xref: /petsc/src/mat/impls/aij/mpi/mpiaij.c (revision bcae8d28993cfbcee9609a5117399fb9261a5173)
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, 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 
135 PetscErrorCode MatFindZeroDiagonals_MPIAIJ(Mat M,IS *zrows)
136 {
137   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)M->data;
138   PetscErrorCode ierr;
139   PetscInt       i,rstart,nrows,*rows;
140 
141   PetscFunctionBegin;
142   *zrows = NULL;
143   ierr   = MatFindZeroDiagonals_SeqAIJ_Private(aij->A,&nrows,&rows);CHKERRQ(ierr);
144   ierr   = MatGetOwnershipRange(M,&rstart,NULL);CHKERRQ(ierr);
145   for (i=0; i<nrows; i++) rows[i] += rstart;
146   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)M),nrows,rows,PETSC_OWN_POINTER,zrows);CHKERRQ(ierr);
147   PetscFunctionReturn(0);
148 }
149 
150 PetscErrorCode MatGetColumnNorms_MPIAIJ(Mat A,NormType type,PetscReal *norms)
151 {
152   PetscErrorCode ierr;
153   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)A->data;
154   PetscInt       i,n,*garray = aij->garray;
155   Mat_SeqAIJ     *a_aij = (Mat_SeqAIJ*) aij->A->data;
156   Mat_SeqAIJ     *b_aij = (Mat_SeqAIJ*) aij->B->data;
157   PetscReal      *work;
158 
159   PetscFunctionBegin;
160   ierr = MatGetSize(A,NULL,&n);CHKERRQ(ierr);
161   ierr = PetscCalloc1(n,&work);CHKERRQ(ierr);
162   if (type == NORM_2) {
163     for (i=0; i<a_aij->i[aij->A->rmap->n]; i++) {
164       work[A->cmap->rstart + a_aij->j[i]] += PetscAbsScalar(a_aij->a[i]*a_aij->a[i]);
165     }
166     for (i=0; i<b_aij->i[aij->B->rmap->n]; i++) {
167       work[garray[b_aij->j[i]]] += PetscAbsScalar(b_aij->a[i]*b_aij->a[i]);
168     }
169   } else if (type == NORM_1) {
170     for (i=0; i<a_aij->i[aij->A->rmap->n]; i++) {
171       work[A->cmap->rstart + a_aij->j[i]] += PetscAbsScalar(a_aij->a[i]);
172     }
173     for (i=0; i<b_aij->i[aij->B->rmap->n]; i++) {
174       work[garray[b_aij->j[i]]] += PetscAbsScalar(b_aij->a[i]);
175     }
176   } else if (type == NORM_INFINITY) {
177     for (i=0; i<a_aij->i[aij->A->rmap->n]; i++) {
178       work[A->cmap->rstart + a_aij->j[i]] = PetscMax(PetscAbsScalar(a_aij->a[i]), work[A->cmap->rstart + a_aij->j[i]]);
179     }
180     for (i=0; i<b_aij->i[aij->B->rmap->n]; i++) {
181       work[garray[b_aij->j[i]]] = PetscMax(PetscAbsScalar(b_aij->a[i]),work[garray[b_aij->j[i]]]);
182     }
183 
184   } else SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_WRONG,"Unknown NormType");
185   if (type == NORM_INFINITY) {
186     ierr = MPIU_Allreduce(work,norms,n,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
187   } else {
188     ierr = MPIU_Allreduce(work,norms,n,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
189   }
190   ierr = PetscFree(work);CHKERRQ(ierr);
191   if (type == NORM_2) {
192     for (i=0; i<n; i++) norms[i] = PetscSqrtReal(norms[i]);
193   }
194   PetscFunctionReturn(0);
195 }
196 
197 PetscErrorCode MatFindOffBlockDiagonalEntries_MPIAIJ(Mat A,IS *is)
198 {
199   Mat_MPIAIJ      *a  = (Mat_MPIAIJ*)A->data;
200   IS              sis,gis;
201   PetscErrorCode  ierr;
202   const PetscInt  *isis,*igis;
203   PetscInt        n,*iis,nsis,ngis,rstart,i;
204 
205   PetscFunctionBegin;
206   ierr = MatFindOffBlockDiagonalEntries(a->A,&sis);CHKERRQ(ierr);
207   ierr = MatFindNonzeroRows(a->B,&gis);CHKERRQ(ierr);
208   ierr = ISGetSize(gis,&ngis);CHKERRQ(ierr);
209   ierr = ISGetSize(sis,&nsis);CHKERRQ(ierr);
210   ierr = ISGetIndices(sis,&isis);CHKERRQ(ierr);
211   ierr = ISGetIndices(gis,&igis);CHKERRQ(ierr);
212 
213   ierr = PetscMalloc1(ngis+nsis,&iis);CHKERRQ(ierr);
214   ierr = PetscMemcpy(iis,igis,ngis*sizeof(PetscInt));CHKERRQ(ierr);
215   ierr = PetscMemcpy(iis+ngis,isis,nsis*sizeof(PetscInt));CHKERRQ(ierr);
216   n    = ngis + nsis;
217   ierr = PetscSortRemoveDupsInt(&n,iis);CHKERRQ(ierr);
218   ierr = MatGetOwnershipRange(A,&rstart,NULL);CHKERRQ(ierr);
219   for (i=0; i<n; i++) iis[i] += rstart;
220   ierr = ISCreateGeneral(PetscObjectComm((PetscObject)A),n,iis,PETSC_OWN_POINTER,is);CHKERRQ(ierr);
221 
222   ierr = ISRestoreIndices(sis,&isis);CHKERRQ(ierr);
223   ierr = ISRestoreIndices(gis,&igis);CHKERRQ(ierr);
224   ierr = ISDestroy(&sis);CHKERRQ(ierr);
225   ierr = ISDestroy(&gis);CHKERRQ(ierr);
226   PetscFunctionReturn(0);
227 }
228 
229 /*
230     Distributes a SeqAIJ matrix across a set of processes. Code stolen from
231     MatLoad_MPIAIJ(). Horrible lack of reuse. Should be a routine for each matrix type.
232 
233     Only for square matrices
234 
235     Used by a preconditioner, hence PETSC_EXTERN
236 */
237 PETSC_EXTERN PetscErrorCode MatDistribute_MPIAIJ(MPI_Comm comm,Mat gmat,PetscInt m,MatReuse reuse,Mat *inmat)
238 {
239   PetscMPIInt    rank,size;
240   PetscInt       *rowners,*dlens,*olens,i,rstart,rend,j,jj,nz = 0,*gmataj,cnt,row,*ld,bses[2];
241   PetscErrorCode ierr;
242   Mat            mat;
243   Mat_SeqAIJ     *gmata;
244   PetscMPIInt    tag;
245   MPI_Status     status;
246   PetscBool      aij;
247   MatScalar      *gmataa,*ao,*ad,*gmataarestore=0;
248 
249   PetscFunctionBegin;
250   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
251   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
252   if (!rank) {
253     ierr = PetscObjectTypeCompare((PetscObject)gmat,MATSEQAIJ,&aij);CHKERRQ(ierr);
254     if (!aij) SETERRQ1(PetscObjectComm((PetscObject)gmat),PETSC_ERR_SUP,"Currently no support for input matrix of type %s\n",((PetscObject)gmat)->type_name);
255   }
256   if (reuse == MAT_INITIAL_MATRIX) {
257     ierr = MatCreate(comm,&mat);CHKERRQ(ierr);
258     ierr = MatSetSizes(mat,m,m,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
259     ierr = MatGetBlockSizes(gmat,&bses[0],&bses[1]);CHKERRQ(ierr);
260     ierr = MPI_Bcast(bses,2,MPIU_INT,0,comm);CHKERRQ(ierr);
261     ierr = MatSetBlockSizes(mat,bses[0],bses[1]);CHKERRQ(ierr);
262     ierr = MatSetType(mat,MATAIJ);CHKERRQ(ierr);
263     ierr = PetscMalloc1(size+1,&rowners);CHKERRQ(ierr);
264     ierr = PetscMalloc2(m,&dlens,m,&olens);CHKERRQ(ierr);
265     ierr = MPI_Allgather(&m,1,MPIU_INT,rowners+1,1,MPIU_INT,comm);CHKERRQ(ierr);
266 
267     rowners[0] = 0;
268     for (i=2; i<=size; i++) rowners[i] += rowners[i-1];
269     rstart = rowners[rank];
270     rend   = rowners[rank+1];
271     ierr   = PetscObjectGetNewTag((PetscObject)mat,&tag);CHKERRQ(ierr);
272     if (!rank) {
273       gmata = (Mat_SeqAIJ*) gmat->data;
274       /* send row lengths to all processors */
275       for (i=0; i<m; i++) dlens[i] = gmata->ilen[i];
276       for (i=1; i<size; i++) {
277         ierr = MPI_Send(gmata->ilen + rowners[i],rowners[i+1]-rowners[i],MPIU_INT,i,tag,comm);CHKERRQ(ierr);
278       }
279       /* determine number diagonal and off-diagonal counts */
280       ierr = PetscMemzero(olens,m*sizeof(PetscInt));CHKERRQ(ierr);
281       ierr = PetscCalloc1(m,&ld);CHKERRQ(ierr);
282       jj   = 0;
283       for (i=0; i<m; i++) {
284         for (j=0; j<dlens[i]; j++) {
285           if (gmata->j[jj] < rstart) ld[i]++;
286           if (gmata->j[jj] < rstart || gmata->j[jj] >= rend) olens[i]++;
287           jj++;
288         }
289       }
290       /* send column indices to other processes */
291       for (i=1; i<size; i++) {
292         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
293         ierr = MPI_Send(&nz,1,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
294         ierr = MPI_Send(gmata->j + gmata->i[rowners[i]],nz,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
295       }
296 
297       /* send numerical values to other processes */
298       for (i=1; i<size; i++) {
299         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
300         ierr = MPI_Send(gmata->a + gmata->i[rowners[i]],nz,MPIU_SCALAR,i,tag,comm);CHKERRQ(ierr);
301       }
302       gmataa = gmata->a;
303       gmataj = gmata->j;
304 
305     } else {
306       /* receive row lengths */
307       ierr = MPI_Recv(dlens,m,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
308       /* receive column indices */
309       ierr = MPI_Recv(&nz,1,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
310       ierr = PetscMalloc2(nz,&gmataa,nz,&gmataj);CHKERRQ(ierr);
311       ierr = MPI_Recv(gmataj,nz,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
312       /* determine number diagonal and off-diagonal counts */
313       ierr = PetscMemzero(olens,m*sizeof(PetscInt));CHKERRQ(ierr);
314       ierr = PetscCalloc1(m,&ld);CHKERRQ(ierr);
315       jj   = 0;
316       for (i=0; i<m; i++) {
317         for (j=0; j<dlens[i]; j++) {
318           if (gmataj[jj] < rstart) ld[i]++;
319           if (gmataj[jj] < rstart || gmataj[jj] >= rend) olens[i]++;
320           jj++;
321         }
322       }
323       /* receive numerical values */
324       ierr = PetscMemzero(gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr);
325       ierr = MPI_Recv(gmataa,nz,MPIU_SCALAR,0,tag,comm,&status);CHKERRQ(ierr);
326     }
327     /* set preallocation */
328     for (i=0; i<m; i++) {
329       dlens[i] -= olens[i];
330     }
331     ierr = MatSeqAIJSetPreallocation(mat,0,dlens);CHKERRQ(ierr);
332     ierr = MatMPIAIJSetPreallocation(mat,0,dlens,0,olens);CHKERRQ(ierr);
333 
334     for (i=0; i<m; i++) {
335       dlens[i] += olens[i];
336     }
337     cnt = 0;
338     for (i=0; i<m; i++) {
339       row  = rstart + i;
340       ierr = MatSetValues(mat,1,&row,dlens[i],gmataj+cnt,gmataa+cnt,INSERT_VALUES);CHKERRQ(ierr);
341       cnt += dlens[i];
342     }
343     if (rank) {
344       ierr = PetscFree2(gmataa,gmataj);CHKERRQ(ierr);
345     }
346     ierr = PetscFree2(dlens,olens);CHKERRQ(ierr);
347     ierr = PetscFree(rowners);CHKERRQ(ierr);
348 
349     ((Mat_MPIAIJ*)(mat->data))->ld = ld;
350 
351     *inmat = mat;
352   } else {   /* column indices are already set; only need to move over numerical values from process 0 */
353     Mat_SeqAIJ *Ad = (Mat_SeqAIJ*)((Mat_MPIAIJ*)((*inmat)->data))->A->data;
354     Mat_SeqAIJ *Ao = (Mat_SeqAIJ*)((Mat_MPIAIJ*)((*inmat)->data))->B->data;
355     mat  = *inmat;
356     ierr = PetscObjectGetNewTag((PetscObject)mat,&tag);CHKERRQ(ierr);
357     if (!rank) {
358       /* send numerical values to other processes */
359       gmata  = (Mat_SeqAIJ*) gmat->data;
360       ierr   = MatGetOwnershipRanges(mat,(const PetscInt**)&rowners);CHKERRQ(ierr);
361       gmataa = gmata->a;
362       for (i=1; i<size; i++) {
363         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
364         ierr = MPI_Send(gmataa + gmata->i[rowners[i]],nz,MPIU_SCALAR,i,tag,comm);CHKERRQ(ierr);
365       }
366       nz = gmata->i[rowners[1]]-gmata->i[rowners[0]];
367     } else {
368       /* receive numerical values from process 0*/
369       nz   = Ad->nz + Ao->nz;
370       ierr = PetscMalloc1(nz,&gmataa);CHKERRQ(ierr); gmataarestore = gmataa;
371       ierr = MPI_Recv(gmataa,nz,MPIU_SCALAR,0,tag,comm,&status);CHKERRQ(ierr);
372     }
373     /* transfer numerical values into the diagonal A and off diagonal B parts of mat */
374     ld = ((Mat_MPIAIJ*)(mat->data))->ld;
375     ad = Ad->a;
376     ao = Ao->a;
377     if (mat->rmap->n) {
378       i  = 0;
379       nz = ld[i];                                   ierr = PetscMemcpy(ao,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ao += nz; gmataa += nz;
380       nz = Ad->i[i+1] - Ad->i[i];                   ierr = PetscMemcpy(ad,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ad += nz; gmataa += nz;
381     }
382     for (i=1; i<mat->rmap->n; i++) {
383       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;
384       nz = Ad->i[i+1] - Ad->i[i];                   ierr = PetscMemcpy(ad,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ad += nz; gmataa += nz;
385     }
386     i--;
387     if (mat->rmap->n) {
388       nz = Ao->i[i+1] - Ao->i[i] - ld[i];           ierr = PetscMemcpy(ao,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr);
389     }
390     if (rank) {
391       ierr = PetscFree(gmataarestore);CHKERRQ(ierr);
392     }
393   }
394   ierr = MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
395   ierr = MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
396   PetscFunctionReturn(0);
397 }
398 
399 /*
400   Local utility routine that creates a mapping from the global column
401 number to the local number in the off-diagonal part of the local
402 storage of the matrix.  When PETSC_USE_CTABLE is used this is scalable at
403 a slightly higher hash table cost; without it it is not scalable (each processor
404 has an order N integer array but is fast to acess.
405 */
406 PetscErrorCode MatCreateColmap_MPIAIJ_Private(Mat mat)
407 {
408   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
409   PetscErrorCode ierr;
410   PetscInt       n = aij->B->cmap->n,i;
411 
412   PetscFunctionBegin;
413   if (!aij->garray) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"MPIAIJ Matrix was assembled but is missing garray");
414 #if defined(PETSC_USE_CTABLE)
415   ierr = PetscTableCreate(n,mat->cmap->N+1,&aij->colmap);CHKERRQ(ierr);
416   for (i=0; i<n; i++) {
417     ierr = PetscTableAdd(aij->colmap,aij->garray[i]+1,i+1,INSERT_VALUES);CHKERRQ(ierr);
418   }
419 #else
420   ierr = PetscCalloc1(mat->cmap->N+1,&aij->colmap);CHKERRQ(ierr);
421   ierr = PetscLogObjectMemory((PetscObject)mat,(mat->cmap->N+1)*sizeof(PetscInt));CHKERRQ(ierr);
422   for (i=0; i<n; i++) aij->colmap[aij->garray[i]] = i+1;
423 #endif
424   PetscFunctionReturn(0);
425 }
426 
427 #define MatSetValues_SeqAIJ_A_Private(row,col,value,addv,orow,ocol)     \
428 { \
429     if (col <= lastcol1)  low1 = 0;     \
430     else                 high1 = nrow1; \
431     lastcol1 = col;\
432     while (high1-low1 > 5) { \
433       t = (low1+high1)/2; \
434       if (rp1[t] > col) high1 = t; \
435       else              low1  = t; \
436     } \
437       for (_i=low1; _i<high1; _i++) { \
438         if (rp1[_i] > col) break; \
439         if (rp1[_i] == col) { \
440           if (addv == ADD_VALUES) ap1[_i] += value;   \
441           else                    ap1[_i] = value; \
442           goto a_noinsert; \
443         } \
444       }  \
445       if (value == 0.0 && ignorezeroentries && row != col) {low1 = 0; high1 = nrow1;goto a_noinsert;} \
446       if (nonew == 1) {low1 = 0; high1 = nrow1; goto a_noinsert;}                \
447       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); \
448       MatSeqXAIJReallocateAIJ(A,am,1,nrow1,row,col,rmax1,aa,ai,aj,rp1,ap1,aimax,nonew,MatScalar); \
449       N = nrow1++ - 1; a->nz++; high1++; \
450       /* shift up all the later entries in this row */ \
451       for (ii=N; ii>=_i; ii--) { \
452         rp1[ii+1] = rp1[ii]; \
453         ap1[ii+1] = ap1[ii]; \
454       } \
455       rp1[_i] = col;  \
456       ap1[_i] = value;  \
457       A->nonzerostate++;\
458       a_noinsert: ; \
459       ailen[row] = nrow1; \
460 }
461 
462 
463 #define MatSetValues_SeqAIJ_B_Private(row,col,value,addv,orow,ocol) \
464   { \
465     if (col <= lastcol2) low2 = 0;                        \
466     else high2 = nrow2;                                   \
467     lastcol2 = col;                                       \
468     while (high2-low2 > 5) {                              \
469       t = (low2+high2)/2;                                 \
470       if (rp2[t] > col) high2 = t;                        \
471       else             low2  = t;                         \
472     }                                                     \
473     for (_i=low2; _i<high2; _i++) {                       \
474       if (rp2[_i] > col) break;                           \
475       if (rp2[_i] == col) {                               \
476         if (addv == ADD_VALUES) ap2[_i] += value;         \
477         else                    ap2[_i] = value;          \
478         goto b_noinsert;                                  \
479       }                                                   \
480     }                                                     \
481     if (value == 0.0 && ignorezeroentries) {low2 = 0; high2 = nrow2; goto b_noinsert;} \
482     if (nonew == 1) {low2 = 0; high2 = nrow2; goto b_noinsert;}                        \
483     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); \
484     MatSeqXAIJReallocateAIJ(B,bm,1,nrow2,row,col,rmax2,ba,bi,bj,rp2,ap2,bimax,nonew,MatScalar); \
485     N = nrow2++ - 1; b->nz++; high2++;                    \
486     /* shift up all the later entries in this row */      \
487     for (ii=N; ii>=_i; ii--) {                            \
488       rp2[ii+1] = rp2[ii];                                \
489       ap2[ii+1] = ap2[ii];                                \
490     }                                                     \
491     rp2[_i] = col;                                        \
492     ap2[_i] = value;                                      \
493     B->nonzerostate++;                                    \
494     b_noinsert: ;                                         \
495     bilen[row] = nrow2;                                   \
496   }
497 
498 PetscErrorCode MatSetValuesRow_MPIAIJ(Mat A,PetscInt row,const PetscScalar v[])
499 {
500   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)A->data;
501   Mat_SeqAIJ     *a   = (Mat_SeqAIJ*)mat->A->data,*b = (Mat_SeqAIJ*)mat->B->data;
502   PetscErrorCode ierr;
503   PetscInt       l,*garray = mat->garray,diag;
504 
505   PetscFunctionBegin;
506   /* code only works for square matrices A */
507 
508   /* find size of row to the left of the diagonal part */
509   ierr = MatGetOwnershipRange(A,&diag,0);CHKERRQ(ierr);
510   row  = row - diag;
511   for (l=0; l<b->i[row+1]-b->i[row]; l++) {
512     if (garray[b->j[b->i[row]+l]] > diag) break;
513   }
514   ierr = PetscMemcpy(b->a+b->i[row],v,l*sizeof(PetscScalar));CHKERRQ(ierr);
515 
516   /* diagonal part */
517   ierr = PetscMemcpy(a->a+a->i[row],v+l,(a->i[row+1]-a->i[row])*sizeof(PetscScalar));CHKERRQ(ierr);
518 
519   /* right of diagonal part */
520   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);
521   PetscFunctionReturn(0);
522 }
523 
524 PetscErrorCode MatSetValues_MPIAIJ(Mat mat,PetscInt m,const PetscInt im[],PetscInt n,const PetscInt in[],const PetscScalar v[],InsertMode addv)
525 {
526   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
527   PetscScalar    value;
528   PetscErrorCode ierr;
529   PetscInt       i,j,rstart  = mat->rmap->rstart,rend = mat->rmap->rend;
530   PetscInt       cstart      = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
531   PetscBool      roworiented = aij->roworiented;
532 
533   /* Some Variables required in the macro */
534   Mat        A                 = aij->A;
535   Mat_SeqAIJ *a                = (Mat_SeqAIJ*)A->data;
536   PetscInt   *aimax            = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
537   MatScalar  *aa               = a->a;
538   PetscBool  ignorezeroentries = a->ignorezeroentries;
539   Mat        B                 = aij->B;
540   Mat_SeqAIJ *b                = (Mat_SeqAIJ*)B->data;
541   PetscInt   *bimax            = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->rmap->n,am = aij->A->rmap->n;
542   MatScalar  *ba               = b->a;
543 
544   PetscInt  *rp1,*rp2,ii,nrow1,nrow2,_i,rmax1,rmax2,N,low1,high1,low2,high2,t,lastcol1,lastcol2;
545   PetscInt  nonew;
546   MatScalar *ap1,*ap2;
547 
548   PetscFunctionBegin;
549   for (i=0; i<m; i++) {
550     if (im[i] < 0) continue;
551 #if defined(PETSC_USE_DEBUG)
552     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);
553 #endif
554     if (im[i] >= rstart && im[i] < rend) {
555       row      = im[i] - rstart;
556       lastcol1 = -1;
557       rp1      = aj + ai[row];
558       ap1      = aa + ai[row];
559       rmax1    = aimax[row];
560       nrow1    = ailen[row];
561       low1     = 0;
562       high1    = nrow1;
563       lastcol2 = -1;
564       rp2      = bj + bi[row];
565       ap2      = ba + bi[row];
566       rmax2    = bimax[row];
567       nrow2    = bilen[row];
568       low2     = 0;
569       high2    = nrow2;
570 
571       for (j=0; j<n; j++) {
572         if (roworiented) value = v[i*n+j];
573         else             value = v[i+j*m];
574         if (in[j] >= cstart && in[j] < cend) {
575           col   = in[j] - cstart;
576           nonew = a->nonew;
577           if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES) && row != col) continue;
578           MatSetValues_SeqAIJ_A_Private(row,col,value,addv,im[i],in[j]);
579         } else if (in[j] < 0) continue;
580 #if defined(PETSC_USE_DEBUG)
581         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);
582 #endif
583         else {
584           if (mat->was_assembled) {
585             if (!aij->colmap) {
586               ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
587             }
588 #if defined(PETSC_USE_CTABLE)
589             ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
590             col--;
591 #else
592             col = aij->colmap[in[j]] - 1;
593 #endif
594             if (col < 0 && !((Mat_SeqAIJ*)(aij->B->data))->nonew) {
595               ierr = MatDisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
596               col  =  in[j];
597               /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
598               B     = aij->B;
599               b     = (Mat_SeqAIJ*)B->data;
600               bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j; ba = b->a;
601               rp2   = bj + bi[row];
602               ap2   = ba + bi[row];
603               rmax2 = bimax[row];
604               nrow2 = bilen[row];
605               low2  = 0;
606               high2 = nrow2;
607               bm    = aij->B->rmap->n;
608               ba    = b->a;
609             } 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]);
610           } else col = in[j];
611           nonew = b->nonew;
612           MatSetValues_SeqAIJ_B_Private(row,col,value,addv,im[i],in[j]);
613         }
614       }
615     } else {
616       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]);
617       if (!aij->donotstash) {
618         mat->assembled = PETSC_FALSE;
619         if (roworiented) {
620           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
621         } else {
622           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
623         }
624       }
625     }
626   }
627   PetscFunctionReturn(0);
628 }
629 
630 PetscErrorCode MatGetValues_MPIAIJ(Mat mat,PetscInt m,const PetscInt idxm[],PetscInt n,const PetscInt idxn[],PetscScalar v[])
631 {
632   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
633   PetscErrorCode ierr;
634   PetscInt       i,j,rstart = mat->rmap->rstart,rend = mat->rmap->rend;
635   PetscInt       cstart = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
636 
637   PetscFunctionBegin;
638   for (i=0; i<m; i++) {
639     if (idxm[i] < 0) continue; /* SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative row: %D",idxm[i]);*/
640     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);
641     if (idxm[i] >= rstart && idxm[i] < rend) {
642       row = idxm[i] - rstart;
643       for (j=0; j<n; j++) {
644         if (idxn[j] < 0) continue; /* SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Negative column: %D",idxn[j]); */
645         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);
646         if (idxn[j] >= cstart && idxn[j] < cend) {
647           col  = idxn[j] - cstart;
648           ierr = MatGetValues(aij->A,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
649         } else {
650           if (!aij->colmap) {
651             ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
652           }
653 #if defined(PETSC_USE_CTABLE)
654           ierr = PetscTableFind(aij->colmap,idxn[j]+1,&col);CHKERRQ(ierr);
655           col--;
656 #else
657           col = aij->colmap[idxn[j]] - 1;
658 #endif
659           if ((col < 0) || (aij->garray[col] != idxn[j])) *(v+i*n+j) = 0.0;
660           else {
661             ierr = MatGetValues(aij->B,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
662           }
663         }
664       }
665     } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Only local values currently supported");
666   }
667   PetscFunctionReturn(0);
668 }
669 
670 extern PetscErrorCode MatMultDiagonalBlock_MPIAIJ(Mat,Vec,Vec);
671 
672 PetscErrorCode MatAssemblyBegin_MPIAIJ(Mat mat,MatAssemblyType mode)
673 {
674   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
675   PetscErrorCode ierr;
676   PetscInt       nstash,reallocs;
677 
678   PetscFunctionBegin;
679   if (aij->donotstash || mat->nooffprocentries) PetscFunctionReturn(0);
680 
681   ierr = MatStashScatterBegin_Private(mat,&mat->stash,mat->rmap->range);CHKERRQ(ierr);
682   ierr = MatStashGetInfo_Private(&mat->stash,&nstash,&reallocs);CHKERRQ(ierr);
683   ierr = PetscInfo2(aij->A,"Stash has %D entries, uses %D mallocs.\n",nstash,reallocs);CHKERRQ(ierr);
684   PetscFunctionReturn(0);
685 }
686 
687 PetscErrorCode MatAssemblyEnd_MPIAIJ(Mat mat,MatAssemblyType mode)
688 {
689   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
690   Mat_SeqAIJ     *a   = (Mat_SeqAIJ*)aij->A->data;
691   PetscErrorCode ierr;
692   PetscMPIInt    n;
693   PetscInt       i,j,rstart,ncols,flg;
694   PetscInt       *row,*col;
695   PetscBool      other_disassembled;
696   PetscScalar    *val;
697 
698   /* do not use 'b = (Mat_SeqAIJ*)aij->B->data' as B can be reset in disassembly */
699 
700   PetscFunctionBegin;
701   if (!aij->donotstash && !mat->nooffprocentries) {
702     while (1) {
703       ierr = MatStashScatterGetMesg_Private(&mat->stash,&n,&row,&col,&val,&flg);CHKERRQ(ierr);
704       if (!flg) break;
705 
706       for (i=0; i<n; ) {
707         /* Now identify the consecutive vals belonging to the same row */
708         for (j=i,rstart=row[j]; j<n; j++) {
709           if (row[j] != rstart) break;
710         }
711         if (j < n) ncols = j-i;
712         else       ncols = n-i;
713         /* Now assemble all these values with a single function call */
714         ierr = MatSetValues_MPIAIJ(mat,1,row+i,ncols,col+i,val+i,mat->insertmode);CHKERRQ(ierr);
715 
716         i = j;
717       }
718     }
719     ierr = MatStashScatterEnd_Private(&mat->stash);CHKERRQ(ierr);
720   }
721   ierr = MatAssemblyBegin(aij->A,mode);CHKERRQ(ierr);
722   ierr = MatAssemblyEnd(aij->A,mode);CHKERRQ(ierr);
723 
724   /* determine if any processor has disassembled, if so we must
725      also disassemble ourselfs, in order that we may reassemble. */
726   /*
727      if nonzero structure of submatrix B cannot change then we know that
728      no processor disassembled thus we can skip this stuff
729   */
730   if (!((Mat_SeqAIJ*)aij->B->data)->nonew) {
731     ierr = MPIU_Allreduce(&mat->was_assembled,&other_disassembled,1,MPIU_BOOL,MPI_PROD,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
732     if (mat->was_assembled && !other_disassembled) {
733       ierr = MatDisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
734     }
735   }
736   if (!mat->was_assembled && mode == MAT_FINAL_ASSEMBLY) {
737     ierr = MatSetUpMultiply_MPIAIJ(mat);CHKERRQ(ierr);
738   }
739   ierr = MatSetOption(aij->B,MAT_USE_INODES,PETSC_FALSE);CHKERRQ(ierr);
740   ierr = MatAssemblyBegin(aij->B,mode);CHKERRQ(ierr);
741   ierr = MatAssemblyEnd(aij->B,mode);CHKERRQ(ierr);
742 
743   ierr = PetscFree2(aij->rowvalues,aij->rowindices);CHKERRQ(ierr);
744 
745   aij->rowvalues = 0;
746 
747   ierr = VecDestroy(&aij->diag);CHKERRQ(ierr);
748   if (a->inode.size) mat->ops->multdiagonalblock = MatMultDiagonalBlock_MPIAIJ;
749 
750   /* if no new nonzero locations are allowed in matrix then only set the matrix state the first time through */
751   if ((!mat->was_assembled && mode == MAT_FINAL_ASSEMBLY) || !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
752     PetscObjectState state = aij->A->nonzerostate + aij->B->nonzerostate;
753     ierr = MPIU_Allreduce(&state,&mat->nonzerostate,1,MPIU_INT64,MPI_SUM,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
754   }
755   PetscFunctionReturn(0);
756 }
757 
758 PetscErrorCode MatZeroEntries_MPIAIJ(Mat A)
759 {
760   Mat_MPIAIJ     *l = (Mat_MPIAIJ*)A->data;
761   PetscErrorCode ierr;
762 
763   PetscFunctionBegin;
764   ierr = MatZeroEntries(l->A);CHKERRQ(ierr);
765   ierr = MatZeroEntries(l->B);CHKERRQ(ierr);
766   PetscFunctionReturn(0);
767 }
768 
769 PetscErrorCode MatZeroRows_MPIAIJ(Mat A,PetscInt N,const PetscInt rows[],PetscScalar diag,Vec x,Vec b)
770 {
771   Mat_MPIAIJ    *mat    = (Mat_MPIAIJ *) A->data;
772   PetscInt      *lrows;
773   PetscInt       r, len;
774   PetscErrorCode ierr;
775 
776   PetscFunctionBegin;
777   /* get locally owned rows */
778   ierr = MatZeroRowsMapLocal_Private(A,N,rows,&len,&lrows);CHKERRQ(ierr);
779   /* fix right hand side if needed */
780   if (x && b) {
781     const PetscScalar *xx;
782     PetscScalar       *bb;
783 
784     ierr = VecGetArrayRead(x, &xx);CHKERRQ(ierr);
785     ierr = VecGetArray(b, &bb);CHKERRQ(ierr);
786     for (r = 0; r < len; ++r) bb[lrows[r]] = diag*xx[lrows[r]];
787     ierr = VecRestoreArrayRead(x, &xx);CHKERRQ(ierr);
788     ierr = VecRestoreArray(b, &bb);CHKERRQ(ierr);
789   }
