xref: /petsc/src/mat/impls/aij/mpi/mpiaij.c (revision db13566965fa33e9fddcf1f8862ee9db4040f424)
1 #define PETSCMAT_DLL
2 
3 #include "../src/mat/impls/aij/mpi/mpiaij.h"   /*I "petscmat.h" I*/
4 
5 #undef __FUNCT__
6 #define __FUNCT__ "MatDistribute_MPIAIJ"
7 /*
8     Distributes a SeqAIJ matrix across a set of processes. Code stolen from
9     MatLoad_MPIAIJ(). Horrible lack of reuse. Should be a routine for each matrix type.
10 
11     Only for square matrices
12 */
13 PetscErrorCode MatDistribute_MPIAIJ(MPI_Comm comm,Mat gmat,PetscInt m,MatReuse reuse,Mat *inmat)
14 {
15   PetscMPIInt    rank,size;
16   PetscInt       *rowners,*dlens,*olens,i,rstart,rend,j,jj,nz,*gmataj,cnt,row,*ld;
17   PetscErrorCode ierr;
18   Mat            mat;
19   Mat_SeqAIJ     *gmata;
20   PetscMPIInt    tag;
21   MPI_Status     status;
22   PetscTruth     aij;
23   MatScalar      *gmataa,*ao,*ad,*gmataarestore=0;
24 
25   PetscFunctionBegin;
26   CHKMEMQ;
27   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
28   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
29   if (!rank) {
30     ierr = PetscTypeCompare((PetscObject)gmat,MATSEQAIJ,&aij);CHKERRQ(ierr);
31     if (!aij) SETERRQ1(PETSC_ERR_SUP,"Currently no support for input matrix of type %s\n",((PetscObject)gmat)->type_name);
32   }
33   if (reuse == MAT_INITIAL_MATRIX) {
34     ierr = MatCreate(comm,&mat);CHKERRQ(ierr);
35     ierr = MatSetSizes(mat,m,m,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
36     ierr = MatSetType(mat,MATAIJ);CHKERRQ(ierr);
37     ierr = PetscMalloc((size+1)*sizeof(PetscInt),&rowners);CHKERRQ(ierr);
38     ierr = PetscMalloc2(m,PetscInt,&dlens,m,PetscInt,&olens);CHKERRQ(ierr);
39     ierr = MPI_Allgather(&m,1,MPIU_INT,rowners+1,1,MPIU_INT,comm);CHKERRQ(ierr);
40     rowners[0] = 0;
41     for (i=2; i<=size; i++) {
42       rowners[i] += rowners[i-1];
43     }
44     rstart = rowners[rank];
45     rend   = rowners[rank+1];
46     ierr   = PetscObjectGetNewTag((PetscObject)mat,&tag);CHKERRQ(ierr);
47     if (!rank) {
48       gmata = (Mat_SeqAIJ*) gmat->data;
49       /* send row lengths to all processors */
50       for (i=0; i<m; i++) dlens[i] = gmata->ilen[i];
51       for (i=1; i<size; i++) {
52 	ierr = MPI_Send(gmata->ilen + rowners[i],rowners[i+1]-rowners[i],MPIU_INT,i,tag,comm);CHKERRQ(ierr);
53       }
54       /* determine number diagonal and off-diagonal counts */
55       ierr = PetscMemzero(olens,m*sizeof(PetscInt));CHKERRQ(ierr);
56       ierr = PetscMalloc(m*sizeof(PetscInt),&ld);CHKERRQ(ierr);
57       ierr = PetscMemzero(ld,m*sizeof(PetscInt));CHKERRQ(ierr);
58       jj = 0;
59       for (i=0; i<m; i++) {
60 	for (j=0; j<dlens[i]; j++) {
61           if (gmata->j[jj] < rstart) ld[i]++;
62 	  if (gmata->j[jj] < rstart || gmata->j[jj] >= rend) olens[i]++;
63 	  jj++;
64 	}
65       }
66       /* send column indices to other processes */
67       for (i=1; i<size; i++) {
68 	nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
69 	ierr = MPI_Send(&nz,1,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
70 	ierr = MPI_Send(gmata->j + gmata->i[rowners[i]],nz,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
71       }
72 
73       /* send numerical values to other processes */
74       for (i=1; i<size; i++) {
75         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
76         ierr = MPI_Send(gmata->a + gmata->i[rowners[i]],nz,MPIU_SCALAR,i,tag,comm);CHKERRQ(ierr);
77       }
78       gmataa = gmata->a;
79       gmataj = gmata->j;
80 
81     } else {
82       /* receive row lengths */
83       ierr = MPI_Recv(dlens,m,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
84       /* receive column indices */
85       ierr = MPI_Recv(&nz,1,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
86       ierr = PetscMalloc2(nz,PetscScalar,&gmataa,nz,PetscInt,&gmataj);CHKERRQ(ierr);
87       ierr = MPI_Recv(gmataj,nz,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
88       /* determine number diagonal and off-diagonal counts */
89       ierr = PetscMemzero(olens,m*sizeof(PetscInt));CHKERRQ(ierr);
90       ierr = PetscMalloc(m*sizeof(PetscInt),&ld);CHKERRQ(ierr);
91       ierr = PetscMemzero(ld,m*sizeof(PetscInt));CHKERRQ(ierr);
92       jj = 0;
93       for (i=0; i<m; i++) {
94 	for (j=0; j<dlens[i]; j++) {
95           if (gmataj[jj] < rstart) ld[i]++;
96 	  if (gmataj[jj] < rstart || gmataj[jj] >= rend) olens[i]++;
97 	  jj++;
98 	}
99       }
100       /* receive numerical values */
101       ierr = PetscMemzero(gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr);
102       ierr = MPI_Recv(gmataa,nz,MPIU_SCALAR,0,tag,comm,&status);CHKERRQ(ierr);
103     }
104     /* set preallocation */
105     for (i=0; i<m; i++) {
106       dlens[i] -= olens[i];
107     }
108     ierr = MatSeqAIJSetPreallocation(mat,0,dlens);CHKERRQ(ierr);
109     ierr = MatMPIAIJSetPreallocation(mat,0,dlens,0,olens);CHKERRQ(ierr);
110 
111     for (i=0; i<m; i++) {
112       dlens[i] += olens[i];
113     }
114     cnt  = 0;
115     for (i=0; i<m; i++) {
116       row  = rstart + i;
117       ierr = MatSetValues(mat,1,&row,dlens[i],gmataj+cnt,gmataa+cnt,INSERT_VALUES);CHKERRQ(ierr);
118       cnt += dlens[i];
119     }
120     if (rank) {
121       ierr = PetscFree2(gmataa,gmataj);CHKERRQ(ierr);
122     }
123     ierr = PetscFree2(dlens,olens);CHKERRQ(ierr);
124     ierr = PetscFree(rowners);CHKERRQ(ierr);
125     ((Mat_MPIAIJ*)(mat->data))->ld = ld;
126     *inmat = mat;
127   } else {   /* column indices are already set; only need to move over numerical values from process 0 */
128     Mat_SeqAIJ *Ad = (Mat_SeqAIJ*)((Mat_MPIAIJ*)((*inmat)->data))->A->data;
129     Mat_SeqAIJ *Ao = (Mat_SeqAIJ*)((Mat_MPIAIJ*)((*inmat)->data))->B->data;
130     mat   = *inmat;
131     ierr  = PetscObjectGetNewTag((PetscObject)mat,&tag);CHKERRQ(ierr);
132     if (!rank) {
133       /* send numerical values to other processes */
134       gmata = (Mat_SeqAIJ*) gmat->data;
135       ierr   = MatGetOwnershipRanges(mat,(const PetscInt**)&rowners);CHKERRQ(ierr);
136       gmataa = gmata->a;
137       for (i=1; i<size; i++) {
138         nz   = gmata->i[rowners[i+1]]-gmata->i[rowners[i]];
139         ierr = MPI_Send(gmataa + gmata->i[rowners[i]],nz,MPIU_SCALAR,i,tag,comm);CHKERRQ(ierr);
140       }
141       nz   = gmata->i[rowners[1]]-gmata->i[rowners[0]];
142     } else {
143       /* receive numerical values from process 0*/
144       nz   = Ad->nz + Ao->nz;
145       ierr = PetscMalloc(nz*sizeof(PetscScalar),&gmataa);CHKERRQ(ierr); gmataarestore = gmataa;
146       ierr = MPI_Recv(gmataa,nz,MPIU_SCALAR,0,tag,comm,&status);CHKERRQ(ierr);
147     }
148     /* transfer numerical values into the diagonal A and off diagonal B parts of mat */
149     ld = ((Mat_MPIAIJ*)(mat->data))->ld;
150     ad = Ad->a;
151     ao = Ao->a;
152     if (mat->rmap->n) {
153       i  = 0;
154       nz = ld[i];                                   ierr = PetscMemcpy(ao,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ao += nz; gmataa += nz;
155       nz = Ad->i[i+1] - Ad->i[i];                   ierr = PetscMemcpy(ad,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ad += nz; gmataa += nz;
156     }
157     for (i=1; i<mat->rmap->n; i++) {
158       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;
159       nz = Ad->i[i+1] - Ad->i[i];                   ierr = PetscMemcpy(ad,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ad += nz; gmataa += nz;
160     }
161     i--;
162     if (mat->rmap->n) {
163       nz = Ao->i[i+1] - Ao->i[i] - ld[i];           ierr = PetscMemcpy(ao,gmataa,nz*sizeof(PetscScalar));CHKERRQ(ierr); ao += nz; gmataa += nz;
164     }
165     if (rank) {
166       ierr = PetscFree(gmataarestore);CHKERRQ(ierr);
167     }
168   }
169   ierr = MatAssemblyBegin(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
170   ierr = MatAssemblyEnd(mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
171   CHKMEMQ;
172   PetscFunctionReturn(0);
173 }
174 
175 /*
176   Local utility routine that creates a mapping from the global column
177 number to the local number in the off-diagonal part of the local
178 storage of the matrix.  When PETSC_USE_CTABLE is used this is scalable at
179 a slightly higher hash table cost; without it it is not scalable (each processor
180 has an order N integer array but is fast to acess.
