026   ierr   = MatCreateSubMatrices(A,1,&isrowa,&iscola,scall,&aloc);CHKERRQ(ierr);
5027   *A_loc = aloc[0];
5028   ierr   = PetscFree(aloc);CHKERRQ(ierr);
5029   if (!row) {
5030     ierr = ISDestroy(&isrowa);CHKERRQ(ierr);
5031   }
5032   if (!col) {
5033     ierr = ISDestroy(&iscola);CHKERRQ(ierr);
5034   }
5035   ierr = PetscLogEventEnd(MAT_Getlocalmatcondensed,A,0,0,0);CHKERRQ(ierr);
5036   PetscFunctionReturn(0);
5037 }
5038 
5039 /*@C
5040     MatGetBrowsOfAcols - Creates a SeqAIJ matrix by taking rows of B that equal to nonzero columns of local A
5041 
5042     Collective on Mat
5043 
5044    Input Parameters:
5045 +    A,B - the matrices in mpiaij format
5046 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
5047 -    rowb, colb - index sets of rows and columns of B to extract (or NULL)
5048 
5049    Output Parameter:
5050 +    rowb, colb - index sets of rows and columns of B to extract
5051 -    B_seq - the sequential matrix generated
5052 
5053     Level: developer
5054 
5055 @*/
5056 PetscErrorCode MatGetBrowsOfAcols(Mat A,Mat B,MatReuse scall,IS *rowb,IS *colb,Mat *B_seq)
5057 {
5058   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)A->data;
5059   PetscErrorCode ierr;
5060   PetscInt       *idx,i,start,ncols,nzA,nzB,*cmap,imark;
5061   IS             isrowb,iscolb;
5062   Mat            *bseq=NULL;
5063 
5064   PetscFunctionBegin;
5065   if (A->cmap->rstart != B->rmap->rstart || A->cmap->rend != B->rmap->rend) {
5066     SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Matrix local dimensions are incompatible, (%D, %D) != (%D,%D)",A->cmap->rstart,A->cmap->rend,B->rmap->rstart,B->rmap->rend);
5067   }
5068   ierr = PetscLogEventBegin(MAT_GetBrowsOfAcols,A,B,0,0);CHKERRQ(ierr);
5069 
5070   if (scall == MAT_INITIAL_MATRIX) {
5071     start = A->cmap->rstart;
5072     cmap  = a->garray;
5073     nzA   = a->A->cmap->n;
5074     nzB   = a->B->cmap->n;
5075     ierr  = PetscMalloc1(nzA+nzB, &idx);CHKERRQ(ierr);
5076     ncols = 0;
5077     for (i=0; i<nzB; i++) {  /* row < local row index */
5078       if (cmap[i] < start) idx[ncols++] = cmap[i];
5079       else break;
5080     }
5081     imark = i;
5082     for (i=0; i<nzA; i++) idx[ncols++] = start + i;  /* local rows */
5083     for (i=imark; i<nzB; i++) idx[ncols++] = cmap[i]; /* row > local row index */
5084     ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,PETSC_OWN_POINTER,&isrowb);CHKERRQ(ierr);
5085     ierr = ISCreateStride(PETSC_COMM_SELF,B->cmap->N,0,1,&iscolb);CHKERRQ(ierr);
5086   } else {
5087     if (!rowb || !colb) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"IS rowb and colb must be provided for MAT_REUSE_MATRIX");
5088     isrowb  = *rowb; iscolb = *colb;
5089     ierr    = PetscMalloc1(1,&bseq);CHKERRQ(ierr);
5090     bseq[0] = *B_seq;
5091   }
5092   ierr   = MatCreateSubMatrices(B,1,&isrowb,&iscolb,scall,&bseq);CHKERRQ(ierr);
5093   *B_seq = bseq[0];
5094   ierr   = PetscFree(bseq);CHKERRQ(ierr);
5095   if (!rowb) {
5096     ierr = ISDestroy(&isrowb);CHKERRQ(ierr);
5097   } else {
5098     *rowb = isrowb;
5099   }
5100   if (!colb) {
5101     ierr = ISDestroy(&iscolb);CHKERRQ(ierr);
5102   } else {
5103     *colb = iscolb;
5104   }
5105   ierr = PetscLogEventEnd(MAT_GetBrowsOfAcols,A,B,0,0);CHKERRQ(ierr);
5106   PetscFunctionReturn(0);
5107 }
5108 
5109 /*
5110     MatGetBrowsOfAoCols_MPIAIJ - Creates a SeqAIJ matrix by taking rows of B that equal to nonzero columns
5111     of the OFF-DIAGONAL portion of local A
5112 
5113     Collective on Mat
5114 
5115    Input Parameters:
5116 +    A,B - the matrices in mpiaij format
5117 -    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
5118 
5119    Output Parameter:
5120 +    startsj_s - starting point in B's sending j-arrays, saved for MAT_REUSE (or NULL)