790   /* Must zero l->B before l->A because the (diag) case below may put values into l->B*/
791   ierr = MatZeroRows(mat->B, len, lrows, 0.0, NULL, NULL);CHKERRQ(ierr);
792   if (A->congruentlayouts == -1) { /* first time we compare rows and cols layouts */
793     PetscBool cong;
794     ierr = PetscLayoutCompare(A->rmap,A->cmap,&cong);CHKERRQ(ierr);
795     if (cong) A->congruentlayouts = 1;
796     else      A->congruentlayouts = 0;
797   }
798   if ((diag != 0.0) && A->congruentlayouts) {
799     ierr = MatZeroRows(mat->A, len, lrows, diag, NULL, NULL);CHKERRQ(ierr);
800   } else if (diag != 0.0) {
801     ierr = MatZeroRows(mat->A, len, lrows, 0.0, NULL, NULL);CHKERRQ(ierr);
802     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");
803     for (r = 0; r < len; ++r) {
804       const PetscInt row = lrows[r] + A->rmap->rstart;
805       ierr = MatSetValues(A, 1, &row, 1, &row, &diag, INSERT_VALUES);CHKERRQ(ierr);
806     }
807     ierr = MatAssemblyBegin(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
808     ierr = MatAssemblyEnd(A, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
809   } else {
810     ierr = MatZeroRows(mat->A, len, lrows, 0.0, NULL, NULL);CHKERRQ(ierr);
811   }
812   ierr = PetscFree(lrows);CHKERRQ(ierr);
813 
814   /* only change matrix nonzero state if pattern was allowed to be changed */
815   if (!((Mat_SeqAIJ*)(mat->A->data))->keepnonzeropattern) {
816     PetscObjectState state = mat->A->nonzerostate + mat->B->nonzerostate;
817     ierr = MPIU_Allreduce(&state,&A->nonzerostate,1,MPIU_INT64,MPI_SUM,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
818   }
819   PetscFunctionReturn(0);
820 }
821 
822 PetscErrorCode MatZeroRowsColumns_MPIAIJ(Mat A,PetscInt N,const PetscInt rows[],PetscScalar diag,Vec x,Vec b)
823 {
824   Mat_MPIAIJ        *l = (Mat_MPIAIJ*)A->data;
825   PetscErrorCode    ierr;
826   PetscMPIInt       n = A->rmap->n;
827   PetscInt          i,j,r,m,p = 0,len = 0;
828   PetscInt          *lrows,*owners = A->rmap->range;
829   PetscSFNode       *rrows;
830   PetscSF           sf;
831   const PetscScalar *xx;
832   PetscScalar       *bb,*mask;
833   Vec               xmask,lmask;
834   Mat_SeqAIJ        *aij = (Mat_SeqAIJ*)l->B->data;
835   const PetscInt    *aj, *ii,*ridx;
836   PetscScalar       *aa;
837 
838   PetscFunctionBegin;
839   /* Create SF where leaves are input rows and roots are owned rows */
840   ierr = PetscMalloc1(n, &lrows);CHKERRQ(ierr);
841   for (r = 0; r < n; ++r) lrows[r] = -1;
842   ierr = PetscMalloc1(N, &rrows);CHKERRQ(ierr);
843   for (r = 0; r < N; ++r) {
844     const PetscInt idx   = rows[r];
845     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);
846     if (idx < owners[p] || owners[p+1] <= idx) { /* short-circuit the search if the last p owns this row too */
847       ierr = PetscLayoutFindOwner(A->rmap,idx,&p);CHKERRQ(ierr);
848     }
849     rrows[r].rank  = p;
850     rrows[r].index = rows[r] - owners[p];
851   }
852   ierr = PetscSFCreate(PetscObjectComm((PetscObject) A), &sf);CHKERRQ(ierr);
853   ierr = PetscSFSetGraph(sf, n, N, NULL, PETSC_OWN_POINTER, rrows, PETSC_OWN_POINTER);CHKERRQ(ierr);
854   /* Collect flags for rows to be zeroed */
855   ierr = PetscSFReduceBegin(sf, MPIU_INT, (PetscInt *) rows, lrows, MPI_LOR);CHKERRQ(ierr);
856   ierr = PetscSFReduceEnd(sf, MPIU_INT, (PetscInt *) rows, lrows, MPI_LOR);CHKERRQ(ierr);
857   ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
858   /* Compress and put in row numbers */
859   for (r = 0; r < n; ++r) if (lrows[r] >= 0) lrows[len++] = r;
860   /* zero diagonal part of matrix */
861   ierr = MatZeroRowsColumns(l->A,len,lrows,diag,x,b);CHKERRQ(ierr);
862   /* handle off diagonal part of matrix */
863   ierr = MatCreateVecs(A,&xmask,NULL);CHKERRQ(ierr);
864   ierr = VecDuplicate(l->lvec,&lmask);CHKERRQ(ierr);
865   ierr = VecGetArray(xmask,&bb);CHKERRQ(ierr);
866   for (i=0; i<len; i++) bb[lrows[i]] = 1;
867   ierr = VecRestoreArray(xmask,&bb);CHKERRQ(ierr);
868   ierr = VecScatterBegin(l->Mvctx,xmask,lmask,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
869   ierr = VecScatterEnd(l->Mvctx,xmask,lmask,ADD_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
870   ierr = VecDestroy(&xmask);CHKERRQ(ierr);
871   if (x) {
872     ierr = VecScatterBegin(l->Mvctx,x,l->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
873     ierr = VecScatterEnd(l->Mvctx,x,l->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
874     ierr = VecGetArrayRead(l->lvec,&xx);CHKERRQ(ierr);
875     ierr = VecGetArray(b,&bb);CHKERRQ(ierr);
876   }
877   ierr = VecGetArray(lmask,&mask);CHKERRQ(ierr);
878   /* remove zeroed rows of off diagonal matrix */
879   ii = aij->i;
880   for (i=0; i<len; i++) {
881     ierr = PetscMemzero(aij->a + ii[lrows[i]],(ii[lrows[i]+1] - ii[lrows[i]])*sizeof(PetscScalar));CHKERRQ(ierr);
882   }
883   /* loop over all elements of off process part of matrix zeroing removed columns*/
884   if (aij->compressedrow.use) {
885     m    = aij->compressedrow.nrows;
886     ii   = aij->compressedrow.i;
887     ridx = aij->compressedrow.rindex;
888     for (i=0; i<m; i++) {
889       n  = ii[i+1] - ii[i];
890       aj = aij->j + ii[i];
891       aa = aij->a + ii[i];
892 
893       for (j=0; j<n; j++) {
894         if (PetscAbsScalar(mask[*aj])) {
895           if (b) bb[*ridx] -= *aa*xx[*aj];
896           *aa = 0.0;
897         }
898         aa++;
899         aj++;
900       }
901       ridx++;
902     }
903   } else { /* do not use compressed row format */
904     m = l->B->rmap->n;
905     for (i=0; i<m; i++) {
906       n  = ii[i+1] - ii[i];
907       aj = aij->j + ii[i];
908       aa = aij->a + ii[i];
909       for (j=0; j<n; j++) {
910         if (PetscAbsScalar(mask[*aj])) {
911           if (b) bb[i] -= *aa*xx[*aj];
912           *aa = 0.0;
913         }
914         aa++;
915         aj++;
916       }
917     }
918   }
919   if (x) {
920     ierr = VecRestoreArray(b,&bb);CHKERRQ(ierr);
921     ierr = VecRestoreArrayRead(l->lvec,&xx);CHKERRQ(ierr);
922   }
923   ierr = VecRestoreArray(lmask,&mask);CHKERRQ(ierr);
924   ierr = VecDestroy(&lmask);CHKERRQ(ierr);
925   ierr = PetscFree(lrows);CHKERRQ(ierr);
926 
927   /* only change matrix nonzero state if pattern was allowed to be changed */
928   if (!((Mat_SeqAIJ*)(l->A->data))->keepnonzeropattern) {
929     PetscObjectState state = l->A->nonzerostate + l->B->nonzerostate;
930     ierr = MPIU_Allreduce(&state,&A->nonzerostate,1,MPIU_INT64,MPI_SUM,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
931   }
932   PetscFunctionReturn(0);
933 }
934 
935 PetscErrorCode MatMult_MPIAIJ(Mat A,Vec xx,Vec yy)
936 {
937   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
938   PetscErrorCode ierr;
939   PetscInt       nt;
940 
941   PetscFunctionBegin;
942   ierr = VecGetLocalSize(xx,&nt);CHKERRQ(ierr);
943   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);
944   ierr = VecScatterBegin(a->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(a->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 
966   PetscFunctionBegin;
967   ierr = VecScatterBegin(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
968   ierr = (*a->A->ops->multadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
969   ierr = VecScatterEnd(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
970   ierr = (*a->B->ops->multadd)(a->B,a->lvec,zz,zz);CHKERRQ(ierr);
971   PetscFunctionReturn(0);
972 }
973 
974 PetscErrorCode MatMultTranspose_MPIAIJ(Mat A,Vec xx,Vec yy)
975 {
976   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
977   PetscErrorCode ierr;
978   PetscBool      merged;
979 
980   PetscFunctionBegin;
981   ierr = VecScatterGetMerged(a->Mvctx,&merged);CHKERRQ(ierr);
982   /* do nondiagonal part */
983   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
984   if (!merged) {
985     /* send it on its way */
986     ierr = VecScatterBegin(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
987     /* do local part */
988     ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
989     /* receive remote parts: note this assumes the values are not actually */
990     /* added in yy until the next line, */
991     ierr = VecScatterEnd(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
992   } else {
993     /* do local part */
994     ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
995     /* send it on its way */
996     ierr = VecScatterBegin(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
997     /* values actually were received in the Begin() but we need to call this nop */
998     ierr = VecScatterEnd(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
999   }
1000   PetscFunctionReturn(0);
1001 }
1002 
1003 PetscErrorCode  MatIsTranspose_MPIAIJ(Mat Amat,Mat Bmat,PetscReal tol,PetscBool  *f)
1004 {
1005   MPI_Comm       comm;
1006   Mat_MPIAIJ     *Aij = (Mat_MPIAIJ*) Amat->data, *Bij;
1007   Mat            Adia = Aij->A, Bdia, Aoff,Boff,*Aoffs,*Boffs;
1008   IS             Me,Notme;
1009   PetscErrorCode ierr;
1010   PetscInt       M,N,first,last,*notme,i;
1011   PetscMPIInt    size;
1012 
1013   PetscFunctionBegin;
1014   /* Easy test: symmetric diagonal block */
1015   Bij  = (Mat_MPIAIJ*) Bmat->data; Bdia = Bij->A;
1016   ierr = MatIsTranspose(Adia,Bdia,tol,f);CHKERRQ(ierr);
1017   if (!*f) PetscFunctionReturn(0);
1018   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
1019   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
1020   if (size == 1) PetscFunctionReturn(0);
1021 
1022   /* Hard test: off-diagonal block. This takes a MatCreateSubMatrix. */
1023   ierr = MatGetSize(Amat,&M,&N);CHKERRQ(ierr);
1024   ierr = MatGetOwnershipRange(Amat,&first,&last);CHKERRQ(ierr);
1025   ierr = PetscMalloc1(N-last+first,&notme);CHKERRQ(ierr);
1026   for (i=0; i<first; i++) notme[i] = i;
1027   for (i=last; i<M; i++) notme[i-last+first] = i;
1028   ierr = ISCreateGeneral(MPI_COMM_SELF,N-last+first,notme,PETSC_COPY_VALUES,&Notme);CHKERRQ(ierr);
1029   ierr = ISCreateStride(MPI_COMM_SELF,last-first,first,1,&Me);CHKERRQ(ierr);
1030   ierr = MatCreateSubMatrices(Amat,1,&Me,&Notme,MAT_INITIAL_MATRIX,&Aoffs);CHKERRQ(ierr);
1031   Aoff = Aoffs[0];
1032   ierr = MatCreateSubMatrices(Bmat,1,&Notme,&Me,MAT_INITIAL_MATRIX,&Boffs);CHKERRQ(ierr);
1033   Boff = Boffs[0];
1034   ierr = MatIsTranspose(Aoff,Boff,tol,f);CHKERRQ(ierr);
1035   ierr = MatDestroyMatrices(1,&Aoffs);CHKERRQ(ierr);
1036   ierr = MatDestroyMatrices(1,&Boffs);CHKERRQ(ierr);
1037   ierr = ISDestroy(&Me);CHKERRQ(ierr);
1038   ierr = ISDestroy(&Notme);CHKERRQ(ierr);
1039   ierr = PetscFree(notme);CHKERRQ(ierr);
1040   PetscFunctionReturn(0);
1041 }
1042 
1043 PetscErrorCode MatMultTransposeAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
1044 {
1045   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1046   PetscErrorCode ierr;
1047 
1048   PetscFunctionBegin;
1049   /* do nondiagonal part */
1050   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
1051   /* send it on its way */
1052   ierr = VecScatterBegin(a->Mvctx,a->lvec,zz,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1053   /* do local part */
1054   ierr = (*a->A->ops->multtransposeadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
1055   /* receive remote parts */
1056   ierr = VecScatterEnd(a->Mvctx,a->lvec,zz,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
1057   PetscFunctionReturn(0);
1058 }
1059 
1060 /*
1061   This only works correctly for square matrices where the subblock A->A is the
1062    diagonal block
1063 */
1064 PetscErrorCode MatGetDiagonal_MPIAIJ(Mat A,Vec v)
1065 {
1066   PetscErrorCode ierr;
1067   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1068 
1069   PetscFunctionBegin;
1070   if (A->rmap->N != A->cmap->N) SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_SUP,"Supports only square matrix where A->A is diag block");
1071   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");
1072   ierr = MatGetDiagonal(a->A,v);CHKERRQ(ierr);
1073   PetscFunctionReturn(0);
1074 }
1075 
1076 PetscErrorCode MatScale_MPIAIJ(Mat A,PetscScalar aa)
1077 {
1078   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1079   PetscErrorCode ierr;
1080 
1081   PetscFunctionBegin;
1082   ierr = MatScale(a->A,aa);CHKERRQ(ierr);
1083   ierr = MatScale(a->B,aa);CHKERRQ(ierr);
1084   PetscFunctionReturn(0);
1085 }
1086 
1087 PetscErrorCode MatDestroy_MPIAIJ(Mat mat)
1088 {
1089   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1090   PetscErrorCode ierr;
1091 
1092   PetscFunctionBegin;
1093 #if defined(PETSC_USE_LOG)
1094   PetscLogObjectState((PetscObject)mat,"Rows=%D, Cols=%D",mat->rmap->N,mat->cmap->N);
1095 #endif
1096   ierr = MatStashDestroy_Private(&mat->stash);CHKERRQ(ierr);
1097   ierr = VecDestroy(&aij->diag);CHKERRQ(ierr);
1098   ierr = MatDestroy(&aij->A);CHKERRQ(ierr);
1099   ierr = MatDestroy(&aij->B);CHKERRQ(ierr);
1100 #if defined(PETSC_USE_CTABLE)
1101   ierr = PetscTableDestroy(&aij->colmap);CHKERRQ(ierr);
1102 #else
1103   ierr = PetscFree(aij->colmap);CHKERRQ(ierr);
1104 #endif
1105   ierr = PetscFree(aij->garray);CHKERRQ(ierr);
1106   ierr = VecDestroy(&aij->lvec);CHKERRQ(ierr);
1107   ierr = VecScatterDestroy(&aij->Mvctx);CHKERRQ(ierr);
1108   ierr = PetscFree2(aij->rowvalues,aij->rowindices);CHKERRQ(ierr);
1109   ierr = PetscFree(aij->ld);CHKERRQ(ierr);
1110   ierr = PetscFree(mat->data);CHKERRQ(ierr);
1111 
1112   ierr = PetscObjectChangeTypeName((PetscObject)mat,0);CHKERRQ(ierr);
1113   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatStoreValues_C",NULL);CHKERRQ(ierr);
1114   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatRetrieveValues_C",NULL);CHKERRQ(ierr);
1115   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatIsTranspose_C",NULL);CHKERRQ(ierr);
1116   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMPIAIJSetPreallocation_C",NULL);CHKERRQ(ierr);
1117   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMPIAIJSetPreallocationCSR_C",NULL);CHKERRQ(ierr);
1118   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatDiagonalScaleLocal_C",NULL);CHKERRQ(ierr);
1119   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatConvert_mpiaij_mpisbaij_C",NULL);CHKERRQ(ierr);
1120 #if defined(PETSC_HAVE_ELEMENTAL)
1121   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatConvert_mpiaij_elemental_C",NULL);CHKERRQ(ierr);
1122 #endif
1123 #if defined(PETSC_HAVE_HYPRE)
1124   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatConvert_mpiaij_hypre_C",NULL);CHKERRQ(ierr);
1125   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMatMatMult_transpose_mpiaij_mpiaij_C",NULL);CHKERRQ(ierr);
1126 #endif
1127   PetscFunctionReturn(0);
1128 }
1129 
1130 PetscErrorCode MatView_MPIAIJ_Binary(Mat mat,PetscViewer viewer)
1131 {
1132   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1133   Mat_SeqAIJ     *A   = (Mat_SeqAIJ*)aij->A->data;
1134   Mat_SeqAIJ     *B   = (Mat_SeqAIJ*)aij->B->data;
1135   PetscErrorCode ierr;
1136   PetscMPIInt    rank,size,tag = ((PetscObject)viewer)->tag;
1137   int            fd;
1138   PetscInt       nz,header[4],*row_lengths,*range=0,rlen,i;
1139   PetscInt       nzmax,*column_indices,j,k,col,*garray = aij->garray,cnt,cstart = mat->cmap->rstart,rnz = 0;
1140   PetscScalar    *column_values;
1141   PetscInt       message_count,flowcontrolcount;
1142   FILE           *file;
1143 
1144   PetscFunctionBegin;
1145   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)mat),&rank);CHKERRQ(ierr);
1146   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)mat),&size);CHKERRQ(ierr);
1147   nz   = A->nz + B->nz;
1148   ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
1149   if (!rank) {
1150     header[0] = MAT_FILE_CLASSID;
1151     header[1] = mat->rmap->N;
1152     header[2] = mat->cmap->N;
1153 
1154     ierr = MPI_Reduce(&nz,&header[3],1,MPIU_INT,MPI_SUM,0,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1155     ierr = PetscBinaryWrite(fd,header,4,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1156     /* get largest number of rows any processor has */
1157     rlen  = mat->rmap->n;
1158     range = mat->rmap->range;
1159     for (i=1; i<size; i++) rlen = PetscMax(rlen,range[i+1] - range[i]);
1160   } else {
1161     ierr = MPI_Reduce(&nz,0,1,MPIU_INT,MPI_SUM,0,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1162     rlen = mat->rmap->n;
1163   }
1164 
1165   /* load up the local row counts */
1166   ierr = PetscMalloc1(rlen+1,&row_lengths);CHKERRQ(ierr);
1167   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];
1168 
1169   /* store the row lengths to the file */
1170   ierr = PetscViewerFlowControlStart(viewer,&message_count,&flowcontrolcount);CHKERRQ(ierr);
1171   if (!rank) {
1172     ierr = PetscBinaryWrite(fd,row_lengths,mat->rmap->n,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1173     for (i=1; i<size; i++) {
1174       ierr = PetscViewerFlowControlStepMaster(viewer,i,&message_count,flowcontrolcount);CHKERRQ(ierr);
1175       rlen = range[i+1] - range[i];
1176       ierr = MPIULong_Recv(row_lengths,rlen,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1177       ierr = PetscBinaryWrite(fd,row_lengths,rlen,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1178     }
1179     ierr = PetscViewerFlowControlEndMaster(viewer,&message_count);CHKERRQ(ierr);
1180   } else {
1181     ierr = PetscViewerFlowControlStepWorker(viewer,rank,&message_count);CHKERRQ(ierr);
1182     ierr = MPIULong_Send(row_lengths,mat->rmap->n,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1183     ierr = PetscViewerFlowControlEndWorker(viewer,&message_count);CHKERRQ(ierr);
1184   }
1185   ierr = PetscFree(row_lengths);CHKERRQ(ierr);
1186 
1187   /* load up the local column indices */
1188   nzmax = nz; /* th processor needs space a largest processor needs */
1189   ierr  = MPI_Reduce(&nz,&nzmax,1,MPIU_INT,MPI_MAX,0,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1190   ierr  = PetscMalloc1(nzmax+1,&column_indices);CHKERRQ(ierr);
1191   cnt   = 0;
1192   for (i=0; i<mat->rmap->n; i++) {
1193     for (j=B->i[i]; j<B->i[i+1]; j++) {
1194       if ((col = garray[B->j[j]]) > cstart) break;
1195       column_indices[cnt++] = col;
1196     }
1197     for (k=A->i[i]; k<A->i[i+1]; k++) column_indices[cnt++] = A->j[k] + cstart;
1198     for (; j<B->i[i+1]; j++) column_indices[cnt++] = garray[B->j[j]];
1199   }
1200   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);
1201 
1202   /* store the column indices to the file */
1203   ierr = PetscViewerFlowControlStart(viewer,&message_count,&flowcontrolcount);CHKERRQ(ierr);
1204   if (!rank) {
1205     MPI_Status status;
1206     ierr = PetscBinaryWrite(fd,column_indices,nz,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1207     for (i=1; i<size; i++) {
1208       ierr = PetscViewerFlowControlStepMaster(viewer,i,&message_count,flowcontrolcount);CHKERRQ(ierr);
1209       ierr = MPI_Recv(&rnz,1,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat),&status);CHKERRQ(ierr);
1210       if (rnz > nzmax) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_LIB,"Internal PETSc error: nz = %D nzmax = %D",nz,nzmax);
1211       ierr = MPIULong_Recv(column_indices,rnz,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1212       ierr = PetscBinaryWrite(fd,column_indices,rnz,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1213     }
1214     ierr = PetscViewerFlowControlEndMaster(viewer,&message_count);CHKERRQ(ierr);
1215   } else {
1216     ierr = PetscViewerFlowControlStepWorker(viewer,rank,&message_count);CHKERRQ(ierr);
1217     ierr = MPI_Send(&nz,1,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1218     ierr = MPIULong_Send(column_indices,nz,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1219     ierr = PetscViewerFlowControlEndWorker(viewer,&message_count);CHKERRQ(ierr);
1220   }
1221   ierr = PetscFree(column_indices);CHKERRQ(ierr);
1222 
1223   /* load up the local column values */
1224   ierr = PetscMalloc1(nzmax+1,&column_values);CHKERRQ(ierr);
1225   cnt  = 0;
1226   for (i=0; i<mat->rmap->n; i++) {
1227     for (j=B->i[i]; j<B->i[i+1]; j++) {
1228       if (garray[B->j[j]] > cstart) break;
1229       column_values[cnt++] = B->a[j];
1230     }
1231     for (k=A->i[i]; k<A->i[i+1]; k++) column_values[cnt++] = A->a[k];
1232     for (; j<B->i[i+1]; j++) column_values[cnt++] = B->a[j];
1233   }
1234   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);
1235 
1236   /* store the column values to the file */
1237   ierr = PetscViewerFlowControlStart(viewer,&message_count,&flowcontrolcount);CHKERRQ(ierr);
1238   if (!rank) {
1239     MPI_Status status;
1240     ierr = PetscBinaryWrite(fd,column_values,nz,PETSC_SCALAR,PETSC_TRUE);CHKERRQ(ierr);
1241     for (i=1; i<size; i++) {
1242       ierr = PetscViewerFlowControlStepMaster(viewer,i,&message_count,flowcontrolcount);CHKERRQ(ierr);
1243       ierr = MPI_Recv(&rnz,1,MPIU_INT,i,tag,PetscObjectComm((PetscObject)mat),&status);CHKERRQ(ierr);
1244       if (rnz > nzmax) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_LIB,"Internal PETSc error: nz = %D nzmax = %D",nz,nzmax);
1245       ierr = MPIULong_Recv(column_values,rnz,MPIU_SCALAR,i,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1246       ierr = PetscBinaryWrite(fd,column_values,rnz,PETSC_SCALAR,PETSC_TRUE);CHKERRQ(ierr);
1247     }
1248     ierr = PetscViewerFlowControlEndMaster(viewer,&message_count);CHKERRQ(ierr);
1249   } else {
1250     ierr = PetscViewerFlowControlStepWorker(viewer,rank,&message_count);CHKERRQ(ierr);
1251     ierr = MPI_Send(&nz,1,MPIU_INT,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1252     ierr = MPIULong_Send(column_values,nz,MPIU_SCALAR,0,tag,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1253     ierr = PetscViewerFlowControlEndWorker(viewer,&message_count);CHKERRQ(ierr);
1254   }
1255   ierr = PetscFree(column_values);CHKERRQ(ierr);
1256 
1257   ierr = PetscViewerBinaryGetInfoPointer(viewer,&file);CHKERRQ(ierr);
1258   if (file) fprintf(file,"-matload_block_size %d\n",(int)PetscAbs(mat->rmap->bs));
1259   PetscFunctionReturn(0);
1260 }
1261 
1262 #include <petscdraw.h>
1263 PetscErrorCode MatView_MPIAIJ_ASCIIorDraworSocket(Mat mat,PetscViewer viewer)
1264 {
1265   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
1266   PetscErrorCode    ierr;
1267   PetscMPIInt       rank = aij->rank,size = aij->size;
1268   PetscBool         isdraw,iascii,isbinary;
1269   PetscViewer       sviewer;
1270   PetscViewerFormat format;
1271 
1272   PetscFunctionBegin;
1273   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr);
1274   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
1275   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1276   if (iascii) {
1277     ierr = PetscViewerGetFormat(viewer,&format);CHKERRQ(ierr);
1278     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
1279       MatInfo   info;
1280       PetscBool inodes;
1281 
1282       ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)mat),&rank);CHKERRQ(ierr);
1283       ierr = MatGetInfo(mat,MAT_LOCAL,&info);CHKERRQ(ierr);
1284       ierr = MatInodeGetInodeSizes(aij->A,NULL,(PetscInt**)&inodes,NULL);CHKERRQ(ierr);
1285       ierr = PetscViewerASCIIPushSynchronized(viewer);CHKERRQ(ierr);
1286       if (!inodes) {
1287         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %D nz %D nz alloced %D mem %D, not using I-node routines\n",
1288                                                   rank,mat->rmap->n,(PetscInt)info.nz_used,(PetscInt)info.nz_allocated,(PetscInt)info.memory);CHKERRQ(ierr);
1289       } else {
1290         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %D nz %D nz alloced %D mem %D, using I-node routines\n",
1291                                                   rank,mat->rmap->n,(PetscInt)info.nz_used,(PetscInt)info.nz_allocated,(PetscInt)info.memory);CHKERRQ(ierr);
1292       }
1293       ierr = MatGetInfo(aij->A,MAT_LOCAL,&info);CHKERRQ(ierr);
1294       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] on-diagonal part: nz %D \n",rank,(PetscInt)info.nz_used);CHKERRQ(ierr);
1295       ierr = MatGetInfo(aij->B,MAT_LOCAL,&info);CHKERRQ(ierr);
1296       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] off-diagonal part: nz %D \n",rank,(PetscInt)info.nz_used);CHKERRQ(ierr);
1297       ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
1298       ierr = PetscViewerASCIIPopSynchronized(viewer);CHKERRQ(ierr);
1299       ierr = PetscViewerASCIIPrintf(viewer,"Information on VecScatter used in matrix-vector product: \n");CHKERRQ(ierr);
1300       ierr = VecScatterView(aij->Mvctx,viewer);CHKERRQ(ierr);
1301       PetscFunctionReturn(0);
1302     } else if (format == PETSC_VIEWER_ASCII_INFO) {
1303       PetscInt inodecount,inodelimit,*inodes;
1304       ierr = MatInodeGetInodeSizes(aij->A,&inodecount,&inodes,&inodelimit);CHKERRQ(ierr);
1305       if (inodes) {
1306         ierr = PetscViewerASCIIPrintf(viewer,"using I-node (on process 0) routines: found %D nodes, limit used is %D\n",inodecount,inodelimit);CHKERRQ(ierr);
1307       } else {
1308         ierr = PetscViewerASCIIPrintf(viewer,"not using I-node (on process 0) routines\n");CHKERRQ(ierr);
1309       }
1310       PetscFunctionReturn(0);
1311     } else if (format == PETSC_VIEWER_ASCII_FACTOR_INFO) {
1312       PetscFunctionReturn(0);
1313     }
1314   } else if (isbinary) {
1315     if (size == 1) {
1316       ierr = PetscObjectSetName((PetscObject)aij->A,((PetscObject)mat)->name);CHKERRQ(ierr);
1317       ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
1318     } else {
1319       ierr = MatView_MPIAIJ_Binary(mat,viewer);CHKERRQ(ierr);
1320     }
1321     PetscFunctionReturn(0);
1322   } else if (isdraw) {
1323     PetscDraw draw;
1324     PetscBool isnull;
1325     ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
1326     ierr = PetscDrawIsNull(draw,&isnull);CHKERRQ(ierr);
1327     if (isnull) PetscFunctionReturn(0);
1328   }
1329 
1330   {
1331     /* assemble the entire matrix onto first processor. */
1332     Mat        A;
1333     Mat_SeqAIJ *Aloc;
1334     PetscInt   M = mat->rmap->N,N = mat->cmap->N,m,*ai,*aj,row,*cols,i,*ct;
1335     MatScalar  *a;
1336 
1337     ierr = MatCreate(PetscObjectComm((PetscObject)mat),&A);CHKERRQ(ierr);
1338     if (!rank) {
1339       ierr = MatSetSizes(A,M,N,M,N);CHKERRQ(ierr);
1340     } else {
1341       ierr = MatSetSizes(A,0,0,M,N);CHKERRQ(ierr);
1342     }
1343     /* This is just a temporary matrix, so explicitly using MATMPIAIJ is probably best */
1344     ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
1345     ierr = MatMPIAIJSetPreallocation(A,0,NULL,0,NULL);CHKERRQ(ierr);
1346     ierr = MatSetOption(A,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr);
1347     ierr = PetscLogObjectParent((PetscObject)mat,(PetscObject)A);CHKERRQ(ierr);
1348 
1349     /* copy over the A part */
1350     Aloc = (Mat_SeqAIJ*)aij->A->data;
1351     m    = aij->A->rmap->n; ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
1352     row  = mat->rmap->rstart;
1353     for (i=0; i<ai[m]; i++) aj[i] += mat->cmap->rstart;
1354     for (i=0; i<m; i++) {
1355       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],aj,a,INSERT_VALUES);CHKERRQ(ierr);
1356       row++;
1357       a += ai[i+1]-ai[i]; aj += ai[i+1]-ai[i];
1358     }
1359     aj = Aloc->j;
1360     for (i=0; i<ai[m]; i++) aj[i] -= mat->cmap->rstart;
1361 
1362     /* copy over the B part */
1363     Aloc = (Mat_SeqAIJ*)aij->B->data;
1364     m    = aij->B->rmap->n;  ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
1365     row  = mat->rmap->rstart;
1366     ierr = PetscMalloc1(ai[m]+1,&cols);CHKERRQ(ierr);
1367     ct   = cols;
1368     for (i=0; i<ai[m]; i++) cols[i] = aij->garray[aj[i]];
1369     for (i=0; i<m; i++) {
1370       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],cols,a,INSERT_VALUES);CHKERRQ(ierr);
1371       row++;
1372       a += ai[i+1]-ai[i]; cols += ai[i+1]-ai[i];
1373     }
1374     ierr = PetscFree(ct);CHKERRQ(ierr);
1375     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1376     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1377     /*
1378        Everyone has to call to draw the matrix since the graphics waits are
1379        synchronized across all processors that share the PetscDraw object
1380     */
1381     ierr = PetscViewerGetSubViewer(viewer,PETSC_COMM_SELF,&sviewer);CHKERRQ(ierr);
1382     if (!rank) {
1383       ierr = PetscObjectSetName((PetscObject)((Mat_MPIAIJ*)(A->data))->A,((PetscObject)mat)->name);CHKERRQ(ierr);
1384       ierr = MatView_SeqAIJ(((Mat_MPIAIJ*)(A->data))->A,sviewer);CHKERRQ(ierr);
1385     }
1386     ierr = PetscViewerRestoreSubViewer(viewer,PETSC_COMM_SELF,&sviewer);CHKERRQ(ierr);
1387     ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
1388     ierr = MatDestroy(&A);CHKERRQ(ierr);
1389   }
1390   PetscFunctionReturn(0);
1391 }
1392 
1393 PetscErrorCode MatView_MPIAIJ(Mat mat,PetscViewer viewer)
1394 {
1395   PetscErrorCode ierr;
1396   PetscBool      iascii,isdraw,issocket,isbinary;
1397 
1398   PetscFunctionBegin;
1399   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
1400   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERDRAW,&isdraw);CHKERRQ(ierr);
1401   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&isbinary);CHKERRQ(ierr);