181 */
182 #undef __FUNCT__
183 #define __FUNCT__ "CreateColmap_MPIAIJ_Private"
184 PetscErrorCode CreateColmap_MPIAIJ_Private(Mat mat)
185 {
186   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
187   PetscErrorCode ierr;
188   PetscInt       n = aij->B->cmap->n,i;
189 
190   PetscFunctionBegin;
191 #if defined (PETSC_USE_CTABLE)
192   ierr = PetscTableCreate(n,&aij->colmap);CHKERRQ(ierr);
193   for (i=0; i<n; i++){
194     ierr = PetscTableAdd(aij->colmap,aij->garray[i]+1,i+1);CHKERRQ(ierr);
195   }
196 #else
197   ierr = PetscMalloc((mat->cmap->N+1)*sizeof(PetscInt),&aij->colmap);CHKERRQ(ierr);
198   ierr = PetscLogObjectMemory(mat,mat->cmap->N*sizeof(PetscInt));CHKERRQ(ierr);
199   ierr = PetscMemzero(aij->colmap,mat->cmap->N*sizeof(PetscInt));CHKERRQ(ierr);
200   for (i=0; i<n; i++) aij->colmap[aij->garray[i]] = i+1;
201 #endif
202   PetscFunctionReturn(0);
203 }
204 
205 
206 #define CHUNKSIZE   15
207 #define MatSetValues_SeqAIJ_A_Private(row,col,value,addv) \
208 { \
209     if (col <= lastcol1) low1 = 0; else high1 = nrow1; \
210     lastcol1 = col;\
211     while (high1-low1 > 5) { \
212       t = (low1+high1)/2; \
213       if (rp1[t] > col) high1 = t; \
214       else             low1  = t; \
215     } \
216       for (_i=low1; _i<high1; _i++) { \
217         if (rp1[_i] > col) break; \
218         if (rp1[_i] == col) { \
219           if (addv == ADD_VALUES) ap1[_i] += value;   \
220           else                    ap1[_i] = value; \
221           goto a_noinsert; \
222         } \
223       }  \
224       if (value == 0.0 && ignorezeroentries) {low1 = 0; high1 = nrow1;goto a_noinsert;} \
225       if (nonew == 1) {low1 = 0; high1 = nrow1; goto a_noinsert;}		\
226       if (nonew == -1) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%D, %D) into matrix", row, col); \
227       MatSeqXAIJReallocateAIJ(A,am,1,nrow1,row,col,rmax1,aa,ai,aj,rp1,ap1,aimax,nonew,MatScalar); \
228       N = nrow1++ - 1; a->nz++; high1++; \
229       /* shift up all the later entries in this row */ \
230       for (ii=N; ii>=_i; ii--) { \
231         rp1[ii+1] = rp1[ii]; \
232         ap1[ii+1] = ap1[ii]; \
233       } \
234       rp1[_i] = col;  \
235       ap1[_i] = value;  \
236       a_noinsert: ; \
237       ailen[row] = nrow1; \
238 }
239 
240 
241 #define MatSetValues_SeqAIJ_B_Private(row,col,value,addv) \
242 { \
243     if (col <= lastcol2) low2 = 0; else high2 = nrow2; \
244     lastcol2 = col;\
245     while (high2-low2 > 5) { \
246       t = (low2+high2)/2; \
247       if (rp2[t] > col) high2 = t; \
248       else             low2  = t; \
249     } \
250     for (_i=low2; _i<high2; _i++) {		\
251       if (rp2[_i] > col) break;			\
252       if (rp2[_i] == col) {			      \
253 	if (addv == ADD_VALUES) ap2[_i] += value;     \
254 	else                    ap2[_i] = value;      \
255 	goto b_noinsert;			      \
256       }						      \
257     }							      \
258     if (value == 0.0 && ignorezeroentries) {low2 = 0; high2 = nrow2; goto b_noinsert;} \
259     if (nonew == 1) {low2 = 0; high2 = nrow2; goto b_noinsert;}		\
260     if (nonew == -1) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%D, %D) into matrix", row, col); \
261     MatSeqXAIJReallocateAIJ(B,bm,1,nrow2,row,col,rmax2,ba,bi,bj,rp2,ap2,bimax,nonew,MatScalar); \
262     N = nrow2++ - 1; b->nz++; high2++;					\
263     /* shift up all the later entries in this row */			\
264     for (ii=N; ii>=_i; ii--) {						\
265       rp2[ii+1] = rp2[ii];						\
266       ap2[ii+1] = ap2[ii];						\
267     }									\
268     rp2[_i] = col;							\
269     ap2[_i] = value;							\
270     b_noinsert: ;								\
271     bilen[row] = nrow2;							\
272 }
273 
274 #undef __FUNCT__
275 #define __FUNCT__ "MatSetValuesRow_MPIAIJ"
276 PetscErrorCode MatSetValuesRow_MPIAIJ(Mat A,PetscInt row,const PetscScalar v[])
277 {
278   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)A->data;
279   Mat_SeqAIJ     *a = (Mat_SeqAIJ*)mat->A->data,*b = (Mat_SeqAIJ*)mat->B->data;
280   PetscErrorCode ierr;
281   PetscInt       l,*garray = mat->garray,diag;
282 
283   PetscFunctionBegin;
284   /* code only works for square matrices A */
285 
286   /* find size of row to the left of the diagonal part */
287   ierr = MatGetOwnershipRange(A,&diag,0);CHKERRQ(ierr);
288   row  = row - diag;
289   for (l=0; l<b->i[row+1]-b->i[row]; l++) {
290     if (garray[b->j[b->i[row]+l]] > diag) break;
291   }
292   ierr = PetscMemcpy(b->a+b->i[row],v,l*sizeof(PetscScalar));CHKERRQ(ierr);
293 
294   /* diagonal part */
295   ierr = PetscMemcpy(a->a+a->i[row],v+l,(a->i[row+1]-a->i[row])*sizeof(PetscScalar));CHKERRQ(ierr);
296 
297   /* right of diagonal part */
298   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);
299   PetscFunctionReturn(0);
300 }
301 
302 #undef __FUNCT__
303 #define __FUNCT__ "MatSetValues_MPIAIJ"
304 PetscErrorCode MatSetValues_MPIAIJ(Mat mat,PetscInt m,const PetscInt im[],PetscInt n,const PetscInt in[],const PetscScalar v[],InsertMode addv)
305 {
306   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
307   PetscScalar    value;
308   PetscErrorCode ierr;
309   PetscInt       i,j,rstart = mat->rmap->rstart,rend = mat->rmap->rend;
310   PetscInt       cstart = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
311   PetscTruth     roworiented = aij->roworiented;
312 
313   /* Some Variables required in the macro */
314   Mat            A = aij->A;
315   Mat_SeqAIJ     *a = (Mat_SeqAIJ*)A->data;
316   PetscInt       *aimax = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
317   MatScalar      *aa = a->a;
318   PetscTruth     ignorezeroentries = a->ignorezeroentries;
319   Mat            B = aij->B;
320   Mat_SeqAIJ     *b = (Mat_SeqAIJ*)B->data;
321   PetscInt       *bimax = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->rmap->n,am = aij->A->rmap->n;
322   MatScalar      *ba = b->a;
323 
324   PetscInt       *rp1,*rp2,ii,nrow1,nrow2,_i,rmax1,rmax2,N,low1,high1,low2,high2,t,lastcol1,lastcol2;
325   PetscInt       nonew = a->nonew;
326   MatScalar      *ap1,*ap2;
327 
328   PetscFunctionBegin;
329   for (i=0; i<m; i++) {
330     if (im[i] < 0) continue;
331 #if defined(PETSC_USE_DEBUG)
332     if (im[i] >= mat->rmap->N) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %D max %D",im[i],mat->rmap->N-1);
333 #endif
334     if (im[i] >= rstart && im[i] < rend) {
335       row      = im[i] - rstart;
336       lastcol1 = -1;
337       rp1      = aj + ai[row];
338       ap1      = aa + ai[row];
339       rmax1    = aimax[row];
340       nrow1    = ailen[row];
341       low1     = 0;
342       high1    = nrow1;
343       lastcol2 = -1;
344       rp2      = bj + bi[row];
345       ap2      = ba + bi[row];
346       rmax2    = bimax[row];
347       nrow2    = bilen[row];
348       low2     = 0;
349       high2    = nrow2;
350 
351       for (j=0; j<n; j++) {
352         if (v) {if (roworiented) value = v[i*n+j]; else value = v[i+j*m];} else value = 0.0;
353         if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES)) continue;
354         if (in[j] >= cstart && in[j] < cend){
355           col = in[j] - cstart;
356           MatSetValues_SeqAIJ_A_Private(row,col,value,addv);
357         } else if (in[j] < 0) continue;
358 #if defined(PETSC_USE_DEBUG)
359         else if (in[j] >= mat->cmap->N) {SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %D max %D",in[j],mat->cmap->N-1);}
360 #endif
361         else {
362           if (mat->was_assembled) {
363             if (!aij->colmap) {
364               ierr = CreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
365             }
366 #if defined (PETSC_USE_CTABLE)
367             ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
368 	    col--;
369 #else
370             col = aij->colmap[in[j]] - 1;
371 #endif
372             if (col < 0 && !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
373               ierr = DisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
374               col =  in[j];
375               /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
376               B = aij->B;
377               b = (Mat_SeqAIJ*)B->data;
378               bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j; ba = b->a;
379               rp2      = bj + bi[row];
380               ap2      = ba + bi[row];
381               rmax2    = bimax[row];
382               nrow2    = bilen[row];
383               low2     = 0;
384               high2    = nrow2;
385               bm       = aij->B->rmap->n;
386               ba = b->a;
387             }
388           } else col = in[j];
389           MatSetValues_SeqAIJ_B_Private(row,col,value,addv);
390         }
391       }
392     } else {
393       if (!aij->donotstash) {
394         if (roworiented) {
395           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n,ignorezeroentries && (addv == ADD_VALUES));CHKERRQ(ierr);
396         } else {
397           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m,ignorezeroentries && (addv == ADD_VALUES));CHKERRQ(ierr);
398         }
399       }
400     }
401   }
402   PetscFunctionReturn(0);
403 }
404 
405 #undef __FUNCT__
406 #define __FUNCT__ "MatGetValues_MPIAIJ"
407 PetscErrorCode MatGetValues_MPIAIJ(Mat mat,PetscInt m,const PetscInt idxm[],PetscInt n,const PetscInt idxn[],PetscScalar v[])
408 {
409   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
410   PetscErrorCode ierr;
411   PetscInt       i,j,rstart = mat->rmap->rstart,rend = mat->rmap->rend;
412   PetscInt       cstart = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
413 
414   PetscFunctionBegin;
415   for (i=0; i<m; i++) {
416     if (idxm[i] < 0) continue; /* SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Negative row: %D",idxm[i]);*/
417     if (idxm[i] >= mat->rmap->N) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %D max %D",idxm[i],mat->rmap->N-1);
418     if (idxm[i] >= rstart && idxm[i] < rend) {
419       row = idxm[i] - rstart;
420       for (j=0; j<n; j++) {
421         if (idxn[j] < 0) continue; /* SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Negative column: %D",idxn[j]); */
422         if (idxn[j] >= mat->cmap->N) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %D max %D",idxn[j],mat->cmap->N-1);