5121 .    startsj_r - starting point in B's receiving j-arrays, saved for MAT_REUSE (or NULL)
5122 .    bufa_ptr - array for sending matrix values, saved for MAT_REUSE (or NULL)
5123 -    B_oth - the sequential matrix generated with size aBn=a->B->cmap->n by B->cmap->N
5124 
5125     Level: developer
5126 
5127 */
5128 PetscErrorCode MatGetBrowsOfAoCols_MPIAIJ(Mat A,Mat B,MatReuse scall,PetscInt **startsj_s,PetscInt **startsj_r,MatScalar **bufa_ptr,Mat *B_oth)
5129 {
5130   VecScatter_MPI_General *gen_to,*gen_from;
5131   PetscErrorCode         ierr;
5132   Mat_MPIAIJ             *a=(Mat_MPIAIJ*)A->data;
5133   Mat_SeqAIJ             *b_oth;
5134   VecScatter             ctx;
5135   MPI_Comm               comm;
5136   PetscMPIInt            *rprocs,*sprocs,tag,rank;
5137   PetscInt               *rowlen,*bufj,*bufJ,ncols,aBn=a->B->cmap->n,row,*b_othi,*b_othj;
5138   PetscInt               *rvalues,*svalues;
5139   MatScalar              *b_otha,*bufa,*bufA;
5140   PetscInt               i,j,k,l,ll,nrecvs,nsends,nrows,*srow,*rstarts,*rstartsj = 0,*sstarts,*sstartsj,len;
5141   MPI_Request            *rwaits = NULL,*swaits = NULL;
5142   MPI_Status             *sstatus,rstatus;
5143   PetscMPIInt            jj,size;
5144   PetscInt               *cols,sbs,rbs;
5145   PetscScalar            *vals;
5146 
5147   PetscFunctionBegin;
5148   ierr = PetscObjectGetComm((PetscObject)A,&comm);CHKERRQ(ierr);
5149   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
5150 
5151   if (A->cmap->rstart != B->rmap->rstart || A->cmap->rend != B->rmap->rend) {
5152     SETERRQ4(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Matrix local dimensions are incompatible, (%d, %d) != (%d,%d)",A->cmap->rstart,A->cmap->rend,B->rmap->rstart,B->rmap->rend);
5153   }
5154   ierr = PetscLogEventBegin(MAT_GetBrowsOfAocols,A,B,0,0);CHKERRQ(ierr);
5155   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
5156 
5157   if (size == 1) {
5158     startsj_s = NULL;
5159     bufa_ptr  = NULL;
5160     *B_oth    = NULL;
5161     PetscFunctionReturn(0);
5162   }
5163 
5164   if (!a->Mvctx_mpi1) { /* create a->Mvctx_mpi1 to be used for Mat-Mat ops */
5165     a->Mvctx_mpi1_flg = PETSC_TRUE;
5166     ierr = MatSetUpMultiply_MPIAIJ(A);CHKERRQ(ierr);
5167   }
5168   ctx = a->Mvctx_mpi1;
5169   tag = ((PetscObject)ctx)->tag;
5170 
5171   gen_to   = (VecScatter_MPI_General*)ctx->todata;
5172   gen_from = (VecScatter_MPI_General*)ctx->fromdata;
5173   nrecvs   = gen_from->n;
5174   nsends   = gen_to->n;
5175 
5176   ierr    = PetscMalloc2(nrecvs,&rwaits,nsends,&swaits);CHKERRQ(ierr);
5177   srow    = gen_to->indices;    /* local row index to be sent */
5178   sstarts = gen_to->starts;
5179   sprocs  = gen_to->procs;
5180   sstatus = gen_to->sstatus;
5181   sbs     = gen_to->bs;
5182   rstarts = gen_from->starts;
5183   rprocs  = gen_from->procs;
5184   rbs     = gen_from->bs;
5185 
5186   if (!startsj_s || !bufa_ptr) scall = MAT_INITIAL_MATRIX;
5187   if (scall == MAT_INITIAL_MATRIX) {
5188     /* i-array */
5189     /*---------*/
5190     /*  post receives */
5191     ierr = PetscMalloc1(rbs*(rstarts[nrecvs] - rstarts[0]),&rvalues);CHKERRQ(ierr);
5192     for (i=0; i<nrecvs; i++) {
5193       rowlen = rvalues + rstarts[i]*rbs;
5194       nrows  = (rstarts[i+1]-rstarts[i])*rbs; /* num of indices to be received */
5195       ierr   = MPI_Irecv(rowlen,nrows,MPIU_INT,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
5196     }
5197 
5198     /* pack the outgoing message */
5199     ierr = PetscMalloc2(nsends+1,&sstartsj,nrecvs+1,&rstartsj);CHKERRQ(ierr);
5200 
5201     sstartsj[0] = 0;
5202     rstartsj[0] = 0;
5203     len         = 0; /* total length of j or a array to be sent */
5204     k           = 0;
5205     ierr = PetscMalloc1(sbs*(sstarts[nsends] - sstarts[0]),&svalues);CHKERRQ(ierr);