1402   ierr = PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERSOCKET,&issocket);CHKERRQ(ierr);
1403   if (iascii || isdraw || isbinary || issocket) {
1404     ierr = MatView_MPIAIJ_ASCIIorDraworSocket(mat,viewer);CHKERRQ(ierr);
1405   }
1406   PetscFunctionReturn(0);
1407 }
1408 
1409 PetscErrorCode MatSOR_MPIAIJ(Mat matin,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
1410 {
1411   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1412   PetscErrorCode ierr;
1413   Vec            bb1 = 0;
1414   PetscBool      hasop;
1415 
1416   PetscFunctionBegin;
1417   if (flag == SOR_APPLY_UPPER) {
1418     ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1419     PetscFunctionReturn(0);
1420   }
1421 
1422   if (its > 1 || ~flag & SOR_ZERO_INITIAL_GUESS || flag & SOR_EISENSTAT) {
1423     ierr = VecDuplicate(bb,&bb1);CHKERRQ(ierr);
1424   }
1425 
1426   if ((flag & SOR_LOCAL_SYMMETRIC_SWEEP) == SOR_LOCAL_SYMMETRIC_SWEEP) {
1427     if (flag & SOR_ZERO_INITIAL_GUESS) {
1428       ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1429       its--;
1430     }
1431 
1432     while (its--) {
1433       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1434       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1435 
1436       /* update rhs: bb1 = bb - B*x */
1437       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1438       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1439 
1440       /* local sweep */
1441       ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,SOR_SYMMETRIC_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1442     }
1443   } else if (flag & SOR_LOCAL_FORWARD_SWEEP) {
1444     if (flag & SOR_ZERO_INITIAL_GUESS) {
1445       ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1446       its--;
1447     }
1448     while (its--) {
1449       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1450       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1451 
1452       /* update rhs: bb1 = bb - B*x */
1453       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1454       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1455 
1456       /* local sweep */
1457       ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,SOR_FORWARD_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1458     }
1459   } else if (flag & SOR_LOCAL_BACKWARD_SWEEP) {
1460     if (flag & SOR_ZERO_INITIAL_GUESS) {
1461       ierr = (*mat->A->ops->sor)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1462       its--;
1463     }
1464     while (its--) {
1465       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1466       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1467 
1468       /* update rhs: bb1 = bb - B*x */
1469       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1470       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1471 
1472       /* local sweep */
1473       ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,SOR_BACKWARD_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1474     }
1475   } else if (flag & SOR_EISENSTAT) {
1476     Vec xx1;
1477 
1478     ierr = VecDuplicate(bb,&xx1);CHKERRQ(ierr);
1479     ierr = (*mat->A->ops->sor)(mat->A,bb,omega,(MatSORType)(SOR_ZERO_INITIAL_GUESS | SOR_LOCAL_BACKWARD_SWEEP),fshift,lits,1,xx);CHKERRQ(ierr);
1480 
1481     ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1482     ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1483     if (!mat->diag) {
1484       ierr = MatCreateVecs(matin,&mat->diag,NULL);CHKERRQ(ierr);
1485       ierr = MatGetDiagonal(matin,mat->diag);CHKERRQ(ierr);
1486     }
1487     ierr = MatHasOperation(matin,MATOP_MULT_DIAGONAL_BLOCK,&hasop);CHKERRQ(ierr);
1488     if (hasop) {
1489       ierr = MatMultDiagonalBlock(matin,xx,bb1);CHKERRQ(ierr);
1490     } else {
1491       ierr = VecPointwiseMult(bb1,mat->diag,xx);CHKERRQ(ierr);
1492     }
1493     ierr = VecAYPX(bb1,(omega-2.0)/omega,bb);CHKERRQ(ierr);
1494 
1495     ierr = MatMultAdd(mat->B,mat->lvec,bb1,bb1);CHKERRQ(ierr);
1496 
1497     /* local sweep */
1498     ierr = (*mat->A->ops->sor)(mat->A,bb1,omega,(MatSORType)(SOR_ZERO_INITIAL_GUESS | SOR_LOCAL_FORWARD_SWEEP),fshift,lits,1,xx1);CHKERRQ(ierr);
1499     ierr = VecAXPY(xx,1.0,xx1);CHKERRQ(ierr);
1500     ierr = VecDestroy(&xx1);CHKERRQ(ierr);
1501   } else SETERRQ(PetscObjectComm((PetscObject)matin),PETSC_ERR_SUP,"Parallel SOR not supported");
1502 
1503   ierr = VecDestroy(&bb1);CHKERRQ(ierr);
1504 
1505   matin->factorerrortype = mat->A->factorerrortype;
1506   PetscFunctionReturn(0);
1507 }
1508 
1509 PetscErrorCode MatPermute_MPIAIJ(Mat A,IS rowp,IS colp,Mat *B)
1510 {
1511   Mat            aA,aB,Aperm;
1512   const PetscInt *rwant,*cwant,*gcols,*ai,*bi,*aj,*bj;
1513   PetscScalar    *aa,*ba;
1514   PetscInt       i,j,m,n,ng,anz,bnz,*dnnz,*onnz,*tdnnz,*tonnz,*rdest,*cdest,*work,*gcdest;
1515   PetscSF        rowsf,sf;
1516   IS             parcolp = NULL;
1517   PetscBool      done;
1518   PetscErrorCode ierr;
1519 
1520   PetscFunctionBegin;
1521   ierr = MatGetLocalSize(A,&m,&n);CHKERRQ(ierr);
1522   ierr = ISGetIndices(rowp,&rwant);CHKERRQ(ierr);
1523   ierr = ISGetIndices(colp,&cwant);CHKERRQ(ierr);
1524   ierr = PetscMalloc3(PetscMax(m,n),&work,m,&rdest,n,&cdest);CHKERRQ(ierr);
1525 
1526   /* Invert row permutation to find out where my rows should go */
1527   ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&rowsf);CHKERRQ(ierr);
1528   ierr = PetscSFSetGraphLayout(rowsf,A->rmap,A->rmap->n,NULL,PETSC_OWN_POINTER,rwant);CHKERRQ(ierr);
1529   ierr = PetscSFSetFromOptions(rowsf);CHKERRQ(ierr);
1530   for (i=0; i<m; i++) work[i] = A->rmap->rstart + i;
1531   ierr = PetscSFReduceBegin(rowsf,MPIU_INT,work,rdest,MPIU_REPLACE);CHKERRQ(ierr);
1532   ierr = PetscSFReduceEnd(rowsf,MPIU_INT,work,rdest,MPIU_REPLACE);CHKERRQ(ierr);
1533 
1534   /* Invert column permutation to find out where my columns should go */
1535   ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&sf);CHKERRQ(ierr);
1536   ierr = PetscSFSetGraphLayout(sf,A->cmap,A->cmap->n,NULL,PETSC_OWN_POINTER,cwant);CHKERRQ(ierr);
1537   ierr = PetscSFSetFromOptions(sf);CHKERRQ(ierr);
1538   for (i=0; i<n; i++) work[i] = A->cmap->rstart + i;
1539   ierr = PetscSFReduceBegin(sf,MPIU_INT,work,cdest,MPIU_REPLACE);CHKERRQ(ierr);
1540   ierr = PetscSFReduceEnd(sf,MPIU_INT,work,cdest,MPIU_REPLACE);CHKERRQ(ierr);
1541   ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
1542 
1543   ierr = ISRestoreIndices(rowp,&rwant);CHKERRQ(ierr);
1544   ierr = ISRestoreIndices(colp,&cwant);CHKERRQ(ierr);
1545   ierr = MatMPIAIJGetSeqAIJ(A,&aA,&aB,&gcols);CHKERRQ(ierr);
1546 
1547   /* Find out where my gcols should go */
1548   ierr = MatGetSize(aB,NULL,&ng);CHKERRQ(ierr);
1549   ierr = PetscMalloc1(ng,&gcdest);CHKERRQ(ierr);
1550   ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&sf);CHKERRQ(ierr);
1551   ierr = PetscSFSetGraphLayout(sf,A->cmap,ng,NULL,PETSC_OWN_POINTER,gcols);CHKERRQ(ierr);
1552   ierr = PetscSFSetFromOptions(sf);CHKERRQ(ierr);
1553   ierr = PetscSFBcastBegin(sf,MPIU_INT,cdest,gcdest);CHKERRQ(ierr);
1554   ierr = PetscSFBcastEnd(sf,MPIU_INT,cdest,gcdest);CHKERRQ(ierr);
1555   ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
1556 
1557   ierr = PetscCalloc4(m,&dnnz,m,&onnz,m,&tdnnz,m,&tonnz);CHKERRQ(ierr);
1558   ierr = MatGetRowIJ(aA,0,PETSC_FALSE,PETSC_FALSE,&anz,&ai,&aj,&done);CHKERRQ(ierr);
1559   ierr = MatGetRowIJ(aB,0,PETSC_FALSE,PETSC_FALSE,&bnz,&bi,&bj,&done);CHKERRQ(ierr);
1560   for (i=0; i<m; i++) {
1561     PetscInt row = rdest[i],rowner;
1562     ierr = PetscLayoutFindOwner(A->rmap,row,&rowner);CHKERRQ(ierr);
1563     for (j=ai[i]; j<ai[i+1]; j++) {
1564       PetscInt cowner,col = cdest[aj[j]];
1565       ierr = PetscLayoutFindOwner(A->cmap,col,&cowner);CHKERRQ(ierr); /* Could build an index for the columns to eliminate this search */
1566       if (rowner == cowner) dnnz[i]++;
1567       else onnz[i]++;
1568     }
1569     for (j=bi[i]; j<bi[i+1]; j++) {
1570       PetscInt cowner,col = gcdest[bj[j]];
1571       ierr = PetscLayoutFindOwner(A->cmap,col,&cowner);CHKERRQ(ierr);
1572       if (rowner == cowner) dnnz[i]++;
1573       else onnz[i]++;
1574     }
1575   }
1576   ierr = PetscSFBcastBegin(rowsf,MPIU_INT,dnnz,tdnnz);CHKERRQ(ierr);
1577   ierr = PetscSFBcastEnd(rowsf,MPIU_INT,dnnz,tdnnz);CHKERRQ(ierr);
1578   ierr = PetscSFBcastBegin(rowsf,MPIU_INT,onnz,tonnz);CHKERRQ(ierr);
1579   ierr = PetscSFBcastEnd(rowsf,MPIU_INT,onnz,tonnz);CHKERRQ(ierr);
1580   ierr = PetscSFDestroy(&rowsf);CHKERRQ(ierr);
1581 
1582   ierr = MatCreateAIJ(PetscObjectComm((PetscObject)A),A->rmap->n,A->cmap->n,A->rmap->N,A->cmap->N,0,tdnnz,0,tonnz,&Aperm);CHKERRQ(ierr);
1583   ierr = MatSeqAIJGetArray(aA,&aa);CHKERRQ(ierr);
1584   ierr = MatSeqAIJGetArray(aB,&ba);CHKERRQ(ierr);
1585   for (i=0; i<m; i++) {
1586     PetscInt *acols = dnnz,*bcols = onnz; /* Repurpose now-unneeded arrays */
1587     PetscInt j0,rowlen;
1588     rowlen = ai[i+1] - ai[i];
1589     for (j0=j=0; j<rowlen; j0=j) { /* rowlen could be larger than number of rows m, so sum in batches */
1590       for ( ; j<PetscMin(rowlen,j0+m); j++) acols[j-j0] = cdest[aj[ai[i]+j]];
1591       ierr = MatSetValues(Aperm,1,&rdest[i],j-j0,acols,aa+ai[i]+j0,INSERT_VALUES);CHKERRQ(ierr);
1592     }
1593     rowlen = bi[i+1] - bi[i];
1594     for (j0=j=0; j<rowlen; j0=j) {
1595       for ( ; j<PetscMin(rowlen,j0+m); j++) bcols[j-j0] = gcdest[bj[bi[i]+j]];
1596       ierr = MatSetValues(Aperm,1,&rdest[i],j-j0,bcols,ba+bi[i]+j0,INSERT_VALUES);CHKERRQ(ierr);
1597     }
1598   }
1599   ierr = MatAssemblyBegin(Aperm,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1600   ierr = MatAssemblyEnd(Aperm,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1601   ierr = MatRestoreRowIJ(aA,0,PETSC_FALSE,PETSC_FALSE,&anz,&ai,&aj,&done);CHKERRQ(ierr);
1602   ierr = MatRestoreRowIJ(aB,0,PETSC_FALSE,PETSC_FALSE,&bnz,&bi,&bj,&done);CHKERRQ(ierr);
1603   ierr = MatSeqAIJRestoreArray(aA,&aa);CHKERRQ(ierr);
1604   ierr = MatSeqAIJRestoreArray(aB,&ba);CHKERRQ(ierr);
1605   ierr = PetscFree4(dnnz,onnz,tdnnz,tonnz);CHKERRQ(ierr);
1606   ierr = PetscFree3(work,rdest,cdest);CHKERRQ(ierr);
1607   ierr = PetscFree(gcdest);CHKERRQ(ierr);
1608   if (parcolp) {ierr = ISDestroy(&colp);CHKERRQ(ierr);}
1609   *B = Aperm;
1610   PetscFunctionReturn(0);
1611 }
1612 
1613 PetscErrorCode  MatGetGhosts_MPIAIJ(Mat mat,PetscInt *nghosts,const PetscInt *ghosts[])
1614 {
1615   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1616   PetscErrorCode ierr;
1617 
1618   PetscFunctionBegin;
1619   ierr = MatGetSize(aij->B,NULL,nghosts);CHKERRQ(ierr);
1620   if (ghosts) *ghosts = aij->garray;
1621   PetscFunctionReturn(0);
1622 }
1623 
1624 PetscErrorCode MatGetInfo_MPIAIJ(Mat matin,MatInfoType flag,MatInfo *info)
1625 {
1626   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1627   Mat            A    = mat->A,B = mat->B;
1628   PetscErrorCode ierr;
1629   PetscReal      isend[5],irecv[5];
1630 
1631   PetscFunctionBegin;
1632   info->block_size = 1.0;
1633   ierr             = MatGetInfo(A,MAT_LOCAL,info);CHKERRQ(ierr);
1634 
1635   isend[0] = info->nz_used; isend[1] = info->nz_allocated; isend[2] = info->nz_unneeded;
1636   isend[3] = info->memory;  isend[4] = info->mallocs;
1637 
1638   ierr = MatGetInfo(B,MAT_LOCAL,info);CHKERRQ(ierr);
1639 
1640   isend[0] += info->nz_used; isend[1] += info->nz_allocated; isend[2] += info->nz_unneeded;
1641   isend[3] += info->memory;  isend[4] += info->mallocs;
1642   if (flag == MAT_LOCAL) {
1643     info->nz_used      = isend[0];
1644     info->nz_allocated = isend[1];
1645     info->nz_unneeded  = isend[2];
1646     info->memory       = isend[3];
1647     info->mallocs      = isend[4];
1648   } else if (flag == MAT_GLOBAL_MAX) {
1649     ierr = MPIU_Allreduce(isend,irecv,5,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)matin));CHKERRQ(ierr);
1650 
1651     info->nz_used      = irecv[0];
1652     info->nz_allocated = irecv[1];
1653     info->nz_unneeded  = irecv[2];
1654     info->memory       = irecv[3];
1655     info->mallocs      = irecv[4];
1656   } else if (flag == MAT_GLOBAL_SUM) {
1657     ierr = MPIU_Allreduce(isend,irecv,5,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)matin));CHKERRQ(ierr);
1658 
1659     info->nz_used      = irecv[0];
1660     info->nz_allocated = irecv[1];
1661     info->nz_unneeded  = irecv[2];
1662     info->memory       = irecv[3];
1663     info->mallocs      = irecv[4];
1664   }
1665   info->fill_ratio_given  = 0; /* no parallel LU/ILU/Cholesky */
1666   info->fill_ratio_needed = 0;
1667   info->factor_mallocs    = 0;
1668   PetscFunctionReturn(0);
1669 }
1670 
1671 PetscErrorCode MatSetOption_MPIAIJ(Mat A,MatOption op,PetscBool flg)
1672 {
1673   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1674   PetscErrorCode ierr;
1675 
1676   PetscFunctionBegin;
1677   switch (op) {
1678   case MAT_NEW_NONZERO_LOCATIONS:
1679   case MAT_NEW_NONZERO_ALLOCATION_ERR:
1680   case MAT_UNUSED_NONZERO_LOCATION_ERR:
1681   case MAT_KEEP_NONZERO_PATTERN:
1682   case MAT_NEW_NONZERO_LOCATION_ERR:
1683   case MAT_USE_INODES:
1684   case MAT_IGNORE_ZERO_ENTRIES:
1685     MatCheckPreallocated(A,1);
1686     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1687     ierr = MatSetOption(a->B,op,flg);CHKERRQ(ierr);
1688     break;
1689   case MAT_ROW_ORIENTED:
1690     MatCheckPreallocated(A,1);
1691     a->roworiented = flg;
1692 
1693     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1694     ierr = MatSetOption(a->B,op,flg);CHKERRQ(ierr);
1695     break;
1696   case MAT_NEW_DIAGONALS:
1697     ierr = PetscInfo1(A,"Option %s ignored\n",MatOptions[op]);CHKERRQ(ierr);
1698     break;
1699   case MAT_IGNORE_OFF_PROC_ENTRIES:
1700     a->donotstash = flg;
1701     break;
1702   case MAT_SPD:
1703     A->spd_set = PETSC_TRUE;
1704     A->spd     = flg;
1705     if (flg) {
1706       A->symmetric                  = PETSC_TRUE;
1707       A->structurally_symmetric     = PETSC_TRUE;
1708       A->symmetric_set              = PETSC_TRUE;
1709       A->structurally_symmetric_set = PETSC_TRUE;
1710     }
1711     break;
1712   case MAT_SYMMETRIC:
1713     MatCheckPreallocated(A,1);
1714     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1715     break;
1716   case MAT_STRUCTURALLY_SYMMETRIC:
1717     MatCheckPreallocated(A,1);
1718     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1719     break;
1720   case MAT_HERMITIAN:
1721     MatCheckPreallocated(A,1);
1722     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1723     break;
1724   case MAT_SYMMETRY_ETERNAL:
1725     MatCheckPreallocated(A,1);
1726     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1727     break;
1728   case MAT_SUBMAT_SINGLEIS:
1729     A->submat_singleis = flg;
1730     break;
1731   default:
1732     SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_SUP,"unknown option %d",op);
1733   }
1734   PetscFunctionReturn(0);
1735 }
1736 
1737 PetscErrorCode MatGetRow_MPIAIJ(Mat matin,PetscInt row,PetscInt *nz,PetscInt **idx,PetscScalar **v)
1738 {
1739   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1740   PetscScalar    *vworkA,*vworkB,**pvA,**pvB,*v_p;
1741   PetscErrorCode ierr;
1742   PetscInt       i,*cworkA,*cworkB,**pcA,**pcB,cstart = matin->cmap->rstart;
1743   PetscInt       nztot,nzA,nzB,lrow,rstart = matin->rmap->rstart,rend = matin->rmap->rend;
1744   PetscInt       *cmap,*idx_p;
1745 
1746   PetscFunctionBegin;
1747   if (mat->getrowactive) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Already active");
1748   mat->getrowactive = PETSC_TRUE;
1749 
1750   if (!mat->rowvalues && (idx || v)) {
1751     /*
1752         allocate enough space to hold information from the longest row.
1753     */
1754     Mat_SeqAIJ *Aa = (Mat_SeqAIJ*)mat->A->data,*Ba = (Mat_SeqAIJ*)mat->B->data;
1755     PetscInt   max = 1,tmp;
1756     for (i=0; i<matin->rmap->n; i++) {
1757       tmp = Aa->i[i+1] - Aa->i[i] + Ba->i[i+1] - Ba->i[i];
1758       if (max < tmp) max = tmp;
1759     }
1760     ierr = PetscMalloc2(max,&mat->rowvalues,max,&mat->rowindices);CHKERRQ(ierr);
1761   }
1762 
1763   if (row < rstart || row >= rend) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Only local rows");
1764   lrow = row - rstart;
1765 
1766   pvA = &vworkA; pcA = &cworkA; pvB = &vworkB; pcB = &cworkB;
1767   if (!v)   {pvA = 0; pvB = 0;}
1768   if (!idx) {pcA = 0; if (!v) pcB = 0;}
1769   ierr  = (*mat->A->ops->getrow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1770   ierr  = (*mat->B->ops->getrow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1771   nztot = nzA + nzB;
1772 
1773   cmap = mat->garray;
1774   if (v  || idx) {
1775     if (nztot) {
1776       /* Sort by increasing column numbers, assuming A and B already sorted */
1777       PetscInt imark = -1;
1778       if (v) {
1779         *v = v_p = mat->rowvalues;
1780         for (i=0; i<nzB; i++) {
1781           if (cmap[cworkB[i]] < cstart) v_p[i] = vworkB[i];
1782           else break;
1783         }
1784         imark = i;
1785         for (i=0; i<nzA; i++)     v_p[imark+i] = vworkA[i];
1786         for (i=imark; i<nzB; i++) v_p[nzA+i]   = vworkB[i];
1787       }
1788       if (idx) {
1789         *idx = idx_p = mat->rowindices;
1790         if (imark > -1) {
1791           for (i=0; i<imark; i++) {
1792             idx_p[i] = cmap[cworkB[i]];
1793           }
1794         } else {
1795           for (i=0; i<nzB; i++) {
1796             if (cmap[cworkB[i]] < cstart) idx_p[i] = cmap[cworkB[i]];
1797             else break;
1798           }
1799           imark = i;
1800         }
1801         for (i=0; i<nzA; i++)     idx_p[imark+i] = cstart + cworkA[i];
1802         for (i=imark; i<nzB; i++) idx_p[nzA+i]   = cmap[cworkB[i]];
1803       }
1804     } else {
1805       if (idx) *idx = 0;
1806       if (v)   *v   = 0;
1807     }
1808   }
1809   *nz  = nztot;
1810   ierr = (*mat->A->ops->restorerow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1811   ierr = (*mat->B->ops->restorerow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1812   PetscFunctionReturn(0);
1813 }
1814 
1815 PetscErrorCode MatRestoreRow_MPIAIJ(Mat mat,PetscInt row,PetscInt *nz,PetscInt **idx,PetscScalar **v)
1816 {
1817   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1818 
1819   PetscFunctionBegin;
1820   if (!aij->getrowactive) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"MatGetRow() must be called first");
1821   aij->getrowactive = PETSC_FALSE;
1822   PetscFunctionReturn(0);
1823 }
1824 
1825 PetscErrorCode MatNorm_MPIAIJ(Mat mat,NormType type,PetscReal *norm)
1826 {
1827   Mat_MPIAIJ     *aij  = (Mat_MPIAIJ*)mat->data;
1828   Mat_SeqAIJ     *amat = (Mat_SeqAIJ*)aij->A->data,*bmat = (Mat_SeqAIJ*)aij->B->data;
1829   PetscErrorCode ierr;
1830   PetscInt       i,j,cstart = mat->cmap->rstart;
1831   PetscReal      sum = 0.0;
1832   MatScalar      *v;
1833 
1834   PetscFunctionBegin;
1835   if (aij->size == 1) {
1836     ierr =  MatNorm(aij->A,type,norm);CHKERRQ(ierr);
1837   } else {
1838     if (type == NORM_FROBENIUS) {
1839       v = amat->a;
1840       for (i=0; i<amat->nz; i++) {
1841         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1842       }
1843       v = bmat->a;
1844       for (i=0; i<bmat->nz; i++) {
1845         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1846       }
1847       ierr  = MPIU_Allreduce(&sum,norm,1,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1848       *norm = PetscSqrtReal(*norm);
1849       ierr = PetscLogFlops(2*amat->nz+2*bmat->nz);CHKERRQ(ierr);
1850     } else if (type == NORM_1) { /* max column norm */
1851       PetscReal *tmp,*tmp2;
1852       PetscInt  *jj,*garray = aij->garray;
1853       ierr  = PetscCalloc1(mat->cmap->N+1,&tmp);CHKERRQ(ierr);
1854       ierr  = PetscMalloc1(mat->cmap->N+1,&tmp2);CHKERRQ(ierr);
1855       *norm = 0.0;
1856       v     = amat->a; jj = amat->j;
1857       for (j=0; j<amat->nz; j++) {
1858         tmp[cstart + *jj++] += PetscAbsScalar(*v);  v++;
1859       }
1860       v = bmat->a; jj = bmat->j;
1861       for (j=0; j<bmat->nz; j++) {
1862         tmp[garray[*jj++]] += PetscAbsScalar(*v); v++;
1863       }
1864       ierr = MPIU_Allreduce(tmp,tmp2,mat->cmap->N,MPIU_REAL,MPIU_SUM,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1865       for (j=0; j<mat->cmap->N; j++) {
1866         if (tmp2[j] > *norm) *norm = tmp2[j];
1867       }
1868       ierr = PetscFree(tmp);CHKERRQ(ierr);
1869       ierr = PetscFree(tmp2);CHKERRQ(ierr);
1870       ierr = PetscLogFlops(PetscMax(amat->nz+bmat->nz-1,0));CHKERRQ(ierr);
1871     } else if (type == NORM_INFINITY) { /* max row norm */
1872       PetscReal ntemp = 0.0;
1873       for (j=0; j<aij->A->rmap->n; j++) {
1874         v   = amat->a + amat->i[j];
1875         sum = 0.0;
1876         for (i=0; i<amat->i[j+1]-amat->i[j]; i++) {
1877           sum += PetscAbsScalar(*v); v++;
1878         }
1879         v = bmat->a + bmat->i[j];
1880         for (i=0; i<bmat->i[j+1]-bmat->i[j]; i++) {
1881           sum += PetscAbsScalar(*v); v++;
1882         }
1883         if (sum > ntemp) ntemp = sum;
1884       }
1885       ierr = MPIU_Allreduce(&ntemp,norm,1,MPIU_REAL,MPIU_MAX,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
1886       ierr = PetscLogFlops(PetscMax(amat->nz+bmat->nz-1,0));CHKERRQ(ierr);
1887     } else SETERRQ(PetscObjectComm((PetscObject)mat),PETSC_ERR_SUP,"No support for two norm");
1888   }
1889   PetscFunctionReturn(0);
1890 }
1891 
1892 PetscErrorCode MatTranspose_MPIAIJ(Mat A,MatReuse reuse,Mat *matout)
1893 {
1894   Mat_MPIAIJ     *a   = (Mat_MPIAIJ*)A->data;
1895   Mat_SeqAIJ     *Aloc=(Mat_SeqAIJ*)a->A->data,*Bloc=(Mat_SeqAIJ*)a->B->data;
1896   PetscErrorCode ierr;
1897   PetscInt       M      = A->rmap->N,N = A->cmap->N,ma,na,mb,nb,*ai,*aj,*bi,*bj,row,*cols,*cols_tmp,i;
1898   PetscInt       cstart = A->cmap->rstart,ncol;
1899   Mat            B;
1900   MatScalar      *array;
1901 
1902   PetscFunctionBegin;
1903   if (reuse == MAT_INPLACE_MATRIX && M != N) SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_SIZ,"Square matrix only for in-place");
1904 
1905   ma = A->rmap->n; na = A->cmap->n; mb = a->B->rmap->n; nb = a->B->cmap->n;
1906   ai = Aloc->i; aj = Aloc->j;
1907   bi = Bloc->i; bj = Bloc->j;
1908   if (reuse == MAT_INITIAL_MATRIX || *matout == A) {
1909     PetscInt             *d_nnz,*g_nnz,*o_nnz;
1910     PetscSFNode          *oloc;
1911     PETSC_UNUSED PetscSF sf;
1912 
1913     ierr = PetscMalloc4(na,&d_nnz,na,&o_nnz,nb,&g_nnz,nb,&oloc);CHKERRQ(ierr);
1914     /* compute d_nnz for preallocation */
1915     ierr = PetscMemzero(d_nnz,na*sizeof(PetscInt));CHKERRQ(ierr);
1916     for (i=0; i<ai[ma]; i++) {
1917       d_nnz[aj[i]]++;
1918       aj[i] += cstart; /* global col index to be used by MatSetValues() */
1919     }
1920     /* compute local off-diagonal contributions */
1921     ierr = PetscMemzero(g_nnz,nb*sizeof(PetscInt));CHKERRQ(ierr);
1922     for (i=0; i<bi[ma]; i++) g_nnz[bj[i]]++;
1923     /* map those to global */
1924     ierr = PetscSFCreate(PetscObjectComm((PetscObject)A),&sf);CHKERRQ(ierr);
1925     ierr = PetscSFSetGraphLayout(sf,A->cmap,nb,NULL,PETSC_USE_POINTER,a->garray);CHKERRQ(ierr);
1926     ierr = PetscSFSetFromOptions(sf);CHKERRQ(ierr);
1927     ierr = PetscMemzero(o_nnz,na*sizeof(PetscInt));CHKERRQ(ierr);
1928     ierr = PetscSFReduceBegin(sf,MPIU_INT,g_nnz,o_nnz,MPIU_SUM);CHKERRQ(ierr);
1929     ierr = PetscSFReduceEnd(sf,MPIU_INT,g_nnz,o_nnz,MPIU_SUM);CHKERRQ(ierr);
1930     ierr = PetscSFDestroy(&sf);CHKERRQ(ierr);
1931 
1932     ierr = MatCreate(PetscObjectComm((PetscObject)A),&B);CHKERRQ(ierr);
1933     ierr = MatSetSizes(B,A->cmap->n,A->rmap->n,N,M);CHKERRQ(ierr);
1934     ierr = MatSetBlockSizes(B,PetscAbs(A->cmap->bs),PetscAbs(A->rmap->bs));CHKERRQ(ierr);
1935     ierr = MatSetType(B,((PetscObject)A)->type_name);CHKERRQ(ierr);
1936     ierr = MatMPIAIJSetPreallocation(B,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
1937     ierr = PetscFree4(d_nnz,o_nnz,g_nnz,oloc);CHKERRQ(ierr);
1938   } else {
1939     B    = *matout;
1940     ierr = MatSetOption(B,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
1941     for (i=0; i<ai[ma]; i++) aj[i] += cstart; /* global col index to be used by MatSetValues() */
1942   }
1943 
1944   /* copy over the A part */
1945   array = Aloc->a;
1946   row   = A->rmap->rstart;
1947   for (i=0; i<ma; i++) {
1948     ncol = ai[i+1]-ai[i];
1949     ierr = MatSetValues(B,ncol,aj,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1950     row++;
1951     array += ncol; aj += ncol;
1952   }
1953   aj = Aloc->j;
1954   for (i=0; i<ai[ma]; i++) aj[i] -= cstart; /* resume local col index */
1955 
1956   /* copy over the B part */
1957   ierr  = PetscCalloc1(bi[mb],&cols);CHKERRQ(ierr);
1958   array = Bloc->a;
1959   row   = A->rmap->rstart;
1960   for (i=0; i<bi[mb]; i++) cols[i] = a->garray[bj[i]];
1961   cols_tmp = cols;
1962   for (i=0; i<mb; i++) {
1963     ncol = bi[i+1]-bi[i];
1964     ierr = MatSetValues(B,ncol,cols_tmp,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1965     row++;
1966     array += ncol; cols_tmp += ncol;
1967   }
1968   ierr = PetscFree(cols);CHKERRQ(ierr);
1969 
1970   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1971   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1972   if (reuse == MAT_INITIAL_MATRIX || reuse == MAT_REUSE_MATRIX) {
1973     *matout = B;
1974   } else {
1975     ierr = MatHeaderMerge(A,&B);CHKERRQ(ierr);
1976   }
1977   PetscFunctionReturn(0);
1978 }
1979 
1980 PetscErrorCode MatDiagonalScale_MPIAIJ(Mat mat,Vec ll,Vec rr)
1981 {
1982   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1983   Mat            a    = aij->A,b = aij->B;
1984   PetscErrorCode ierr;
1985   PetscInt       s1,s2,s3;
1986 
1987   PetscFunctionBegin;
1988   ierr = MatGetLocalSize(mat,&s2,&s3);CHKERRQ(ierr);
1989   if (rr) {
1990     ierr = VecGetLocalSize(rr,&s1);CHKERRQ(ierr);
1991     if (s1!=s3) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"right vector non-conforming local size");
1992     /* Overlap communication with computation. */
1993     ierr = VecScatterBegin(aij->Mvctx,rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1994   }
1995   if (ll) {
1996     ierr = VecGetLocalSize(ll,&s1);CHKERRQ(ierr);
1997     if (s1!=s2) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"left vector non-conforming local size");
1998     ierr = (*b->ops->diagonalscale)(b,ll,0);CHKERRQ(ierr);
1999   }
2000   /* scale  the diagonal block */
2001   ierr = (*a->ops->diagonalscale)(a,ll,rr);CHKERRQ(ierr);
2002 
2003   if (rr) {
2004     /* Do a scatter end and then right scale the off-diagonal block */
2005     ierr = VecScatterEnd(aij->Mvctx,rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
2006     ierr = (*b->ops->diagonalscale)(b,0,aij->lvec);CHKERRQ(ierr);
2007   }
2008   PetscFunctionReturn(0);
2009 }
2010 
2011 PetscErrorCode MatSetUnfactored_MPIAIJ(Mat A)
2012 {
2013   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2014   PetscErrorCode ierr;
2015 
2016   PetscFunctionBegin;
2017   ierr = MatSetUnfactored(a->A);CHKERRQ(ierr);
2018   PetscFunctionReturn(0);
2019 }
2020 
2021 PetscErrorCode MatEqual_MPIAIJ(Mat A,Mat B,PetscBool  *flag)
2022 {
2023   Mat_MPIAIJ     *matB = (Mat_MPIAIJ*)B->data,*matA = (Mat_MPIAIJ*)A->data;
2024   Mat            a,b,c,d;
2025   PetscBool      flg;
2026   PetscErrorCode ierr;
2027 
2028   PetscFunctionBegin;
2029   a = matA->A; b = matA->B;
2030   c = matB->A; d = matB->B;
2031 
2032   ierr = MatEqual(a,c,&flg);CHKERRQ(ierr);
2033   if (flg) {
2034     ierr = MatEqual(b,d,&flg);CHKERRQ(ierr);
2035   }
2036   ierr = MPIU_Allreduce(&flg,flag,1,MPIU_BOOL,MPI_LAND,PetscObjectComm((PetscObject)A));CHKERRQ(ierr);
2037   PetscFunctionReturn(0);
2038 }
2039 
2040 PetscErrorCode MatCopy_MPIAIJ(Mat A,Mat B,MatStructure str)
2041 {
2042   PetscErrorCode ierr;
2043   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2044   Mat_MPIAIJ     *b = (Mat_MPIAIJ*)B->data;
2045 
2046   PetscFunctionBegin;
2047   /* If the two matrices don't have the same copy implementation, they aren't compatible for fast copy. */
2048   if ((str != SAME_NONZERO_PATTERN) || (A->ops->copy != B->ops->copy)) {
2049     /* because of the column compression in the off-processor part of the matrix a->B,
2050        the number of columns in a->B and b->B may be different, hence we cannot call
2051        the MatCopy() directly on the two parts. If need be, we can provide a more
2052        efficient copy than the MatCopy_Basic() by first uncompressing the a->B matrices
2053        then copying the submatrices */
2054     ierr = MatCopy_Basic(A,B,str);CHKERRQ(ierr);
2055   } else {
2056     ierr = MatCopy(a->A,b->A,str);CHKERRQ(ierr);
2057     ierr = MatCopy(a->B,b->B,str);CHKERRQ(ierr);
2058   }
2059   PetscFunctionReturn(0);
2060 }
2061 
2062 PetscErrorCode MatSetUp_MPIAIJ(Mat A)
2063 {
2064   PetscErrorCode ierr;
2065 
2066   PetscFunctionBegin;
2067   ierr =  MatMPIAIJSetPreallocation(A,PETSC_DEFAULT,0,PETSC_DEFAULT,0);CHKERRQ(ierr);
2068   PetscFunctionReturn(0);
2069 }
2070 
2071 /*
2072    Computes the number of nonzeros per row needed for preallocation when X and Y
2073    have different nonzero structure.