423         if (idxn[j] >= cstart && idxn[j] < cend){
424           col = idxn[j] - cstart;
425           ierr = MatGetValues(aij->A,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
426         } else {
427           if (!aij->colmap) {
428             ierr = CreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
429           }
430 #if defined (PETSC_USE_CTABLE)
431           ierr = PetscTableFind(aij->colmap,idxn[j]+1,&col);CHKERRQ(ierr);
432           col --;
433 #else
434           col = aij->colmap[idxn[j]] - 1;
435 #endif
436           if ((col < 0) || (aij->garray[col] != idxn[j])) *(v+i*n+j) = 0.0;
437           else {
438             ierr = MatGetValues(aij->B,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
439           }
440         }
441       }
442     } else {
443       SETERRQ(PETSC_ERR_SUP,"Only local values currently supported");
444     }
445   }
446   PetscFunctionReturn(0);
447 }
448 
449 extern PetscErrorCode MatMultDiagonalBlock_MPIAIJ(Mat,Vec,Vec);
450 
451 #undef __FUNCT__
452 #define __FUNCT__ "MatAssemblyBegin_MPIAIJ"
453 PetscErrorCode MatAssemblyBegin_MPIAIJ(Mat mat,MatAssemblyType mode)
454 {
455   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
456   PetscErrorCode ierr;
457   PetscInt       nstash,reallocs;
458   InsertMode     addv;
459 
460   PetscFunctionBegin;
461   if (aij->donotstash) {
462     PetscFunctionReturn(0);
463   }
464 
465   /* make sure all processors are either in INSERTMODE or ADDMODE */
466   ierr = MPI_Allreduce(&mat->insertmode,&addv,1,MPI_INT,MPI_BOR,((PetscObject)mat)->comm);CHKERRQ(ierr);
467   if (addv == (ADD_VALUES|INSERT_VALUES)) {
468     SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Some processors inserted others added");
469   }
470   mat->insertmode = addv; /* in case this processor had no cache */
471 
472   ierr = MatStashScatterBegin_Private(mat,&mat->stash,mat->rmap->range);CHKERRQ(ierr);
473   ierr = MatStashGetInfo_Private(&mat->stash,&nstash,&reallocs);CHKERRQ(ierr);
474   ierr = PetscInfo2(aij->A,"Stash has %D entries, uses %D mallocs.\n",nstash,reallocs);CHKERRQ(ierr);
475   PetscFunctionReturn(0);
476 }
477 
478 #undef __FUNCT__
479 #define __FUNCT__ "MatAssemblyEnd_MPIAIJ"
480 PetscErrorCode MatAssemblyEnd_MPIAIJ(Mat mat,MatAssemblyType mode)
481 {
482   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
483   Mat_SeqAIJ     *a=(Mat_SeqAIJ *)aij->A->data;
484   PetscErrorCode ierr;
485   PetscMPIInt    n;
486   PetscInt       i,j,rstart,ncols,flg;
487   PetscInt       *row,*col;
488   PetscTruth     other_disassembled;
489   PetscScalar    *val;
490   InsertMode     addv = mat->insertmode;
491 
492   /* do not use 'b = (Mat_SeqAIJ *)aij->B->data' as B can be reset in disassembly */
493   PetscFunctionBegin;
494   if (!aij->donotstash) {
495     while (1) {
496       ierr = MatStashScatterGetMesg_Private(&mat->stash,&n,&row,&col,&val,&flg);CHKERRQ(ierr);
497       if (!flg) break;
498 
499       for (i=0; i<n;) {
500         /* Now identify the consecutive vals belonging to the same row */
501         for (j=i,rstart=row[j]; j<n; j++) { if (row[j] != rstart) break; }
502         if (j < n) ncols = j-i;
503         else       ncols = n-i;
504         /* Now assemble all these values with a single function call */
505         ierr = MatSetValues_MPIAIJ(mat,1,row+i,ncols,col+i,val+i,addv);CHKERRQ(ierr);
506         i = j;
507       }
508     }
509     ierr = MatStashScatterEnd_Private(&mat->stash);CHKERRQ(ierr);
510   }
511   a->compressedrow.use     = PETSC_FALSE;
512   ierr = MatAssemblyBegin(aij->A,mode);CHKERRQ(ierr);
513   ierr = MatAssemblyEnd(aij->A,mode);CHKERRQ(ierr);
514 
515   /* determine if any processor has disassembled, if so we must
516      also disassemble ourselfs, in order that we may reassemble. */
517   /*
518      if nonzero structure of submatrix B cannot change then we know that
519      no processor disassembled thus we can skip this stuff
520   */
521   if (!((Mat_SeqAIJ*)aij->B->data)->nonew)  {
522     ierr = MPI_Allreduce(&mat->was_assembled,&other_disassembled,1,MPI_INT,MPI_PROD,((PetscObject)mat)->comm);CHKERRQ(ierr);
523     if (mat->was_assembled && !other_disassembled) {
524       ierr = DisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
525     }
526   }
527   if (!mat->was_assembled && mode == MAT_FINAL_ASSEMBLY) {
528     ierr = MatSetUpMultiply_MPIAIJ(mat);CHKERRQ(ierr);
529   }
530   ierr = MatSetOption(aij->B,MAT_USE_INODES,PETSC_FALSE);CHKERRQ(ierr);
531   ((Mat_SeqAIJ *)aij->B->data)->compressedrow.use = PETSC_TRUE; /* b->compressedrow.use */
532   ierr = MatAssemblyBegin(aij->B,mode);CHKERRQ(ierr);
533   ierr = MatAssemblyEnd(aij->B,mode);CHKERRQ(ierr);
534 
535   ierr = PetscFree(aij->rowvalues);CHKERRQ(ierr);
536   aij->rowvalues = 0;
537 
538   /* used by MatAXPY() */
539   a->xtoy = 0; ((Mat_SeqAIJ *)aij->B->data)->xtoy = 0;  /* b->xtoy = 0 */
540   a->XtoY = 0; ((Mat_SeqAIJ *)aij->B->data)->XtoY = 0;  /* b->XtoY = 0 */
541 
542   if (aij->diag) {ierr = VecDestroy(aij->diag);CHKERRQ(ierr);aij->diag = 0;}
543   if (a->inode.size) mat->ops->multdiagonalblock = MatMultDiagonalBlock_MPIAIJ;
544   PetscFunctionReturn(0);
545 }
546 
547 #undef __FUNCT__
548 #define __FUNCT__ "MatZeroEntries_MPIAIJ"
549 PetscErrorCode MatZeroEntries_MPIAIJ(Mat A)
550 {
551   Mat_MPIAIJ     *l = (Mat_MPIAIJ*)A->data;
552   PetscErrorCode ierr;
553 
554   PetscFunctionBegin;
555   ierr = MatZeroEntries(l->A);CHKERRQ(ierr);
556   ierr = MatZeroEntries(l->B);CHKERRQ(ierr);
557   PetscFunctionReturn(0);
558 }
559 
560 #undef __FUNCT__
561 #define __FUNCT__ "MatZeroRows_MPIAIJ"
562 PetscErrorCode MatZeroRows_MPIAIJ(Mat A,PetscInt N,const PetscInt rows[],PetscScalar diag)
563 {
564   Mat_MPIAIJ     *l = (Mat_MPIAIJ*)A->data;
565   PetscErrorCode ierr;
566   PetscMPIInt    size = l->size,imdex,n,rank = l->rank,tag = ((PetscObject)A)->tag,lastidx = -1;
567   PetscInt       i,*owners = A->rmap->range;
568   PetscInt       *nprocs,j,idx,nsends,row;
569   PetscInt       nmax,*svalues,*starts,*owner,nrecvs;
570   PetscInt       *rvalues,count,base,slen,*source;
571   PetscInt       *lens,*lrows,*values,rstart=A->rmap->rstart;
572   MPI_Comm       comm = ((PetscObject)A)->comm;
573   MPI_Request    *send_waits,*recv_waits;
574   MPI_Status     recv_status,*send_status;
575 #if defined(PETSC_DEBUG)
576   PetscTruth     found = PETSC_FALSE;
577 #endif
578 
579   PetscFunctionBegin;
580   /*  first count number of contributors to each processor */
581   ierr = PetscMalloc(2*size*sizeof(PetscInt),&nprocs);CHKERRQ(ierr);
582   ierr = PetscMemzero(nprocs,2*size*sizeof(PetscInt));CHKERRQ(ierr);
583   ierr = PetscMalloc((N+1)*sizeof(PetscInt),&owner);CHKERRQ(ierr); /* see note*/
584   j = 0;
585   for (i=0; i<N; i++) {
586     if (lastidx > (idx = rows[i])) j = 0;
587     lastidx = idx;
588     for (; j<size; j++) {
589       if (idx >= owners[j] && idx < owners[j+1]) {
590         nprocs[2*j]++;
591         nprocs[2*j+1] = 1;
592         owner[i] = j;
593 #if defined(PETSC_DEBUG)
594         found = PETSC_TRUE;
595 #endif
596         break;
597       }
598     }
599 #if defined(PETSC_DEBUG)
600     if (!found) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Index out of range");
601     found = PETSC_FALSE;
602 #endif
603   }
604   nsends = 0;  for (i=0; i<size; i++) { nsends += nprocs[2*i+1];}
605 
606   /* inform other processors of number of messages and max length*/
607   ierr = PetscMaxSum(comm,nprocs,&nmax,&nrecvs);CHKERRQ(ierr);
608 
609   /* post receives:   */
610   ierr = PetscMalloc((nrecvs+1)*(nmax+1)*sizeof(PetscInt),&rvalues);CHKERRQ(ierr);
611   ierr = PetscMalloc((nrecvs+1)*sizeof(MPI_Request),&recv_waits);CHKERRQ(ierr);
612   for (i=0; i<nrecvs; i++) {
613     ierr = MPI_Irecv(rvalues+nmax*i,nmax,MPIU_INT,MPI_ANY_SOURCE,tag,comm,recv_waits+i);CHKERRQ(ierr);
614   }
615 
616   /* do sends:
617       1) starts[i] gives the starting index in svalues for stuff going to
618          the ith processor
619   */
620   ierr = PetscMalloc((N+1)*sizeof(PetscInt),&svalues);CHKERRQ(ierr);
621   ierr = PetscMalloc((nsends+1)*sizeof(MPI_Request),&send_waits);CHKERRQ(ierr);
622   ierr = PetscMalloc((size+1)*sizeof(PetscInt),&starts);CHKERRQ(ierr);
623   starts[0] = 0;
624   for (i=1; i<size; i++) { starts[i] = starts[i-1] + nprocs[2*i-2];}
625   for (i=0; i<N; i++) {
626     svalues[starts[owner[i]]++] = rows[i];
627   }
628 
629   starts[0] = 0;
630   for (i=1; i<size+1; i++) { starts[i] = starts[i-1] + nprocs[2*i-2];}
631   count = 0;
632   for (i=0; i<size; i++) {
633     if (nprocs[2*i+1]) {
634       ierr = MPI_Isend(svalues+starts[i],nprocs[2*i],MPIU_INT,i,tag,comm,send_waits+count++);CHKERRQ(ierr);
635     }
636   }
637   ierr = PetscFree(starts);CHKERRQ(ierr);
638 
639   base = owners[rank];
640 
641   /*  wait on receives */
642   ierr   = PetscMalloc(2*(nrecvs+1)*sizeof(PetscInt),&lens);CHKERRQ(ierr);
643   source = lens + nrecvs;
644   count  = nrecvs; slen = 0;
645   while (count) {
646     ierr = MPI_Waitany(nrecvs,recv_waits,&imdex,&recv_status);CHKERRQ(ierr);
647     /* unpack receives into our local space */
648     ierr = MPI_Get_count(&recv_status,MPIU_INT,&n);CHKERRQ(ierr);
649     source[imdex]  = recv_status.MPI_SOURCE;
650     lens[imdex]    = n;
651     slen          += n;
652     count--;
653   }
654   ierr = PetscFree(recv_waits);CHKERRQ(ierr);
655 
656   /* move the data into the send scatter */
657   ierr = PetscMalloc((slen+1)*sizeof(PetscInt),&lrows);CHKERRQ(ierr);
658   count = 0;
659   for (i=0; i<nrecvs; i++) {
660     values = rvalues + i*nmax;
661     for (j=0; j<lens[i]; j++) {
662       lrows[count++] = values[j] - base;
663     }
664   }
665   ierr = PetscFree(rvalues);CHKERRQ(ierr);
666   ierr = PetscFree(lens);CHKERRQ(ierr);
667   ierr = PetscFree(owner);CHKERRQ(ierr);
668   ierr = PetscFree(nprocs);CHKERRQ(ierr);
669 
670   /* actually zap the local rows */
671   /*
672         Zero the required rows. If the "diagonal block" of the matrix
673      is square and the user wishes to set the diagonal we use separate
674      code so that MatSetValues() is not called for each diagonal allocating
675      new memory, thus calling lots of mallocs and slowing things down.