5206     for (i=0; i<nsends; i++) {
5207       rowlen = svalues + sstarts[i]*sbs;
5208       nrows  = sstarts[i+1]-sstarts[i]; /* num of block rows */
5209       for (j=0; j<nrows; j++) {
5210         row = srow[k] + B->rmap->range[rank]; /* global row idx */
5211         for (l=0; l<sbs; l++) {
5212           ierr = MatGetRow_MPIAIJ(B,row+l,&ncols,NULL,NULL);CHKERRQ(ierr); /* rowlength */
5213 
5214           rowlen[j*sbs+l] = ncols;
5215 
5216           len += ncols;
5217           ierr = MatRestoreRow_MPIAIJ(B,row+l,&ncols,NULL,NULL);CHKERRQ(ierr);
5218         }
5219         k++;
5220       }
5221       ierr = MPI_Isend(rowlen,nrows*sbs,MPIU_INT,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
5222 
5223       sstartsj[i+1] = len;  /* starting point of (i+1)-th outgoing msg in bufj and bufa */
5224     }
5225     /* recvs and sends of i-array are completed */
5226     i = nrecvs;
5227     while (i--) {
5228       ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
5229     }
5230     if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
5231     ierr = PetscFree(svalues);CHKERRQ(ierr);
5232 
5233     /* allocate buffers for sending j and a arrays */
5234     ierr = PetscMalloc1(len+1,&bufj);CHKERRQ(ierr);
5235     ierr = PetscMalloc1(len+1,&bufa);CHKERRQ(ierr);
5236 
5237     /* create i-array of B_oth */
5238     ierr = PetscMalloc1(aBn+2,&b_othi);CHKERRQ(ierr);
5239 
5240     b_othi[0] = 0;
5241     len       = 0; /* total length of j or a array to be received */
5242     k         = 0;
5243     for (i=0; i<nrecvs; i++) {
5244       rowlen = rvalues + rstarts[i]*rbs;
5245       nrows  = rbs*(rstarts[i+1]-rstarts[i]); /* num of rows to be received */
5246       for (j=0; j<nrows; j++) {
5247         b_othi[k+1] = b_othi[k] + rowlen[j];
5248         ierr = PetscIntSumError(rowlen[j],len,&len);CHKERRQ(ierr);
5249         k++;
5250       }
5251       rstartsj[i+1] = len; /* starting point of (i+1)-th incoming msg in bufj and bufa */
5252     }
5253     ierr = PetscFree(rvalues);CHKERRQ(ierr);
5254 
5255     /* allocate space for j and a arrrays of B_oth */
5256     ierr = PetscMalloc1(b_othi[aBn]+1,&b_othj);CHKERRQ(ierr);
5257     ierr = PetscMalloc1(b_othi[aBn]+1,&b_otha);CHKERRQ(ierr);
5258 
5259     /* j-array */
5260     /*---------*/
5261     /*  post receives of j-array */
5262     for (i=0; i<nrecvs; i++) {
5263       nrows = rstartsj[i+1]-rstartsj[i]; /* length of the msg received */
5264       ierr  = MPI_Irecv(b_othj+rstartsj[i],nrows,MPIU_INT,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
5265     }
5266 
5267     /* pack the outgoing message j-array */
5268     k = 0;
5269     for (i=0; i<nsends; i++) {
5270       nrows = sstarts[i+1]-sstarts[i]; /* num of block rows */
5271       bufJ  = bufj+sstartsj[i];
5272       for (j=0; j<nrows; j++) {
5273         row = srow[k++] + B->rmap->range[rank];  /* global row idx */
5274         for (ll=0; ll<sbs; ll++) {
5275           ierr = MatGetRow_MPIAIJ(B,row+ll,&ncols,&cols,NULL);CHKERRQ(ierr);
5276           for (l=0; l<ncols; l++) {
5277             *bufJ++ = cols[l];
5278           }
5279           ierr = MatRestoreRow_MPIAIJ(B,row+ll,&ncols,&cols,NULL);CHKERRQ(ierr);
5280         }
5281       }
5282       ierr = MPI_Isend(bufj+sstartsj[i],sstartsj[i+1]-sstartsj[i],MPIU_INT,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
5283     }
5284 
5285     /* recvs and sends of j-array are completed */
5286     i = nrecvs;
5287     while (i--) {
5288       ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
5289     }
5290     if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
5291   } else if (scall == MAT_REUSE_MATRIX) {
5292     sstartsj = *startsj_s;
5293     rstartsj = *startsj_r;
5294     bufa     = *bufa_ptr;
5295     b_oth    = (Mat_SeqAIJ*)(*B_oth)->data;