2074 */
2075 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)
2076 {
2077   PetscInt       i,j,k,nzx,nzy;
2078 
2079   PetscFunctionBegin;
2080   /* Set the number of nonzeros in the new matrix */
2081   for (i=0; i<m; i++) {
2082     const PetscInt *xjj = xj+xi[i],*yjj = yj+yi[i];
2083     nzx = xi[i+1] - xi[i];
2084     nzy = yi[i+1] - yi[i];
2085     nnz[i] = 0;
2086     for (j=0,k=0; j<nzx; j++) {                   /* Point in X */
2087       for (; k<nzy && yltog[yjj[k]]<xltog[xjj[j]]; k++) nnz[i]++; /* Catch up to X */
2088       if (k<nzy && yltog[yjj[k]]==xltog[xjj[j]]) k++;             /* Skip duplicate */
2089       nnz[i]++;
2090     }
2091     for (; k<nzy; k++) nnz[i]++;
2092   }
2093   PetscFunctionReturn(0);
2094 }
2095 
2096 /* This is the same as MatAXPYGetPreallocation_SeqAIJ, except that the local-to-global map is provided */
2097 static PetscErrorCode MatAXPYGetPreallocation_MPIAIJ(Mat Y,const PetscInt *yltog,Mat X,const PetscInt *xltog,PetscInt *nnz)
2098 {
2099   PetscErrorCode ierr;
2100   PetscInt       m = Y->rmap->N;
2101   Mat_SeqAIJ     *x = (Mat_SeqAIJ*)X->data;
2102   Mat_SeqAIJ     *y = (Mat_SeqAIJ*)Y->data;
2103 
2104   PetscFunctionBegin;
2105   ierr = MatAXPYGetPreallocation_MPIX_private(m,x->i,x->j,xltog,y->i,y->j,yltog,nnz);CHKERRQ(ierr);
2106   PetscFunctionReturn(0);
2107 }
2108 
2109 PetscErrorCode MatAXPY_MPIAIJ(Mat Y,PetscScalar a,Mat X,MatStructure str)
2110 {
2111   PetscErrorCode ierr;
2112   Mat_MPIAIJ     *xx = (Mat_MPIAIJ*)X->data,*yy = (Mat_MPIAIJ*)Y->data;
2113   PetscBLASInt   bnz,one=1;
2114   Mat_SeqAIJ     *x,*y;
2115 
2116   PetscFunctionBegin;
2117   if (str == SAME_NONZERO_PATTERN) {
2118     PetscScalar alpha = a;
2119     x    = (Mat_SeqAIJ*)xx->A->data;
2120     ierr = PetscBLASIntCast(x->nz,&bnz);CHKERRQ(ierr);
2121     y    = (Mat_SeqAIJ*)yy->A->data;
2122     PetscStackCallBLAS("BLASaxpy",BLASaxpy_(&bnz,&alpha,x->a,&one,y->a,&one));
2123     x    = (Mat_SeqAIJ*)xx->B->data;
2124     y    = (Mat_SeqAIJ*)yy->B->data;
2125     ierr = PetscBLASIntCast(x->nz,&bnz);CHKERRQ(ierr);
2126     PetscStackCallBLAS("BLASaxpy",BLASaxpy_(&bnz,&alpha,x->a,&one,y->a,&one));
2127     ierr = PetscObjectStateIncrease((PetscObject)Y);CHKERRQ(ierr);
2128   } else if (str == SUBSET_NONZERO_PATTERN) { /* nonzeros of X is a subset of Y's */
2129     ierr = MatAXPY_Basic(Y,a,X,str);CHKERRQ(ierr);
2130   } else {
2131     Mat      B;
2132     PetscInt *nnz_d,*nnz_o;
2133     ierr = PetscMalloc1(yy->A->rmap->N,&nnz_d);CHKERRQ(ierr);
2134     ierr = PetscMalloc1(yy->B->rmap->N,&nnz_o);CHKERRQ(ierr);
2135     ierr = MatCreate(PetscObjectComm((PetscObject)Y),&B);CHKERRQ(ierr);
2136     ierr = PetscObjectSetName((PetscObject)B,((PetscObject)Y)->name);CHKERRQ(ierr);
2137     ierr = MatSetSizes(B,Y->rmap->n,Y->cmap->n,Y->rmap->N,Y->cmap->N);CHKERRQ(ierr);
2138     ierr = MatSetBlockSizesFromMats(B,Y,Y);CHKERRQ(ierr);
2139     ierr = MatSetType(B,MATMPIAIJ);CHKERRQ(ierr);
2140     ierr = MatAXPYGetPreallocation_SeqAIJ(yy->A,xx->A,nnz_d);CHKERRQ(ierr);
2141     ierr = MatAXPYGetPreallocation_MPIAIJ(yy->B,yy->garray,xx->B,xx->garray,nnz_o);CHKERRQ(ierr);
2142     ierr = MatMPIAIJSetPreallocation(B,0,nnz_d,0,nnz_o);CHKERRQ(ierr);
2143     ierr = MatAXPY_BasicWithPreallocation(B,Y,a,X,str);CHKERRQ(ierr);
2144     ierr = MatHeaderReplace(Y,&B);CHKERRQ(ierr);
2145     ierr = PetscFree(nnz_d);CHKERRQ(ierr);
2146     ierr = PetscFree(nnz_o);CHKERRQ(ierr);
2147   }
2148   PetscFunctionReturn(0);
2149 }
2150 
2151 extern PetscErrorCode  MatConjugate_SeqAIJ(Mat);
2152 
2153 PetscErrorCode  MatConjugate_MPIAIJ(Mat mat)
2154 {
2155 #if defined(PETSC_USE_COMPLEX)
2156   PetscErrorCode ierr;
2157   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
2158 
2159   PetscFunctionBegin;
2160   ierr = MatConjugate_SeqAIJ(aij->A);CHKERRQ(ierr);
2161   ierr = MatConjugate_SeqAIJ(aij->B);CHKERRQ(ierr);
2162 #else
2163   PetscFunctionBegin;
2164 #endif
2165   PetscFunctionReturn(0);
2166 }
2167 
2168 PetscErrorCode MatRealPart_MPIAIJ(Mat A)
2169 {
2170   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2171   PetscErrorCode ierr;
2172 
2173   PetscFunctionBegin;
2174   ierr = MatRealPart(a->A);CHKERRQ(ierr);
2175   ierr = MatRealPart(a->B);CHKERRQ(ierr);
2176   PetscFunctionReturn(0);
2177 }
2178 
2179 PetscErrorCode MatImaginaryPart_MPIAIJ(Mat A)
2180 {
2181   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2182   PetscErrorCode ierr;
2183 
2184   PetscFunctionBegin;
2185   ierr = MatImaginaryPart(a->A);CHKERRQ(ierr);
2186   ierr = MatImaginaryPart(a->B);CHKERRQ(ierr);
2187   PetscFunctionReturn(0);
2188 }
2189 
2190 PetscErrorCode MatGetRowMaxAbs_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2191 {
2192   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2193   PetscErrorCode ierr;
2194   PetscInt       i,*idxb = 0;
2195   PetscScalar    *va,*vb;
2196   Vec            vtmp;
2197 
2198   PetscFunctionBegin;
2199   ierr = MatGetRowMaxAbs(a->A,v,idx);CHKERRQ(ierr);
2200   ierr = VecGetArray(v,&va);CHKERRQ(ierr);
2201   if (idx) {
2202     for (i=0; i<A->rmap->n; i++) {
2203       if (PetscAbsScalar(va[i])) idx[i] += A->cmap->rstart;
2204     }
2205   }
2206 
2207   ierr = VecCreateSeq(PETSC_COMM_SELF,A->rmap->n,&vtmp);CHKERRQ(ierr);
2208   if (idx) {
2209     ierr = PetscMalloc1(A->rmap->n,&idxb);CHKERRQ(ierr);
2210   }
2211   ierr = MatGetRowMaxAbs(a->B,vtmp,idxb);CHKERRQ(ierr);
2212   ierr = VecGetArray(vtmp,&vb);CHKERRQ(ierr);
2213 
2214   for (i=0; i<A->rmap->n; i++) {
2215     if (PetscAbsScalar(va[i]) < PetscAbsScalar(vb[i])) {
2216       va[i] = vb[i];
2217       if (idx) idx[i] = a->garray[idxb[i]];
2218     }
2219   }
2220 
2221   ierr = VecRestoreArray(v,&va);CHKERRQ(ierr);
2222   ierr = VecRestoreArray(vtmp,&vb);CHKERRQ(ierr);
2223   ierr = PetscFree(idxb);CHKERRQ(ierr);
2224   ierr = VecDestroy(&vtmp);CHKERRQ(ierr);
2225   PetscFunctionReturn(0);
2226 }
2227 
2228 PetscErrorCode MatGetRowMinAbs_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2229 {
2230   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2231   PetscErrorCode ierr;
2232   PetscInt       i,*idxb = 0;
2233   PetscScalar    *va,*vb;
2234   Vec            vtmp;
2235 
2236   PetscFunctionBegin;
2237   ierr = MatGetRowMinAbs(a->A,v,idx);CHKERRQ(ierr);
2238   ierr = VecGetArray(v,&va);CHKERRQ(ierr);
2239   if (idx) {
2240     for (i=0; i<A->cmap->n; i++) {
2241       if (PetscAbsScalar(va[i])) idx[i] += A->cmap->rstart;
2242     }
2243   }
2244 
2245   ierr = VecCreateSeq(PETSC_COMM_SELF,A->rmap->n,&vtmp);CHKERRQ(ierr);
2246   if (idx) {
2247     ierr = PetscMalloc1(A->rmap->n,&idxb);CHKERRQ(ierr);
2248   }
2249   ierr = MatGetRowMinAbs(a->B,vtmp,idxb);CHKERRQ(ierr);
2250   ierr = VecGetArray(vtmp,&vb);CHKERRQ(ierr);
2251 
2252   for (i=0; i<A->rmap->n; i++) {
2253     if (PetscAbsScalar(va[i]) > PetscAbsScalar(vb[i])) {
2254       va[i] = vb[i];
2255       if (idx) idx[i] = a->garray[idxb[i]];
2256     }
2257   }
2258 
2259   ierr = VecRestoreArray(v,&va);CHKERRQ(ierr);
2260   ierr = VecRestoreArray(vtmp,&vb);CHKERRQ(ierr);
2261   ierr = PetscFree(idxb);CHKERRQ(ierr);
2262   ierr = VecDestroy(&vtmp);CHKERRQ(ierr);
2263   PetscFunctionReturn(0);
2264 }
2265 
2266 PetscErrorCode MatGetRowMin_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2267 {
2268   Mat_MPIAIJ     *mat   = (Mat_MPIAIJ*) A->data;
2269   PetscInt       n      = A->rmap->n;
2270   PetscInt       cstart = A->cmap->rstart;
2271   PetscInt       *cmap  = mat->garray;
2272   PetscInt       *diagIdx, *offdiagIdx;
2273   Vec            diagV, offdiagV;
2274   PetscScalar    *a, *diagA, *offdiagA;
2275   PetscInt       r;
2276   PetscErrorCode ierr;
2277 
2278   PetscFunctionBegin;
2279   ierr = PetscMalloc2(n,&diagIdx,n,&offdiagIdx);CHKERRQ(ierr);
2280   ierr = VecCreateSeq(PetscObjectComm((PetscObject)A), n, &diagV);CHKERRQ(ierr);
2281   ierr = VecCreateSeq(PetscObjectComm((PetscObject)A), n, &offdiagV);CHKERRQ(ierr);
2282   ierr = MatGetRowMin(mat->A, diagV,    diagIdx);CHKERRQ(ierr);
2283   ierr = MatGetRowMin(mat->B, offdiagV, offdiagIdx);CHKERRQ(ierr);
2284   ierr = VecGetArray(v,        &a);CHKERRQ(ierr);
2285   ierr = VecGetArray(diagV,    &diagA);CHKERRQ(ierr);
2286   ierr = VecGetArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2287   for (r = 0; r < n; ++r) {
2288     if (PetscAbsScalar(diagA[r]) <= PetscAbsScalar(offdiagA[r])) {
2289       a[r]   = diagA[r];
2290       idx[r] = cstart + diagIdx[r];
2291     } else {
2292       a[r]   = offdiagA[r];
2293       idx[r] = cmap[offdiagIdx[r]];
2294     }
2295   }
2296   ierr = VecRestoreArray(v,        &a);CHKERRQ(ierr);
2297   ierr = VecRestoreArray(diagV,    &diagA);CHKERRQ(ierr);
2298   ierr = VecRestoreArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2299   ierr = VecDestroy(&diagV);CHKERRQ(ierr);
2300   ierr = VecDestroy(&offdiagV);CHKERRQ(ierr);
2301   ierr = PetscFree2(diagIdx, offdiagIdx);CHKERRQ(ierr);
2302   PetscFunctionReturn(0);
2303 }
2304 
2305 PetscErrorCode MatGetRowMax_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2306 {
2307   Mat_MPIAIJ     *mat   = (Mat_MPIAIJ*) A->data;
2308   PetscInt       n      = A->rmap->n;
2309   PetscInt       cstart = A->cmap->rstart;
2310   PetscInt       *cmap  = mat->garray;
2311   PetscInt       *diagIdx, *offdiagIdx;
2312   Vec            diagV, offdiagV;
2313   PetscScalar    *a, *diagA, *offdiagA;
2314   PetscInt       r;
2315   PetscErrorCode ierr;
2316 
2317   PetscFunctionBegin;
2318   ierr = PetscMalloc2(n,&diagIdx,n,&offdiagIdx);CHKERRQ(ierr);
2319   ierr = VecCreateSeq(PETSC_COMM_SELF, n, &diagV);CHKERRQ(ierr);
2320   ierr = VecCreateSeq(PETSC_COMM_SELF, n, &offdiagV);CHKERRQ(ierr);
2321   ierr = MatGetRowMax(mat->A, diagV,    diagIdx);CHKERRQ(ierr);
2322   ierr = MatGetRowMax(mat->B, offdiagV, offdiagIdx);CHKERRQ(ierr);
2323   ierr = VecGetArray(v,        &a);CHKERRQ(ierr);
2324   ierr = VecGetArray(diagV,    &diagA);CHKERRQ(ierr);
2325   ierr = VecGetArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2326   for (r = 0; r < n; ++r) {
2327     if (PetscAbsScalar(diagA[r]) >= PetscAbsScalar(offdiagA[r])) {
2328       a[r]   = diagA[r];
2329       idx[r] = cstart + diagIdx[r];
2330     } else {
2331       a[r]   = offdiagA[r];
2332       idx[r] = cmap[offdiagIdx[r]];
2333     }
2334   }
2335   ierr = VecRestoreArray(v,        &a);CHKERRQ(ierr);
2336   ierr = VecRestoreArray(diagV,    &diagA);CHKERRQ(ierr);
2337   ierr = VecRestoreArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2338   ierr = VecDestroy(&diagV);CHKERRQ(ierr);
2339   ierr = VecDestroy(&offdiagV);CHKERRQ(ierr);
2340   ierr = PetscFree2(diagIdx, offdiagIdx);CHKERRQ(ierr);
2341   PetscFunctionReturn(0);
2342 }
2343 
2344 PetscErrorCode MatGetSeqNonzeroStructure_MPIAIJ(Mat mat,Mat *newmat)
2345 {
2346   PetscErrorCode ierr;
2347   Mat            *dummy;
2348 
2349   PetscFunctionBegin;
2350   ierr    = MatCreateSubMatrix_MPIAIJ_All(mat,MAT_DO_NOT_GET_VALUES,MAT_INITIAL_MATRIX,&dummy);CHKERRQ(ierr);
2351   *newmat = *dummy;
2352   ierr    = PetscFree(dummy);CHKERRQ(ierr);
2353   PetscFunctionReturn(0);
2354 }
2355 
2356 PetscErrorCode  MatInvertBlockDiagonal_MPIAIJ(Mat A,const PetscScalar **values)
2357 {
2358   Mat_MPIAIJ     *a = (Mat_MPIAIJ*) A->data;
2359   PetscErrorCode ierr;
2360 
2361   PetscFunctionBegin;
2362   ierr = MatInvertBlockDiagonal(a->A,values);CHKERRQ(ierr);
2363   A->factorerrortype = a->A->factorerrortype;
2364   PetscFunctionReturn(0);
2365 }
2366 
2367 static PetscErrorCode  MatSetRandom_MPIAIJ(Mat x,PetscRandom rctx)
2368 {
2369   PetscErrorCode ierr;
2370   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)x->data;
2371 
2372   PetscFunctionBegin;
2373   ierr = MatSetRandom(aij->A,rctx);CHKERRQ(ierr);
2374   ierr = MatSetRandom(aij->B,rctx);CHKERRQ(ierr);
2375   ierr = MatAssemblyBegin(x,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2376   ierr = MatAssemblyEnd(x,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2377   PetscFunctionReturn(0);
2378 }
2379 
2380 PetscErrorCode MatMPIAIJSetUseScalableIncreaseOverlap_MPIAIJ(Mat A,PetscBool sc)
2381 {
2382   PetscFunctionBegin;
2383   if (sc) A->ops->increaseoverlap = MatIncreaseOverlap_MPIAIJ_Scalable;
2384   else A->ops->increaseoverlap    = MatIncreaseOverlap_MPIAIJ;
2385   PetscFunctionReturn(0);
2386 }
2387 
2388 /*@
2389    MatMPIAIJSetUseScalableIncreaseOverlap - Determine if the matrix uses a scalable algorithm to compute the overlap
2390 
2391    Collective on Mat
2392 
2393    Input Parameters:
2394 +    A - the matrix
2395 -    sc - PETSC_TRUE indicates use the scalable algorithm (default is not to use the scalable algorithm)
2396 
2397  Level: advanced
2398 
2399 @*/
2400 PetscErrorCode MatMPIAIJSetUseScalableIncreaseOverlap(Mat A,PetscBool sc)
2401 {
2402   PetscErrorCode       ierr;
2403 
2404   PetscFunctionBegin;
2405   ierr = PetscTryMethod(A,"MatMPIAIJSetUseScalableIncreaseOverlap_C",(Mat,PetscBool),(A,sc));CHKERRQ(ierr);
2406   PetscFunctionReturn(0);
2407 }
2408 
2409 PetscErrorCode MatSetFromOptions_MPIAIJ(PetscOptionItems *PetscOptionsObject,Mat A)
2410 {
2411   PetscErrorCode       ierr;
2412   PetscBool            sc = PETSC_FALSE,flg;
2413 
2414   PetscFunctionBegin;
2415   ierr = PetscOptionsHead(PetscOptionsObject,"MPIAIJ options");CHKERRQ(ierr);
2416   ierr = PetscObjectOptionsBegin((PetscObject)A);
2417     if (A->ops->increaseoverlap == MatIncreaseOverlap_MPIAIJ_Scalable) sc = PETSC_TRUE;
2418     ierr = PetscOptionsBool("-mat_increase_overlap_scalable","Use a scalable algorithm to compute the overlap","MatIncreaseOverlap",sc,&sc,&flg);CHKERRQ(ierr);
2419     if (flg) {
2420       ierr = MatMPIAIJSetUseScalableIncreaseOverlap(A,sc);CHKERRQ(ierr);
2421     }
2422   ierr = PetscOptionsEnd();CHKERRQ(ierr);
2423   PetscFunctionReturn(0);
2424 }
2425 
2426 PetscErrorCode MatShift_MPIAIJ(Mat Y,PetscScalar a)
2427 {
2428   PetscErrorCode ierr;
2429   Mat_MPIAIJ     *maij = (Mat_MPIAIJ*)Y->data;
2430   Mat_SeqAIJ     *aij = (Mat_SeqAIJ*)maij->A->data;
2431 
2432   PetscFunctionBegin;
2433   if (!Y->preallocated) {
2434     ierr = MatMPIAIJSetPreallocation(Y,1,NULL,0,NULL);CHKERRQ(ierr);
2435   } else if (!aij->nz) {
2436     PetscInt nonew = aij->nonew;
2437     ierr = MatSeqAIJSetPreallocation(maij->A,1,NULL);CHKERRQ(ierr);
2438     aij->nonew = nonew;
2439   }
2440   ierr = MatShift_Basic(Y,a);CHKERRQ(ierr);
2441   PetscFunctionReturn(0);
2442 }
2443 
2444 PetscErrorCode MatMissingDiagonal_MPIAIJ(Mat A,PetscBool  *missing,PetscInt *d)
2445 {
2446   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2447   PetscErrorCode ierr;
2448 
2449   PetscFunctionBegin;
2450   if (A->rmap->n != A->cmap->n) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"Only works for square matrices");
2451   ierr = MatMissingDiagonal(a->A,missing,d);CHKERRQ(ierr);
2452   if (d) {
2453     PetscInt rstart;
2454     ierr = MatGetOwnershipRange(A,&rstart,NULL);CHKERRQ(ierr);
2455     *d += rstart;
2456 
2457   }
2458   PetscFunctionReturn(0);
2459 }
2460 
2461 
2462 /* -------------------------------------------------------------------*/
2463 static struct _MatOps MatOps_Values = {MatSetValues_MPIAIJ,
2464                                        MatGetRow_MPIAIJ,
2465                                        MatRestoreRow_MPIAIJ,
2466                                        MatMult_MPIAIJ,
2467                                 /* 4*/ MatMultAdd_MPIAIJ,
2468                                        MatMultTranspose_MPIAIJ,
2469                                        MatMultTransposeAdd_MPIAIJ,
2470                                        0,
2471                                        0,
2472                                        0,
2473                                 /*10*/ 0,
2474                                        0,
2475                                        0,
2476                                        MatSOR_MPIAIJ,
2477                                        MatTranspose_MPIAIJ,
2478                                 /*15*/ MatGetInfo_MPIAIJ,
2479                                        MatEqual_MPIAIJ,
2480                                        MatGetDiagonal_MPIAIJ,
2481                                        MatDiagonalScale_MPIAIJ,
2482                                        MatNorm_MPIAIJ,
2483                                 /*20*/ MatAssemblyBegin_MPIAIJ,
2484                                        MatAssemblyEnd_MPIAIJ,
2485                                        MatSetOption_MPIAIJ,
2486                                        MatZeroEntries_MPIAIJ,
2487                                 /*24*/ MatZeroRows_MPIAIJ,
2488                                        0,
2489                                        0,
2490                                        0,
2491                                        0,
2492                                 /*29*/ MatSetUp_MPIAIJ,
2493                                        0,
2494                                        0,
2495                                        MatGetDiagonalBlock_MPIAIJ,
2496                                        0,
2497                                 /*34*/ MatDuplicate_MPIAIJ,
2498                                        0,
2499                                        0,
2500                                        0,
2501                                        0,
2502                                 /*39*/ MatAXPY_MPIAIJ,
2503                                        MatCreateSubMatrices_MPIAIJ,
2504                                        MatIncreaseOverlap_MPIAIJ,
2505                                        MatGetValues_MPIAIJ,
2506                                        MatCopy_MPIAIJ,
2507                                 /*44*/ MatGetRowMax_MPIAIJ,
2508                                        MatScale_MPIAIJ,
2509                                        MatShift_MPIAIJ,
2510                                        MatDiagonalSet_MPIAIJ,
2511                                        MatZeroRowsColumns_MPIAIJ,
2512                                 /*49*/ MatSetRandom_MPIAIJ,
2513                                        0,
2514                                        0,
2515                                        0,
2516                                        0,
2517                                 /*54*/ MatFDColoringCreate_MPIXAIJ,
2518                                        0,
2519                                        MatSetUnfactored_MPIAIJ,
2520                                        MatPermute_MPIAIJ,
2521                                        0,
2522                                 /*59*/ MatCreateSubMatrix_MPIAIJ,
2523                                        MatDestroy_MPIAIJ,
2524                                        MatView_MPIAIJ,
2525                                        0,
2526                                        MatMatMatMult_MPIAIJ_MPIAIJ_MPIAIJ,
2527                                 /*64*/ MatMatMatMultSymbolic_MPIAIJ_MPIAIJ_MPIAIJ,
2528                                        MatMatMatMultNumeric_MPIAIJ_MPIAIJ_MPIAIJ,
2529                                        0,
2530                                        0,
2531                                        0,
2532                                 /*69*/ MatGetRowMaxAbs_MPIAIJ,
2533                                        MatGetRowMinAbs_MPIAIJ,
2534                                        0,
2535                                        0,
2536                                        0,
2537                                        0,
2538                                 /*75*/ MatFDColoringApply_AIJ,
2539                                        MatSetFromOptions_MPIAIJ,
2540                                        0,
2541                                        0,
2542                                        MatFindZeroDiagonals_MPIAIJ,
2543                                 /*80*/ 0,
2544                                        0,
2545                                        0,
2546                                 /*83*/ MatLoad_MPIAIJ,
2547                                        0,
2548                                        0,
2549                                        0,
2550                                        0,
2551                                        0,
2552                                 /*89*/ MatMatMult_MPIAIJ_MPIAIJ,
2553                                        MatMatMultSymbolic_MPIAIJ_MPIAIJ,
2554                                        MatMatMultNumeric_MPIAIJ_MPIAIJ,
2555                                        MatPtAP_MPIAIJ_MPIAIJ,
2556                                        MatPtAPSymbolic_MPIAIJ_MPIAIJ,
2557                                 /*94*/ MatPtAPNumeric_MPIAIJ_MPIAIJ,
2558                                        0,
2559                                        0,
2560                                        0,
2561                                        0,
2562                                 /*99*/ 0,
2563                                        0,
2564                                        0,
2565                                        MatConjugate_MPIAIJ,
2566                                        0,
2567                                 /*104*/MatSetValuesRow_MPIAIJ,
2568                                        MatRealPart_MPIAIJ,
2569                                        MatImaginaryPart_MPIAIJ,
2570                                        0,
2571                                        0,
2572                                 /*109*/0,
2573                                        0,
2574                                        MatGetRowMin_MPIAIJ,
2575                                        0,
2576                                        MatMissingDiagonal_MPIAIJ,
2577                                 /*114*/MatGetSeqNonzeroStructure_MPIAIJ,
2578                                        0,
2579                                        MatGetGhosts_MPIAIJ,
2580                                        0,
2581                                        0,
2582                                 /*119*/0,
2583                                        0,
2584                                        0,
2585                                        0,
2586                                        MatGetMultiProcBlock_MPIAIJ,
2587                                 /*124*/MatFindNonzeroRows_MPIAIJ,
2588                                        MatGetColumnNorms_MPIAIJ,
2589                                        MatInvertBlockDiagonal_MPIAIJ,
2590                                        0,
2591                                        MatCreateSubMatricesMPI_MPIAIJ,
2592                                 /*129*/0,
2593                                        MatTransposeMatMult_MPIAIJ_MPIAIJ,
2594                                        MatTransposeMatMultSymbolic_MPIAIJ_MPIAIJ,
2595                                        MatTransposeMatMultNumeric_MPIAIJ_MPIAIJ,
2596                                        0,
2597                                 /*134*/0,
2598                                        0,
2599                                        0,
2600                                        0,
2601                                        0,
2602                                 /*139*/MatSetBlockSizes_MPIAIJ,
2603                                        0,
2604                                        0,
2605                                        MatFDColoringSetUp_MPIXAIJ,
2606                                        MatFindOffBlockDiagonalEntries_MPIAIJ,
2607                                 /*144*/MatCreateMPIMatConcatenateSeqMat_MPIAIJ
2608 };
2609 
2610 /* ----------------------------------------------------------------------------------------*/
2611 
2612 PetscErrorCode  MatStoreValues_MPIAIJ(Mat mat)
2613 {
2614   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
2615   PetscErrorCode ierr;
2616 
2617   PetscFunctionBegin;
2618   ierr = MatStoreValues(aij->A);CHKERRQ(ierr);
2619   ierr = MatStoreValues(aij->B);CHKERRQ(ierr);
2620   PetscFunctionReturn(0);
2621 }
2622 
2623 PetscErrorCode  MatRetrieveValues_MPIAIJ(Mat mat)
2624 {
2625   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
2626   PetscErrorCode ierr;
2627 
2628   PetscFunctionBegin;
2629   ierr = MatRetrieveValues(aij->A);CHKERRQ(ierr);
2630   ierr = MatRetrieveValues(aij->B);CHKERRQ(ierr);
2631   PetscFunctionReturn(0);
2632 }
2633 
2634 PetscErrorCode  MatMPIAIJSetPreallocation_MPIAIJ(Mat B,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[])
2635 {
2636   Mat_MPIAIJ     *b;
2637   PetscErrorCode ierr;
2638 
2639   PetscFunctionBegin;
2640   ierr = PetscLayoutSetUp(B->rmap);CHKERRQ(ierr);
2641   ierr = PetscLayoutSetUp(B->cmap);CHKERRQ(ierr);
2642   b = (Mat_MPIAIJ*)B->data;
2643 
2644 #if defined(PETSC_USE_CTABLE)
2645   ierr = PetscTableDestroy(&b->colmap);CHKERRQ(ierr);
2646 #else
2647   ierr = PetscFree(b->colmap);CHKERRQ(ierr);
2648 #endif
2649   ierr = PetscFree(b->garray);CHKERRQ(ierr);
2650   ierr = VecDestroy(&b->lvec);CHKERRQ(ierr);
2651   ierr = VecScatterDestroy(&b->Mvctx);CHKERRQ(ierr);
2652 
2653   /* Because the B will have been resized we simply destroy it and create a new one each time */
2654   ierr = MatDestroy(&b->B);CHKERRQ(ierr);
2655   ierr = MatCreate(PETSC_COMM_SELF,&b->B);CHKERRQ(ierr);
2656   ierr = MatSetSizes(b->B,B->rmap->n,B->cmap->N,B->rmap->n,B->cmap->N);CHKERRQ(ierr);
2657   ierr = MatSetBlockSizesFromMats(b->B,B,B);CHKERRQ(ierr);
2658   ierr = MatSetType(b->B,MATSEQAIJ);CHKERRQ(ierr);
2659   ierr = PetscLogObjectParent((PetscObject)B,(PetscObject)b->B);CHKERRQ(ierr);
2660 
2661   if (!B->preallocated) {
2662     ierr = MatCreate(PETSC_COMM_SELF,&b->A);CHKERRQ(ierr);
2663     ierr = MatSetSizes(b->A,B->rmap->n,B->cmap->n,B->rmap->n,B->cmap->n);CHKERRQ(ierr);
2664     ierr = MatSetBlockSizesFromMats(b->A,B,B);CHKERRQ(ierr);
2665     ierr = MatSetType(b->A,MATSEQAIJ);CHKERRQ(ierr);
2666     ierr = PetscLogObjectParent((PetscObject)B,(PetscObject)b->A);CHKERRQ(ierr);
2667   }
2668 
2669   ierr = MatSeqAIJSetPreallocation(b->A,d_nz,d_nnz);CHKERRQ(ierr);
2670   ierr = MatSeqAIJSetPreallocation(b->B,o_nz,o_nnz);CHKERRQ(ierr);
2671   B->preallocated  = PETSC_TRUE;
2672   B->was_assembled = PETSC_FALSE;
2673   B->assembled     = PETSC_FALSE;;
2674   PetscFunctionReturn(0);
2675 }
2676 
2677 PetscErrorCode MatDuplicate_MPIAIJ(Mat matin,MatDuplicateOption cpvalues,Mat *newmat)
2678 {
2679   Mat            mat;
2680   Mat_MPIAIJ     *a,*oldmat = (Mat_MPIAIJ*)matin->data;
2681   PetscErrorCode ierr;
2682 
2683   PetscFunctionBegin;
2684   *newmat = 0;
2685   ierr    = MatCreate(PetscObjectComm((PetscObject)matin),&mat);CHKERRQ(ierr);
2686   ierr    = MatSetSizes(mat,matin->rmap->n,matin->cmap->n,matin->rmap->N,matin->cmap->N);CHKERRQ(ierr);
2687   ierr    = MatSetBlockSizesFromMats(mat,matin,matin);CHKERRQ(ierr);
2688   ierr    = MatSetType(mat,((PetscObject)matin)->type_name);CHKERRQ(ierr);
2689   ierr    = PetscMemcpy(mat->ops,matin->ops,sizeof(struct _MatOps));CHKERRQ(ierr);
2690   a       = (Mat_MPIAIJ*)mat->data;
2691 
2692   mat->factortype   = matin->factortype;
2693   mat->assembled    = PETSC_TRUE;
2694   mat->insertmode   = NOT_SET_VALUES;
2695   mat->preallocated = PETSC_TRUE;
2696 
2697   a->size         = oldmat->size;
2698   a->rank         = oldmat->rank;
2699   a->donotstash   = oldmat->donotstash;
2700   a->roworiented  = oldmat->roworiented;
2701   a->rowindices   = 0;
2702   a->rowvalues    = 0;
2703   a->getrowactive = PETSC_FALSE;
2704 
2705   ierr = PetscLayoutReference(matin->rmap,&mat->rmap);CHKERRQ(ierr);
2706   ierr = PetscLayoutReference(matin->cmap,&mat->cmap);CHKERRQ(ierr);
2707 
2708   if (oldmat->colmap) {
2709 #if defined(PETSC_USE_CTABLE)
2710     ierr = PetscTableCreateCopy(oldmat->colmap,&a->colmap);CHKERRQ(ierr);
2711 #else
2712     ierr = PetscMalloc1(mat->cmap->N,&a->colmap);CHKERRQ(ierr);
2713     ierr = PetscLogObjectMemory((PetscObject)mat,(mat->cmap->N)*sizeof(PetscInt));CHKERRQ(ierr);
2714     ierr = PetscMemcpy(a->colmap,oldmat->colmap,(mat->cmap->N)*sizeof(PetscInt));CHKERRQ(ierr);
2715 #endif
2716   } else a->colmap = 0;
2717   if (oldmat->garray) {
2718     PetscInt len;
2719     len  = oldmat->B->cmap->n;
2720     ierr = PetscMalloc1(len+1,&a->garray);CHKERRQ(ierr);
2721     ierr = PetscLogObjectMemory((PetscObject)mat,len*sizeof(PetscInt));CHKERRQ(ierr);
2722     if (len) { ierr = PetscMemcpy(a->garray,oldmat->garray,len*sizeof(PetscInt));CHKERRQ(ierr); }
2723   } else a->garray = 0;
2724 
2725   ierr    = VecDuplicate(oldmat->lvec,&a->lvec);CHKERRQ(ierr);