676 
677        Contributed by: Matthew Knepley
678   */
679   /* must zero l->B before l->A because the (diag) case below may put values into l->B*/
680   ierr = MatZeroRows(l->B,slen,lrows,0.0);CHKERRQ(ierr);
681   if ((diag != 0.0) && (l->A->rmap->N == l->A->cmap->N)) {
682     ierr      = MatZeroRows(l->A,slen,lrows,diag);CHKERRQ(ierr);
683   } else if (diag != 0.0) {
684     ierr = MatZeroRows(l->A,slen,lrows,0.0);CHKERRQ(ierr);
685     if (((Mat_SeqAIJ*)l->A->data)->nonew) {
686       SETERRQ(PETSC_ERR_SUP,"MatZeroRows() on rectangular matrices cannot be used with the Mat options\n\
687 MAT_NEW_NONZERO_LOCATIONS,MAT_NEW_NONZERO_LOCATION_ERR,MAT_NEW_NONZERO_ALLOCATION_ERR");
688     }
689     for (i = 0; i < slen; i++) {
690       row  = lrows[i] + rstart;
691       ierr = MatSetValues(A,1,&row,1,&row,&diag,INSERT_VALUES);CHKERRQ(ierr);
692     }
693     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
694     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
695   } else {
696     ierr = MatZeroRows(l->A,slen,lrows,0.0);CHKERRQ(ierr);
697   }
698   ierr = PetscFree(lrows);CHKERRQ(ierr);
699 
700   /* wait on sends */
701   if (nsends) {
702     ierr = PetscMalloc(nsends*sizeof(MPI_Status),&send_status);CHKERRQ(ierr);
703     ierr = MPI_Waitall(nsends,send_waits,send_status);CHKERRQ(ierr);
704     ierr = PetscFree(send_status);CHKERRQ(ierr);
705   }
706   ierr = PetscFree(send_waits);CHKERRQ(ierr);
707   ierr = PetscFree(svalues);CHKERRQ(ierr);
708 
709   PetscFunctionReturn(0);
710 }
711 
712 #undef __FUNCT__
713 #define __FUNCT__ "MatMult_MPIAIJ"
714 PetscErrorCode MatMult_MPIAIJ(Mat A,Vec xx,Vec yy)
715 {
716   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
717   PetscErrorCode ierr;
718   PetscInt       nt;
719 
720   PetscFunctionBegin;
721   ierr = VecGetLocalSize(xx,&nt);CHKERRQ(ierr);
722   if (nt != A->cmap->n) {
723     SETERRQ2(PETSC_ERR_ARG_SIZ,"Incompatible partition of A (%D) and xx (%D)",A->cmap->n,nt);
724   }
725   ierr = VecScatterBegin(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
726   ierr = (*a->A->ops->mult)(a->A,xx,yy);CHKERRQ(ierr);
727   ierr = VecScatterEnd(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
728   ierr = (*a->B->ops->multadd)(a->B,a->lvec,yy,yy);CHKERRQ(ierr);
729   PetscFunctionReturn(0);
730 }
731 
732 #undef __FUNCT__
733 #define __FUNCT__ "MatMultDiagonalBlock_MPIAIJ"
734 PetscErrorCode MatMultDiagonalBlock_MPIAIJ(Mat A,Vec bb,Vec xx)
735 {
736   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
737   PetscErrorCode ierr;
738 
739   PetscFunctionBegin;
740   ierr = MatMultDiagonalBlock(a->A,bb,xx);CHKERRQ(ierr);
741   PetscFunctionReturn(0);
742 }
743 
744 #undef __FUNCT__
745 #define __FUNCT__ "MatMultAdd_MPIAIJ"
746 PetscErrorCode MatMultAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
747 {
748   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
749   PetscErrorCode ierr;
750 
751   PetscFunctionBegin;
752   ierr = VecScatterBegin(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
753   ierr = (*a->A->ops->multadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
754   ierr = VecScatterEnd(a->Mvctx,xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
755   ierr = (*a->B->ops->multadd)(a->B,a->lvec,zz,zz);CHKERRQ(ierr);
756   PetscFunctionReturn(0);
757 }
758 
759 #undef __FUNCT__
760 #define __FUNCT__ "MatMultTranspose_MPIAIJ"
761 PetscErrorCode MatMultTranspose_MPIAIJ(Mat A,Vec xx,Vec yy)
762 {
763   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
764   PetscErrorCode ierr;
765   PetscTruth     merged;
766 
767   PetscFunctionBegin;
768   ierr = VecScatterGetMerged(a->Mvctx,&merged);CHKERRQ(ierr);
769   /* do nondiagonal part */
770   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
771   if (!merged) {
772     /* send it on its way */
773     ierr = VecScatterBegin(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
774     /* do local part */
775     ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
776     /* receive remote parts: note this assumes the values are not actually */
777     /* added in yy until the next line, */
778     ierr = VecScatterEnd(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
779   } else {
780     /* do local part */
781     ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
782     /* send it on its way */
783     ierr = VecScatterBegin(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
784     /* values actually were received in the Begin() but we need to call this nop */
785     ierr = VecScatterEnd(a->Mvctx,a->lvec,yy,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
786   }
787   PetscFunctionReturn(0);
788 }
789 
790 EXTERN_C_BEGIN
791 #undef __FUNCT__
792 #define __FUNCT__ "MatIsTranspose_MPIAIJ"
793 PetscErrorCode PETSCMAT_DLLEXPORT MatIsTranspose_MPIAIJ(Mat Amat,Mat Bmat,PetscReal tol,PetscTruth *f)
794 {
795   MPI_Comm       comm;
796   Mat_MPIAIJ     *Aij = (Mat_MPIAIJ *) Amat->data, *Bij;
797   Mat            Adia = Aij->A, Bdia, Aoff,Boff,*Aoffs,*Boffs;
798   IS             Me,Notme;
799   PetscErrorCode ierr;
800   PetscInt       M,N,first,last,*notme,i;
801   PetscMPIInt    size;
802 
803   PetscFunctionBegin;
804 
805   /* Easy test: symmetric diagonal block */
806   Bij = (Mat_MPIAIJ *) Bmat->data; Bdia = Bij->A;
807   ierr = MatIsTranspose(Adia,Bdia,tol,f);CHKERRQ(ierr);
808   if (!*f) PetscFunctionReturn(0);
809   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
810   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
811   if (size == 1) PetscFunctionReturn(0);
812 
813   /* Hard test: off-diagonal block. This takes a MatGetSubMatrix. */
814   ierr = MatGetSize(Amat,&M,&N);CHKERRQ(ierr);
815   ierr = MatGetOwnershipRange(Amat,&first,&last);CHKERRQ(ierr);
816   ierr = PetscMalloc((N-last+first)*sizeof(PetscInt),&notme);CHKERRQ(ierr);
817   for (i=0; i<first; i++) notme[i] = i;
818   for (i=last; i<M; i++) notme[i-last+first] = i;
819   ierr = ISCreateGeneral(MPI_COMM_SELF,N-last+first,notme,&Notme);CHKERRQ(ierr);
820   ierr = ISCreateStride(MPI_COMM_SELF,last-first,first,1,&Me);CHKERRQ(ierr);
821   ierr = MatGetSubMatrices(Amat,1,&Me,&Notme,MAT_INITIAL_MATRIX,&Aoffs);CHKERRQ(ierr);
822   Aoff = Aoffs[0];
823   ierr = MatGetSubMatrices(Bmat,1,&Notme,&Me,MAT_INITIAL_MATRIX,&Boffs);CHKERRQ(ierr);
824   Boff = Boffs[0];
825   ierr = MatIsTranspose(Aoff,Boff,tol,f);CHKERRQ(ierr);
826   ierr = MatDestroyMatrices(1,&Aoffs);CHKERRQ(ierr);
827   ierr = MatDestroyMatrices(1,&Boffs);CHKERRQ(ierr);
828   ierr = ISDestroy(Me);CHKERRQ(ierr);
829   ierr = ISDestroy(Notme);CHKERRQ(ierr);
830 
831   PetscFunctionReturn(0);
832 }
833 EXTERN_C_END
834 
835 #undef __FUNCT__
836 #define __FUNCT__ "MatMultTransposeAdd_MPIAIJ"
837 PetscErrorCode MatMultTransposeAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
838 {
839   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
840   PetscErrorCode ierr;
841 
842   PetscFunctionBegin;
843   /* do nondiagonal part */
844   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
845   /* send it on its way */
846   ierr = VecScatterBegin(a->Mvctx,a->lvec,zz,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
847   /* do local part */
848   ierr = (*a->A->ops->multtransposeadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
849   /* receive remote parts */
850   ierr = VecScatterEnd(a->Mvctx,a->lvec,zz,ADD_VALUES,SCATTER_REVERSE);CHKERRQ(ierr);
851   PetscFunctionReturn(0);
852 }
853 
854 /*
855   This only works correctly for square matrices where the subblock A->A is the
856    diagonal block
857 */
858 #undef __FUNCT__
859 #define __FUNCT__ "MatGetDiagonal_MPIAIJ"
860 PetscErrorCode MatGetDiagonal_MPIAIJ(Mat A,Vec v)
861 {
862   PetscErrorCode ierr;
863   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
864 
865   PetscFunctionBegin;
866   if (A->rmap->N != A->cmap->N) SETERRQ(PETSC_ERR_SUP,"Supports only square matrix where A->A is diag block");
867   if (A->rmap->rstart != A->cmap->rstart || A->rmap->rend != A->cmap->rend) {
868     SETERRQ(PETSC_ERR_ARG_SIZ,"row partition must equal col partition");
869   }
870   ierr = MatGetDiagonal(a->A,v);CHKERRQ(ierr);
871   PetscFunctionReturn(0);
872 }
873 
874 #undef __FUNCT__
875 #define __FUNCT__ "MatScale_MPIAIJ"
876 PetscErrorCode MatScale_MPIAIJ(Mat A,PetscScalar aa)
877 {
878   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
879   PetscErrorCode ierr;
880 
881   PetscFunctionBegin;
882   ierr = MatScale(a->A,aa);CHKERRQ(ierr);
883   ierr = MatScale(a->B,aa);CHKERRQ(ierr);
884   PetscFunctionReturn(0);
885 }
886 
887 #undef __FUNCT__
888 #define __FUNCT__ "MatDestroy_MPIAIJ"
889 PetscErrorCode MatDestroy_MPIAIJ(Mat mat)
890 {
891   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
892   PetscErrorCode ierr;
893 
894   PetscFunctionBegin;
895 #if defined(PETSC_USE_LOG)
896   PetscLogObjectState((PetscObject)mat,"Rows=%D, Cols=%D",mat->rmap->N,mat->cmap->N);
897 #endif
898   ierr = MatStashDestroy_Private(&mat->stash);CHKERRQ(ierr);