5296     b_otha   = b_oth->a;
5297   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Matrix P does not posses an object container");
5298 
5299   /* a-array */
5300   /*---------*/
5301   /*  post receives of a-array */
5302   for (i=0; i<nrecvs; i++) {
5303     nrows = rstartsj[i+1]-rstartsj[i]; /* length of the msg received */
5304     ierr  = MPI_Irecv(b_otha+rstartsj[i],nrows,MPIU_SCALAR,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
5305   }
5306 
5307   /* pack the outgoing message a-array */
5308   k = 0;
5309   for (i=0; i<nsends; i++) {
5310     nrows = sstarts[i+1]-sstarts[i]; /* num of block rows */
5311     bufA  = bufa+sstartsj[i];
5312     for (j=0; j<nrows; j++) {
5313       row = srow[k++] + B->rmap->range[rank];  /* global row idx */
5314       for (ll=0; ll<sbs; ll++) {
5315         ierr = MatGetRow_MPIAIJ(B,row+ll,&ncols,NULL,&vals);CHKERRQ(ierr);
5316         for (l=0; l<ncols; l++) {
5317           *bufA++ = vals[l];
5318         }
5319         ierr = MatRestoreRow_MPIAIJ(B,row+ll,&ncols,NULL,&vals);CHKERRQ(ierr);
5320       }
5321     }
5322     ierr = MPI_Isend(bufa+sstartsj[i],sstartsj[i+1]-sstartsj[i],MPIU_SCALAR,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
5323   }
5324   /* recvs and sends of a-array are completed */
5325   i = nrecvs;
5326   while (i--) {
5327     ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
5328   }
5329   if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
5330   ierr = PetscFree2(rwaits,swaits);CHKERRQ(ierr);
5331 
5332   if (scall == MAT_INITIAL_MATRIX) {
5333     /* put together the new matrix */
5334     ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,aBn,B->cmap->N,b_othi,b_othj,b_otha,B_oth);CHKERRQ(ierr);
5335 
5336     /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
5337     /* Since these are PETSc arrays, change flags to free them as necessary. */
5338     b_oth          = (Mat_SeqAIJ*)(*B_oth)->data;
5339     b_oth->free_a  = PETSC_TRUE;
5340     b_oth->free_ij = PETSC_TRUE;
5341     b_oth->nonew   = 0;
5342 
5343     ierr = PetscFree(bufj);CHKERRQ(ierr);
5344     if (!startsj_s || !bufa_ptr) {
5345       ierr = PetscFree2(sstartsj,rstartsj);CHKERRQ(ierr);
5346       ierr = PetscFree(bufa_ptr);CHKERRQ(ierr);
5347     } else {
5348       *startsj_s = sstartsj;
5349       *startsj_r = rstartsj;
5350       *bufa_ptr  = bufa;
5351     }
5352   }
5353   ierr = PetscLogEventEnd(MAT_GetBrowsOfAocols,A,B,0,0);CHKERRQ(ierr);
5354   PetscFunctionReturn(0);
5355 }
5356 
5357 /*@C
5358   MatGetCommunicationStructs - Provides access to the communication structures used in matrix-vector multiplication.
5359 
5360   Not Collective
5361 
5362   Input Parameters:
5363 . A - The matrix in mpiaij format
5364 
5365   Output Parameter:
5366 + lvec - The local vector holding off-process values from the argument to a matrix-vector product
5367 . colmap - A map from global column index to local index into lvec
5368 - multScatter - A scatter from the argument of a matrix-vector product to lvec
5369 
5370   Level: developer
5371 
5372 @*/
5373 #if defined(PETSC_USE_CTABLE)
5374 PetscErrorCode MatGetCommunicationStructs(Mat A, Vec *lvec, PetscTable *colmap, VecScatter *multScatter)
5375 #else
5376 PetscErrorCode MatGetCommunicationStructs(Mat A, Vec *lvec, PetscInt *colmap[], VecScatter *multScatter)
5377 #endif
5378 {
5379   Mat_MPIAIJ *a;
5380 
5381   PetscFunctionBegin;
5382   PetscValidHeaderSpecific(A, MAT_CLASSID, 1);
5383   PetscValidPointer(lvec, 2);
5384   PetscValidPointer(colmap, 3);
5385   PetscValidPointer(multScatter, 4);
5386   a = (Mat_MPIAIJ*) A->data;
5387   if (lvec) *lvec = a->lvec;
5388   if (colmap) *colmap = a->colmap;
5389   if (multScatter) *multScatter = a->Mvctx;
5390   PetscFunctionReturn(0);
5391 }
5392 