2726   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->lvec);CHKERRQ(ierr);
2727   ierr    = VecScatterCopy(oldmat->Mvctx,&a->Mvctx);CHKERRQ(ierr);
2728   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->Mvctx);CHKERRQ(ierr);
2729   ierr    = MatDuplicate(oldmat->A,cpvalues,&a->A);CHKERRQ(ierr);
2730   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->A);CHKERRQ(ierr);
2731   ierr    = MatDuplicate(oldmat->B,cpvalues,&a->B);CHKERRQ(ierr);
2732   ierr    = PetscLogObjectParent((PetscObject)mat,(PetscObject)a->B);CHKERRQ(ierr);
2733   ierr    = PetscFunctionListDuplicate(((PetscObject)matin)->qlist,&((PetscObject)mat)->qlist);CHKERRQ(ierr);
2734   *newmat = mat;
2735   PetscFunctionReturn(0);
2736 }
2737 
2738 
2739 
2740 PetscErrorCode MatLoad_MPIAIJ(Mat newMat, PetscViewer viewer)
2741 {
2742   PetscScalar    *vals,*svals;
2743   MPI_Comm       comm;
2744   PetscErrorCode ierr;
2745   PetscMPIInt    rank,size,tag = ((PetscObject)viewer)->tag;
2746   PetscInt       i,nz,j,rstart,rend,mmax,maxnz = 0;
2747   PetscInt       header[4],*rowlengths = 0,M,N,m,*cols;
2748   PetscInt       *ourlens = NULL,*procsnz = NULL,*offlens = NULL,jj,*mycols,*smycols;
2749   PetscInt       cend,cstart,n,*rowners;
2750   int            fd;
2751   PetscInt       bs = newMat->rmap->bs;
2752 
2753   PetscFunctionBegin;
2754   /* force binary viewer to load .info file if it has not yet done so */
2755   ierr = PetscViewerSetUp(viewer);CHKERRQ(ierr);
2756   ierr = PetscObjectGetComm((PetscObject)viewer,&comm);CHKERRQ(ierr);
2757   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2758   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
2759   ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
2760   if (!rank) {
2761     ierr = PetscBinaryRead(fd,(char*)header,4,PETSC_INT);CHKERRQ(ierr);
2762     if (header[0] != MAT_FILE_CLASSID) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_FILE_UNEXPECTED,"not matrix object");
2763     if (header[3] < 0) SETERRQ(PetscObjectComm((PetscObject)newMat),PETSC_ERR_FILE_UNEXPECTED,"Matrix stored in special format on disk,cannot load as MATMPIAIJ");
2764   }
2765 
2766   ierr = PetscOptionsBegin(comm,NULL,"Options for loading MATMPIAIJ matrix","Mat");CHKERRQ(ierr);
2767   ierr = PetscOptionsInt("-matload_block_size","Set the blocksize used to store the matrix","MatLoad",bs,&bs,NULL);CHKERRQ(ierr);
2768   ierr = PetscOptionsEnd();CHKERRQ(ierr);
2769   if (bs < 0) bs = 1;
2770 
2771   ierr = MPI_Bcast(header+1,3,MPIU_INT,0,comm);CHKERRQ(ierr);
2772   M    = header[1]; N = header[2];
2773 
2774   /* If global sizes are set, check if they are consistent with that given in the file */
2775   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);
2776   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);
2777 
2778   /* determine ownership of all (block) rows */
2779   if (M%bs) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_FILE_UNEXPECTED, "Inconsistent # of rows (%d) and block size (%d)",M,bs);
2780   if (newMat->rmap->n < 0) m = bs*((M/bs)/size + (((M/bs) % size) > rank));    /* PETSC_DECIDE */
2781   else m = newMat->rmap->n; /* Set by user */
2782 
2783   ierr = PetscMalloc1(size+1,&rowners);CHKERRQ(ierr);
2784   ierr = MPI_Allgather(&m,1,MPIU_INT,rowners+1,1,MPIU_INT,comm);CHKERRQ(ierr);
2785 
2786   /* First process needs enough room for process with most rows */
2787   if (!rank) {
2788     mmax = rowners[1];
2789     for (i=2; i<=size; i++) {
2790       mmax = PetscMax(mmax, rowners[i]);
2791     }
2792   } else mmax = -1;             /* unused, but compilers complain */
2793 
2794   rowners[0] = 0;
2795   for (i=2; i<=size; i++) {
2796     rowners[i] += rowners[i-1];
2797   }
2798   rstart = rowners[rank];
2799   rend   = rowners[rank+1];
2800 
2801   /* distribute row lengths to all processors */
2802   ierr = PetscMalloc2(m,&ourlens,m,&offlens);CHKERRQ(ierr);
2803   if (!rank) {
2804     ierr = PetscBinaryRead(fd,ourlens,m,PETSC_INT);CHKERRQ(ierr);
2805     ierr = PetscMalloc1(mmax,&rowlengths);CHKERRQ(ierr);
2806     ierr = PetscCalloc1(size,&procsnz);CHKERRQ(ierr);
2807     for (j=0; j<m; j++) {
2808       procsnz[0] += ourlens[j];
2809     }
2810     for (i=1; i<size; i++) {
2811       ierr = PetscBinaryRead(fd,rowlengths,rowners[i+1]-rowners[i],PETSC_INT);CHKERRQ(ierr);
2812       /* calculate the number of nonzeros on each processor */
2813       for (j=0; j<rowners[i+1]-rowners[i]; j++) {
2814         procsnz[i] += rowlengths[j];
2815       }
2816       ierr = MPIULong_Send(rowlengths,rowners[i+1]-rowners[i],MPIU_INT,i,tag,comm);CHKERRQ(ierr);
2817     }
2818     ierr = PetscFree(rowlengths);CHKERRQ(ierr);
2819   } else {
2820     ierr = MPIULong_Recv(ourlens,m,MPIU_INT,0,tag,comm);CHKERRQ(ierr);
2821   }
2822 
2823   if (!rank) {
2824     /* determine max buffer needed and allocate it */
2825     maxnz = 0;
2826     for (i=0; i<size; i++) {
2827       maxnz = PetscMax(maxnz,procsnz[i]);
2828     }
2829     ierr = PetscMalloc1(maxnz,&cols);CHKERRQ(ierr);
2830 
2831     /* read in my part of the matrix column indices  */
2832     nz   = procsnz[0];
2833     ierr = PetscMalloc1(nz,&mycols);CHKERRQ(ierr);
2834     ierr = PetscBinaryRead(fd,mycols,nz,PETSC_INT);CHKERRQ(ierr);
2835 
2836     /* read in every one elses and ship off */
2837     for (i=1; i<size; i++) {
2838       nz   = procsnz[i];
2839       ierr = PetscBinaryRead(fd,cols,nz,PETSC_INT);CHKERRQ(ierr);
2840       ierr = MPIULong_Send(cols,nz,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
2841     }
2842     ierr = PetscFree(cols);CHKERRQ(ierr);
2843   } else {
2844     /* determine buffer space needed for message */
2845     nz = 0;
2846     for (i=0; i<m; i++) {
2847       nz += ourlens[i];
2848     }
2849     ierr = PetscMalloc1(nz,&mycols);CHKERRQ(ierr);
2850 
2851     /* receive message of column indices*/
2852     ierr = MPIULong_Recv(mycols,nz,MPIU_INT,0,tag,comm);CHKERRQ(ierr);
2853   }
2854 
2855   /* determine column ownership if matrix is not square */
2856   if (N != M) {
2857     if (newMat->cmap->n < 0) n = N/size + ((N % size) > rank);
2858     else n = newMat->cmap->n;
2859     ierr   = MPI_Scan(&n,&cend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
2860     cstart = cend - n;
2861   } else {
2862     cstart = rstart;
2863     cend   = rend;
2864     n      = cend - cstart;
2865   }
2866 
2867   /* loop over local rows, determining number of off diagonal entries */
2868   ierr = PetscMemzero(offlens,m*sizeof(PetscInt));CHKERRQ(ierr);
2869   jj   = 0;
2870   for (i=0; i<m; i++) {
2871     for (j=0; j<ourlens[i]; j++) {
2872       if (mycols[jj] < cstart || mycols[jj] >= cend) offlens[i]++;
2873       jj++;
2874     }
2875   }
2876 
2877   for (i=0; i<m; i++) {
2878     ourlens[i] -= offlens[i];
2879   }
2880   ierr = MatSetSizes(newMat,m,n,M,N);CHKERRQ(ierr);
2881 
2882   if (bs > 1) {ierr = MatSetBlockSize(newMat,bs);CHKERRQ(ierr);}
2883 
2884   ierr = MatMPIAIJSetPreallocation(newMat,0,ourlens,0,offlens);CHKERRQ(ierr);
2885 
2886   for (i=0; i<m; i++) {
2887     ourlens[i] += offlens[i];
2888   }
2889 
2890   if (!rank) {
2891     ierr = PetscMalloc1(maxnz+1,&vals);CHKERRQ(ierr);
2892 
2893     /* read in my part of the matrix numerical values  */
2894     nz   = procsnz[0];
2895     ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2896 
2897     /* insert into matrix */
2898     jj      = rstart;
2899     smycols = mycols;
2900     svals   = vals;
2901     for (i=0; i<m; i++) {
2902       ierr     = MatSetValues_MPIAIJ(newMat,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2903       smycols += ourlens[i];
2904       svals   += ourlens[i];
2905       jj++;
2906     }
2907 
2908     /* read in other processors and ship out */
2909     for (i=1; i<size; i++) {
2910       nz   = procsnz[i];
2911       ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2912       ierr = MPIULong_Send(vals,nz,MPIU_SCALAR,i,((PetscObject)newMat)->tag,comm);CHKERRQ(ierr);
2913     }
2914     ierr = PetscFree(procsnz);CHKERRQ(ierr);
2915   } else {
2916     /* receive numeric values */
2917     ierr = PetscMalloc1(nz+1,&vals);CHKERRQ(ierr);
2918 
2919     /* receive message of values*/
2920     ierr = MPIULong_Recv(vals,nz,MPIU_SCALAR,0,((PetscObject)newMat)->tag,comm);CHKERRQ(ierr);
2921 
2922     /* insert into matrix */
2923     jj      = rstart;
2924     smycols = mycols;
2925     svals   = vals;
2926     for (i=0; i<m; i++) {
2927       ierr     = MatSetValues_MPIAIJ(newMat,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2928       smycols += ourlens[i];
2929       svals   += ourlens[i];
2930       jj++;
2931     }
2932   }
2933   ierr = PetscFree2(ourlens,offlens);CHKERRQ(ierr);
2934   ierr = PetscFree(vals);CHKERRQ(ierr);
2935   ierr = PetscFree(mycols);CHKERRQ(ierr);
2936   ierr = PetscFree(rowners);CHKERRQ(ierr);
2937   ierr = MatAssemblyBegin(newMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2938   ierr = MatAssemblyEnd(newMat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2939   PetscFunctionReturn(0);
2940 }
2941 
2942 /* Not scalable because of ISAllGather() unless getting all columns. */
2943 PetscErrorCode ISGetSeqIS_Private(Mat mat,IS iscol,IS *isseq)
2944 {
2945   PetscErrorCode ierr;
2946   IS             iscol_local;
2947   PetscBool      isstride;
2948   PetscMPIInt    lisstride=0,gisstride;
2949 
2950   PetscFunctionBegin;
2951   /* check if we are grabbing all columns*/
2952   ierr = PetscObjectTypeCompare((PetscObject)iscol,ISSTRIDE,&isstride);CHKERRQ(ierr);
2953 
2954   if (isstride) {
2955     PetscInt  start,len,mstart,mlen;
2956     ierr = ISStrideGetInfo(iscol,&start,NULL);CHKERRQ(ierr);
2957     ierr = ISGetLocalSize(iscol,&len);CHKERRQ(ierr);
2958     ierr = MatGetOwnershipRangeColumn(mat,&mstart,&mlen);CHKERRQ(ierr);
2959     if (mstart == start && mlen-mstart == len) lisstride = 1;
2960   }
2961 
2962   ierr = MPIU_Allreduce(&lisstride,&gisstride,1,MPI_INT,MPI_MIN,PetscObjectComm((PetscObject)mat));CHKERRQ(ierr);
2963   if (gisstride) {
2964     PetscInt N;
2965     ierr = MatGetSize(mat,NULL,&N);CHKERRQ(ierr);
2966     ierr = ISCreateStride(PetscObjectComm((PetscObject)mat),N,0,1,&iscol_local);CHKERRQ(ierr);
2967     ierr = ISSetIdentity(iscol_local);CHKERRQ(ierr);
2968     ierr = PetscInfo(mat,"Optimizing for obtaining all columns of the matrix; skipping ISAllGather()\n");CHKERRQ(ierr);
2969   } else {
2970     PetscInt cbs;
2971     ierr = ISGetBlockSize(iscol,&cbs);CHKERRQ(ierr);
2972     ierr = ISAllGather(iscol,&iscol_local);CHKERRQ(ierr);
2973     ierr = ISSetBlockSize(iscol_local,cbs);CHKERRQ(ierr);
2974   }
2975 
2976   *isseq = iscol_local;
2977   PetscFunctionReturn(0);
2978 }
2979 
2980 PetscErrorCode ISGetSeqIS_SameDist_Private(Mat mat,IS iscol,IS *iscol_sub,IS *iscmap)
2981 {
2982   PetscErrorCode ierr;
2983   Vec            x,cmap;
2984   const PetscInt *is_idx;
2985   PetscScalar    *xarray,*cmaparray;
2986   PetscInt       n,isstart,*idx,*cmap1,count;
2987   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)mat->data;
2988   Mat            B=a->B;
2989   Vec            lvec = a->lvec,lcmap;
2990   PetscInt       i,j,cstart,cend,Bn=B->cmap->N,*garray = a->garray;
2991   MPI_Comm       comm;
2992   PetscMPIInt    rank;
2993 
2994   PetscFunctionBegin;
2995   ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
2996   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
2997 
2998   ierr = ISGetLocalSize(iscol,&n);CHKERRQ(ierr);
2999 
3000   /* find isstart */
3001   ierr = MPI_Scan(&n,&isstart,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3002   isstart -= n;
3003   //printf("[%d] n %d, isstart %d\n",rank,n,isstart);
3004 
3005   /* (1) iscol is a sub-vector of mat, pad it with '-1.' to form a full vector x */
3006   ierr = MatCreateVecs(mat,&x,NULL);CHKERRQ(ierr);
3007   ierr = VecSet(x,-1.0);CHKERRQ(ierr);
3008 
3009   ierr = MatCreateVecs(mat,&cmap,NULL);CHKERRQ(ierr);
3010   ierr = VecSet(cmap,-1.0);CHKERRQ(ierr);
3011 
3012   ierr = MatGetOwnershipRangeColumn(mat,&cstart,&cend);CHKERRQ(ierr);
3013 
3014   ierr = ISGetIndices(iscol,&is_idx);CHKERRQ(ierr);
3015   ierr = VecGetArray(x,&xarray);CHKERRQ(ierr);
3016   ierr = VecGetArray(cmap,&cmaparray);CHKERRQ(ierr);
3017   for (i=0; i<n; i++) {
3018     xarray[is_idx[i]-cstart]    = (PetscScalar)is_idx[i];
3019     cmaparray[is_idx[i]-cstart] = i + isstart;
3020   }
3021   ierr = VecRestoreArray(x,&xarray);CHKERRQ(ierr);
3022   ierr = VecRestoreArray(cmap,&cmaparray);CHKERRQ(ierr);
3023   ierr = ISRestoreIndices(iscol,&is_idx);CHKERRQ(ierr);
3024 
3025   /* (2) scatter x and cmap using aij->Mvctx to get their off-process portions (see MatMult_MPIAIJ) */
3026   ierr = VecDuplicate(lvec,&lcmap);CHKERRQ(ierr);
3027 
3028   ierr = VecScatterBegin(a->Mvctx,x,lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3029   ierr = VecScatterEnd(a->Mvctx,x,lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3030 
3031   ierr = VecScatterBegin(a->Mvctx,cmap,lcmap,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3032   ierr = VecScatterEnd(a->Mvctx,cmap,lcmap,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
3033 
3034   if (lvec->map->n != Bn) SETERRQ2(PETSC_COMM_SELF,0,"n(lvec) %d != Bn %d",lvec->map->n,Bn);
3035   if (rank == -1) {
3036     printf("[%d] lvec:\n",rank);
3037     ierr = VecView(lvec,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
3038   }
3039 
3040   /* (3) create scalable iscol_sub (a subset of iscol) and iscmap */
3041   ierr = PetscMalloc2(n+Bn,&idx,n+Bn,&cmap1);CHKERRQ(ierr);
3042   count = 0;
3043 
3044   /* A part */
3045   ierr = ISGetIndices(iscol,&is_idx);CHKERRQ(ierr);
3046   j = cstart;
3047   for (i=0; i<n; i++) {
3048     if (j >= cend) break;
3049     if (is_idx[i] == j) {
3050       idx[count]  = j;
3051       cmap1[count] = i + isstart; /* column index in submat */
3052       count++; j++;
3053     } else if (is_idx[i] > j) {
3054       while (is_idx[i] > j && j < cend-1) j++;
3055       if (is_idx[i] == j) {
3056         idx[count]  = j;
3057         cmap1[count] = i + isstart; /* column index in submat */
3058         count++; j++;
3059       }
3060     }
3061   }
3062   ierr = ISRestoreIndices(iscol,&is_idx);CHKERRQ(ierr);
3063 
3064   /* B part */
3065   ierr = VecGetArray(lvec,&xarray);CHKERRQ(ierr);
3066   ierr = VecGetArray(lcmap,&cmaparray);CHKERRQ(ierr);
3067   j = 0;
3068   for (i=0; i<Bn; i++) {
3069     if (j >= Bn) break;
3070     if ((PetscInt)xarray[i] == garray[j]) {
3071       idx[count]   = garray[j];
3072       cmap1[count] = cmaparray[i];  /* column index in submat */
3073       count++; j++;
3074     } else if ((PetscInt)xarray[i] > garray[j]) {
3075       while ((PetscInt)xarray[i] > garray[j] && j < Bn-1) j++;
3076       if ((PetscInt)xarray[i] == garray[j]) {
3077         idx[count]  = garray[j];
3078         cmap1[count] = cmaparray[i]; /* column index in submat */
3079         count++; j++;
3080       }
3081     }
3082   }
3083   ierr = VecRestoreArray(lvec,&xarray);CHKERRQ(ierr);
3084   ierr = VecRestoreArray(lcmap,&cmaparray);CHKERRQ(ierr);
3085   //printf("[%d] n %d + Bn %d = %d; count %d, isN %d, matN %d\n",rank,n,Bn,n+Bn,count,N,mat->cmap->N);
3086 
3087   ierr = PetscSortInt(count,idx);CHKERRQ(ierr);  //should idx be sorted with cmap1???
3088   ierr = PetscSortInt(count,cmap1);CHKERRQ(ierr);
3089 
3090   ierr = ISCreateGeneral(PETSC_COMM_SELF,count,idx,PETSC_COPY_VALUES,iscol_sub);CHKERRQ(ierr);
3091   ierr = ISCreateGeneral(PETSC_COMM_SELF,count,cmap1,PETSC_COPY_VALUES,iscmap);CHKERRQ(ierr);
3092 
3093   if (rank == -1) {
3094     printf("[%d] iscmap:\n",rank);
3095     ierr = ISView(*iscmap,PETSC_VIEWER_STDOUT_SELF);CHKERRQ(ierr);
3096   }
3097 
3098   ierr = PetscFree2(idx,cmap1);CHKERRQ(ierr);
3099   ierr = VecDestroy(&x);CHKERRQ(ierr);
3100   ierr = VecDestroy(&cmap);CHKERRQ(ierr);
3101   ierr = VecDestroy(&lcmap);CHKERRQ(ierr);
3102   PetscFunctionReturn(0);
3103 }
3104 
3105 extern PetscErrorCode MatCreateSubMatrix_MPIAIJ_SameDist(Mat,IS,IS,MatReuse,Mat*);
3106 
3107 PetscErrorCode MatCreateSubMatrix_MPIAIJ(Mat mat,IS isrow,IS iscol,MatReuse call,Mat *newmat)
3108 {
3109   PetscErrorCode ierr;
3110   IS             iscol_local;
3111   PetscInt       csize;
3112   PetscInt       n,i,j,rstart,rend;
3113   PetscBool      sameRowDist=PETSC_FALSE,tsameRowDist;
3114   MPI_Comm       comm;
3115 
3116   PetscFunctionBegin;
3117   /* If isrow has same processor distribution as mat,
3118      call MatCreateSubMatrix_MPIAIJ_SameDist() to avoid using a hash table with global size of iscol */
3119   if (call == MAT_REUSE_MATRIX) {
3120     ierr = PetscObjectQuery((PetscObject)*newmat,"SubIScol",(PetscObject*)&iscol_local);CHKERRQ(ierr);
3121     if (iscol_local) tsameRowDist = PETSC_TRUE;
3122   } else {
3123     ierr = ISGetLocalSize(isrow,&n);CHKERRQ(ierr);
3124     if (!n) {
3125       sameRowDist = PETSC_TRUE;
3126     } else {
3127       ierr = ISGetMinMax(isrow,&i,&j);CHKERRQ(ierr);
3128       ierr = MatGetOwnershipRange(mat,&rstart,&rend);CHKERRQ(ierr);
3129       if (i >= rstart && j < rend) sameRowDist = PETSC_TRUE;
3130     }
3131     ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3132     ierr = MPIU_Allreduce(&sameRowDist,&tsameRowDist,1,MPIU_BOOL,MPI_LAND,comm);CHKERRQ(ierr);
3133   }
3134 
3135   if (tsameRowDist) {
3136     ierr = MatCreateSubMatrix_MPIAIJ_SameDist(mat,isrow,iscol,call,newmat);CHKERRQ(ierr);
3137     PetscFunctionReturn(0);
3138   }
3139 
3140   /* General case: iscol -> iscol_local which has global size of iscol */
3141   if (call == MAT_REUSE_MATRIX) {
3142     ierr = PetscObjectQuery((PetscObject)*newmat,"ISAllGather",(PetscObject*)&iscol_local);CHKERRQ(ierr);
3143     if (!iscol_local) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3144   } else {
3145     ierr = ISGetSeqIS_Private(mat,iscol,&iscol_local);CHKERRQ(ierr);
3146   }
3147 
3148   ierr = ISGetLocalSize(iscol,&csize);CHKERRQ(ierr);
3149   ierr = MatCreateSubMatrix_MPIAIJ_Private(mat,isrow,iscol_local,csize,call,newmat);CHKERRQ(ierr);
3150 
3151   if (call == MAT_INITIAL_MATRIX) {
3152     ierr = PetscObjectCompose((PetscObject)*newmat,"ISAllGather",(PetscObject)iscol_local);CHKERRQ(ierr);
3153     ierr = ISDestroy(&iscol_local);CHKERRQ(ierr);
3154   }
3155   PetscFunctionReturn(0);
3156 }
3157 
3158 extern PetscErrorCode MatCreateSubMatrices_MPIAIJ_Local(Mat,PetscInt,const IS[],const IS[],MatReuse,Mat*);
3159 extern PetscErrorCode MatCreateSubMatrices_MPIAIJ_SingleIS_Local(Mat,PetscInt,const IS[],const IS[],MatReuse,PetscBool,Mat*);
3160 
3161 PetscErrorCode MatCreateSubMatrix_MPIAIJ_SameDist(Mat mat,IS isrow,IS iscol,MatReuse call,Mat *newmat)
3162 {
3163   PetscErrorCode ierr;
3164   PetscInt       i,m,n,rstart,row,rend,nz,j,bs,cbs;
3165   PetscInt       *ii,*jj,nlocal,*dlens,*olens,dlen,olen,jend,mglobal;
3166   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)mat->data;
3167   Mat            M,Msub,B=a->B;
3168   MatScalar      *aa;
3169   Mat_SeqAIJ     *aij;
3170   PetscInt       *garray = a->garray,*colsub,N;
3171   PetscInt       count,Bn=B->cmap->N,cstart=mat->cmap->rstart,cend=mat->cmap->rend;
3172   IS             iscol_sub,iscmap;
3173   const PetscInt *is_idx,*cmap;
3174   PetscBool      sameColDist=PETSC_FALSE,tsameColDist;
3175   IS             iscol_local=NULL;
3176 
3177   PetscFunctionBegin;
3178   MPI_Comm       comm;
3179   PetscMPIInt    rank;
3180   ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3181   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
3182 
3183   if (call == MAT_INITIAL_MATRIX) {
3184     /* If iscol has same processor distribution as mat, then use a scalable routine */
3185     ierr = ISGetLocalSize(iscol,&n);CHKERRQ(ierr);
3186     ierr = ISGetSize(iscol,&N);CHKERRQ(ierr);
3187     if (!n) {
3188       sameColDist = PETSC_TRUE;
3189     } else {
3190       ierr = ISGetMinMax(iscol,&i,&j);CHKERRQ(ierr);
3191       ierr = MatGetOwnershipRangeColumn(mat,&cstart,&cend);CHKERRQ(ierr);
3192       if (i >= cstart && j < cend) sameColDist = PETSC_TRUE;
3193     }
3194     ierr = MPIU_Allreduce(&sameColDist,&tsameColDist,1,MPIU_BOOL,MPI_LAND,comm);CHKERRQ(ierr);
3195 
3196     /* create scalable iscol_sub (a subset of iscol_local) */
3197     if (tsameColDist) {
3198       ierr = ISGetSeqIS_SameDist_Private(mat,iscol,&iscol_sub,&iscmap);CHKERRQ(ierr);
3199       ierr = ISGetSize(iscol,&n);CHKERRQ(ierr); /* global size of iscol = global columns of newmat */
3200     } else { /* iscol -> nonscalable iscol_local, then get iscol_sub and iscmap */
3201 
3202       /* (1) iscol -> nonscalable iscol_local */
3203       ierr = ISGetSeqIS_Private(mat,iscol,&iscol_local);CHKERRQ(ierr);
3204       ierr = ISGetLocalSize(iscol_local,&n);CHKERRQ(ierr); /* local size of iscol_local = global columns of newmat */
3205 
3206     PetscInt *idx,*cmap1;
3207 
3208     ierr = PetscMalloc2(n,&idx,n,&cmap1);CHKERRQ(ierr);
3209     ierr = ISGetIndices(iscol_local,&is_idx);CHKERRQ(ierr);
3210     count = 0;
3211 
3212     /* A part */
3213     j = cstart;
3214     for (i=0; i<n; i++) {
3215       if (j >= cend) break;
3216       if (is_idx[i] == j) {
3217         idx[count]  = j;
3218         cmap1[count] = i; /* column index in submat */
3219         count++; j++;
3220       } else if (is_idx[i] > j) {
3221         while (is_idx[i] > j && j < cend-1) j++;
3222         if (is_idx[i] == j) {
3223           idx[count]  = j;
3224           cmap1[count] = i; /* column index in submat */
3225           count++; j++;
3226         }
3227       }
3228     }
3229 
3230     /* B part */
3231     j = 0;
3232     for (i=0; i<n; i++) {
3233       if (j >= Bn) break;
3234       if (is_idx[i] == garray[j]) {
3235         idx[count]  = garray[j];
3236         cmap1[count] = i;  /* column index in submat */
3237         count++; j++;
3238       } else if (is_idx[i] > garray[j]) {
3239         while (is_idx[i] > garray[j] && j < Bn-1) j++;
3240         if (is_idx[i] == garray[j]) {
3241           idx[count]  = garray[j];
3242           cmap1[count] = i; /* column index in submat */
3243           count++; j++;
3244         }
3245       }
3246     }
3247     ierr = PetscSortInt(count,cmap1);CHKERRQ(ierr);
3248     ierr = ISRestoreIndices(iscol_local,&is_idx);CHKERRQ(ierr);
3249 
3250     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)iscol_local),count,idx,PETSC_COPY_VALUES,&iscol_sub);CHKERRQ(ierr);
3251     ierr = ISSort(iscol_sub);CHKERRQ(ierr);
3252 
3253     ierr = ISCreateGeneral(PetscObjectComm((PetscObject)iscol_local),count,cmap1,PETSC_COPY_VALUES,&iscmap);CHKERRQ(ierr);
3254     ierr = PetscFree2(idx,cmap1);CHKERRQ(ierr);
3255 
3256     } // --------- old -------------------
3257 
3258     ierr = MatCreateSubMatrices_MPIAIJ_SingleIS_Local(mat,1,&isrow,&iscol_sub,MAT_INITIAL_MATRIX,PETSC_FALSE,&Msub);CHKERRQ(ierr);
3259 
3260   } else { /* call ==  MAT_REUSE_MATRIX */
3261     ierr = PetscObjectQuery((PetscObject)*newmat,"SubIScol",(PetscObject*)&iscol_sub);CHKERRQ(ierr);
3262     if (!iscol_sub) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"SubIScol passed in was not used before, cannot reuse");
3263     ierr = ISGetLocalSize(iscol_sub,&count);CHKERRQ(ierr);
3264 
3265     ierr = PetscObjectQuery((PetscObject)*newmat,"Subcmap",(PetscObject*)&iscmap);CHKERRQ(ierr);
3266     if (!iscmap) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Subcmap passed in was not used before, cannot reuse");
3267 
3268     ierr = PetscObjectQuery((PetscObject)*newmat,"SubMatrix",(PetscObject*)&Msub);CHKERRQ(ierr);
3269     if (!Msub) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3270 
3271     ierr = MatCreateSubMatrices_MPIAIJ_SingleIS_Local(mat,1,&isrow,&iscol_sub,MAT_REUSE_MATRIX,PETSC_FALSE,&Msub);CHKERRQ(ierr);
3272   }
3273 
3274   ierr = ISGetLocalSize(iscol_sub,&count);CHKERRQ(ierr);
3275   aij = (Mat_SeqAIJ*)(Msub)->data;
3276   ii  = aij->i;
3277   ierr = ISGetIndices(iscmap,&cmap);CHKERRQ(ierr);
3278 
3279   /*
3280       m - number of local rows
3281       n - number of columns (same on all processors)
3282       rstart - first row in new global matrix generated
3283   */
3284   ierr = MatGetSize(Msub,&m,NULL);CHKERRQ(ierr);
3285 
3286   if (call == MAT_INITIAL_MATRIX) {
3287     MPI_Comm       comm;
3288     PetscMPIInt    rank,size;
3289     PetscInt       csize;
3290 
3291     ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3292     ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3293     ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
3294 
3295     /*
3296         Determine the number of non-zeros in the diagonal and off-diagonal
3297         portions of the matrix in order to do correct preallocation
3298     */
3299 
3300     /* first get start and end of "diagonal" columns */
3301     ierr = ISGetLocalSize(iscol,&csize);CHKERRQ(ierr);
3302     if (csize == PETSC_DECIDE) {
3303       ierr = ISGetSize(isrow,&mglobal);CHKERRQ(ierr);
3304       if (mglobal == n) { /* square matrix */
3305         nlocal = m;
3306       } else {
3307         nlocal = n/size + ((n % size) > rank);
3308       }
3309     } else {
3310       nlocal = csize;
3311     }
3312     ierr   = MPI_Scan(&nlocal,&rend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3313     rstart = rend - nlocal;
3314     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);
3315 
3316     /* next, compute all the lengths */
3317     jj    = aij->j;
3318     ierr  = PetscMalloc1(2*m+1,&dlens);CHKERRQ(ierr);
3319     olens = dlens + m;
3320     for (i=0; i<m; i++) {
3321       jend = ii[i+1] - ii[i];
3322       olen = 0;
3323       dlen = 0;
3324       for (j=0; j<jend; j++) {
3325         if (cmap[*jj] < rstart || cmap[*jj] >= rend) olen++;
3326         else dlen++;
3327         jj++;
3328       }
3329       olens[i] = olen;
3330       dlens[i] = dlen;
3331     }
3332     ierr = MatGetBlockSizes(Msub,&bs,&cbs);CHKERRQ(ierr);
3333 
3334     ierr = MatCreate(comm,&M);CHKERRQ(ierr);
3335     ierr = MatSetSizes(M,m,nlocal,PETSC_DECIDE,n);CHKERRQ(ierr);
3336     ierr = MatSetBlockSizes(M,bs,cbs);CHKERRQ(ierr);
3337     ierr = MatSetType(M,((PetscObject)mat)->type_name);CHKERRQ(ierr);
3338     ierr = MatMPIAIJSetPreallocation(M,0,dlens,0,olens);CHKERRQ(ierr);
3339     ierr = PetscFree(dlens);CHKERRQ(ierr);
3340   } else {
3341     M    = *newmat;
3342     ierr = MatGetLocalSize(M,&i,NULL);CHKERRQ(ierr);
3343     if (i != m) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Previous matrix must be same size/layout as request");
3344     ierr = MatZeroEntries(M);CHKERRQ(ierr);
3345     /*
3346          The next two lines are needed so we may call MatSetValues_MPIAIJ() below directly,
3347        rather than the slower MatSetValues().
3348     */
3349     M->was_assembled = PETSC_TRUE;
3350     M->assembled     = PETSC_FALSE;
3351   }
3352 
3353   /* set values of Msub to *newmat */
3354   ierr = PetscMalloc1(count,&colsub);CHKERRQ(ierr);
3355   ierr = MatGetOwnershipRange(M,&rstart,NULL);CHKERRQ(ierr);
3356 
3357   jj   = aij->j;
3358   aa   = aij->a;
3359   for (i=0; i<m; i++) {
3360     row = rstart + i;
3361     nz  = ii[i+1] - ii[i];
3362     for (j=0; j<nz; j++) colsub[j] = cmap[jj[j]];
3363     ierr  = MatSetValues_MPIAIJ(M,1,&row,nz,colsub,aa,INSERT_VALUES);CHKERRQ(ierr);
3364     jj += nz; aa += nz;
3365   }
3366   ierr = ISRestoreIndices(iscmap,&cmap);CHKERRQ(ierr);
3367 
3368   ierr    = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3369   ierr    = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3370   *newmat = M;
3371 
3372   ierr = PetscFree(colsub);CHKERRQ(ierr);
3373 
3374   /* save Msub, iscol_sub and iscmap used in processor for next request */
3375   if (call ==  MAT_INITIAL_MATRIX) {
3376     ierr = PetscObjectCompose((PetscObject)M,"SubMatrix",(PetscObject)Msub);CHKERRQ(ierr);
3377     ierr = MatDestroy(&Msub);CHKERRQ(ierr);
3378 
3379     ierr = PetscObjectCompose((PetscObject)M,"SubIScol",(PetscObject)iscol_sub);CHKERRQ(ierr);
3380     ierr = ISDestroy(&iscol_sub);CHKERRQ(ierr);
3381 
3382     ierr = PetscObjectCompose((PetscObject)M,"Subcmap",(PetscObject)iscmap);CHKERRQ(ierr);
3383     ierr = ISDestroy(&iscmap);CHKERRQ(ierr);
3384 
3385     if (iscol_local) {
3386       ierr = PetscObjectCompose((PetscObject)*newmat,"ISAllGather",(PetscObject)iscol_local);CHKERRQ(ierr);
3387       ierr = ISDestroy(&iscol_local);CHKERRQ(ierr);
3388     }
3389   }
3390   PetscFunctionReturn(0);
3391 }
3392 
3393 /*
3394     Not great since it makes two copies of the submatrix, first an SeqAIJ
3395   in local and then by concatenating the local matrices the end result.