899   if (aij->diag) {ierr = VecDestroy(aij->diag);CHKERRQ(ierr);}
900   ierr = MatDestroy(aij->A);CHKERRQ(ierr);
901   ierr = MatDestroy(aij->B);CHKERRQ(ierr);
902 #if defined (PETSC_USE_CTABLE)
903   if (aij->colmap) {ierr = PetscTableDestroy(aij->colmap);CHKERRQ(ierr);}
904 #else
905   ierr = PetscFree(aij->colmap);CHKERRQ(ierr);
906 #endif
907   ierr = PetscFree(aij->garray);CHKERRQ(ierr);
908   if (aij->lvec)   {ierr = VecDestroy(aij->lvec);CHKERRQ(ierr);}
909   if (aij->Mvctx)  {ierr = VecScatterDestroy(aij->Mvctx);CHKERRQ(ierr);}
910   ierr = PetscFree(aij->rowvalues);CHKERRQ(ierr);
911   ierr = PetscFree(aij->ld);CHKERRQ(ierr);
912   ierr = PetscFree(aij);CHKERRQ(ierr);
913 
914   ierr = PetscObjectChangeTypeName((PetscObject)mat,0);CHKERRQ(ierr);
915   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatStoreValues_C","",PETSC_NULL);CHKERRQ(ierr);
916   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatRetrieveValues_C","",PETSC_NULL);CHKERRQ(ierr);
917   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatGetDiagonalBlock_C","",PETSC_NULL);CHKERRQ(ierr);
918   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatIsTranspose_C","",PETSC_NULL);CHKERRQ(ierr);
919   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMPIAIJSetPreallocation_C","",PETSC_NULL);CHKERRQ(ierr);
920   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatMPIAIJSetPreallocationCSR_C","",PETSC_NULL);CHKERRQ(ierr);
921   ierr = PetscObjectComposeFunction((PetscObject)mat,"MatDiagonalScaleLocal_C","",PETSC_NULL);CHKERRQ(ierr);
922   PetscFunctionReturn(0);
923 }
924 
925 #undef __FUNCT__
926 #define __FUNCT__ "MatView_MPIAIJ_Binary"
927 PetscErrorCode MatView_MPIAIJ_Binary(Mat mat,PetscViewer viewer)
928 {
929   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
930   Mat_SeqAIJ*       A = (Mat_SeqAIJ*)aij->A->data;
931   Mat_SeqAIJ*       B = (Mat_SeqAIJ*)aij->B->data;
932   PetscErrorCode    ierr;
933   PetscMPIInt       rank,size,tag = ((PetscObject)viewer)->tag;
934   int               fd;
935   PetscInt          nz,header[4],*row_lengths,*range=0,rlen,i;
936   PetscInt          nzmax,*column_indices,j,k,col,*garray = aij->garray,cnt,cstart = mat->cmap->rstart,rnz;
937   PetscScalar       *column_values;
938 
939   PetscFunctionBegin;
940   ierr = MPI_Comm_rank(((PetscObject)mat)->comm,&rank);CHKERRQ(ierr);
941   ierr = MPI_Comm_size(((PetscObject)mat)->comm,&size);CHKERRQ(ierr);
942   nz   = A->nz + B->nz;
943   if (!rank) {
944     header[0] = MAT_FILE_COOKIE;
945     header[1] = mat->rmap->N;
946     header[2] = mat->cmap->N;
947     ierr = MPI_Reduce(&nz,&header[3],1,MPIU_INT,MPI_SUM,0,((PetscObject)mat)->comm);CHKERRQ(ierr);
948     ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
949     ierr = PetscBinaryWrite(fd,header,4,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
950     /* get largest number of rows any processor has */
951     rlen = mat->rmap->n;
952     range = mat->rmap->range;
953     for (i=1; i<size; i++) {
954       rlen = PetscMax(rlen,range[i+1] - range[i]);
955     }
956   } else {
957     ierr = MPI_Reduce(&nz,0,1,MPIU_INT,MPI_SUM,0,((PetscObject)mat)->comm);CHKERRQ(ierr);
958     rlen = mat->rmap->n;
959   }
960 
961   /* load up the local row counts */
962   ierr = PetscMalloc((rlen+1)*sizeof(PetscInt),&row_lengths);CHKERRQ(ierr);
963   for (i=0; i<mat->rmap->n; i++) {
964     row_lengths[i] = A->i[i+1] - A->i[i] + B->i[i+1] - B->i[i];
965   }
966 
967   /* store the row lengths to the file */
968   if (!rank) {
969     MPI_Status status;
970     ierr = PetscBinaryWrite(fd,row_lengths,mat->rmap->n,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
971     for (i=1; i<size; i++) {
972       rlen = range[i+1] - range[i];
973       ierr = MPI_Recv(row_lengths,rlen,MPIU_INT,i,tag,((PetscObject)mat)->comm,&status);CHKERRQ(ierr);
974       ierr = PetscBinaryWrite(fd,row_lengths,rlen,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
975     }
976   } else {
977     ierr = MPI_Send(row_lengths,mat->rmap->n,MPIU_INT,0,tag,((PetscObject)mat)->comm);CHKERRQ(ierr);
978   }
979   ierr = PetscFree(row_lengths);CHKERRQ(ierr);
980 
981   /* load up the local column indices */
982   nzmax = nz; /* )th processor needs space a largest processor needs */
983   ierr = MPI_Reduce(&nz,&nzmax,1,MPIU_INT,MPI_MAX,0,((PetscObject)mat)->comm);CHKERRQ(ierr);
984   ierr = PetscMalloc((nzmax+1)*sizeof(PetscInt),&column_indices);CHKERRQ(ierr);
985   cnt  = 0;
986   for (i=0; i<mat->rmap->n; i++) {
987     for (j=B->i[i]; j<B->i[i+1]; j++) {
988       if ( (col = garray[B->j[j]]) > cstart) break;
989       column_indices[cnt++] = col;
990     }
991     for (k=A->i[i]; k<A->i[i+1]; k++) {
992       column_indices[cnt++] = A->j[k] + cstart;
993     }
994     for (; j<B->i[i+1]; j++) {
995       column_indices[cnt++] = garray[B->j[j]];
996     }
997   }
998   if (cnt != A->nz + B->nz) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: cnt = %D nz = %D",cnt,A->nz+B->nz);
999 
1000   /* store the column indices to the file */
1001   if (!rank) {
1002     MPI_Status status;
1003     ierr = PetscBinaryWrite(fd,column_indices,nz,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1004     for (i=1; i<size; i++) {
1005       ierr = MPI_Recv(&rnz,1,MPIU_INT,i,tag,((PetscObject)mat)->comm,&status);CHKERRQ(ierr);
1006       if (rnz > nzmax) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: nz = %D nzmax = %D",nz,nzmax);
1007       ierr = MPI_Recv(column_indices,rnz,MPIU_INT,i,tag,((PetscObject)mat)->comm,&status);CHKERRQ(ierr);
1008       ierr = PetscBinaryWrite(fd,column_indices,rnz,PETSC_INT,PETSC_TRUE);CHKERRQ(ierr);
1009     }
1010   } else {
1011     ierr = MPI_Send(&nz,1,MPIU_INT,0,tag,((PetscObject)mat)->comm);CHKERRQ(ierr);
1012     ierr = MPI_Send(column_indices,nz,MPIU_INT,0,tag,((PetscObject)mat)->comm);CHKERRQ(ierr);
1013   }
1014   ierr = PetscFree(column_indices);CHKERRQ(ierr);
1015 
1016   /* load up the local column values */
1017   ierr = PetscMalloc((nzmax+1)*sizeof(PetscScalar),&column_values);CHKERRQ(ierr);
1018   cnt  = 0;
1019   for (i=0; i<mat->rmap->n; i++) {
1020     for (j=B->i[i]; j<B->i[i+1]; j++) {
1021       if ( garray[B->j[j]] > cstart) break;
1022       column_values[cnt++] = B->a[j];
1023     }
1024     for (k=A->i[i]; k<A->i[i+1]; k++) {
1025       column_values[cnt++] = A->a[k];
1026     }
1027     for (; j<B->i[i+1]; j++) {
1028       column_values[cnt++] = B->a[j];
1029     }
1030   }
1031   if (cnt != A->nz + B->nz) SETERRQ2(PETSC_ERR_PLIB,"Internal PETSc error: cnt = %D nz = %D",cnt,A->nz+B->nz);
1032 
1033   /* store the column values to the file */
1034   if (!rank) {
1035     MPI_Status status;
1036     ierr = PetscBinaryWrite(fd,column_values,nz,PETSC_SCALAR,PETSC_TRUE);CHKERRQ(ierr);
1037     for (i=1; i<size; i++) {
1038       ierr = MPI_Recv(&rnz,1,MPIU_INT,i,tag,((PetscObject)mat)->comm,&status);CHKERRQ(ierr);
1039       if (rnz > nzmax) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: nz = %D nzmax = %D",nz,nzmax);
1040       ierr = MPI_Recv(column_values,rnz,MPIU_SCALAR,i,tag,((PetscObject)mat)->comm,&status);CHKERRQ(ierr);
1041       ierr = PetscBinaryWrite(fd,column_values,rnz,PETSC_SCALAR,PETSC_TRUE);CHKERRQ(ierr);
1042     }
1043   } else {
1044     ierr = MPI_Send(&nz,1,MPIU_INT,0,tag,((PetscObject)mat)->comm);CHKERRQ(ierr);
1045     ierr = MPI_Send(column_values,nz,MPIU_SCALAR,0,tag,((PetscObject)mat)->comm);CHKERRQ(ierr);
1046   }
1047   ierr = PetscFree(column_values);CHKERRQ(ierr);
1048   PetscFunctionReturn(0);
1049 }
1050 
1051 #undef __FUNCT__
1052 #define __FUNCT__ "MatView_MPIAIJ_ASCIIorDraworSocket"
1053 PetscErrorCode MatView_MPIAIJ_ASCIIorDraworSocket(Mat mat,PetscViewer viewer)
1054 {
1055   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
1056   PetscErrorCode    ierr;
1057   PetscMPIInt       rank = aij->rank,size = aij->size;
1058   PetscTruth        isdraw,iascii,isbinary;
1059   PetscViewer       sviewer;
1060   PetscViewerFormat format;
1061 
1062   PetscFunctionBegin;
1063   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_DRAW,&isdraw);CHKERRQ(ierr);
1064   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);CHKERRQ(ierr);
1065   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_BINARY,&isbinary);CHKERRQ(ierr);
1066   if (iascii) {
1067     ierr = PetscViewerGetFormat(viewer,&format);CHKERRQ(ierr);
1068     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
1069       MatInfo    info;
1070       PetscTruth inodes;
1071 
1072       ierr = MPI_Comm_rank(((PetscObject)mat)->comm,&rank);CHKERRQ(ierr);
1073       ierr = MatGetInfo(mat,MAT_LOCAL,&info);CHKERRQ(ierr);
1074       ierr = MatInodeGetInodeSizes(aij->A,PETSC_NULL,(PetscInt **)&inodes,PETSC_NULL);CHKERRQ(ierr);
1075       if (!inodes) {
1076         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %D nz %D nz alloced %D mem %D, not using I-node routines\n",
1077 					      rank,mat->rmap->n,(PetscInt)info.nz_used,(PetscInt)info.nz_allocated,(PetscInt)info.memory);CHKERRQ(ierr);