5393 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPIAIJCRL(Mat,MatType,MatReuse,Mat*);
5394 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPIAIJPERM(Mat,MatType,MatReuse,Mat*);
5395 #if defined(PETSC_HAVE_MKL_SPARSE)
5396 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPIAIJMKL(Mat,MatType,MatReuse,Mat*);
5397 #endif
5398 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPISBAIJ(Mat,MatType,MatReuse,Mat*);
5399 #if defined(PETSC_HAVE_ELEMENTAL)
5400 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_Elemental(Mat,MatType,MatReuse,Mat*);
5401 #endif
5402 #if defined(PETSC_HAVE_HYPRE)
5403 PETSC_INTERN PetscErrorCode MatConvert_AIJ_HYPRE(Mat,MatType,MatReuse,Mat*);
5404 PETSC_INTERN PetscErrorCode MatMatMatMult_Transpose_AIJ_AIJ(Mat,Mat,Mat,MatReuse,PetscReal,Mat*);
5405 #endif
5406 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_IS(Mat,MatType,MatReuse,Mat*);
5407 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPISELL(Mat,MatType,MatReuse,Mat*);
5408 
5409 /*
5410     Computes (B'*A')' since computing B*A directly is untenable
5411 
5412                n                       p                          p
5413         (              )       (              )         (                  )
5414       m (      A       )  *  n (       B      )   =   m (         C        )
5415         (              )       (              )         (                  )
5416 
5417 */
5418 PetscErrorCode MatMatMultNumeric_MPIDense_MPIAIJ(Mat A,Mat B,Mat C)
5419 {
5420   PetscErrorCode ierr;
5421   Mat            At,Bt,Ct;
5422 
5423   PetscFunctionBegin;
5424   ierr = MatTranspose(A,MAT_INITIAL_MATRIX,&At);CHKERRQ(ierr);
5425   ierr = MatTranspose(B,MAT_INITIAL_MATRIX,&Bt);CHKERRQ(ierr);
5426   ierr = MatMatMult(Bt,At,MAT_INITIAL_MATRIX,1.0,&Ct);CHKERRQ(ierr);
5427   ierr = MatDestroy(&At);CHKERRQ(ierr);
5428   ierr = MatDestroy(&Bt);CHKERRQ(ierr);
5429   ierr = MatTranspose(Ct,MAT_REUSE_MATRIX,&C);CHKERRQ(ierr);
5430   ierr = MatDestroy(&Ct);CHKERRQ(ierr);
5431   PetscFunctionReturn(0);
5432 }
5433 
5434 PetscErrorCode MatMatMultSymbolic_MPIDense_MPIAIJ(Mat A,Mat B,PetscReal fill,Mat *C)
5435 {
5436   PetscErrorCode ierr;
5437   PetscInt       m=A->rmap->n,n=B->cmap->n;
5438   Mat            Cmat;
5439 
5440   PetscFunctionBegin;
5441   if (A->cmap->n != B->rmap->n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"A->cmap->n %d != B->rmap->n %d\n",A->cmap->n,B->rmap->n);
5442   ierr = MatCreate(PetscObjectComm((PetscObject)A),&Cmat);CHKERRQ(ierr);
5443   ierr = MatSetSizes(Cmat,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
5444   ierr = MatSetBlockSizesFromMats(Cmat,A,B);CHKERRQ(ierr);
5445   ierr = MatSetType(Cmat,MATMPIDENSE);CHKERRQ(ierr);
5446   ierr = MatMPIDenseSetPreallocation(Cmat,NULL);CHKERRQ(ierr);
5447   ierr = MatAssemblyBegin(Cmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5448   ierr = MatAssemblyEnd(Cmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5449 
5450   Cmat->ops->matmultnumeric = MatMatMultNumeric_MPIDense_MPIAIJ;
5451 
5452   *C = Cmat;
5453   PetscFunctionReturn(0);
5454 }
5455 
5456 /* ----------------------------------------------------------------*/
5457 PETSC_INTERN PetscErrorCode MatMatMult_MPIDense_MPIAIJ(Mat A,Mat B,MatReuse scall,PetscReal fill,Mat *C)
5458 {
5459   PetscErrorCode ierr;
5460 
5461   PetscFunctionBegin;
5462   if (scall == MAT_INITIAL_MATRIX) {
5463     ierr = PetscLogEventBegin(MAT_MatMultSymbolic,A,B,0,0);CHKERRQ(ierr);
5464     ierr = MatMatMultSymbolic_MPIDense_MPIAIJ(A,B,fill,C);CHKERRQ(ierr);
5465     ierr = PetscLogEventEnd(MAT_MatMultSymbolic,A,B,0,0);CHKERRQ(ierr);
5466   }
5467   ierr = PetscLogEventBegin(MAT_MatMultNumeric,A,B,0,0);CHKERRQ(ierr);
5468   ierr = MatMatMultNumeric_MPIDense_MPIAIJ(A,B,*C);CHKERRQ(ierr);
5469   ierr = PetscLogEventEnd(MAT_MatMultNumeric,A,B,0,0);CHKERRQ(ierr);