3396   Writing it directly would be much like MatCreateSubMatrices_MPIAIJ()
3397 
3398   Note: This requires a sequential iscol with all indices.
3399 */
3400 PetscErrorCode MatCreateSubMatrix_MPIAIJ_Private(Mat mat,IS isrow,IS iscol,PetscInt csize,MatReuse call,Mat *newmat)
3401 {
3402   PetscErrorCode ierr;
3403   PetscMPIInt    rank,size;
3404   PetscInt       i,m,n,rstart,row,rend,nz,*cwork,j,bs,cbs;
3405   PetscInt       *ii,*jj,nlocal,*dlens,*olens,dlen,olen,jend,mglobal;
3406   Mat            M,Mreuse;
3407   MatScalar      *aa,*vwork;
3408   MPI_Comm       comm;
3409   Mat_SeqAIJ     *aij;
3410 
3411   PetscFunctionBegin;
3412   ierr = PetscObjectGetComm((PetscObject)mat,&comm);CHKERRQ(ierr);
3413   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
3414   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3415 
3416   if (call ==  MAT_REUSE_MATRIX) {
3417     ierr = PetscObjectQuery((PetscObject)*newmat,"SubMatrix",(PetscObject*)&Mreuse);CHKERRQ(ierr);
3418     if (!Mreuse) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3419     ierr = MatCreateSubMatrices_MPIAIJ_Local(mat,1,&isrow,&iscol,MAT_REUSE_MATRIX,&Mreuse);CHKERRQ(ierr);
3420   } else {
3421     ierr = MatCreateSubMatrices_MPIAIJ_Local(mat,1,&isrow,&iscol,MAT_INITIAL_MATRIX,&Mreuse);CHKERRQ(ierr);
3422   }
3423 
3424   /*
3425       m - number of local rows
3426       n - number of columns (same on all processors)
3427       rstart - first row in new global matrix generated
3428   */
3429   ierr = MatGetSize(Mreuse,&m,&n);CHKERRQ(ierr);
3430   ierr = MatGetBlockSizes(Mreuse,&bs,&cbs);CHKERRQ(ierr);
3431   if (call == MAT_INITIAL_MATRIX) {
3432     aij = (Mat_SeqAIJ*)(Mreuse)->data;
3433     ii  = aij->i;
3434     jj  = aij->j;
3435 
3436     /*
3437         Determine the number of non-zeros in the diagonal and off-diagonal
3438         portions of the matrix in order to do correct preallocation
3439     */
3440 
3441     /* first get start and end of "diagonal" columns */
3442     if (csize == PETSC_DECIDE) {
3443       ierr = ISGetSize(isrow,&mglobal);CHKERRQ(ierr);
3444       if (mglobal == n) { /* square matrix */
3445         nlocal = m;
3446       } else {
3447         nlocal = n/size + ((n % size) > rank);
3448       }
3449     } else {
3450       nlocal = csize;
3451     }
3452     ierr   = MPI_Scan(&nlocal,&rend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3453     rstart = rend - nlocal;
3454     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);
3455 
3456     /* next, compute all the lengths */
3457     ierr  = PetscMalloc1(2*m+1,&dlens);CHKERRQ(ierr);
3458     olens = dlens + m;
3459     for (i=0; i<m; i++) {
3460       jend = ii[i+1] - ii[i];
3461       olen = 0;
3462       dlen = 0;
3463       for (j=0; j<jend; j++) {
3464         if (*jj < rstart || *jj >= rend) olen++;
3465         else dlen++;
3466         jj++;
3467       }
3468       olens[i] = olen;
3469       dlens[i] = dlen;
3470     }
3471     ierr = MatCreate(comm,&M);CHKERRQ(ierr);
3472     ierr = MatSetSizes(M,m,nlocal,PETSC_DECIDE,n);CHKERRQ(ierr);
3473     ierr = MatSetBlockSizes(M,bs,cbs);CHKERRQ(ierr);
3474     ierr = MatSetType(M,((PetscObject)mat)->type_name);CHKERRQ(ierr);
3475     ierr = MatMPIAIJSetPreallocation(M,0,dlens,0,olens);CHKERRQ(ierr);
3476     ierr = PetscFree(dlens);CHKERRQ(ierr);
3477   } else {
3478     PetscInt ml,nl;
3479 
3480     M    = *newmat;
3481     ierr = MatGetLocalSize(M,&ml,&nl);CHKERRQ(ierr);
3482     if (ml != m) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Previous matrix must be same size/layout as request");
3483     ierr = MatZeroEntries(M);CHKERRQ(ierr);
3484     /*
3485          The next two lines are needed so we may call MatSetValues_MPIAIJ() below directly,
3486        rather than the slower MatSetValues().
3487     */
3488     M->was_assembled = PETSC_TRUE;
3489     M->assembled     = PETSC_FALSE;
3490   }
3491   ierr = MatGetOwnershipRange(M,&rstart,&rend);CHKERRQ(ierr);
3492   aij  = (Mat_SeqAIJ*)(Mreuse)->data;
3493   ii   = aij->i;
3494   jj   = aij->j;
3495   aa   = aij->a;
3496   for (i=0; i<m; i++) {
3497     row   = rstart + i;
3498     nz    = ii[i+1] - ii[i];
3499     cwork = jj;     jj += nz;
3500     vwork = aa;     aa += nz;
3501     ierr  = MatSetValues_MPIAIJ(M,1,&row,nz,cwork,vwork,INSERT_VALUES);CHKERRQ(ierr);
3502   }
3503 
3504   ierr    = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3505   ierr    = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3506   *newmat = M;
3507 
3508   /* save submatrix used in processor for next request */
3509   if (call ==  MAT_INITIAL_MATRIX) {
3510     ierr = PetscObjectCompose((PetscObject)M,"SubMatrix",(PetscObject)Mreuse);CHKERRQ(ierr);
3511     ierr = MatDestroy(&Mreuse);CHKERRQ(ierr);
3512   }
3513   PetscFunctionReturn(0);
3514 }
3515 
3516 PetscErrorCode  MatMPIAIJSetPreallocationCSR_MPIAIJ(Mat B,const PetscInt Ii[],const PetscInt J[],const PetscScalar v[])
3517 {
3518   PetscInt       m,cstart, cend,j,nnz,i,d;
3519   PetscInt       *d_nnz,*o_nnz,nnz_max = 0,rstart,ii;
3520   const PetscInt *JJ;
3521   PetscScalar    *values;
3522   PetscErrorCode ierr;
3523   PetscBool      nooffprocentries;
3524 
3525   PetscFunctionBegin;
3526   if (Ii[0]) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Ii[0] must be 0 it is %D",Ii[0]);
3527 
3528   ierr   = PetscLayoutSetUp(B->rmap);CHKERRQ(ierr);
3529   ierr   = PetscLayoutSetUp(B->cmap);CHKERRQ(ierr);
3530   m      = B->rmap->n;
3531   cstart = B->cmap->rstart;
3532   cend   = B->cmap->rend;
3533   rstart = B->rmap->rstart;
3534 
3535   ierr = PetscMalloc2(m,&d_nnz,m,&o_nnz);CHKERRQ(ierr);
3536 
3537 #if defined(PETSC_USE_DEBUGGING)
3538   for (i=0; i<m; i++) {
3539     nnz = Ii[i+1]- Ii[i];
3540     JJ  = J + Ii[i];
3541     if (nnz < 0) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"Local row %D has a negative %D number of columns",i,nnz);
3542     if (nnz && (JJ[0] < 0)) SETERRRQ1(PETSC_ERR_ARG_WRONGSTATE,"Row %D starts with negative column index",i,j);
3543     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);
3544   }
3545 #endif
3546 
3547   for (i=0; i<m; i++) {
3548     nnz     = Ii[i+1]- Ii[i];
3549     JJ      = J + Ii[i];
3550     nnz_max = PetscMax(nnz_max,nnz);
3551     d       = 0;
3552     for (j=0; j<nnz; j++) {
3553       if (cstart <= JJ[j] && JJ[j] < cend) d++;
3554     }
3555     d_nnz[i] = d;
3556     o_nnz[i] = nnz - d;
3557   }
3558   ierr = MatMPIAIJSetPreallocation(B,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
3559   ierr = PetscFree2(d_nnz,o_nnz);CHKERRQ(ierr);
3560 
3561   if (v) values = (PetscScalar*)v;
3562   else {
3563     ierr = PetscCalloc1(nnz_max+1,&values);CHKERRQ(ierr);
3564   }
3565 
3566   for (i=0; i<m; i++) {
3567     ii   = i + rstart;
3568     nnz  = Ii[i+1]- Ii[i];
3569     ierr = MatSetValues_MPIAIJ(B,1,&ii,nnz,J+Ii[i],values+(v ? Ii[i] : 0),INSERT_VALUES);CHKERRQ(ierr);
3570   }
3571   nooffprocentries    = B->nooffprocentries;
3572   B->nooffprocentries = PETSC_TRUE;
3573   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3574   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3575   B->nooffprocentries = nooffprocentries;
3576 
3577   if (!v) {
3578     ierr = PetscFree(values);CHKERRQ(ierr);
3579   }
3580   ierr = MatSetOption(B,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
3581   PetscFunctionReturn(0);
3582 }
3583 
3584 /*@
3585    MatMPIAIJSetPreallocationCSR - Allocates memory for a sparse parallel matrix in AIJ format
3586    (the default parallel PETSc format).
3587 
3588    Collective on MPI_Comm
3589 
3590    Input Parameters:
3591 +  B - the matrix
3592 .  i - the indices into j for the start of each local row (starts with zero)
3593 .  j - the column indices for each local row (starts with zero)
3594 -  v - optional values in the matrix
3595 
3596    Level: developer
3597 
3598    Notes:
3599        The i, j, and a arrays ARE copied by this routine into the internal format used by PETSc;
3600      thus you CANNOT change the matrix entries by changing the values of a[] after you have
3601      called this routine. Use MatCreateMPIAIJWithSplitArrays() to avoid needing to copy the arrays.
3602 
3603        The i and j indices are 0 based, and i indices are indices corresponding to the local j array.
3604 
3605        The format which is used for the sparse matrix input, is equivalent to a
3606     row-major ordering.. i.e for the following matrix, the input data expected is
3607     as shown
3608 
3609 $        1 0 0
3610 $        2 0 3     P0
3611 $       -------
3612 $        4 5 6     P1
3613 $
3614 $     Process0 [P0]: rows_owned=[0,1]
3615 $        i =  {0,1,3}  [size = nrow+1  = 2+1]
3616 $        j =  {0,0,2}  [size = 3]
3617 $        v =  {1,2,3}  [size = 3]
3618 $
3619 $     Process1 [P1]: rows_owned=[2]
3620 $        i =  {0,3}    [size = nrow+1  = 1+1]
3621 $        j =  {0,1,2}  [size = 3]
3622 $        v =  {4,5,6}  [size = 3]
3623 
3624 .keywords: matrix, aij, compressed row, sparse, parallel
3625 
3626 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatCreateAIJ(), MATMPIAIJ,
3627           MatCreateSeqAIJWithArrays(), MatCreateMPIAIJWithSplitArrays()
3628 @*/
3629 PetscErrorCode  MatMPIAIJSetPreallocationCSR(Mat B,const PetscInt i[],const PetscInt j[], const PetscScalar v[])
3630 {
3631   PetscErrorCode ierr;
3632 
3633   PetscFunctionBegin;
3634   ierr = PetscTryMethod(B,"MatMPIAIJSetPreallocationCSR_C",(Mat,const PetscInt[],const PetscInt[],const PetscScalar[]),(B,i,j,v));CHKERRQ(ierr);
3635   PetscFunctionReturn(0);
3636 }
3637 
3638 /*@C
3639    MatMPIAIJSetPreallocation - Preallocates memory for a sparse parallel matrix in AIJ format
3640    (the default parallel PETSc format).  For good matrix assembly performance
3641    the user should preallocate the matrix storage by setting the parameters
3642    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
3643    performance can be increased by more than a factor of 50.
3644 
3645    Collective on MPI_Comm
3646 
3647    Input Parameters:
3648 +  B - the matrix
3649 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
3650            (same value is used for all local rows)
3651 .  d_nnz - array containing the number of nonzeros in the various rows of the
3652            DIAGONAL portion of the local submatrix (possibly different for each row)
3653            or NULL (PETSC_NULL_INTEGER in Fortran), if d_nz is used to specify the nonzero structure.
3654            The size of this array is equal to the number of local rows, i.e 'm'.
3655            For matrices that will be factored, you must leave room for (and set)
3656            the diagonal entry even if it is zero.
3657 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
3658            submatrix (same value is used for all local rows).
3659 -  o_nnz - array containing the number of nonzeros in the various rows of the
3660            OFF-DIAGONAL portion of the local submatrix (possibly different for
3661            each row) or NULL (PETSC_NULL_INTEGER in Fortran), if o_nz is used to specify the nonzero
3662            structure. The size of this array is equal to the number
3663            of local rows, i.e 'm'.
3664 
3665    If the *_nnz parameter is given then the *_nz parameter is ignored
3666 
3667    The AIJ format (also called the Yale sparse matrix format or
3668    compressed row storage (CSR)), is fully compatible with standard Fortran 77
3669    storage.  The stored row and column indices begin with zero.
3670    See Users-Manual: ch_mat for details.
3671 
3672    The parallel matrix is partitioned such that the first m0 rows belong to
3673    process 0, the next m1 rows belong to process 1, the next m2 rows belong
3674    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.
3675 
3676    The DIAGONAL portion of the local submatrix of a processor can be defined
3677    as the submatrix which is obtained by extraction the part corresponding to
3678    the rows r1-r2 and columns c1-c2 of the global matrix, where r1 is the
3679    first row that belongs to the processor, r2 is the last row belonging to
3680    the this processor, and c1-c2 is range of indices of the local part of a
3681    vector suitable for applying the matrix to.  This is an mxn matrix.  In the
3682    common case of a square matrix, the row and column ranges are the same and
3683    the DIAGONAL part is also square. The remaining portion of the local
3684    submatrix (mxN) constitute the OFF-DIAGONAL portion.
3685 
3686    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
3687 
3688    You can call MatGetInfo() to get information on how effective the preallocation was;
3689    for example the fields mallocs,nz_allocated,nz_used,nz_unneeded;
3690    You can also run with the option -info and look for messages with the string
3691    malloc in them to see if additional memory allocation was needed.
3692 
3693    Example usage:
3694 
3695    Consider the following 8x8 matrix with 34 non-zero values, that is
3696    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
3697    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
3698    as follows:
3699 
3700 .vb
3701             1  2  0  |  0  3  0  |  0  4
3702     Proc0   0  5  6  |  7  0  0  |  8  0
3703             9  0 10  | 11  0  0  | 12  0
3704     -------------------------------------
3705            13  0 14  | 15 16 17  |  0  0
3706     Proc1   0 18  0  | 19 20 21  |  0  0
3707             0  0  0  | 22 23  0  | 24  0
3708     -------------------------------------
3709     Proc2  25 26 27  |  0  0 28  | 29  0
3710            30  0  0  | 31 32 33  |  0 34
3711 .ve
3712 
3713    This can be represented as a collection of submatrices as:
3714 
3715 .vb
3716       A B C
3717       D E F
3718       G H I
3719 .ve
3720 
3721    Where the submatrices A,B,C are owned by proc0, D,E,F are
3722    owned by proc1, G,H,I are owned by proc2.
3723 
3724    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3725    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3726    The 'M','N' parameters are 8,8, and have the same values on all procs.
3727 
3728    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
3729    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
3730    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
3731    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
3732    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
3733    matrix, ans [DF] as another SeqAIJ matrix.
3734 
3735    When d_nz, o_nz parameters are specified, d_nz storage elements are
3736    allocated for every row of the local diagonal submatrix, and o_nz
3737    storage locations are allocated for every row of the OFF-DIAGONAL submat.
3738    One way to choose d_nz and o_nz is to use the max nonzerors per local
3739    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
3740    In this case, the values of d_nz,o_nz are:
3741 .vb
3742      proc0 : dnz = 2, o_nz = 2
3743      proc1 : dnz = 3, o_nz = 2
3744      proc2 : dnz = 1, o_nz = 4
3745 .ve
3746    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
3747    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
3748    for proc3. i.e we are using 12+15+10=37 storage locations to store
3749    34 values.
3750 
3751    When d_nnz, o_nnz parameters are specified, the storage is specified
3752    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
3753    In the above case the values for d_nnz,o_nnz are:
3754 .vb
3755      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
3756      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
3757      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
3758 .ve
3759    Here the space allocated is sum of all the above values i.e 34, and
3760    hence pre-allocation is perfect.
3761 
3762    Level: intermediate
3763 
3764 .keywords: matrix, aij, compressed row, sparse, parallel
3765 
3766 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatCreateAIJ(), MatMPIAIJSetPreallocationCSR(),
3767           MATMPIAIJ, MatGetInfo(), PetscSplitOwnership()
3768 @*/
3769 PetscErrorCode  MatMPIAIJSetPreallocation(Mat B,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[])
3770 {
3771   PetscErrorCode ierr;
3772 
3773   PetscFunctionBegin;
3774   PetscValidHeaderSpecific(B,MAT_CLASSID,1);
3775   PetscValidType(B,1);
3776   ierr = PetscTryMethod(B,"MatMPIAIJSetPreallocation_C",(Mat,PetscInt,const PetscInt[],PetscInt,const PetscInt[]),(B,d_nz,d_nnz,o_nz,o_nnz));CHKERRQ(ierr);
3777   PetscFunctionReturn(0);
3778 }
3779 
3780 /*@
3781      MatCreateMPIAIJWithArrays - creates a MPI AIJ matrix using arrays that contain in standard
3782          CSR format the local rows.
3783 
3784    Collective on MPI_Comm
3785 
3786    Input Parameters:
3787 +  comm - MPI communicator
3788 .  m - number of local rows (Cannot be PETSC_DECIDE)
3789 .  n - This value should be the same as the local size used in creating the
3790        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
3791        calculated if N is given) For square matrices n is almost always m.
3792 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
3793 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
3794 .   i - row indices
3795 .   j - column indices
3796 -   a - matrix values
3797 
3798    Output Parameter:
3799 .   mat - the matrix
3800 
3801    Level: intermediate
3802 
3803    Notes:
3804        The i, j, and a arrays ARE copied by this routine into the internal format used by PETSc;
3805      thus you CANNOT change the matrix entries by changing the values of a[] after you have
3806      called this routine. Use MatCreateMPIAIJWithSplitArrays() to avoid needing to copy the arrays.
3807 
3808        The i and j indices are 0 based, and i indices are indices corresponding to the local j array.
3809 
3810        The format which is used for the sparse matrix input, is equivalent to a
3811     row-major ordering.. i.e for the following matrix, the input data expected is
3812     as shown
3813 
3814 $        1 0 0
3815 $        2 0 3     P0
3816 $       -------
3817 $        4 5 6     P1
3818 $
3819 $     Process0 [P0]: rows_owned=[0,1]
3820 $        i =  {0,1,3}  [size = nrow+1  = 2+1]
3821 $        j =  {0,0,2}  [size = 3]
3822 $        v =  {1,2,3}  [size = 3]
3823 $
3824 $     Process1 [P1]: rows_owned=[2]
3825 $        i =  {0,3}    [size = nrow+1  = 1+1]
3826 $        j =  {0,1,2}  [size = 3]
3827 $        v =  {4,5,6}  [size = 3]
3828 
3829 .keywords: matrix, aij, compressed row, sparse, parallel
3830 
3831 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
3832           MATMPIAIJ, MatCreateAIJ(), MatCreateMPIAIJWithSplitArrays()
3833 @*/
3834 PetscErrorCode  MatCreateMPIAIJWithArrays(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,const PetscInt i[],const PetscInt j[],const PetscScalar a[],Mat *mat)
3835 {
3836   PetscErrorCode ierr;
3837 
3838   PetscFunctionBegin;
3839   if (i[0]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"i (row indices) must start with 0");
3840   if (m < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"local number of rows (m) cannot be PETSC_DECIDE, or negative");
3841   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
3842   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
3843   /* ierr = MatSetBlockSizes(M,bs,cbs);CHKERRQ(ierr); */
3844   ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
3845   ierr = MatMPIAIJSetPreallocationCSR(*mat,i,j,a);CHKERRQ(ierr);
3846   PetscFunctionReturn(0);
3847 }
3848 
3849 /*@C
3850    MatCreateAIJ - Creates a sparse parallel matrix in AIJ format
3851    (the default parallel PETSc format).  For good matrix assembly performance
3852    the user should preallocate the matrix storage by setting the parameters
3853    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
3854    performance can be increased by more than a factor of 50.
3855 
3856    Collective on MPI_Comm
3857 
3858    Input Parameters:
3859 +  comm - MPI communicator
3860 .  m - number of local rows (or PETSC_DECIDE to have calculated if M is given)
3861            This value should be the same as the local size used in creating the
3862            y vector for the matrix-vector product y = Ax.
3863 .  n - This value should be the same as the local size used in creating the
3864        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
3865        calculated if N is given) For square matrices n is almost always m.
3866 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
3867 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
3868 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
3869            (same value is used for all local rows)
3870 .  d_nnz - array containing the number of nonzeros in the various rows of the
3871            DIAGONAL portion of the local submatrix (possibly different for each row)
3872            or NULL, if d_nz is used to specify the nonzero structure.
3873            The size of this array is equal to the number of local rows, i.e 'm'.
3874 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
3875            submatrix (same value is used for all local rows).
3876 -  o_nnz - array containing the number of nonzeros in the various rows of the
3877            OFF-DIAGONAL portion of the local submatrix (possibly different for
3878            each row) or NULL, if o_nz is used to specify the nonzero
3879            structure. The size of this array is equal to the number
3880            of local rows, i.e 'm'.
3881 
3882    Output Parameter:
3883 .  A - the matrix
3884 
3885    It is recommended that one use the MatCreate(), MatSetType() and/or MatSetFromOptions(),
3886    MatXXXXSetPreallocation() paradgm instead of this routine directly.
3887    [MatXXXXSetPreallocation() is, for example, MatSeqAIJSetPreallocation]
3888 
3889    Notes:
3890    If the *_nnz parameter is given then the *_nz parameter is ignored
3891 
3892    m,n,M,N parameters specify the size of the matrix, and its partitioning across
3893    processors, while d_nz,d_nnz,o_nz,o_nnz parameters specify the approximate
3894    storage requirements for this matrix.
3895 
3896    If PETSC_DECIDE or  PETSC_DETERMINE is used for a particular argument on one
3897    processor than it must be used on all processors that share the object for
3898    that argument.
3899 
3900    The user MUST specify either the local or global matrix dimensions
3901    (possibly both).
3902 
3903    The parallel matrix is partitioned across processors such that the
3904    first m0 rows belong to process 0, the next m1 rows belong to
3905    process 1, the next m2 rows belong to process 2 etc.. where
3906    m0,m1,m2,.. are the input parameter 'm'. i.e each processor stores
3907    values corresponding to [m x N] submatrix.
3908 
3909    The columns are logically partitioned with the n0 columns belonging
3910    to 0th partition, the next n1 columns belonging to the next
3911    partition etc.. where n0,n1,n2... are the input parameter 'n'.
3912 
3913    The DIAGONAL portion of the local submatrix on any given processor
3914    is the submatrix corresponding to the rows and columns m,n
3915    corresponding to the given processor. i.e diagonal matrix on
3916    process 0 is [m0 x n0], diagonal matrix on process 1 is [m1 x n1]
3917    etc. The remaining portion of the local submatrix [m x (N-n)]
3918    constitute the OFF-DIAGONAL portion. The example below better
3919    illustrates this concept.
3920 
3921    For a square global matrix we define each processor's diagonal portion
3922    to be its local rows and the corresponding columns (a square submatrix);
3923    each processor's off-diagonal portion encompasses the remainder of the
3924    local matrix (a rectangular submatrix).
3925 
3926    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
3927 
3928    When calling this routine with a single process communicator, a matrix of
3929    type SEQAIJ is returned.  If a matrix of type MATMPIAIJ is desired for this
3930    type of communicator, use the construction mechanism:
3931      MatCreate(...,&A); MatSetType(A,MATMPIAIJ); MatSetSizes(A, m,n,M,N); MatMPIAIJSetPreallocation(A,...);
3932 
3933    By default, this format uses inodes (identical nodes) when possible.
3934    We search for consecutive rows with the same nonzero structure, thereby
3935    reusing matrix information to achieve increased efficiency.
3936 
3937    Options Database Keys:
3938 +  -mat_no_inode  - Do not use inodes
3939 .  -mat_inode_limit <limit> - Sets inode limit (max limit=5)
3940 -  -mat_aij_oneindex - Internally use indexing starting at 1
3941         rather than 0.  Note that when calling MatSetValues(),
3942         the user still MUST index entries starting at 0!
3943 
3944 
3945    Example usage:
3946 
3947    Consider the following 8x8 matrix with 34 non-zero values, that is
3948    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
3949    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
3950    as follows:
3951 
3952 .vb
3953             1  2  0  |  0  3  0  |  0  4
3954     Proc0   0  5  6  |  7  0  0  |  8  0
3955             9  0 10  | 11  0  0  | 12  0
3956     -------------------------------------
3957            13  0 14  | 15 16 17  |  0  0
3958     Proc1   0 18  0  | 19 20 21  |  0  0
3959             0  0  0  | 22 23  0  | 24  0
3960     -------------------------------------
3961     Proc2  25 26 27  |  0  0 28  | 29  0
3962            30  0  0  | 31 32 33  |  0 34
3963 .ve
3964 
3965    This can be represented as a collection of submatrices as:
3966 
3967 .vb
3968       A B C
3969       D E F
3970       G H I
3971 .ve
3972 
3973    Where the submatrices A,B,C are owned by proc0, D,E,F are
3974    owned by proc1, G,H,I are owned by proc2.
3975 
3976    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3977    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3978    The 'M','N' parameters are 8,8, and have the same values on all procs.
3979 
3980    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
3981    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
3982    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
3983    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
3984    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
3985    matrix, ans [DF] as another SeqAIJ matrix.
3986 
3987    When d_nz, o_nz parameters are specified, d_nz storage elements are
3988    allocated for every row of the local diagonal submatrix, and o_nz
3989    storage locations are allocated for every row of the OFF-DIAGONAL submat.
3990    One way to choose d_nz and o_nz is to use the max nonzerors per local
3991    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
3992    In this case, the values of d_nz,o_nz are:
3993 .vb
3994      proc0 : dnz = 2, o_nz = 2
3995      proc1 : dnz = 3, o_nz = 2
3996      proc2 : dnz = 1, o_nz = 4
3997 .ve
3998    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
3999    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
4000    for proc3. i.e we are using 12+15+10=37 storage locations to store
4001    34 values.
4002 
4003    When d_nnz, o_nnz parameters are specified, the storage is specified
4004    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
4005    In the above case the values for d_nnz,o_nnz are:
4006 .vb
4007      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
4008      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
4009      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
4010 .ve
4011    Here the space allocated is sum of all the above values i.e 34, and
4012    hence pre-allocation is perfect.