1078       } else {
1079         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %D nz %D nz alloced %D mem %D, using I-node routines\n",
1080 		    rank,mat->rmap->n,(PetscInt)info.nz_used,(PetscInt)info.nz_allocated,(PetscInt)info.memory);CHKERRQ(ierr);
1081       }
1082       ierr = MatGetInfo(aij->A,MAT_LOCAL,&info);CHKERRQ(ierr);
1083       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] on-diagonal part: nz %D \n",rank,(PetscInt)info.nz_used);CHKERRQ(ierr);
1084       ierr = MatGetInfo(aij->B,MAT_LOCAL,&info);CHKERRQ(ierr);
1085       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] off-diagonal part: nz %D \n",rank,(PetscInt)info.nz_used);CHKERRQ(ierr);
1086       ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
1087       ierr = PetscViewerASCIIPrintf(viewer,"Information on VecScatter used in matrix-vector product: \n");CHKERRQ(ierr);
1088       ierr = VecScatterView(aij->Mvctx,viewer);CHKERRQ(ierr);
1089       PetscFunctionReturn(0);
1090     } else if (format == PETSC_VIEWER_ASCII_INFO) {
1091       PetscInt   inodecount,inodelimit,*inodes;
1092       ierr = MatInodeGetInodeSizes(aij->A,&inodecount,&inodes,&inodelimit);CHKERRQ(ierr);
1093       if (inodes) {
1094         ierr = PetscViewerASCIIPrintf(viewer,"using I-node (on process 0) routines: found %D nodes, limit used is %D\n",inodecount,inodelimit);CHKERRQ(ierr);
1095       } else {
1096         ierr = PetscViewerASCIIPrintf(viewer,"not using I-node (on process 0) routines\n");CHKERRQ(ierr);
1097       }
1098       PetscFunctionReturn(0);
1099     } else if (format == PETSC_VIEWER_ASCII_FACTOR_INFO) {
1100       PetscFunctionReturn(0);
1101     }
1102   } else if (isbinary) {
1103     if (size == 1) {
1104       ierr = PetscObjectSetName((PetscObject)aij->A,((PetscObject)mat)->name);CHKERRQ(ierr);
1105       ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
1106     } else {
1107       ierr = MatView_MPIAIJ_Binary(mat,viewer);CHKERRQ(ierr);
1108     }
1109     PetscFunctionReturn(0);
1110   } else if (isdraw) {
1111     PetscDraw  draw;
1112     PetscTruth isnull;
1113     ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
1114     ierr = PetscDrawIsNull(draw,&isnull);CHKERRQ(ierr); if (isnull) PetscFunctionReturn(0);
1115   }
1116 
1117   if (size == 1) {
1118     ierr = PetscObjectSetName((PetscObject)aij->A,((PetscObject)mat)->name);CHKERRQ(ierr);
1119     ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
1120   } else {
1121     /* assemble the entire matrix onto first processor. */
1122     Mat         A;
1123     Mat_SeqAIJ  *Aloc;
1124     PetscInt    M = mat->rmap->N,N = mat->cmap->N,m,*ai,*aj,row,*cols,i,*ct;
1125     MatScalar   *a;
1126 
1127     if (mat->rmap->N > 1024) {
1128       PetscTruth flg = PETSC_FALSE;
1129 
1130       ierr = PetscOptionsGetTruth(((PetscObject) mat)->prefix, "-mat_ascii_output_large", &flg,PETSC_NULL);CHKERRQ(ierr);
1131       if (!flg) {
1132         SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"ASCII matrix output not allowed for matrices with more than 1024 rows, use binary format instead.\nYou can override this restriction using -mat_ascii_output_large.");
1133       }
1134     }
1135 
1136     ierr = MatCreate(((PetscObject)mat)->comm,&A);CHKERRQ(ierr);
1137     if (!rank) {
1138       ierr = MatSetSizes(A,M,N,M,N);CHKERRQ(ierr);
1139     } else {
1140       ierr = MatSetSizes(A,0,0,M,N);CHKERRQ(ierr);
1141     }
1142     /* This is just a temporary matrix, so explicitly using MATMPIAIJ is probably best */
1143     ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
1144     ierr = MatMPIAIJSetPreallocation(A,0,PETSC_NULL,0,PETSC_NULL);CHKERRQ(ierr);
1145     ierr = PetscLogObjectParent(mat,A);CHKERRQ(ierr);
1146 
1147     /* copy over the A part */
1148     Aloc = (Mat_SeqAIJ*)aij->A->data;
1149     m = aij->A->rmap->n; ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
1150     row = mat->rmap->rstart;
1151     for (i=0; i<ai[m]; i++) {aj[i] += mat->cmap->rstart ;}
1152     for (i=0; i<m; i++) {
1153       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],aj,a,INSERT_VALUES);CHKERRQ(ierr);
1154       row++; a += ai[i+1]-ai[i]; aj += ai[i+1]-ai[i];
1155     }
1156     aj = Aloc->j;
1157     for (i=0; i<ai[m]; i++) {aj[i] -= mat->cmap->rstart;}
1158 
1159     /* copy over the B part */
1160     Aloc = (Mat_SeqAIJ*)aij->B->data;
1161     m    = aij->B->rmap->n;  ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
1162     row  = mat->rmap->rstart;
1163     ierr = PetscMalloc((ai[m]+1)*sizeof(PetscInt),&cols);CHKERRQ(ierr);
1164     ct   = cols;
1165     for (i=0; i<ai[m]; i++) {cols[i] = aij->garray[aj[i]];}
1166     for (i=0; i<m; i++) {
1167       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],cols,a,INSERT_VALUES);CHKERRQ(ierr);
1168       row++; a += ai[i+1]-ai[i]; cols += ai[i+1]-ai[i];
1169     }
1170     ierr = PetscFree(ct);CHKERRQ(ierr);
1171     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1172     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1173     /*
1174        Everyone has to call to draw the matrix since the graphics waits are
1175        synchronized across all processors that share the PetscDraw object
1176     */
1177     ierr = PetscViewerGetSingleton(viewer,&sviewer);CHKERRQ(ierr);
1178     if (!rank) {
1179       ierr = PetscObjectSetName((PetscObject)((Mat_MPIAIJ*)(A->data))->A,((PetscObject)mat)->name);CHKERRQ(ierr);
1180       ierr = MatView(((Mat_MPIAIJ*)(A->data))->A,sviewer);CHKERRQ(ierr);
1181     }
1182     ierr = PetscViewerRestoreSingleton(viewer,&sviewer);CHKERRQ(ierr);
1183     ierr = MatDestroy(A);CHKERRQ(ierr);
1184   }
1185   PetscFunctionReturn(0);
1186 }
1187 
1188 #undef __FUNCT__
1189 #define __FUNCT__ "MatView_MPIAIJ"
1190 PetscErrorCode MatView_MPIAIJ(Mat mat,PetscViewer viewer)
1191 {
1192   PetscErrorCode ierr;
1193   PetscTruth     iascii,isdraw,issocket,isbinary;
1194 
1195   PetscFunctionBegin;
1196   ierr  = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);CHKERRQ(ierr);
1197   ierr  = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_DRAW,&isdraw);CHKERRQ(ierr);
1198   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_BINARY,&isbinary);CHKERRQ(ierr);
1199   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_SOCKET,&issocket);CHKERRQ(ierr);
1200   if (iascii || isdraw || isbinary || issocket) {
1201     ierr = MatView_MPIAIJ_ASCIIorDraworSocket(mat,viewer);CHKERRQ(ierr);
1202   } else {
1203     SETERRQ1(PETSC_ERR_SUP,"Viewer type %s not supported by MPIAIJ matrices",((PetscObject)viewer)->type_name);
1204   }
1205   PetscFunctionReturn(0);
1206 }
1207 
1208 #undef __FUNCT__
1209 #define __FUNCT__ "MatRelax_MPIAIJ"
1210 PetscErrorCode MatRelax_MPIAIJ(Mat matin,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,PetscInt its,PetscInt lits,Vec xx)
1211 {
1212   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1213   PetscErrorCode ierr;
1214   Vec            bb1 = 0;
1215   PetscTruth     hasop;
1216 
1217   PetscFunctionBegin;
1218   if (its > 1 || ~flag & SOR_ZERO_INITIAL_GUESS || flag & SOR_EISENSTAT) {
1219     ierr = VecDuplicate(bb,&bb1);CHKERRQ(ierr);
1220   }
1221 
1222   if ((flag & SOR_LOCAL_SYMMETRIC_SWEEP) == SOR_LOCAL_SYMMETRIC_SWEEP){
1223     if (flag & SOR_ZERO_INITIAL_GUESS) {
1224       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1225       its--;
1226     }
1227 
1228     while (its--) {
1229       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1230       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1231 
1232       /* update rhs: bb1 = bb - B*x */
1233       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1234       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1235 
1236       /* local sweep */
1237       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_SYMMETRIC_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1238     }
1239   } else if (flag & SOR_LOCAL_FORWARD_SWEEP){
1240     if (flag & SOR_ZERO_INITIAL_GUESS) {
1241       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1242       its--;
1243     }
1244     while (its--) {
1245       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1246       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1247 
1248       /* update rhs: bb1 = bb - B*x */
1249       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1250       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1251 
1252       /* local sweep */
1253       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_FORWARD_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1254     }
1255   } else if (flag & SOR_LOCAL_BACKWARD_SWEEP){
1256     if (flag & SOR_ZERO_INITIAL_GUESS) {
1257       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,1,xx);CHKERRQ(ierr);
1258       its--;
1259     }
1260     while (its--) {
1261       ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1262       ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1263 