5470   PetscFunctionReturn(0);
5471 }
5472 
5473 /*MC
5474    MATMPIAIJ - MATMPIAIJ = "mpiaij" - A matrix type to be used for parallel sparse matrices.
5475 
5476    Options Database Keys:
5477 . -mat_type mpiaij - sets the matrix type to "mpiaij" during a call to MatSetFromOptions()
5478 
5479   Level: beginner
5480 
5481 .seealso: MatCreateAIJ()
5482 M*/
5483 
5484 PETSC_EXTERN PetscErrorCode MatCreate_MPIAIJ(Mat B)
5485 {
5486   Mat_MPIAIJ     *b;
5487   PetscErrorCode ierr;
5488   PetscMPIInt    size;
5489 
5490   PetscFunctionBegin;
5491   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)B),&size);CHKERRQ(ierr);
5492 
5493   ierr          = PetscNewLog(B,&b);CHKERRQ(ierr);
5494   B->data       = (void*)b;
5495   ierr          = PetscMemcpy(B->ops,&MatOps_Values,sizeof(struct _MatOps));CHKERRQ(ierr);
5496   B->assembled  = PETSC_FALSE;
5497   B->insertmode = NOT_SET_VALUES;
5498   b->size       = size;
5499 
5500   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)B),&b->rank);CHKERRQ(ierr);
5501 
5502   /* build cache for off array entries formed */
5503   ierr = MatStashCreate_Private(PetscObjectComm((PetscObject)B),1,&B->stash);CHKERRQ(ierr);
5504 
5505   b->donotstash  = PETSC_FALSE;
5506   b->colmap      = 0;
5507   b->garray      = 0;
5508   b->roworiented = PETSC_TRUE;
5509 
5510   /* stuff used for matrix vector multiply */
5511   b->lvec  = NULL;
5512   b->Mvctx = NULL;
5513 
5514   /* stuff for MatGetRow() */
5515   b->rowindices   = 0;
5516   b->rowvalues    = 0;
5517   b->getrowactive = PETSC_FALSE;
5518 
5519   /* flexible pointer used in CUSP/CUSPARSE classes */
5520   b->spptr = NULL;
5521 
5522   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMPIAIJSetUseScalableIncreaseOverlap_C",MatMPIAIJSetUseScalableIncreaseOverlap_MPIAIJ);CHKERRQ(ierr);
5523   ierr = PetscObjectComposeFunction((PetscObject)B,"MatStoreValues_C",MatStoreValues_MPIAIJ);CHKERRQ(ierr);
5524   ierr = PetscObjectComposeFunction((PetscObject)B,"MatRetrieveValues_C",MatRetrieveValues_MPIAIJ);CHKERRQ(ierr);
5525   ierr = PetscObjectComposeFunction((PetscObject)B,"MatIsTranspose_C",MatIsTranspose_MPIAIJ);CHKERRQ(ierr);
5526   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMPIAIJSetPreallocation_C",MatMPIAIJSetPreallocation_MPIAIJ);CHKERRQ(ierr);
5527   ierr = PetscObjectComposeFunction((PetscObject)B,"MatResetPreallocation_C",MatResetPreallocation_MPIAIJ);CHKERRQ(ierr);
5528   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMPIAIJSetPreallocationCSR_C",MatMPIAIJSetPreallocationCSR_MPIAIJ);CHKERRQ(ierr);
5529   ierr = PetscObjectComposeFunction((PetscObject)B,"MatDiagonalScaleLocal_C",MatDiagonalScaleLocal_MPIAIJ);CHKERRQ(ierr);
5530   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpiaijperm_C",MatConvert_MPIAIJ_MPIAIJPERM);CHKERRQ(ierr);
5531 #if defined(PETSC_HAVE_MKL_SPARSE)
5532   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpiaijmkl_C",MatConvert_MPIAIJ_MPIAIJMKL);CHKERRQ(ierr);
5533 #endif
5534   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpiaijcrl_C",MatConvert_MPIAIJ_MPIAIJCRL);CHKERRQ(ierr);
5535   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpisbaij_C",MatConvert_MPIAIJ_MPISBAIJ);CHKERRQ(ierr);
5536 #if defined(PETSC_HAVE_ELEMENTAL)
5537   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_elemental_C",MatConvert_MPIAIJ_Elemental);CHKERRQ(ierr);
5538 #endif
5539 #if defined(PETSC_HAVE_HYPRE)
5540   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_hypre_C",MatConvert_AIJ_HYPRE);CHKERRQ(ierr);
5541 #endif
5542   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_is_C",MatConvert_MPIAIJ_IS);CHKERRQ(ierr);
5543   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpisell_C",MatConvert_MPIAIJ_MPISELL);CHKERRQ(ierr);
5544   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMult_mpidense_mpiaij_C",MatMatMult_MPIDense_MPIAIJ);CHKERRQ(ierr);
5545   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMultSymbolic_mpidense_mpiaij_C",MatMatMultSymbolic_MPIDense_MPIAIJ);CHKERRQ(ierr);
5546   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMultNumeric_mpidense_mpiaij_C",MatMatMultNumeric_MPIDense_MPIAIJ);CHKERRQ(ierr);
5547 #if defined(PETSC_HAVE_HYPRE)
5548   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMatMult_transpose_mpiaij_mpiaij_C",MatMatMatMult_Transpose_AIJ_AIJ);CHKERRQ(ierr);
5549 #endif
5550   ierr = PetscObjectChangeTypeName((PetscObject)B,MATMPIAIJ);CHKERRQ(ierr);
5551   PetscFunctionReturn(0);
5552 }
5553 
5554 /*@C
5555      MatCreateMPIAIJWithSplitArrays - creates a MPI AIJ matrix using arrays that contain the "diagonal"
5556          and "off-diagonal" part of the matrix in CSR format.