4013 
4014    Level: intermediate
4015 
4016 .keywords: matrix, aij, compressed row, sparse, parallel
4017 
4018 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
4019           MATMPIAIJ, MatCreateMPIAIJWithArrays()
4020 @*/
4021 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)
4022 {
4023   PetscErrorCode ierr;
4024   PetscMPIInt    size;
4025 
4026   PetscFunctionBegin;
4027   ierr = MatCreate(comm,A);CHKERRQ(ierr);
4028   ierr = MatSetSizes(*A,m,n,M,N);CHKERRQ(ierr);
4029   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4030   if (size > 1) {
4031     ierr = MatSetType(*A,MATMPIAIJ);CHKERRQ(ierr);
4032     ierr = MatMPIAIJSetPreallocation(*A,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
4033   } else {
4034     ierr = MatSetType(*A,MATSEQAIJ);CHKERRQ(ierr);
4035     ierr = MatSeqAIJSetPreallocation(*A,d_nz,d_nnz);CHKERRQ(ierr);
4036   }
4037   PetscFunctionReturn(0);
4038 }
4039 
4040 PetscErrorCode  MatMPIAIJGetSeqAIJ(Mat A,Mat *Ad,Mat *Ao,const PetscInt *colmap[])
4041 {
4042   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
4043   PetscBool      flg;
4044   PetscErrorCode ierr;
4045 
4046   PetscFunctionBegin;
4047   ierr = PetscObjectTypeCompare((PetscObject)A,MATMPIAIJ,&flg);CHKERRQ(ierr);
4048   if (!flg) SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_SUP,"This function requires a MATMPIAIJ matrix as input");
4049   if (Ad)     *Ad     = a->A;
4050   if (Ao)     *Ao     = a->B;
4051   if (colmap) *colmap = a->garray;
4052   PetscFunctionReturn(0);
4053 }
4054 
4055 PetscErrorCode MatCreateMPIMatConcatenateSeqMat_MPIAIJ(MPI_Comm comm,Mat inmat,PetscInt n,MatReuse scall,Mat *outmat)
4056 {
4057   PetscErrorCode ierr;
4058   PetscInt       m,N,i,rstart,nnz,Ii;
4059   PetscInt       *indx;
4060   PetscScalar    *values;
4061 
4062   PetscFunctionBegin;
4063   ierr = MatGetSize(inmat,&m,&N);CHKERRQ(ierr);
4064   if (scall == MAT_INITIAL_MATRIX) { /* symbolic phase */
4065     PetscInt       *dnz,*onz,sum,bs,cbs;
4066 
4067     if (n == PETSC_DECIDE) {
4068       ierr = PetscSplitOwnership(comm,&n,&N);CHKERRQ(ierr);
4069     }
4070     /* Check sum(n) = N */
4071     ierr = MPIU_Allreduce(&n,&sum,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
4072     if (sum != N) SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_INCOMP,"Sum of local columns != global columns %d",N);
4073 
4074     ierr    = MPI_Scan(&m, &rstart,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
4075     rstart -= m;
4076 
4077     ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
4078     for (i=0; i<m; i++) {
4079       ierr = MatGetRow_SeqAIJ(inmat,i,&nnz,&indx,NULL);CHKERRQ(ierr);
4080       ierr = MatPreallocateSet(i+rstart,nnz,indx,dnz,onz);CHKERRQ(ierr);
4081       ierr = MatRestoreRow_SeqAIJ(inmat,i,&nnz,&indx,NULL);CHKERRQ(ierr);
4082     }
4083 
4084     ierr = MatCreate(comm,outmat);CHKERRQ(ierr);
4085     ierr = MatSetSizes(*outmat,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
4086     ierr = MatGetBlockSizes(inmat,&bs,&cbs);CHKERRQ(ierr);
4087     ierr = MatSetBlockSizes(*outmat,bs,cbs);CHKERRQ(ierr);
4088     ierr = MatSetType(*outmat,MATAIJ);CHKERRQ(ierr);
4089     ierr = MatSeqAIJSetPreallocation(*outmat,0,dnz);CHKERRQ(ierr);
4090     ierr = MatMPIAIJSetPreallocation(*outmat,0,dnz,0,onz);CHKERRQ(ierr);
4091     ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
4092   }
4093 
4094   /* numeric phase */
4095   ierr = MatGetOwnershipRange(*outmat,&rstart,NULL);CHKERRQ(ierr);
4096   for (i=0; i<m; i++) {
4097     ierr = MatGetRow_SeqAIJ(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
4098     Ii   = i + rstart;
4099     ierr = MatSetValues(*outmat,1,&Ii,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
4100     ierr = MatRestoreRow_SeqAIJ(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
4101   }
4102   ierr = MatAssemblyBegin(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4103   ierr = MatAssemblyEnd(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4104   PetscFunctionReturn(0);
4105 }
4106 
4107 PetscErrorCode MatFileSplit(Mat A,char *outfile)
4108 {
4109   PetscErrorCode    ierr;
4110   PetscMPIInt       rank;
4111   PetscInt          m,N,i,rstart,nnz;
4112   size_t            len;
4113   const PetscInt    *indx;
4114   PetscViewer       out;
4115   char              *name;
4116   Mat               B;
4117   const PetscScalar *values;
4118 
4119   PetscFunctionBegin;
4120   ierr = MatGetLocalSize(A,&m,0);CHKERRQ(ierr);
4121   ierr = MatGetSize(A,0,&N);CHKERRQ(ierr);
4122   /* Should this be the type of the diagonal block of A? */
4123   ierr = MatCreate(PETSC_COMM_SELF,&B);CHKERRQ(ierr);
4124   ierr = MatSetSizes(B,m,N,m,N);CHKERRQ(ierr);
4125   ierr = MatSetBlockSizesFromMats(B,A,A);CHKERRQ(ierr);
4126   ierr = MatSetType(B,MATSEQAIJ);CHKERRQ(ierr);
4127   ierr = MatSeqAIJSetPreallocation(B,0,NULL);CHKERRQ(ierr);
4128   ierr = MatGetOwnershipRange(A,&rstart,0);CHKERRQ(ierr);
4129   for (i=0; i<m; i++) {
4130     ierr = MatGetRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
4131     ierr = MatSetValues(B,1,&i,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
4132     ierr = MatRestoreRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
4133   }
4134   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4135   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4136 
4137   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)A),&rank);CHKERRQ(ierr);
4138   ierr = PetscStrlen(outfile,&len);CHKERRQ(ierr);
4139   ierr = PetscMalloc1(len+5,&name);CHKERRQ(ierr);
4140   sprintf(name,"%s.%d",outfile,rank);
4141   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,name,FILE_MODE_APPEND,&out);CHKERRQ(ierr);
4142   ierr = PetscFree(name);CHKERRQ(ierr);
4143   ierr = MatView(B,out);CHKERRQ(ierr);
4144   ierr = PetscViewerDestroy(&out);CHKERRQ(ierr);
4145   ierr = MatDestroy(&B);CHKERRQ(ierr);
4146   PetscFunctionReturn(0);
4147 }
4148 
4149 PetscErrorCode  MatDestroy_MPIAIJ_SeqsToMPI(Mat A)
4150 {
4151   PetscErrorCode      ierr;
4152   Mat_Merge_SeqsToMPI *merge;
4153   PetscContainer      container;
4154 
4155   PetscFunctionBegin;
4156   ierr = PetscObjectQuery((PetscObject)A,"MatMergeSeqsToMPI",(PetscObject*)&container);CHKERRQ(ierr);
4157   if (container) {
4158     ierr = PetscContainerGetPointer(container,(void**)&merge);CHKERRQ(ierr);
4159     ierr = PetscFree(merge->id_r);CHKERRQ(ierr);
4160     ierr = PetscFree(merge->len_s);CHKERRQ(ierr);
4161     ierr = PetscFree(merge->len_r);CHKERRQ(ierr);
4162     ierr = PetscFree(merge->bi);CHKERRQ(ierr);
4163     ierr = PetscFree(merge->bj);CHKERRQ(ierr);
4164     ierr = PetscFree(merge->buf_ri[0]);CHKERRQ(ierr);
4165     ierr = PetscFree(merge->buf_ri);CHKERRQ(ierr);
4166     ierr = PetscFree(merge->buf_rj[0]);CHKERRQ(ierr);
4167     ierr = PetscFree(merge->buf_rj);CHKERRQ(ierr);
4168     ierr = PetscFree(merge->coi);CHKERRQ(ierr);
4169     ierr = PetscFree(merge->coj);CHKERRQ(ierr);
4170     ierr = PetscFree(merge->owners_co);CHKERRQ(ierr);
4171     ierr = PetscLayoutDestroy(&merge->rowmap);CHKERRQ(ierr);
4172     ierr = PetscFree(merge);CHKERRQ(ierr);
4173     ierr = PetscObjectCompose((PetscObject)A,"MatMergeSeqsToMPI",0);CHKERRQ(ierr);
4174   }
4175   ierr = MatDestroy_MPIAIJ(A);CHKERRQ(ierr);
4176   PetscFunctionReturn(0);
4177 }
4178 
4179 #include <../src/mat/utils/freespace.h>
4180 #include <petscbt.h>
4181 
4182 PetscErrorCode  MatCreateMPIAIJSumSeqAIJNumeric(Mat seqmat,Mat mpimat)
4183 {
4184   PetscErrorCode      ierr;
4185   MPI_Comm            comm;
4186   Mat_SeqAIJ          *a  =(Mat_SeqAIJ*)seqmat->data;
4187   PetscMPIInt         size,rank,taga,*len_s;
4188   PetscInt            N=mpimat->cmap->N,i,j,*owners,*ai=a->i,*aj;
4189   PetscInt            proc,m;
4190   PetscInt            **buf_ri,**buf_rj;
4191   PetscInt            k,anzi,*bj_i,*bi,*bj,arow,bnzi,nextaj;
4192   PetscInt            nrows,**buf_ri_k,**nextrow,**nextai;
4193   MPI_Request         *s_waits,*r_waits;
4194   MPI_Status          *status;
4195   MatScalar           *aa=a->a;
4196   MatScalar           **abuf_r,*ba_i;
4197   Mat_Merge_SeqsToMPI *merge;
4198   PetscContainer      container;
4199 
4200   PetscFunctionBegin;
4201   ierr = PetscObjectGetComm((PetscObject)mpimat,&comm);CHKERRQ(ierr);
4202   ierr = PetscLogEventBegin(MAT_Seqstompinum,seqmat,0,0,0);CHKERRQ(ierr);
4203 
4204   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4205   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4206 
4207   ierr = PetscObjectQuery((PetscObject)mpimat,"MatMergeSeqsToMPI",(PetscObject*)&container);CHKERRQ(ierr);
4208   ierr = PetscContainerGetPointer(container,(void**)&merge);CHKERRQ(ierr);
4209 
4210   bi     = merge->bi;
4211   bj     = merge->bj;
4212   buf_ri = merge->buf_ri;
4213   buf_rj = merge->buf_rj;
4214 
4215   ierr   = PetscMalloc1(size,&status);CHKERRQ(ierr);
4216   owners = merge->rowmap->range;
4217   len_s  = merge->len_s;
4218 
4219   /* send and recv matrix values */
4220   /*-----------------------------*/
4221   ierr = PetscObjectGetNewTag((PetscObject)mpimat,&taga);CHKERRQ(ierr);
4222   ierr = PetscPostIrecvScalar(comm,taga,merge->nrecv,merge->id_r,merge->len_r,&abuf_r,&r_waits);CHKERRQ(ierr);
4223 
4224   ierr = PetscMalloc1(merge->nsend+1,&s_waits);CHKERRQ(ierr);
4225   for (proc=0,k=0; proc<size; proc++) {
4226     if (!len_s[proc]) continue;
4227     i    = owners[proc];
4228     ierr = MPI_Isend(aa+ai[i],len_s[proc],MPIU_MATSCALAR,proc,taga,comm,s_waits+k);CHKERRQ(ierr);
4229     k++;
4230   }
4231 
4232   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,r_waits,status);CHKERRQ(ierr);}
4233   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,s_waits,status);CHKERRQ(ierr);}
4234   ierr = PetscFree(status);CHKERRQ(ierr);
4235 
4236   ierr = PetscFree(s_waits);CHKERRQ(ierr);
4237   ierr = PetscFree(r_waits);CHKERRQ(ierr);
4238 
4239   /* insert mat values of mpimat */
4240   /*----------------------------*/
4241   ierr = PetscMalloc1(N,&ba_i);CHKERRQ(ierr);
4242   ierr = PetscMalloc3(merge->nrecv,&buf_ri_k,merge->nrecv,&nextrow,merge->nrecv,&nextai);CHKERRQ(ierr);
4243 
4244   for (k=0; k<merge->nrecv; k++) {
4245     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
4246     nrows       = *(buf_ri_k[k]);
4247     nextrow[k]  = buf_ri_k[k]+1;  /* next row number of k-th recved i-structure */
4248     nextai[k]   = buf_ri_k[k] + (nrows + 1); /* poins to the next i-structure of k-th recved i-structure  */
4249   }
4250 
4251   /* set values of ba */
4252   m = merge->rowmap->n;
4253   for (i=0; i<m; i++) {
4254     arow = owners[rank] + i;
4255     bj_i = bj+bi[i];  /* col indices of the i-th row of mpimat */
4256     bnzi = bi[i+1] - bi[i];
4257     ierr = PetscMemzero(ba_i,bnzi*sizeof(PetscScalar));CHKERRQ(ierr);
4258 
4259     /* add local non-zero vals of this proc's seqmat into ba */
4260     anzi   = ai[arow+1] - ai[arow];
4261     aj     = a->j + ai[arow];
4262     aa     = a->a + ai[arow];
4263     nextaj = 0;
4264     for (j=0; nextaj<anzi; j++) {
4265       if (*(bj_i + j) == aj[nextaj]) { /* bcol == acol */
4266         ba_i[j] += aa[nextaj++];
4267       }
4268     }
4269 
4270     /* add received vals into ba */
4271     for (k=0; k<merge->nrecv; k++) { /* k-th received message */
4272       /* i-th row */
4273       if (i == *nextrow[k]) {
4274         anzi   = *(nextai[k]+1) - *nextai[k];
4275         aj     = buf_rj[k] + *(nextai[k]);
4276         aa     = abuf_r[k] + *(nextai[k]);
4277         nextaj = 0;
4278         for (j=0; nextaj<anzi; j++) {
4279           if (*(bj_i + j) == aj[nextaj]) { /* bcol == acol */
4280             ba_i[j] += aa[nextaj++];
4281           }
4282         }
4283         nextrow[k]++; nextai[k]++;
4284       }
4285     }
4286     ierr = MatSetValues(mpimat,1,&arow,bnzi,bj_i,ba_i,INSERT_VALUES);CHKERRQ(ierr);
4287   }
4288   ierr = MatAssemblyBegin(mpimat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4289   ierr = MatAssemblyEnd(mpimat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4290 
4291   ierr = PetscFree(abuf_r[0]);CHKERRQ(ierr);
4292   ierr = PetscFree(abuf_r);CHKERRQ(ierr);
4293   ierr = PetscFree(ba_i);CHKERRQ(ierr);
4294   ierr = PetscFree3(buf_ri_k,nextrow,nextai);CHKERRQ(ierr);
4295   ierr = PetscLogEventEnd(MAT_Seqstompinum,seqmat,0,0,0);CHKERRQ(ierr);
4296   PetscFunctionReturn(0);
4297 }
4298 
4299 PetscErrorCode  MatCreateMPIAIJSumSeqAIJSymbolic(MPI_Comm comm,Mat seqmat,PetscInt m,PetscInt n,Mat *mpimat)
4300 {
4301   PetscErrorCode      ierr;
4302   Mat                 B_mpi;
4303   Mat_SeqAIJ          *a=(Mat_SeqAIJ*)seqmat->data;
4304   PetscMPIInt         size,rank,tagi,tagj,*len_s,*len_si,*len_ri;
4305   PetscInt            **buf_rj,**buf_ri,**buf_ri_k;
4306   PetscInt            M=seqmat->rmap->n,N=seqmat->cmap->n,i,*owners,*ai=a->i,*aj=a->j;
4307   PetscInt            len,proc,*dnz,*onz,bs,cbs;
4308   PetscInt            k,anzi,*bi,*bj,*lnk,nlnk,arow,bnzi,nspacedouble=0;
4309   PetscInt            nrows,*buf_s,*buf_si,*buf_si_i,**nextrow,**nextai;
4310   MPI_Request         *si_waits,*sj_waits,*ri_waits,*rj_waits;
4311   MPI_Status          *status;
4312   PetscFreeSpaceList  free_space=NULL,current_space=NULL;
4313   PetscBT             lnkbt;
4314   Mat_Merge_SeqsToMPI *merge;
4315   PetscContainer      container;
4316 
4317   PetscFunctionBegin;
4318   ierr = PetscLogEventBegin(MAT_Seqstompisym,seqmat,0,0,0);CHKERRQ(ierr);
4319 
4320   /* make sure it is a PETSc comm */
4321   ierr = PetscCommDuplicate(comm,&comm,NULL);CHKERRQ(ierr);
4322   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4323   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4324 
4325   ierr = PetscNew(&merge);CHKERRQ(ierr);
4326   ierr = PetscMalloc1(size,&status);CHKERRQ(ierr);
4327 
4328   /* determine row ownership */
4329   /*---------------------------------------------------------*/
4330   ierr = PetscLayoutCreate(comm,&merge->rowmap);CHKERRQ(ierr);
4331   ierr = PetscLayoutSetLocalSize(merge->rowmap,m);CHKERRQ(ierr);
4332   ierr = PetscLayoutSetSize(merge->rowmap,M);CHKERRQ(ierr);
4333   ierr = PetscLayoutSetBlockSize(merge->rowmap,1);CHKERRQ(ierr);
4334   ierr = PetscLayoutSetUp(merge->rowmap);CHKERRQ(ierr);
4335   ierr = PetscMalloc1(size,&len_si);CHKERRQ(ierr);
4336   ierr = PetscMalloc1(size,&merge->len_s);CHKERRQ(ierr);
4337 
4338   m      = merge->rowmap->n;
4339   owners = merge->rowmap->range;
4340 
4341   /* determine the number of messages to send, their lengths */
4342   /*---------------------------------------------------------*/
4343   len_s = merge->len_s;
4344 
4345   len          = 0; /* length of buf_si[] */
4346   merge->nsend = 0;
4347   for (proc=0; proc<size; proc++) {
4348     len_si[proc] = 0;
4349     if (proc == rank) {
4350       len_s[proc] = 0;
4351     } else {
4352       len_si[proc] = owners[proc+1] - owners[proc] + 1;
4353       len_s[proc]  = ai[owners[proc+1]] - ai[owners[proc]]; /* num of rows to be sent to [proc] */
4354     }
4355     if (len_s[proc]) {
4356       merge->nsend++;
4357       nrows = 0;
4358       for (i=owners[proc]; i<owners[proc+1]; i++) {
4359         if (ai[i+1] > ai[i]) nrows++;
4360       }
4361       len_si[proc] = 2*(nrows+1);
4362       len         += len_si[proc];
4363     }
4364   }
4365 
4366   /* determine the number and length of messages to receive for ij-structure */
4367   /*-------------------------------------------------------------------------*/
4368   ierr = PetscGatherNumberOfMessages(comm,NULL,len_s,&merge->nrecv);CHKERRQ(ierr);
4369   ierr = PetscGatherMessageLengths2(comm,merge->nsend,merge->nrecv,len_s,len_si,&merge->id_r,&merge->len_r,&len_ri);CHKERRQ(ierr);
4370 
4371   /* post the Irecv of j-structure */
4372   /*-------------------------------*/
4373   ierr = PetscCommGetNewTag(comm,&tagj);CHKERRQ(ierr);
4374   ierr = PetscPostIrecvInt(comm,tagj,merge->nrecv,merge->id_r,merge->len_r,&buf_rj,&rj_waits);CHKERRQ(ierr);
4375 
4376   /* post the Isend of j-structure */
4377   /*--------------------------------*/
4378   ierr = PetscMalloc2(merge->nsend,&si_waits,merge->nsend,&sj_waits);CHKERRQ(ierr);
4379 
4380   for (proc=0, k=0; proc<size; proc++) {
4381     if (!len_s[proc]) continue;
4382     i    = owners[proc];
4383     ierr = MPI_Isend(aj+ai[i],len_s[proc],MPIU_INT,proc,tagj,comm,sj_waits+k);CHKERRQ(ierr);
4384     k++;
4385   }
4386 
4387   /* receives and sends of j-structure are complete */
4388   /*------------------------------------------------*/
4389   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,rj_waits,status);CHKERRQ(ierr);}
4390   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,sj_waits,status);CHKERRQ(ierr);}
4391 
4392   /* send and recv i-structure */
4393   /*---------------------------*/
4394   ierr = PetscCommGetNewTag(comm,&tagi);CHKERRQ(ierr);
4395   ierr = PetscPostIrecvInt(comm,tagi,merge->nrecv,merge->id_r,len_ri,&buf_ri,&ri_waits);CHKERRQ(ierr);
4396 
4397   ierr   = PetscMalloc1(len+1,&buf_s);CHKERRQ(ierr);
4398   buf_si = buf_s;  /* points to the beginning of k-th msg to be sent */
4399   for (proc=0,k=0; proc<size; proc++) {
4400     if (!len_s[proc]) continue;
4401     /* form outgoing message for i-structure:
4402          buf_si[0]:                 nrows to be sent
4403                [1:nrows]:           row index (global)
4404                [nrows+1:2*nrows+1]: i-structure index
4405     */
4406     /*-------------------------------------------*/
4407     nrows       = len_si[proc]/2 - 1;
4408     buf_si_i    = buf_si + nrows+1;
4409     buf_si[0]   = nrows;
4410     buf_si_i[0] = 0;
4411     nrows       = 0;
4412     for (i=owners[proc]; i<owners[proc+1]; i++) {
4413       anzi = ai[i+1] - ai[i];
4414       if (anzi) {
4415         buf_si_i[nrows+1] = buf_si_i[nrows] + anzi; /* i-structure */
4416         buf_si[nrows+1]   = i-owners[proc]; /* local row index */
4417         nrows++;
4418       }
4419     }
4420     ierr = MPI_Isend(buf_si,len_si[proc],MPIU_INT,proc,tagi,comm,si_waits+k);CHKERRQ(ierr);
4421     k++;
4422     buf_si += len_si[proc];
4423   }
4424 
4425   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,ri_waits,status);CHKERRQ(ierr);}
4426   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,si_waits,status);CHKERRQ(ierr);}
4427 
4428   ierr = PetscInfo2(seqmat,"nsend: %D, nrecv: %D\n",merge->nsend,merge->nrecv);CHKERRQ(ierr);
4429   for (i=0; i<merge->nrecv; i++) {
4430     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);
4431   }
4432 
4433   ierr = PetscFree(len_si);CHKERRQ(ierr);
4434   ierr = PetscFree(len_ri);CHKERRQ(ierr);
4435   ierr = PetscFree(rj_waits);CHKERRQ(ierr);
4436   ierr = PetscFree2(si_waits,sj_waits);CHKERRQ(ierr);
4437   ierr = PetscFree(ri_waits);CHKERRQ(ierr);
4438   ierr = PetscFree(buf_s);CHKERRQ(ierr);
4439   ierr = PetscFree(status);CHKERRQ(ierr);
4440 
4441   /* compute a local seq matrix in each processor */
4442   /*----------------------------------------------*/
4443   /* allocate bi array and free space for accumulating nonzero column info */
4444   ierr  = PetscMalloc1(m+1,&bi);CHKERRQ(ierr);
4445   bi[0] = 0;
4446 
4447   /* create and initialize a linked list */
4448   nlnk = N+1;
4449   ierr = PetscLLCreate(N,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4450 
4451   /* initial FreeSpace size is 2*(num of local nnz(seqmat)) */
4452   len  = ai[owners[rank+1]] - ai[owners[rank]];
4453   ierr = PetscFreeSpaceGet(PetscIntMultTruncate(2,len)+1,&free_space);CHKERRQ(ierr);
4454 
4455   current_space = free_space;
4456 
4457   /* determine symbolic info for each local row */
4458   ierr = PetscMalloc3(merge->nrecv,&buf_ri_k,merge->nrecv,&nextrow,merge->nrecv,&nextai);CHKERRQ(ierr);
4459 
4460   for (k=0; k<merge->nrecv; k++) {
4461     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
4462     nrows       = *buf_ri_k[k];
4463     nextrow[k]  = buf_ri_k[k] + 1;  /* next row number of k-th recved i-structure */
4464     nextai[k]   = buf_ri_k[k] + (nrows + 1); /* poins to the next i-structure of k-th recved i-structure  */
4465   }
4466 
4467   ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
4468   len  = 0;
4469   for (i=0; i<m; i++) {
4470     bnzi = 0;
4471     /* add local non-zero cols of this proc's seqmat into lnk */
4472     arow  = owners[rank] + i;
4473     anzi  = ai[arow+1] - ai[arow];
4474     aj    = a->j + ai[arow];
4475     ierr  = PetscLLAddSorted(anzi,aj,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4476     bnzi += nlnk;
4477     /* add received col data into lnk */
4478     for (k=0; k<merge->nrecv; k++) { /* k-th received message */
4479       if (i == *nextrow[k]) { /* i-th row */
4480         anzi  = *(nextai[k]+1) - *nextai[k];
4481         aj    = buf_rj[k] + *nextai[k];
4482         ierr  = PetscLLAddSorted(anzi,aj,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4483         bnzi += nlnk;
4484         nextrow[k]++; nextai[k]++;
4485       }
4486     }
4487     if (len < bnzi) len = bnzi;  /* =max(bnzi) */
4488 
4489     /* if free space is not available, make more free space */
4490     if (current_space->local_remaining<bnzi) {
4491       ierr = PetscFreeSpaceGet(PetscIntSumTruncate(bnzi,current_space->total_array_size),&current_space);CHKERRQ(ierr);
4492       nspacedouble++;
4493     }
4494     /* copy data into free space, then initialize lnk */
4495     ierr = PetscLLClean(N,N,bnzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
4496     ierr = MatPreallocateSet(i+owners[rank],bnzi,current_space->array,dnz,onz);CHKERRQ(ierr);
4497 
4498     current_space->array           += bnzi;
4499     current_space->local_used      += bnzi;
4500     current_space->local_remaining -= bnzi;
4501 
4502     bi[i+1] = bi[i] + bnzi;
4503   }
4504 
4505   ierr = PetscFree3(buf_ri_k,nextrow,nextai);CHKERRQ(ierr);
4506 
4507   ierr = PetscMalloc1(bi[m]+1,&bj);CHKERRQ(ierr);
4508   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr);
4509   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
4510 
4511   /* create symbolic parallel matrix B_mpi */
4512   /*---------------------------------------*/
4513   ierr = MatGetBlockSizes(seqmat,&bs,&cbs);CHKERRQ(ierr);
4514   ierr = MatCreate(comm,&B_mpi);CHKERRQ(ierr);
4515   if (n==PETSC_DECIDE) {
4516     ierr = MatSetSizes(B_mpi,m,n,PETSC_DETERMINE,N);CHKERRQ(ierr);
4517   } else {
4518     ierr = MatSetSizes(B_mpi,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
4519   }
4520   ierr = MatSetBlockSizes(B_mpi,bs,cbs);CHKERRQ(ierr);
4521   ierr = MatSetType(B_mpi,MATMPIAIJ);CHKERRQ(ierr);
4522   ierr = MatMPIAIJSetPreallocation(B_mpi,0,dnz,0,onz);CHKERRQ(ierr);
4523   ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
4524   ierr = MatSetOption(B_mpi,MAT_NEW_NONZERO_ALLOCATION_ERR,PETSC_FALSE);CHKERRQ(ierr);
4525 
4526   /* B_mpi is not ready for use - assembly will be done by MatCreateMPIAIJSumSeqAIJNumeric() */
4527   B_mpi->assembled    = PETSC_FALSE;
4528   B_mpi->ops->destroy = MatDestroy_MPIAIJ_SeqsToMPI;
4529   merge->bi           = bi;
4530   merge->bj           = bj;
4531   merge->buf_ri       = buf_ri;
4532   merge->buf_rj       = buf_rj;
4533   merge->coi          = NULL;
4534   merge->coj          = NULL;
4535   merge->owners_co    = NULL;
4536 
4537   ierr = PetscCommDestroy(&comm);CHKERRQ(ierr);
4538 
4539   /* attach the supporting struct to B_mpi for reuse */
4540   ierr    = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
4541   ierr    = PetscContainerSetPointer(container,merge);CHKERRQ(ierr);
4542   ierr    = PetscObjectCompose((PetscObject)B_mpi,"MatMergeSeqsToMPI",(PetscObject)container);CHKERRQ(ierr);
4543   ierr    = PetscContainerDestroy(&container);CHKERRQ(ierr);
4544   *mpimat = B_mpi;
4545 
4546   ierr = PetscLogEventEnd(MAT_Seqstompisym,seqmat,0,0,0);CHKERRQ(ierr);
4547   PetscFunctionReturn(0);
4548 }
4549 
4550 /*@C
4551       MatCreateMPIAIJSumSeqAIJ - Creates a MATMPIAIJ matrix by adding sequential
4552                  matrices from each processor
4553 
4554     Collective on MPI_Comm
4555 
4556    Input Parameters:
4557 +    comm - the communicators the parallel matrix will live on
4558 .    seqmat - the input sequential matrices
4559 .    m - number of local rows (or PETSC_DECIDE)
4560 .    n - number of local columns (or PETSC_DECIDE)
4561 -    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4562 
4563    Output Parameter:
4564 .    mpimat - the parallel matrix generated
4565 
4566     Level: advanced
4567 
4568    Notes:
4569      The dimensions of the sequential matrix in each processor MUST be the same.
4570      The input seqmat is included into the container "Mat_Merge_SeqsToMPI", and will be
4571      destroyed when mpimat is destroyed. Call PetscObjectQuery() to access seqmat.
4572 @*/
4573 PetscErrorCode  MatCreateMPIAIJSumSeqAIJ(MPI_Comm comm,Mat seqmat,PetscInt m,PetscInt n,MatReuse scall,Mat *mpimat)
4574 {
4575   PetscErrorCode ierr;
4576   PetscMPIInt    size;
4577 
4578   PetscFunctionBegin;
4579   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4580   if (size == 1) {
4581     ierr = PetscLogEventBegin(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4582     if (scall == MAT_INITIAL_MATRIX) {
4583       ierr = MatDuplicate(seqmat,MAT_COPY_VALUES,mpimat);CHKERRQ(ierr);
4584     } else {
4585       ierr = MatCopy(seqmat,*mpimat,SAME_NONZERO_PATTERN);CHKERRQ(ierr);
4586     }
4587     ierr = PetscLogEventEnd(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4588     PetscFunctionReturn(0);
4589   }
4590   ierr = PetscLogEventBegin(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4591   if (scall == MAT_INITIAL_MATRIX) {
4592     ierr = MatCreateMPIAIJSumSeqAIJSymbolic(comm,seqmat,m,n,mpimat);CHKERRQ(ierr);
4593   }
4594   ierr = MatCreateMPIAIJSumSeqAIJNumeric(seqmat,*mpimat);CHKERRQ(ierr);
4595   ierr = PetscLogEventEnd(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4596   PetscFunctionReturn(0);
4597 }
4598 
4599 /*@
4600      MatMPIAIJGetLocalMat - Creates a SeqAIJ from a MATMPIAIJ matrix by taking all its local rows and putting them into a sequential vector with
4601           mlocal rows and n columns. Where mlocal is the row count obtained with MatGetLocalSize() and n is the global column count obtained
4602           with MatGetSize()
4603 
4604     Not Collective
4605 
4606    Input Parameters:
4607 +    A - the matrix
4608 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4609 
4610    Output Parameter:
4611 .    A_loc - the local sequential matrix generated
4612 
4613     Level: developer
4614 
4615 .seealso: MatGetOwnerShipRange(), MatMPIAIJGetLocalMatCondensed()
4616 
4617 @*/
4618 PetscErrorCode  MatMPIAIJGetLocalMat(Mat A,MatReuse scall,Mat *A_loc)
4619 {
4620   PetscErrorCode ierr;
4621   Mat_MPIAIJ     *mpimat=(Mat_MPIAIJ*)A->data;
4622   Mat_SeqAIJ     *mat,*a,*b;
4623   PetscInt       *ai,*aj,*bi,*bj,*cmap=mpimat->garray;
4624   MatScalar      *aa,*ba,*cam;
4625   PetscScalar    *ca;
4626   PetscInt       am=A->rmap->n,i,j,k,cstart=A->cmap->rstart;
4627   PetscInt       *ci,*cj,col,ncols_d,ncols_o,jo;
4628   PetscBool      match;
4629   MPI_Comm       comm;
4630   PetscMPIInt    size;
4631 
4632   PetscFunctionBegin;
4633   ierr = PetscObjectTypeCompare((PetscObject)A,MATMPIAIJ,&match);CHKERRQ(ierr);
4634   if (!match) SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_SUP,"Requires MATMPIAIJ matrix as input");
4635   ierr = PetscObjectGetComm((PetscObject)A,&comm);CHKERRQ(ierr);
4636   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4637   if (size == 1 && scall == MAT_REUSE_MATRIX) PetscFunctionReturn(0);
4638 
4639   ierr = PetscLogEventBegin(MAT_Getlocalmat,A,0,0,0);CHKERRQ(ierr);
4640   a = (Mat_SeqAIJ*)(mpimat->A)->data;
4641   b = (Mat_SeqAIJ*)(mpimat->B)->data;
4642   ai = a->i; aj = a->j; bi = b->i; bj = b->j;
4643   aa = a->a; ba = b->a;
4644   if (scall == MAT_INITIAL_MATRIX) {
4645     if (size == 1) {
4646       ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,am,A->cmap->N,ai,aj,aa,A_loc);CHKERRQ(ierr);
4647       PetscFunctionReturn(0);
4648     }
4649 
4650     ierr  = PetscMalloc1(1+am,&ci);CHKERRQ(ierr);
4651     ci[0] = 0;
4652     for (i=0; i<am; i++) {
4653       ci[i+1] = ci[i] + (ai[i+1] - ai[i]) + (bi[i+1] - bi[i]);
4654     }
4655     ierr = PetscMalloc1(1+ci[am],&cj);CHKERRQ(ierr);
4656     ierr = PetscMalloc1(1+ci[am],&ca);CHKERRQ(ierr);
4657     k    = 0;
4658     for (i=0; i<am; i++) {
4659       ncols_o = bi[i+1] - bi[i];
4660       ncols_d = ai[i+1] - ai[i];
4661       /* off-diagonal portion of A */
4662       for (jo=0; jo<ncols_o; jo++) {
4663         col = cmap[*bj];
4664         if (col >= cstart) break;
4665         cj[k]   = col; bj++;
4666         ca[k++] = *ba++;
4667       }
4668       /* diagonal portion of A */
4669       for (j=0; j<ncols_d; j++) {
4670         cj[k]   = cstart + *aj++;
4671         ca[k++] = *aa++;
4672       }
4673       /* off-diagonal portion of A */
4674       for (j=jo; j<ncols_o; j++) {
4675         cj[k]   = cmap[*bj++];
4676         ca[k++] = *ba++;
4677       }
4678     }
4679     /* put together the new matrix */
4680     ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,am,A->cmap->N,ci,cj,ca,A_loc);CHKERRQ(ierr);
4681     /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
4682     /* Since these are PETSc arrays, change flags to free them as necessary. */
4683     mat          = (Mat_SeqAIJ*)(*A_loc)->data;
4684     mat->free_a  = PETSC_TRUE;
4685     mat->free_ij = PETSC_TRUE;
4686     mat->nonew   = 0;
4687   } else if (scall == MAT_REUSE_MATRIX) {
4688     mat=(Mat_SeqAIJ*)(*A_loc)->data;
4689     ci = mat->i; cj = mat->j; cam = mat->a;
4690     for (i=0; i<am; i++) {
4691       /* off-diagonal portion of A */
4692       ncols_o = bi[i+1] - bi[i];
4693       for (jo=0; jo<ncols_o; jo++) {
4694         col = cmap[*bj];
4695         if (col >= cstart) break;
4696         *cam++ = *ba++; bj++;
4697       }
4698       /* diagonal portion of A */
4699       ncols_d = ai[i+1] - ai[i];
4700       for (j=0; j<ncols_d; j++) *cam++ = *aa++;
4701       /* off-diagonal portion of A */
4702       for (j=jo; j<ncols_o; j++) {
4703         *cam++ = *ba++; bj++;
4704       }
4705     }
4706   } else SETERRQ1(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid MatReuse %d",(int)scall);
4707   ierr = PetscLogEventEnd(MAT_Getlocalmat,A,0,0,0);CHKERRQ(ierr);
4708   PetscFunctionReturn(0);
4709 }
4710 
4711 /*@C
4712      MatMPIAIJGetLocalMatCondensed - Creates a SeqAIJ matrix from an MATMPIAIJ matrix by taking all its local rows and NON-ZERO columns
4713 
4714     Not Collective
4715 
4716    Input Parameters:
4717 +    A - the matrix
4718 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4719 -    row, col - index sets of rows and columns to extract (or NULL)
4720 
4721    Output Parameter:
4722 .    A_loc - the local sequential matrix generated
4723 
4724     Level: developer
4725 
4726 .seealso: MatGetOwnershipRange(), MatMPIAIJGetLocalMat()
4727 
4728 @*/
4729 PetscErrorCode  MatMPIAIJGetLocalMatCondensed(Mat A,MatReuse scall,IS *row,IS *col,Mat *A_loc)
4730 {
4731   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)A->data;
4732   PetscErrorCode ierr;
4733   PetscInt       i,start,end,ncols,nzA,nzB,*cmap,imark,*idx;
4734   IS             isrowa,iscola;
4735   Mat            *aloc;
4736   PetscBool      match;
4737 
4738   PetscFunctionBegin;
4739   ierr = PetscObjectTypeCompare((PetscObject)A,MATMPIAIJ,&match);CHKERRQ(ierr);
4740   if (!match) SETERRQ(PetscObjectComm((PetscObject)A), PETSC_ERR_SUP,"Requires MATMPIAIJ matrix as input");
4741   ierr = PetscLogEventBegin(MAT_Getlocalmatcondensed,A,0,0,0);CHKERRQ(ierr);
4742   if (!row) {
4743     start = A->rmap->rstart; end = A->rmap->rend;
4744     ierr  = ISCreateStride(PETSC_COMM_SELF,end-start,start,1,&isrowa);CHKERRQ(ierr);
4745   } else {
4746     isrowa = *row;
4747   }
4748   if (!col) {
4749     start = A->cmap->rstart;
4750     cmap  = a->garray;
4751     nzA   = a->A->cmap->n;
4752     nzB   = a->B->cmap->n;
4753     ierr  = PetscMalloc1(nzA+nzB, &idx);CHKERRQ(ierr);
4754     ncols = 0;
4755     for (i=0; i<nzB; i++) {
4756       if (cmap[i] < start) idx[ncols++] = cmap[i];
4757       else break;
4758     }
4759     imark = i;
4760     for (i=0; i<nzA; i++) idx[ncols++] = start + i;
4761     for (i=imark; i<nzB; i++) idx[ncols++] = cmap[i];
4762     ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,PETSC_OWN_POINTER,&iscola);CHKERRQ(ierr);
4763   } else {