1264       /* update rhs: bb1 = bb - B*x */
1265       ierr = VecScale(mat->lvec,-1.0);CHKERRQ(ierr);
1266       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1267 
1268       /* local sweep */
1269       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_BACKWARD_SWEEP,fshift,lits,1,xx);CHKERRQ(ierr);
1270     }
1271   }  else if (flag & SOR_EISENSTAT) {
1272     Vec         xx1;
1273 
1274     ierr = VecDuplicate(bb,&xx1);CHKERRQ(ierr);
1275     ierr = (*mat->A->ops->relax)(mat->A,bb,omega,(MatSORType)(SOR_ZERO_INITIAL_GUESS | SOR_LOCAL_BACKWARD_SWEEP),fshift,lits,1,xx);CHKERRQ(ierr);
1276 
1277     ierr = VecScatterBegin(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1278     ierr = VecScatterEnd(mat->Mvctx,xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1279     if (!mat->diag) {
1280       ierr = MatGetVecs(matin,&mat->diag,PETSC_NULL);CHKERRQ(ierr);
1281       ierr = MatGetDiagonal(matin,mat->diag);CHKERRQ(ierr);
1282     }
1283     ierr = MatHasOperation(matin,MATOP_MULT_DIAGONAL_BLOCK,&hasop);CHKERRQ(ierr);
1284     if (hasop) {
1285       ierr = MatMultDiagonalBlock(matin,xx,bb1);CHKERRQ(ierr);
1286     } else {
1287       ierr = VecPointwiseMult(bb1,mat->diag,xx);CHKERRQ(ierr);
1288     }
1289     ierr = VecWAXPY(bb1,-1.0,bb1,bb);CHKERRQ(ierr);
1290     ierr = MatMultAdd(mat->B,mat->lvec,bb1,bb1);CHKERRQ(ierr);
1291 
1292     /* local sweep */
1293     ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,(MatSORType)(SOR_ZERO_INITIAL_GUESS | SOR_LOCAL_FORWARD_SWEEP),fshift,lits,1,xx1);CHKERRQ(ierr);
1294     ierr = VecAXPY(xx,1.0,xx1);CHKERRQ(ierr);
1295     ierr = VecDestroy(xx1);CHKERRQ(ierr);
1296   } else {
1297     SETERRQ(PETSC_ERR_SUP,"Parallel SOR not supported");
1298   }
1299 
1300   if (bb1) {ierr = VecDestroy(bb1);CHKERRQ(ierr);}
1301   PetscFunctionReturn(0);
1302 }
1303 
1304 #undef __FUNCT__
1305 #define __FUNCT__ "MatPermute_MPIAIJ"
1306 PetscErrorCode MatPermute_MPIAIJ(Mat A,IS rowp,IS colp,Mat *B)
1307 {
1308   MPI_Comm       comm,pcomm;
1309   PetscInt       first,local_size,nrows;
1310   const PetscInt *rows;
1311   PetscMPIInt    size;
1312   IS             crowp,growp,irowp,lrowp,lcolp,icolp;
1313   PetscErrorCode ierr;
1314 
1315   PetscFunctionBegin;
1316   ierr = PetscObjectGetComm((PetscObject)A,&comm);CHKERRQ(ierr);
1317   /* make a collective version of 'rowp' */
1318   ierr = PetscObjectGetComm((PetscObject)rowp,&pcomm);CHKERRQ(ierr);
1319   if (pcomm==comm) {
1320     crowp = rowp;
1321   } else {
1322     ierr = ISGetSize(rowp,&nrows);CHKERRQ(ierr);
1323     ierr = ISGetIndices(rowp,&rows);CHKERRQ(ierr);
1324     ierr = ISCreateGeneral(comm,nrows,rows,&crowp);CHKERRQ(ierr);
1325     ierr = ISRestoreIndices(rowp,&rows);CHKERRQ(ierr);
1326   }
1327   /* collect the global row permutation and invert it */
1328   ierr = ISAllGather(crowp,&growp);CHKERRQ(ierr);
1329   ierr = ISSetPermutation(growp);CHKERRQ(ierr);
1330   if (pcomm!=comm) {
1331     ierr = ISDestroy(crowp);CHKERRQ(ierr);
1332   }
1333   ierr = ISInvertPermutation(growp,PETSC_DECIDE,&irowp);CHKERRQ(ierr);
1334   /* get the local target indices */
1335   ierr = MatGetOwnershipRange(A,&first,PETSC_NULL);CHKERRQ(ierr);
1336   ierr = MatGetLocalSize(A,&local_size,PETSC_NULL);CHKERRQ(ierr);
1337   ierr = ISGetIndices(irowp,&rows);CHKERRQ(ierr);
1338   ierr = ISCreateGeneral(MPI_COMM_SELF,local_size,rows+first,&lrowp);CHKERRQ(ierr);
1339   ierr = ISRestoreIndices(irowp,&rows);CHKERRQ(ierr);
1340   ierr = ISDestroy(irowp);CHKERRQ(ierr);
1341   /* the column permutation is so much easier;
1342      make a local version of 'colp' and invert it */
1343   ierr = PetscObjectGetComm((PetscObject)colp,&pcomm);CHKERRQ(ierr);
1344   ierr = MPI_Comm_size(pcomm,&size);CHKERRQ(ierr);
1345   if (size==1) {
1346     lcolp = colp;
1347   } else {
1348     ierr = ISGetSize(colp,&nrows);CHKERRQ(ierr);
1349     ierr = ISGetIndices(colp,&rows);CHKERRQ(ierr);
1350     ierr = ISCreateGeneral(MPI_COMM_SELF,nrows,rows,&lcolp);CHKERRQ(ierr);
1351   }
1352   ierr = ISSetPermutation(lcolp);CHKERRQ(ierr);
1353   ierr = ISInvertPermutation(lcolp,PETSC_DECIDE,&icolp);CHKERRQ(ierr);
1354   ierr = ISSetPermutation(icolp);CHKERRQ(ierr);
1355   if (size>1) {
1356     ierr = ISRestoreIndices(colp,&rows);CHKERRQ(ierr);
1357     ierr = ISDestroy(lcolp);CHKERRQ(ierr);
1358   }
1359   /* now we just get the submatrix */
1360   ierr = MatGetSubMatrix_MPIAIJ_Private(A,lrowp,icolp,local_size,MAT_INITIAL_MATRIX,B);CHKERRQ(ierr);
1361   /* clean up */
1362   ierr = ISDestroy(lrowp);CHKERRQ(ierr);
1363   ierr = ISDestroy(icolp);CHKERRQ(ierr);
1364   PetscFunctionReturn(0);
1365 }
1366 
1367 #undef __FUNCT__
1368 #define __FUNCT__ "MatGetInfo_MPIAIJ"
1369 PetscErrorCode MatGetInfo_MPIAIJ(Mat matin,MatInfoType flag,MatInfo *info)
1370 {
1371   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1372   Mat            A = mat->A,B = mat->B;
1373   PetscErrorCode ierr;
1374   PetscReal      isend[5],irecv[5];
1375 
1376   PetscFunctionBegin;
1377   info->block_size     = 1.0;
1378   ierr = MatGetInfo(A,MAT_LOCAL,info);CHKERRQ(ierr);
1379   isend[0] = info->nz_used; isend[1] = info->nz_allocated; isend[2] = info->nz_unneeded;
1380   isend[3] = info->memory;  isend[4] = info->mallocs;
1381   ierr = MatGetInfo(B,MAT_LOCAL,info);CHKERRQ(ierr);
1382   isend[0] += info->nz_used; isend[1] += info->nz_allocated; isend[2] += info->nz_unneeded;
1383   isend[3] += info->memory;  isend[4] += info->mallocs;
1384   if (flag == MAT_LOCAL) {
1385     info->nz_used      = isend[0];
1386     info->nz_allocated = isend[1];
1387     info->nz_unneeded  = isend[2];
1388     info->memory       = isend[3];
1389     info->mallocs      = isend[4];
1390   } else if (flag == MAT_GLOBAL_MAX) {
1391     ierr = MPI_Allreduce(isend,irecv,5,MPIU_REAL,MPI_MAX,((PetscObject)matin)->comm);CHKERRQ(ierr);
1392     info->nz_used      = irecv[0];
1393     info->nz_allocated = irecv[1];
1394     info->nz_unneeded  = irecv[2];
1395     info->memory       = irecv[3];
1396     info->mallocs      = irecv[4];
1397   } else if (flag == MAT_GLOBAL_SUM) {
1398     ierr = MPI_Allreduce(isend,irecv,5,MPIU_REAL,MPI_SUM,((PetscObject)matin)->comm);CHKERRQ(ierr);
1399     info->nz_used      = irecv[0];
1400     info->nz_allocated = irecv[1];
1401     info->nz_unneeded  = irecv[2];
1402     info->memory       = irecv[3];
1403     info->mallocs      = irecv[4];
1404   }
1405   info->fill_ratio_given  = 0; /* no parallel LU/ILU/Cholesky */
1406   info->fill_ratio_needed = 0;
1407   info->factor_mallocs    = 0;
1408 
1409   PetscFunctionReturn(0);
1410 }
1411 
1412 #undef __FUNCT__
1413 #define __FUNCT__ "MatSetOption_MPIAIJ"
1414 PetscErrorCode MatSetOption_MPIAIJ(Mat A,MatOption op,PetscTruth flg)
1415 {
1416   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1417   PetscErrorCode ierr;
1418 
1419   PetscFunctionBegin;
1420   switch (op) {
1421   case MAT_NEW_NONZERO_LOCATIONS:
1422   case MAT_NEW_NONZERO_ALLOCATION_ERR:
1423   case MAT_UNUSED_NONZERO_LOCATION_ERR:
1424   case MAT_KEEP_NONZERO_PATTERN:
1425   case MAT_NEW_NONZERO_LOCATION_ERR:
1426   case MAT_USE_INODES:
1427   case MAT_IGNORE_ZERO_ENTRIES:
1428     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1429     ierr = MatSetOption(a->B,op,flg);CHKERRQ(ierr);
1430     break;
1431   case MAT_ROW_ORIENTED:
1432     a->roworiented = flg;
1433     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1434     ierr = MatSetOption(a->B,op,flg);CHKERRQ(ierr);
1435     break;
1436   case MAT_NEW_DIAGONALS:
1437     ierr = PetscInfo1(A,"Option %s ignored\n",MatOptions[op]);CHKERRQ(ierr);
1438     break;
1439   case MAT_IGNORE_OFF_PROC_ENTRIES:
1440     a->donotstash = PETSC_TRUE;
1441     break;
1442   case MAT_SYMMETRIC:
1443     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1444     break;
1445   case MAT_STRUCTURALLY_SYMMETRIC:
1446   case MAT_HERMITIAN:
1447   case MAT_SYMMETRY_ETERNAL:
1448     ierr = MatSetOption(a->A,op,flg);CHKERRQ(ierr);
1449     break;
1450   default:
1451     SETERRQ1(PETSC_ERR_SUP,"unknown option %d",op);
1452   }
1453   PetscFunctionReturn(0);
1454 }
1455 
1456 #undef __FUNCT__
1457 #define __FUNCT__ "MatGetRow_MPIAIJ"
1458 PetscErrorCode MatGetRow_MPIAIJ(Mat matin,PetscInt row,PetscInt *nz,PetscInt **idx,PetscScalar **v)
1459 {
1460   Mat_MPIAIJ     *mat = (Mat_MPIAIJ*)matin->data;
1461   PetscScalar    *vworkA,*vworkB,**pvA,**pvB,*v_p;
1462   PetscErrorCode ierr;
1463   PetscInt       i,*cworkA,*cworkB,**pcA,**pcB,cstart = matin->cmap->rstart;
1464   PetscInt       nztot,nzA,nzB,lrow,rstart = matin->rmap->rstart,rend = matin->rmap->rend;
1465   PetscInt       *cmap,*idx_p;
1466 
1467   PetscFunctionBegin;
1468   if (mat->getrowactive) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Already active");
1469   mat->getrowactive = PETSC_TRUE;
1470 
1471   if (!mat->rowvalues && (idx || v)) {
1472     /*
1473         allocate enough space to hold information from the longest row.