5557 
5558    Collective on MPI_Comm
5559 
5560    Input Parameters:
5561 +  comm - MPI communicator
5562 .  m - number of local rows (Cannot be PETSC_DECIDE)
5563 .  n - This value should be the same as the local size used in creating the
5564        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
5565        calculated if N is given) For square matrices n is almost always m.
5566 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
5567 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
5568 .   i - row indices for "diagonal" portion of matrix
5569 .   j - column indices
5570 .   a - matrix values
5571 .   oi - row indices for "off-diagonal" portion of matrix
5572 .   oj - column indices
5573 -   oa - matrix values
5574 
5575    Output Parameter:
5576 .   mat - the matrix
5577 
5578    Level: advanced
5579 
5580    Notes:
5581        The i, j, and a arrays ARE NOT copied by this routine into the internal format used by PETSc. The user
5582        must free the arrays once the matrix has been destroyed and not before.
5583 
5584        The i and j indices are 0 based
5585 
5586        See MatCreateAIJ() for the definition of "diagonal" and "off-diagonal" portion of the matrix
5587 
5588        This sets local rows and cannot be used to set off-processor values.
5589 
5590        Use of this routine is discouraged because it is inflexible and cumbersome to use. It is extremely rare that a
5591        legacy application natively assembles into exactly this split format. The code to do so is nontrivial and does
5592        not easily support in-place reassembly. It is recommended to use MatSetValues() (or a variant thereof) because
5593        the resulting assembly is easier to implement, will work with any matrix format, and the user does not have to
5594        keep track of the underlying array. Use MatSetOption(A,MAT_NO_OFF_PROC_ENTRIES,PETSC_TRUE) to disable all
5595        communication if it is known that only local entries will be set.
5596 
5597 .keywords: matrix, aij, compressed row, sparse, parallel
5598 
5599 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
5600           MATMPIAIJ, MatCreateAIJ(), MatCreateMPIAIJWithArrays()
5601 @*/
5602 PetscErrorCode MatCreateMPIAIJWithSplitArrays(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,PetscInt i[],PetscInt j[],PetscScalar a[],PetscInt oi[], PetscInt oj[],PetscScalar oa[],Mat *mat)
5603 {
5604   PetscErrorCode ierr;
5605   Mat_MPIAIJ     *maij;
5606 
5607   PetscFunctionBegin;
5608   if (m < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"local number of rows (m) cannot be PETSC_DECIDE, or negative");
5609   if (i[0]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"i (row indices) must start with 0");
5610   if (oi[0]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"oi (row indices) must start with 0");
5611   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
5612   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
5613   ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
5614   maij = (Mat_MPIAIJ*) (*mat)->data;
5615 
5616   (*mat)->preallocated = PETSC_TRUE;
5617 
5618   ierr = PetscLayoutSetUp((*mat)->rmap);CHKERRQ(ierr);
5619   ierr = PetscLayoutSetUp((*mat)->cmap);CHKERRQ(ierr);
5620 
5621   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,m,n,i,j,a,&maij->A);CHKERRQ(ierr);
5622   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,m,(*mat)->cmap->N,oi,oj,oa,&maij->B);CHKERRQ(ierr);
5623 
5624   ierr = MatAssemblyBegin(maij->A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5625   ierr = MatAssemblyEnd(maij->A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5626   ierr = MatAssemblyBegin(maij->B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5627   ierr = MatAssemblyEnd(maij->B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5628 
5629   ierr = MatSetOption(*mat,MAT_NO_OFF_PROC_ENTRIES,PETSC_TRUE);CHKERRQ(ierr);
5630   ierr = MatAssemblyBegin(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5631   ierr = MatAssemblyEnd(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5632   ierr = MatSetOption(*mat,MAT_NO_OFF_PROC_ENTRIES,PETSC_FALSE);CHKERRQ(ierr);
5633   ierr = MatSetOption(*mat,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
5634   PetscFunctionReturn(0);
5635 }
5636 
5637 /*
5638     Special version for direct calls from Fortran
5639 */
5640 #include <petsc/private/fortranimpl.h>
5641 
5642 /* Change these macros so can be used in void function */
5643 #undef CHKERRQ
5644 #define CHKERRQ(ierr) CHKERRABORT(PETSC_COMM_WORLD,ierr)
5645 #undef SETERRQ2
5646 #define SETERRQ2(comm,ierr,b,c,d) CHKERRABORT(comm,ierr)
5647 #undef SETERRQ3
5648 #define SETERRQ3(comm,ierr,b,c,d,e) CHKERRABORT(comm,ierr)
5649 #undef SETERRQ
5650 #define SETERRQ(c,ierr,b) CHKERRABORT(c,ierr)
5651 
5652 #if defined(PETSC_HAVE_FORTRAN_CAPS)
5653 #define matsetvaluesmpiaij_ MATSETVALUESMPIAIJ
5654 #elif !defined(PETSC_HAVE_FORTRAN_UNDERSCORE)
5655 #define matsetvaluesmpiaij_ matsetvaluesmpiaij
5656 #else
5657 #endif