4764     iscola = *col;
4765   }
4766   if (scall != MAT_INITIAL_MATRIX) {
4767     ierr    = PetscMalloc1(1,&aloc);CHKERRQ(ierr);
4768     aloc[0] = *A_loc;
4769   }
4770   ierr   = MatCreateSubMatrices(A,1,&isrowa,&iscola,scall,&aloc);CHKERRQ(ierr);
4771   *A_loc = aloc[0];
4772   ierr   = PetscFree(aloc);CHKERRQ(ierr);
4773   if (!row) {
4774     ierr = ISDestroy(&isrowa);CHKERRQ(ierr);
4775   }
4776   if (!col) {
4777     ierr = ISDestroy(&iscola);CHKERRQ(ierr);
4778   }
4779   ierr = PetscLogEventEnd(MAT_Getlocalmatcondensed,A,0,0,0);CHKERRQ(ierr);
4780   PetscFunctionReturn(0);
4781 }
4782 
4783 /*@C
4784     MatGetBrowsOfAcols - Creates a SeqAIJ matrix by taking rows of B that equal to nonzero columns of local A
4785 
4786     Collective on Mat
4787 
4788    Input Parameters:
4789 +    A,B - the matrices in mpiaij format
4790 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4791 -    rowb, colb - index sets of rows and columns of B to extract (or NULL)
4792 
4793    Output Parameter:
4794 +    rowb, colb - index sets of rows and columns of B to extract
4795 -    B_seq - the sequential matrix generated
4796 
4797     Level: developer
4798 
4799 @*/
4800 PetscErrorCode  MatGetBrowsOfAcols(Mat A,Mat B,MatReuse scall,IS *rowb,IS *colb,Mat *B_seq)
4801 {
4802   Mat_MPIAIJ     *a=(Mat_MPIAIJ*)A->data;
4803   PetscErrorCode ierr;
4804   PetscInt       *idx,i,start,ncols,nzA,nzB,*cmap,imark;
4805   IS             isrowb,iscolb;
4806   Mat            *bseq=NULL;
4807 
4808   PetscFunctionBegin;
4809   if (A->cmap->rstart != B->rmap->rstart || A->cmap->rend != B->rmap->rend) {
4810     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);
4811   }
4812   ierr = PetscLogEventBegin(MAT_GetBrowsOfAcols,A,B,0,0);CHKERRQ(ierr);
4813 
4814   if (scall == MAT_INITIAL_MATRIX) {
4815     start = A->cmap->rstart;
4816     cmap  = a->garray;
4817     nzA   = a->A->cmap->n;
4818     nzB   = a->B->cmap->n;
4819     ierr  = PetscMalloc1(nzA+nzB, &idx);CHKERRQ(ierr);
4820     ncols = 0;
4821     for (i=0; i<nzB; i++) {  /* row < local row index */
4822       if (cmap[i] < start) idx[ncols++] = cmap[i];
4823       else break;
4824     }
4825     imark = i;
4826     for (i=0; i<nzA; i++) idx[ncols++] = start + i;  /* local rows */
4827     for (i=imark; i<nzB; i++) idx[ncols++] = cmap[i]; /* row > local row index */
4828     ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,PETSC_OWN_POINTER,&isrowb);CHKERRQ(ierr);
4829     ierr = ISCreateStride(PETSC_COMM_SELF,B->cmap->N,0,1,&iscolb);CHKERRQ(ierr);
4830   } else {
4831     if (!rowb || !colb) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_SUP,"IS rowb and colb must be provided for MAT_REUSE_MATRIX");
4832     isrowb  = *rowb; iscolb = *colb;
4833     ierr    = PetscMalloc1(1,&bseq);CHKERRQ(ierr);
4834     bseq[0] = *B_seq;
4835   }
4836   ierr   = MatCreateSubMatrices(B,1,&isrowb,&iscolb,scall,&bseq);CHKERRQ(ierr);
4837   *B_seq = bseq[0];
4838   ierr   = PetscFree(bseq);CHKERRQ(ierr);
4839   if (!rowb) {
4840     ierr = ISDestroy(&isrowb);CHKERRQ(ierr);
4841   } else {
4842     *rowb = isrowb;
4843   }
4844   if (!colb) {
4845     ierr = ISDestroy(&iscolb);CHKERRQ(ierr);
4846   } else {
4847     *colb = iscolb;
4848   }
4849   ierr = PetscLogEventEnd(MAT_GetBrowsOfAcols,A,B,0,0);CHKERRQ(ierr);
4850   PetscFunctionReturn(0);
4851 }
4852 
4853 /*
4854     MatGetBrowsOfAoCols_MPIAIJ - Creates a SeqAIJ matrix by taking rows of B that equal to nonzero columns
4855     of the OFF-DIAGONAL portion of local A
4856 
4857     Collective on Mat
4858 
4859    Input Parameters:
4860 +    A,B - the matrices in mpiaij format
4861 -    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4862 
4863    Output Parameter:
4864 +    startsj_s - starting point in B's sending j-arrays, saved for MAT_REUSE (or NULL)
4865 .    startsj_r - starting point in B's receiving j-arrays, saved for MAT_REUSE (or NULL)
4866 .    bufa_ptr - array for sending matrix values, saved for MAT_REUSE (or NULL)
4867 -    B_oth - the sequential matrix generated with size aBn=a->B->cmap->n by B->cmap->N
4868 
4869     Level: developer
4870 
4871 */
4872 PetscErrorCode  MatGetBrowsOfAoCols_MPIAIJ(Mat A,Mat B,MatReuse scall,PetscInt **startsj_s,PetscInt **startsj_r,MatScalar **bufa_ptr,Mat *B_oth)
4873 {
4874   VecScatter_MPI_General *gen_to,*gen_from;
4875   PetscErrorCode         ierr;
4876   Mat_MPIAIJ             *a=(Mat_MPIAIJ*)A->data;
4877   Mat_SeqAIJ             *b_oth;
4878   VecScatter             ctx =a->Mvctx;
4879   MPI_Comm               comm;
4880   PetscMPIInt            *rprocs,*sprocs,tag=((PetscObject)ctx)->tag,rank;
4881   PetscInt               *rowlen,*bufj,*bufJ,ncols,aBn=a->B->cmap->n,row,*b_othi,*b_othj;
4882   PetscInt               *rvalues,*svalues;
4883   MatScalar              *b_otha,*bufa,*bufA;
4884   PetscInt               i,j,k,l,ll,nrecvs,nsends,nrows,*srow,*rstarts,*rstartsj = 0,*sstarts,*sstartsj,len;
4885   MPI_Request            *rwaits = NULL,*swaits = NULL;
4886   MPI_Status             *sstatus,rstatus;
4887   PetscMPIInt            jj,size;
4888   PetscInt               *cols,sbs,rbs;
4889   PetscScalar            *vals;
4890 
4891   PetscFunctionBegin;
4892   ierr = PetscObjectGetComm((PetscObject)A,&comm);CHKERRQ(ierr);
4893   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4894 
4895   if (A->cmap->rstart != B->rmap->rstart || A->cmap->rend != B->rmap->rend) {
4896     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);
4897   }
4898   ierr = PetscLogEventBegin(MAT_GetBrowsOfAocols,A,B,0,0);CHKERRQ(ierr);
4899   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4900 
4901   if (size == 1) {
4902     startsj_s = NULL;
4903     bufa_ptr  = NULL;
4904     *B_oth    = NULL;
4905     PetscFunctionReturn(0);
4906   }
4907 
4908   gen_to   = (VecScatter_MPI_General*)ctx->todata;
4909   gen_from = (VecScatter_MPI_General*)ctx->fromdata;
4910   nrecvs   = gen_from->n;
4911   nsends   = gen_to->n;
4912 
4913   ierr    = PetscMalloc2(nrecvs,&rwaits,nsends,&swaits);CHKERRQ(ierr);
4914   srow    = gen_to->indices;    /* local row index to be sent */
4915   sstarts = gen_to->starts;
4916   sprocs  = gen_to->procs;
4917   sstatus = gen_to->sstatus;
4918   sbs     = gen_to->bs;
4919   rstarts = gen_from->starts;
4920   rprocs  = gen_from->procs;
4921   rbs     = gen_from->bs;
4922 
4923   if (!startsj_s || !bufa_ptr) scall = MAT_INITIAL_MATRIX;
4924   if (scall == MAT_INITIAL_MATRIX) {
4925     /* i-array */
4926     /*---------*/
4927     /*  post receives */
4928     ierr = PetscMalloc1(rbs*(rstarts[nrecvs] - rstarts[0]),&rvalues);CHKERRQ(ierr);
4929     for (i=0; i<nrecvs; i++) {
4930       rowlen = rvalues + rstarts[i]*rbs;
4931       nrows  = (rstarts[i+1]-rstarts[i])*rbs; /* num of indices to be received */
4932       ierr   = MPI_Irecv(rowlen,nrows,MPIU_INT,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
4933     }
4934 
4935     /* pack the outgoing message */
4936     ierr = PetscMalloc2(nsends+1,&sstartsj,nrecvs+1,&rstartsj);CHKERRQ(ierr);
4937 
4938     sstartsj[0] = 0;
4939     rstartsj[0] = 0;
4940     len         = 0; /* total length of j or a array to be sent */
4941     k           = 0;
4942     ierr = PetscMalloc1(sbs*(sstarts[nsends] - sstarts[0]),&svalues);CHKERRQ(ierr);
4943     for (i=0; i<nsends; i++) {
4944       rowlen = svalues + sstarts[i]*sbs;
4945       nrows  = sstarts[i+1]-sstarts[i]; /* num of block rows */
4946       for (j=0; j<nrows; j++) {
4947         row = srow[k] + B->rmap->range[rank]; /* global row idx */
4948         for (l=0; l<sbs; l++) {
4949           ierr = MatGetRow_MPIAIJ(B,row+l,&ncols,NULL,NULL);CHKERRQ(ierr); /* rowlength */
4950 
4951           rowlen[j*sbs+l] = ncols;
4952 
4953           len += ncols;
4954           ierr = MatRestoreRow_MPIAIJ(B,row+l,&ncols,NULL,NULL);CHKERRQ(ierr);
4955         }
4956         k++;
4957       }
4958       ierr = MPI_Isend(rowlen,nrows*sbs,MPIU_INT,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
4959 
4960       sstartsj[i+1] = len;  /* starting point of (i+1)-th outgoing msg in bufj and bufa */
4961     }
4962     /* recvs and sends of i-array are completed */
4963     i = nrecvs;
4964     while (i--) {
4965       ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
4966     }
4967     if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
4968     ierr = PetscFree(svalues);CHKERRQ(ierr);
4969 
4970     /* allocate buffers for sending j and a arrays */
4971     ierr = PetscMalloc1(len+1,&bufj);CHKERRQ(ierr);
4972     ierr = PetscMalloc1(len+1,&bufa);CHKERRQ(ierr);
4973 
4974     /* create i-array of B_oth */
4975     ierr = PetscMalloc1(aBn+2,&b_othi);CHKERRQ(ierr);
4976 
4977     b_othi[0] = 0;
4978     len       = 0; /* total length of j or a array to be received */
4979     k         = 0;
4980     for (i=0; i<nrecvs; i++) {
4981       rowlen = rvalues + rstarts[i]*rbs;
4982       nrows  = rbs*(rstarts[i+1]-rstarts[i]); /* num of rows to be received */
4983       for (j=0; j<nrows; j++) {
4984         b_othi[k+1] = b_othi[k] + rowlen[j];
4985         ierr = PetscIntSumError(rowlen[j],len,&len);CHKERRQ(ierr);
4986         k++;
4987       }
4988       rstartsj[i+1] = len; /* starting point of (i+1)-th incoming msg in bufj and bufa */
4989     }
4990     ierr = PetscFree(rvalues);CHKERRQ(ierr);
4991 
4992     /* allocate space for j and a arrrays of B_oth */
4993     ierr = PetscMalloc1(b_othi[aBn]+1,&b_othj);CHKERRQ(ierr);
4994     ierr = PetscMalloc1(b_othi[aBn]+1,&b_otha);CHKERRQ(ierr);
4995 
4996     /* j-array */
4997     /*---------*/
4998     /*  post receives of j-array */
4999     for (i=0; i<nrecvs; i++) {
5000       nrows = rstartsj[i+1]-rstartsj[i]; /* length of the msg received */
5001       ierr  = MPI_Irecv(b_othj+rstartsj[i],nrows,MPIU_INT,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
5002     }
5003 
5004     /* pack the outgoing message j-array */
5005     k = 0;
5006     for (i=0; i<nsends; i++) {
5007       nrows = sstarts[i+1]-sstarts[i]; /* num of block rows */
5008       bufJ  = bufj+sstartsj[i];
5009       for (j=0; j<nrows; j++) {
5010         row = srow[k++] + B->rmap->range[rank];  /* global row idx */
5011         for (ll=0; ll<sbs; ll++) {
5012           ierr = MatGetRow_MPIAIJ(B,row+ll,&ncols,&cols,NULL);CHKERRQ(ierr);
5013           for (l=0; l<ncols; l++) {
5014             *bufJ++ = cols[l];
5015           }
5016           ierr = MatRestoreRow_MPIAIJ(B,row+ll,&ncols,&cols,NULL);CHKERRQ(ierr);
5017         }
5018       }
5019       ierr = MPI_Isend(bufj+sstartsj[i],sstartsj[i+1]-sstartsj[i],MPIU_INT,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
5020     }
5021 
5022     /* recvs and sends of j-array are completed */
5023     i = nrecvs;
5024     while (i--) {
5025       ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
5026     }
5027     if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
5028   } else if (scall == MAT_REUSE_MATRIX) {
5029     sstartsj = *startsj_s;
5030     rstartsj = *startsj_r;
5031     bufa     = *bufa_ptr;
5032     b_oth    = (Mat_SeqAIJ*)(*B_oth)->data;
5033     b_otha   = b_oth->a;
5034   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Matrix P does not posses an object container");
5035 
5036   /* a-array */
5037   /*---------*/
5038   /*  post receives of a-array */
5039   for (i=0; i<nrecvs; i++) {
5040     nrows = rstartsj[i+1]-rstartsj[i]; /* length of the msg received */
5041     ierr  = MPI_Irecv(b_otha+rstartsj[i],nrows,MPIU_SCALAR,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
5042   }
5043 
5044   /* pack the outgoing message a-array */
5045   k = 0;
5046   for (i=0; i<nsends; i++) {
5047     nrows = sstarts[i+1]-sstarts[i]; /* num of block rows */
5048     bufA  = bufa+sstartsj[i];
5049     for (j=0; j<nrows; j++) {
5050       row = srow[k++] + B->rmap->range[rank];  /* global row idx */
5051       for (ll=0; ll<sbs; ll++) {
5052         ierr = MatGetRow_MPIAIJ(B,row+ll,&ncols,NULL,&vals);CHKERRQ(ierr);
5053         for (l=0; l<ncols; l++) {
5054           *bufA++ = vals[l];
5055         }
5056         ierr = MatRestoreRow_MPIAIJ(B,row+ll,&ncols,NULL,&vals);CHKERRQ(ierr);
5057       }
5058     }
5059     ierr = MPI_Isend(bufa+sstartsj[i],sstartsj[i+1]-sstartsj[i],MPIU_SCALAR,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
5060   }
5061   /* recvs and sends of a-array are completed */
5062   i = nrecvs;
5063   while (i--) {
5064     ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
5065   }
5066   if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
5067   ierr = PetscFree2(rwaits,swaits);CHKERRQ(ierr);
5068 
5069   if (scall == MAT_INITIAL_MATRIX) {
5070     /* put together the new matrix */
5071     ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,aBn,B->cmap->N,b_othi,b_othj,b_otha,B_oth);CHKERRQ(ierr);
5072 
5073     /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
5074     /* Since these are PETSc arrays, change flags to free them as necessary. */
5075     b_oth          = (Mat_SeqAIJ*)(*B_oth)->data;
5076     b_oth->free_a  = PETSC_TRUE;
5077     b_oth->free_ij = PETSC_TRUE;
5078     b_oth->nonew   = 0;
5079 
5080     ierr = PetscFree(bufj);CHKERRQ(ierr);
5081     if (!startsj_s || !bufa_ptr) {
5082       ierr = PetscFree2(sstartsj,rstartsj);CHKERRQ(ierr);
5083       ierr = PetscFree(bufa_ptr);CHKERRQ(ierr);
5084     } else {
5085       *startsj_s = sstartsj;
5086       *startsj_r = rstartsj;
5087       *bufa_ptr  = bufa;
5088     }
5089   }
5090   ierr = PetscLogEventEnd(MAT_GetBrowsOfAocols,A,B,0,0);CHKERRQ(ierr);
5091   PetscFunctionReturn(0);
5092 }
5093 
5094 /*@C
5095   MatGetCommunicationStructs - Provides access to the communication structures used in matrix-vector multiplication.
5096 
5097   Not Collective
5098 
5099   Input Parameters:
5100 . A - The matrix in mpiaij format
5101 
5102   Output Parameter:
5103 + lvec - The local vector holding off-process values from the argument to a matrix-vector product
5104 . colmap - A map from global column index to local index into lvec
5105 - multScatter - A scatter from the argument of a matrix-vector product to lvec
5106 
5107   Level: developer
5108 
5109 @*/
5110 #if defined(PETSC_USE_CTABLE)
5111 PetscErrorCode  MatGetCommunicationStructs(Mat A, Vec *lvec, PetscTable *colmap, VecScatter *multScatter)
5112 #else
5113 PetscErrorCode  MatGetCommunicationStructs(Mat A, Vec *lvec, PetscInt *colmap[], VecScatter *multScatter)
5114 #endif
5115 {
5116   Mat_MPIAIJ *a;
5117 
5118   PetscFunctionBegin;
5119   PetscValidHeaderSpecific(A, MAT_CLASSID, 1);
5120   PetscValidPointer(lvec, 2);
5121   PetscValidPointer(colmap, 3);
5122   PetscValidPointer(multScatter, 4);
5123   a = (Mat_MPIAIJ*) A->data;
5124   if (lvec) *lvec = a->lvec;
5125   if (colmap) *colmap = a->colmap;
5126   if (multScatter) *multScatter = a->Mvctx;
5127   PetscFunctionReturn(0);
5128 }
5129 
5130 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPIAIJCRL(Mat,MatType,MatReuse,Mat*);
5131 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPIAIJPERM(Mat,MatType,MatReuse,Mat*);
5132 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_MPISBAIJ(Mat,MatType,MatReuse,Mat*);
5133 #if defined(PETSC_HAVE_ELEMENTAL)
5134 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_Elemental(Mat,MatType,MatReuse,Mat*);
5135 #endif
5136 #if defined(PETSC_HAVE_HYPRE)
5137 PETSC_INTERN PetscErrorCode MatConvert_AIJ_HYPRE(Mat,MatType,MatReuse,Mat*);
5138 PETSC_INTERN PetscErrorCode MatMatMatMult_Transpose_AIJ_AIJ(Mat,Mat,Mat,MatReuse,PetscReal,Mat*);
5139 #endif
5140 PETSC_INTERN PetscErrorCode MatConvert_MPIAIJ_IS(Mat,MatType,MatReuse,Mat*);
5141 
5142 /*
5143     Computes (B'*A')' since computing B*A directly is untenable
5144 
5145                n                       p                          p
5146         (              )       (              )         (                  )
5147       m (      A       )  *  n (       B      )   =   m (         C        )
5148         (              )       (              )         (                  )
5149 
5150 */
5151 PetscErrorCode MatMatMultNumeric_MPIDense_MPIAIJ(Mat A,Mat B,Mat C)
5152 {
5153   PetscErrorCode ierr;
5154   Mat            At,Bt,Ct;
5155 
5156   PetscFunctionBegin;
5157   ierr = MatTranspose(A,MAT_INITIAL_MATRIX,&At);CHKERRQ(ierr);
5158   ierr = MatTranspose(B,MAT_INITIAL_MATRIX,&Bt);CHKERRQ(ierr);
5159   ierr = MatMatMult(Bt,At,MAT_INITIAL_MATRIX,1.0,&Ct);CHKERRQ(ierr);
5160   ierr = MatDestroy(&At);CHKERRQ(ierr);
5161   ierr = MatDestroy(&Bt);CHKERRQ(ierr);
5162   ierr = MatTranspose(Ct,MAT_REUSE_MATRIX,&C);CHKERRQ(ierr);
5163   ierr = MatDestroy(&Ct);CHKERRQ(ierr);
5164   PetscFunctionReturn(0);
5165 }
5166 
5167 PetscErrorCode MatMatMultSymbolic_MPIDense_MPIAIJ(Mat A,Mat B,PetscReal fill,Mat *C)
5168 {
5169   PetscErrorCode ierr;
5170   PetscInt       m=A->rmap->n,n=B->cmap->n;
5171   Mat            Cmat;
5172 
5173   PetscFunctionBegin;
5174   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);
5175   ierr = MatCreate(PetscObjectComm((PetscObject)A),&Cmat);CHKERRQ(ierr);
5176   ierr = MatSetSizes(Cmat,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
5177   ierr = MatSetBlockSizesFromMats(Cmat,A,B);CHKERRQ(ierr);
5178   ierr = MatSetType(Cmat,MATMPIDENSE);CHKERRQ(ierr);
5179   ierr = MatMPIDenseSetPreallocation(Cmat,NULL);CHKERRQ(ierr);
5180   ierr = MatAssemblyBegin(Cmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5181   ierr = MatAssemblyEnd(Cmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5182 
5183   Cmat->ops->matmultnumeric = MatMatMultNumeric_MPIDense_MPIAIJ;
5184 
5185   *C = Cmat;
5186   PetscFunctionReturn(0);
5187 }
5188 
5189 /* ----------------------------------------------------------------*/
5190 PETSC_INTERN PetscErrorCode MatMatMult_MPIDense_MPIAIJ(Mat A,Mat B,MatReuse scall,PetscReal fill,Mat *C)
5191 {
5192   PetscErrorCode ierr;
5193 
5194   PetscFunctionBegin;
5195   if (scall == MAT_INITIAL_MATRIX) {
5196     ierr = PetscLogEventBegin(MAT_MatMultSymbolic,A,B,0,0);CHKERRQ(ierr);
5197     ierr = MatMatMultSymbolic_MPIDense_MPIAIJ(A,B,fill,C);CHKERRQ(ierr);
5198     ierr = PetscLogEventEnd(MAT_MatMultSymbolic,A,B,0,0);CHKERRQ(ierr);
5199   }
5200   ierr = PetscLogEventBegin(MAT_MatMultNumeric,A,B,0,0);CHKERRQ(ierr);
5201   ierr = MatMatMultNumeric_MPIDense_MPIAIJ(A,B,*C);CHKERRQ(ierr);
5202   ierr = PetscLogEventEnd(MAT_MatMultNumeric,A,B,0,0);CHKERRQ(ierr);
5203   PetscFunctionReturn(0);
5204 }
5205 
5206 /*MC
5207    MATMPIAIJ - MATMPIAIJ = "mpiaij" - A matrix type to be used for parallel sparse matrices.
5208 
5209    Options Database Keys:
5210 . -mat_type mpiaij - sets the matrix type to "mpiaij" during a call to MatSetFromOptions()
5211 
5212   Level: beginner
5213 
5214 .seealso: MatCreateAIJ()
5215 M*/
5216 
5217 PETSC_EXTERN PetscErrorCode MatCreate_MPIAIJ(Mat B)
5218 {
5219   Mat_MPIAIJ     *b;
5220   PetscErrorCode ierr;
5221   PetscMPIInt    size;
5222 
5223   PetscFunctionBegin;
5224   ierr = MPI_Comm_size(PetscObjectComm((PetscObject)B),&size);CHKERRQ(ierr);
5225 
5226   ierr          = PetscNewLog(B,&b);CHKERRQ(ierr);
5227   B->data       = (void*)b;
5228   ierr          = PetscMemcpy(B->ops,&MatOps_Values,sizeof(struct _MatOps));CHKERRQ(ierr);
5229   B->assembled  = PETSC_FALSE;
5230   B->insertmode = NOT_SET_VALUES;
5231   b->size       = size;
5232 
5233   ierr = MPI_Comm_rank(PetscObjectComm((PetscObject)B),&b->rank);CHKERRQ(ierr);
5234 
5235   /* build cache for off array entries formed */
5236   ierr = MatStashCreate_Private(PetscObjectComm((PetscObject)B),1,&B->stash);CHKERRQ(ierr);
5237 
5238   b->donotstash  = PETSC_FALSE;
5239   b->colmap      = 0;
5240   b->garray      = 0;
5241   b->roworiented = PETSC_TRUE;
5242 
5243   /* stuff used for matrix vector multiply */
5244   b->lvec  = NULL;
5245   b->Mvctx = NULL;
5246 
5247   /* stuff for MatGetRow() */
5248   b->rowindices   = 0;
5249   b->rowvalues    = 0;
5250   b->getrowactive = PETSC_FALSE;
5251 
5252   /* flexible pointer used in CUSP/CUSPARSE classes */
5253   b->spptr = NULL;
5254 
5255   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMPIAIJSetUseScalableIncreaseOverlap_C",MatMPIAIJSetUseScalableIncreaseOverlap_MPIAIJ);CHKERRQ(ierr);
5256   ierr = PetscObjectComposeFunction((PetscObject)B,"MatStoreValues_C",MatStoreValues_MPIAIJ);CHKERRQ(ierr);
5257   ierr = PetscObjectComposeFunction((PetscObject)B,"MatRetrieveValues_C",MatRetrieveValues_MPIAIJ);CHKERRQ(ierr);
5258   ierr = PetscObjectComposeFunction((PetscObject)B,"MatIsTranspose_C",MatIsTranspose_MPIAIJ);CHKERRQ(ierr);
5259   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMPIAIJSetPreallocation_C",MatMPIAIJSetPreallocation_MPIAIJ);CHKERRQ(ierr);
5260   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMPIAIJSetPreallocationCSR_C",MatMPIAIJSetPreallocationCSR_MPIAIJ);CHKERRQ(ierr);
5261   ierr = PetscObjectComposeFunction((PetscObject)B,"MatDiagonalScaleLocal_C",MatDiagonalScaleLocal_MPIAIJ);CHKERRQ(ierr);
5262   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpiaijperm_C",MatConvert_MPIAIJ_MPIAIJPERM);CHKERRQ(ierr);
5263   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpiaijcrl_C",MatConvert_MPIAIJ_MPIAIJCRL);CHKERRQ(ierr);
5264   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_mpisbaij_C",MatConvert_MPIAIJ_MPISBAIJ);CHKERRQ(ierr);
5265 #if defined(PETSC_HAVE_ELEMENTAL)
5266   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_elemental_C",MatConvert_MPIAIJ_Elemental);CHKERRQ(ierr);
5267 #endif
5268 #if defined(PETSC_HAVE_HYPRE)
5269   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_hypre_C",MatConvert_AIJ_HYPRE);CHKERRQ(ierr);
5270 #endif
5271   ierr = PetscObjectComposeFunction((PetscObject)B,"MatConvert_mpiaij_is_C",MatConvert_MPIAIJ_IS);CHKERRQ(ierr);
5272   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMult_mpidense_mpiaij_C",MatMatMult_MPIDense_MPIAIJ);CHKERRQ(ierr);
5273   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMultSymbolic_mpidense_mpiaij_C",MatMatMultSymbolic_MPIDense_MPIAIJ);CHKERRQ(ierr);
5274   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMultNumeric_mpidense_mpiaij_C",MatMatMultNumeric_MPIDense_MPIAIJ);CHKERRQ(ierr);
5275 #if defined(PETSC_HAVE_HYPRE)
5276   ierr = PetscObjectComposeFunction((PetscObject)B,"MatMatMatMult_transpose_mpiaij_mpiaij_C",MatMatMatMult_Transpose_AIJ_AIJ);CHKERRQ(ierr);
5277 #endif
5278   ierr = PetscObjectChangeTypeName((PetscObject)B,MATMPIAIJ);CHKERRQ(ierr);
5279   PetscFunctionReturn(0);
5280 }
5281 
5282 /*@C
5283      MatCreateMPIAIJWithSplitArrays - creates a MPI AIJ matrix using arrays that contain the "diagonal"
5284          and "off-diagonal" part of the matrix in CSR format.
5285 
5286    Collective on MPI_Comm
5287 
5288    Input Parameters:
5289 +  comm - MPI communicator
5290 .  m - number of local rows (Cannot be PETSC_DECIDE)
5291 .  n - This value should be the same as the local size used in creating the
5292        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
5293        calculated if N is given) For square matrices n is almost always m.
5294 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
5295 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
5296 .   i - row indices for "diagonal" portion of matrix
5297 .   j - column indices
5298 .   a - matrix values
5299 .   oi - row indices for "off-diagonal" portion of matrix
5300 .   oj - column indices
5301 -   oa - matrix values
5302 
5303    Output Parameter:
5304 .   mat - the matrix
5305 
5306    Level: advanced
5307 
5308    Notes:
5309        The i, j, and a arrays ARE NOT copied by this routine into the internal format used by PETSc. The user
5310        must free the arrays once the matrix has been destroyed and not before.
5311 
5312        The i and j indices are 0 based
5313 
5314        See MatCreateAIJ() for the definition of "diagonal" and "off-diagonal" portion of the matrix
5315 
5316        This sets local rows and cannot be used to set off-processor values.
5317 
5318        Use of this routine is discouraged because it is inflexible and cumbersome to use. It is extremely rare that a
5319        legacy application natively assembles into exactly this split format. The code to do so is nontrivial and does
5320        not easily support in-place reassembly. It is recommended to use MatSetValues() (or a variant thereof) because
5321        the resulting assembly is easier to implement, will work with any matrix format, and the user does not have to
5322        keep track of the underlying array. Use MatSetOption(A,MAT_NO_OFF_PROC_ENTRIES,PETSC_TRUE) to disable all
5323        communication if it is known that only local entries will be set.
5324 
5325 .keywords: matrix, aij, compressed row, sparse, parallel
5326 
5327 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
5328           MATMPIAIJ, MatCreateAIJ(), MatCreateMPIAIJWithArrays()
5329 @*/
5330 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)
5331 {
5332   PetscErrorCode ierr;
5333   Mat_MPIAIJ     *maij;
5334 
5335   PetscFunctionBegin;
5336   if (m < 0) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"local number of rows (m) cannot be PETSC_DECIDE, or negative");
5337   if (i[0]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"i (row indices) must start with 0");
5338   if (oi[0]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_OUTOFRANGE,"oi (row indices) must start with 0");
5339   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
5340   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
5341   ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
5342   maij = (Mat_MPIAIJ*) (*mat)->data;
5343 
5344   (*mat)->preallocated = PETSC_TRUE;
5345 
5346   ierr = PetscLayoutSetUp((*mat)->rmap);CHKERRQ(ierr);
5347   ierr = PetscLayoutSetUp((*mat)->cmap);CHKERRQ(ierr);
5348 
5349   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,m,n,i,j,a,&maij->A);CHKERRQ(ierr);
5350   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,m,(*mat)->cmap->N,oi,oj,oa,&maij->B);CHKERRQ(ierr);
5351 
5352   ierr = MatAssemblyBegin(maij->A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5353   ierr = MatAssemblyEnd(maij->A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5354   ierr = MatAssemblyBegin(maij->B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5355   ierr = MatAssemblyEnd(maij->B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5356 
5357   ierr = MatSetOption(*mat,MAT_NO_OFF_PROC_ENTRIES,PETSC_TRUE);CHKERRQ(ierr);
5358   ierr = MatAssemblyBegin(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5359   ierr = MatAssemblyEnd(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5360   ierr = MatSetOption(*mat,MAT_NO_OFF_PROC_ENTRIES,PETSC_FALSE);CHKERRQ(ierr);
5361   ierr = MatSetOption(*mat,MAT_NEW_NONZERO_LOCATION_ERR,PETSC_TRUE);CHKERRQ(ierr);
5362   PetscFunctionReturn(0);
5363 }
5364 
5365 /*
5366     Special version for direct calls from Fortran
5367 */
5368 #include <petsc/private/fortranimpl.h>
5369 
5370 /* Change these macros so can be used in void function */
5371 #undef CHKERRQ
5372 #define CHKERRQ(ierr) CHKERRABORT(PETSC_COMM_WORLD,ierr)
5373 #undef SETERRQ2
5374 #define SETERRQ2(comm,ierr,b,c,d) CHKERRABORT(comm,ierr)
5375 #undef SETERRQ3
5376 #define SETERRQ3(comm,ierr,b,c,d,e) CHKERRABORT(comm,ierr)
5377 #undef SETERRQ
5378 #define SETERRQ(c,ierr,b) CHKERRABORT(c,ierr)
5379 
5380 #if defined(PETSC_HAVE_FORTRAN_CAPS)
5381 #define matsetvaluesmpiaij_ MATSETVALUESMPIAIJ
5382 #elif !defined(PETSC_HAVE_FORTRAN_UNDERSCORE)
5383 #define matsetvaluesmpiaij_ matsetvaluesmpiaij
5384 #else
5385 #endif
5386 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)
5387 {
5388   Mat            mat  = *mmat;
5389   PetscInt       m    = *mm, n = *mn;
5390   InsertMode     addv = *maddv;
5391   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
5392   PetscScalar    value;
5393   PetscErrorCode ierr;
5394 
5395   MatCheckPreallocated(mat,1);
5396   if (mat->insertmode == NOT_SET_VALUES) mat->insertmode = addv;
5397 
5398 #if defined(PETSC_USE_DEBUG)
5399   else if (mat->insertmode != addv) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"Cannot mix add values and insert values");
5400 #endif
5401   {
5402     PetscInt  i,j,rstart  = mat->rmap->rstart,rend = mat->rmap->rend;
5403     PetscInt  cstart      = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
5404     PetscBool roworiented = aij->roworiented;
5405 
5406     /* Some Variables required in the macro */
5407     Mat        A                 = aij->A;
5408     Mat_SeqAIJ *a                = (Mat_SeqAIJ*)A->data;
5409     PetscInt   *aimax            = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
5410     MatScalar  *aa               = a->a;
5411     PetscBool  ignorezeroentries = (((a->ignorezeroentries)&&(addv==ADD_VALUES)) ? PETSC_TRUE : PETSC_FALSE);
5412     Mat        B                 = aij->B;
5413     Mat_SeqAIJ *b                = (Mat_SeqAIJ*)B->data;
5414     PetscInt   *bimax            = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->rmap->n,am = aij->A->rmap->n;
5415     MatScalar  *ba               = b->a;
5416 
5417     PetscInt  *rp1,*rp2,ii,nrow1,nrow2,_i,rmax1,rmax2,N,low1,high1,low2,high2,t,lastcol1,lastcol2;
5418     PetscInt  nonew = a->nonew;
5419     MatScalar *ap1,*ap2;
5420 
5421     PetscFunctionBegin;
5422     for (i=0; i<m; i++) {
5423       if (im[i] < 0) continue;
5424 #if defined(PETSC_USE_DEBUG)
5425       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);
5426 #endif
5427       if (im[i] >= rstart && im[i] < rend) {
5428         row      = im[i] - rstart;
5429         lastcol1 = -1;
5430         rp1      = aj + ai[row];
5431         ap1      = aa + ai[row];
5432         rmax1    = aimax[row];
5433         nrow1    = ailen[row];
5434         low1     = 0;
5435         high1    = nrow1;
5436         lastcol2 = -1;
5437         rp2      = bj + bi[row];
5438         ap2      = ba + bi[row];
5439         rmax2    = bimax[row];
5440         nrow2    = bilen[row];
5441         low2     = 0;
5442         high2    = nrow2;
5443 
5444         for (j=0; j<n; j++) {
5445           if (roworiented) value = v[i*n+j];
5446           else value = v[i+j*m];
5447           if (in[j] >= cstart && in[j] < cend) {
5448             col = in[j] - cstart;
5449             if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES) && row != col) continue;
5450             MatSetValues_SeqAIJ_A_Private(row,col,value,addv,im[i],in[j]);
5451           } else if (in[j] < 0) continue;
5452 #if defined(PETSC_USE_DEBUG)
5453           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);
5454 #endif
5455           else {
5456             if (mat->was_assembled) {
5457               if (!aij->colmap) {
5458                 ierr = MatCreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
5459               }
5460 #if defined(PETSC_USE_CTABLE)
5461               ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
5462               col--;
5463 #else
5464               col = aij->colmap[in[j]] - 1;
5465 #endif
5466               if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES) && row != col) continue;
5467               if (col < 0 && !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
5468                 ierr = MatDisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
5469                 col  =  in[j];
5470                 /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
5471                 B     = aij->B;
5472                 b     = (Mat_SeqAIJ*)B->data;
5473                 bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j;
5474                 rp2   = bj + bi[row];
5475                 ap2   = ba + bi[row];
5476                 rmax2 = bimax[row];
5477                 nrow2 = bilen[row];
5478                 low2  = 0;
5479                 high2 = nrow2;
5480                 bm    = aij->B->rmap->n;
5481                 ba    = b->a;
5482               }
5483             } else col = in[j];
5484             MatSetValues_SeqAIJ_B_Private(row,col,value,addv,im[i],in[j]);
5485           }
5486         }
5487       } else if (!aij->donotstash) {
5488         if (roworiented) {
5489           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
5490         } else {
5491           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m,(PetscBool)(ignorezeroentries && (addv == ADD_VALUES)));CHKERRQ(ierr);
5492         }
5493       }
5494     }
5495   }
5496   PetscFunctionReturnVoid();
5497 }
5498 
5499