5658 PETSC_EXTERN void PETSC_STDCALL matsetvaluesmpiaij_(Mat *mmat,PetscInt *mm,const PetscInt im[],PetscInt *mn,const PetscInt in[],const PetscScalar v[],InsertMode *maddv,PetscErrorCode *_ierr)
5659 {
5660   Mat            mat  = *mmat;
5661   PetscInt       m    = *mm, n = *mn;
5662   InsertMode     addv = *maddv;
5663   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
5664   PetscScalar    value;
5665   PetscErrorCode ierr;
5666 
5667   MatCheckPreallocated(mat,1);
5668   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
5669 
5670 #if defined(PETSC_USE_DEBUG)
5671   else if (mat->insertmode != addv) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Cannot mix add values and insert values");
5672 #endif
5673   {
5674     PetscInt  i,j,rstart  = mat->rmap->rstart,rend = mat->rmap->rend;
5675     PetscInt  cstart      = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
5676     PetscBool roworiented = aij->roworiented;
5677 
5678     /* Some Variables required in the macro */
5679     Mat        A                 = aij->A;
5680     Mat_SeqAIJ *a                = (Mat_SeqAIJ*)A->data;
5681     PetscInt   *aimax            = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
5682     MatScalar  *aa               = a->a;
5683     PetscBool  ignorezeroentries = (((a->ignorezeroentries)&&(addv==ADD_VALUES)) ? PETSC_TRUE : PETSC_FALSE);
5684     Mat        B                 = aij->B;
5685     Mat_SeqAIJ *b                = (Mat_SeqAIJ*)B->data;
5686     PetscInt   *bimax            = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->rmap->n,am = aij->A->rmap->n;
5687     MatScalar  *ba               = b->a;
5688 
5689     PetscInt  *rp1,*rp2,ii,nrow1,nrow2,_i,rmax1,rmax2,N,low1,high1,low2,high2,t,lastcol1,lastcol2;
5690     PetscInt  nonew = a->nonew;
5691     MatScalar *ap1,*ap2;
5692 
5693     PetscFunctionBegin;
5694     for (i=0; i<m; i++) {
5695       if (im[i] < 0) continue;
5696 #if defined(PETSC_USE_DEBUG)
5697       if (im[i] >= mat->rmap->N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %D max %D",im[i],mat->rmap->N-1);
5698 #endif
5699       if (im[i] >= rstart && im[i] < rend) {
5700         row      = im[i] - rstart;
5701         lastcol1 = -1;
5702         rp1      = aj + ai[row];
5703         ap1      = aa + ai[row];
5704         rmax1    = aimax[row];
5705         nrow1    = ailen[row];
5706         low1     = 0;
5707         high1    = nrow1;
5708         lastcol2 = -1;
5709         rp2      = bj + bi[row];
5710         ap2      = ba + bi[row];
5711         rmax2    = bimax[row];
5712         nrow2    = bilen[row];
5713         low2     = 0;
5714         high2    = nrow2;
5715 
5716         for (j=0; j<n; j++) {
5717           if (roworiented) value = v[i*n+j];
5718           else value = v[i+j*m];
5719           if (in[j] >= cstart && in[j] < cend) {
5720             col = in[j] - cstart;
5721             if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES) && row != col) continue;
5722             MatSetValues_SeqAIJ_A_Private(row,col,value,addv,im[i],in[j]);
5723           } else if (in[j] < 0) continue;
5724 #if defined(PETSC_USE_DEBUG)
5725           else if (in[j] >= mat->cmap->N) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %D max %D",in[j],mat->cmap->N-1);
5726 #endif
5727           else {
5728             if (mat->was_assembled) {
5729               if (!aij->colmap) {
5730                 ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
5731               }
5732 #if defined(PETSC_USE_CTABLE)
5733               ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
5734               col--;
5735 #else
5736               col = aij->colmap[in[j]] - 1;
5737 #endif
5738               if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES) && row != col) continue;
5739               if (col < 0 && !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
5740                 ierr = MatDisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
5741                 col  =  in[j];
5742                 /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
5743                 B     = aij->B;
5744                 b     = (Mat_SeqAIJ*)B->data;
5745                 bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j;
5746                 rp2   = bj + bi[row];
5747                 ap2   = ba + bi[row];
5748                 rmax2 = bimax[row];
5749                 nrow2 = bilen[row];
5750                 low2  = 0;
5751                 high2 = nrow2;
5752                 bm    = aij->B->rmap->n;
5753                 ba    = b->a;
5754               }
5755             } else col = in[j];
5756             MatSetValues_SeqAIJ_B_Private(row,col,value,addv,im[i],in[j]);
5757           }
5758         }
5759       } else if (!aij->donotstash) {
5760         if (roworiented) {
5761           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
5762         } else {
5763           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
5764         }
5765       }
5766     }
5767   }
5768   PetscFunctionReturnVoid();
5769 }
5770 
5771