1474     */
1475     Mat_SeqAIJ *Aa = (Mat_SeqAIJ*)mat->A->data,*Ba = (Mat_SeqAIJ*)mat->B->data;
1476     PetscInt     max = 1,tmp;
1477     for (i=0; i<matin->rmap->n; i++) {
1478       tmp = Aa->i[i+1] - Aa->i[i] + Ba->i[i+1] - Ba->i[i];
1479       if (max < tmp) { max = tmp; }
1480     }
1481     ierr = PetscMalloc(max*(sizeof(PetscInt)+sizeof(PetscScalar)),&mat->rowvalues);CHKERRQ(ierr);
1482     mat->rowindices = (PetscInt*)(mat->rowvalues + max);
1483   }
1484 
1485   if (row < rstart || row >= rend) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Only local rows")
1486   lrow = row - rstart;
1487 
1488   pvA = &vworkA; pcA = &cworkA; pvB = &vworkB; pcB = &cworkB;
1489   if (!v)   {pvA = 0; pvB = 0;}
1490   if (!idx) {pcA = 0; if (!v) pcB = 0;}
1491   ierr = (*mat->A->ops->getrow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1492   ierr = (*mat->B->ops->getrow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1493   nztot = nzA + nzB;
1494 
1495   cmap  = mat->garray;
1496   if (v  || idx) {
1497     if (nztot) {
1498       /* Sort by increasing column numbers, assuming A and B already sorted */
1499       PetscInt imark = -1;
1500       if (v) {
1501         *v = v_p = mat->rowvalues;
1502         for (i=0; i<nzB; i++) {
1503           if (cmap[cworkB[i]] < cstart)   v_p[i] = vworkB[i];
1504           else break;
1505         }
1506         imark = i;
1507         for (i=0; i<nzA; i++)     v_p[imark+i] = vworkA[i];
1508         for (i=imark; i<nzB; i++) v_p[nzA+i]   = vworkB[i];
1509       }
1510       if (idx) {
1511         *idx = idx_p = mat->rowindices;
1512         if (imark > -1) {
1513           for (i=0; i<imark; i++) {
1514             idx_p[i] = cmap[cworkB[i]];
1515           }
1516         } else {
1517           for (i=0; i<nzB; i++) {
1518             if (cmap[cworkB[i]] < cstart)   idx_p[i] = cmap[cworkB[i]];
1519             else break;
1520           }
1521           imark = i;
1522         }
1523         for (i=0; i<nzA; i++)     idx_p[imark+i] = cstart + cworkA[i];
1524         for (i=imark; i<nzB; i++) idx_p[nzA+i]   = cmap[cworkB[i]];
1525       }
1526     } else {
1527       if (idx) *idx = 0;
1528       if (v)   *v   = 0;
1529     }
1530   }
1531   *nz = nztot;
1532   ierr = (*mat->A->ops->restorerow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1533   ierr = (*mat->B->ops->restorerow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1534   PetscFunctionReturn(0);
1535 }
1536 
1537 #undef __FUNCT__
1538 #define __FUNCT__ "MatRestoreRow_MPIAIJ"
1539 PetscErrorCode MatRestoreRow_MPIAIJ(Mat mat,PetscInt row,PetscInt *nz,PetscInt **idx,PetscScalar **v)
1540 {
1541   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1542 
1543   PetscFunctionBegin;
1544   if (!aij->getrowactive) {
1545     SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"MatGetRow() must be called first");
1546   }
1547   aij->getrowactive = PETSC_FALSE;
1548   PetscFunctionReturn(0);
1549 }
1550 
1551 #undef __FUNCT__
1552 #define __FUNCT__ "MatNorm_MPIAIJ"
1553 PetscErrorCode MatNorm_MPIAIJ(Mat mat,NormType type,PetscReal *norm)
1554 {
1555   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1556   Mat_SeqAIJ     *amat = (Mat_SeqAIJ*)aij->A->data,*bmat = (Mat_SeqAIJ*)aij->B->data;
1557   PetscErrorCode ierr;
1558   PetscInt       i,j,cstart = mat->cmap->rstart;
1559   PetscReal      sum = 0.0;
1560   MatScalar      *v;
1561 
1562   PetscFunctionBegin;
1563   if (aij->size == 1) {
1564     ierr =  MatNorm(aij->A,type,norm);CHKERRQ(ierr);
1565   } else {
1566     if (type == NORM_FROBENIUS) {
1567       v = amat->a;
1568       for (i=0; i<amat->nz; i++) {
1569 #if defined(PETSC_USE_COMPLEX)
1570         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1571 #else
1572         sum += (*v)*(*v); v++;
1573 #endif
1574       }
1575       v = bmat->a;
1576       for (i=0; i<bmat->nz; i++) {
1577 #if defined(PETSC_USE_COMPLEX)
1578         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1579 #else
1580         sum += (*v)*(*v); v++;
1581 #endif
1582       }
1583       ierr = MPI_Allreduce(&sum,norm,1,MPIU_REAL,MPI_SUM,((PetscObject)mat)->comm);CHKERRQ(ierr);
1584       *norm = sqrt(*norm);
1585     } else if (type == NORM_1) { /* max column norm */
1586       PetscReal *tmp,*tmp2;
1587       PetscInt  *jj,*garray = aij->garray;
1588       ierr = PetscMalloc((mat->cmap->N+1)*sizeof(PetscReal),&tmp);CHKERRQ(ierr);
1589       ierr = PetscMalloc((mat->cmap->N+1)*sizeof(PetscReal),&tmp2);CHKERRQ(ierr);
1590       ierr = PetscMemzero(tmp,mat->cmap->N*sizeof(PetscReal));CHKERRQ(ierr);
1591       *norm = 0.0;
1592       v = amat->a; jj = amat->j;
1593       for (j=0; j<amat->nz; j++) {
1594         tmp[cstart + *jj++ ] += PetscAbsScalar(*v);  v++;
1595       }
1596       v = bmat->a; jj = bmat->j;
1597       for (j=0; j<bmat->nz; j++) {
1598         tmp[garray[*jj++]] += PetscAbsScalar(*v); v++;
1599       }
1600       ierr = MPI_Allreduce(tmp,tmp2,mat->cmap->N,MPIU_REAL,MPI_SUM,((PetscObject)mat)->comm);CHKERRQ(ierr);
1601       for (j=0; j<mat->cmap->N; j++) {
1602         if (tmp2[j] > *norm) *norm = tmp2[j];
1603       }
1604       ierr = PetscFree(tmp);CHKERRQ(ierr);
1605       ierr = PetscFree(tmp2);CHKERRQ(ierr);
1606     } else if (type == NORM_INFINITY) { /* max row norm */
1607       PetscReal ntemp = 0.0;
1608       for (j=0; j<aij->A->rmap->n; j++) {
1609         v = amat->a + amat->i[j];
1610         sum = 0.0;
1611         for (i=0; i<amat->i[j+1]-amat->i[j]; i++) {
1612           sum += PetscAbsScalar(*v); v++;
1613         }
1614         v = bmat->a + bmat->i[j];
1615         for (i=0; i<bmat->i[j+1]-bmat->i[j]; i++) {
1616           sum += PetscAbsScalar(*v); v++;
1617         }
1618         if (sum > ntemp) ntemp = sum;
1619       }
1620       ierr = MPI_Allreduce(&ntemp,norm,1,MPIU_REAL,MPI_MAX,((PetscObject)mat)->comm);CHKERRQ(ierr);
1621     } else {
1622       SETERRQ(PETSC_ERR_SUP,"No support for two norm");
1623     }
1624   }
1625   PetscFunctionReturn(0);
1626 }
1627 
1628 #undef __FUNCT__
1629 #define __FUNCT__ "MatTranspose_MPIAIJ"
1630 PetscErrorCode MatTranspose_MPIAIJ(Mat A,MatReuse reuse,Mat *matout)
1631 {
1632   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
1633   Mat_SeqAIJ     *Aloc=(Mat_SeqAIJ*)a->A->data,*Bloc=(Mat_SeqAIJ*)a->B->data;
1634   PetscErrorCode ierr;
1635   PetscInt       M = A->rmap->N,N = A->cmap->N,ma,na,mb,*ai,*aj,*bi,*bj,row,*cols,*cols_tmp,i,*d_nnz;
1636   PetscInt       cstart=A->cmap->rstart,ncol;
1637   Mat            B;
1638   MatScalar      *array;
1639 
1640   PetscFunctionBegin;
1641   if (reuse == MAT_REUSE_MATRIX && A == *matout && M != N) SETERRQ(PETSC_ERR_ARG_SIZ,"Square matrix only for in-place");
1642 
1643   ma = A->rmap->n; na = A->cmap->n; mb = a->B->rmap->n;
1644   ai = Aloc->i; aj = Aloc->j;
1645   bi = Bloc->i; bj = Bloc->j;
1646   if (reuse == MAT_INITIAL_MATRIX || *matout == A) {
1647     /* compute d_nnz for preallocation; o_nnz is approximated by d_nnz to avoid communication */
1648     ierr = PetscMalloc((1+na)*sizeof(PetscInt),&d_nnz);CHKERRQ(ierr);
1649     ierr = PetscMemzero(d_nnz,(1+na)*sizeof(PetscInt));CHKERRQ(ierr);
1650     for (i=0; i<ai[ma]; i++){
1651       d_nnz[aj[i]] ++;
1652       aj[i] += cstart; /* global col index to be used by MatSetValues() */
1653     }
1654 
1655     ierr = MatCreate(((PetscObject)A)->comm,&B);CHKERRQ(ierr);
1656     ierr = MatSetSizes(B,A->cmap->n,A->rmap->n,N,M);CHKERRQ(ierr);
1657     ierr = MatSetType(B,((PetscObject)A)->type_name);CHKERRQ(ierr);
1658     ierr = MatMPIAIJSetPreallocation(B,0,d_nnz,0,d_nnz);CHKERRQ(ierr);
1659     ierr = PetscFree(d_nnz);CHKERRQ(ierr);
1660   } else {
1661     B = *matout;
1662   }
1663 
1664   /* copy over the A part */
1665   array = Aloc->a;
1666   row = A->rmap->rstart;
1667   for (i=0; i<ma; i++) {
1668     ncol = ai[i+1]-ai[i];
1669     ierr = MatSetValues(B,ncol,aj,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1670     row++; array += ncol; aj += ncol;
1671   }
1672   aj = Aloc->j;
1673   for (i=0; i<ai[ma]; i++) aj[i] -= cstart; /* resume local col index */
1674 
1675   /* copy over the B part */
1676   ierr = PetscMalloc(bi[mb]*sizeof(PetscInt),&cols);CHKERRQ(ierr);
1677   ierr = PetscMemzero(cols,bi[mb]*sizeof(PetscInt));CHKERRQ(ierr);
1678   array = Bloc->a;
1679   row = A->rmap->rstart;
1680   for (i=0; i<bi[mb]; i++) {cols[i] = a->garray[bj[i]];}
1681   cols_tmp = cols;
1682   for (i=0; i<mb; i++) {
1683     ncol = bi[i+1]-bi[i];
1684     ierr = MatSetValues(B,ncol,cols_tmp,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1685     row++; array += ncol; cols_tmp += ncol;
1686   }
1687   ierr = PetscFree(cols);CHKERRQ(ierr);
1688 
1689   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1690   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1691   if (reuse == MAT_INITIAL_MATRIX || *matout != A) {
1692     *matout = B;
1693   } else {
1694     ierr = MatHeaderCopy(A,B);CHKERRQ(ierr);
1695   }
1696   PetscFunctionReturn(0);
1697 }
1698 
1699 #undef __FUNCT__
1700 #define __FUNCT__ "MatDiagonalScale_MPIAIJ"
1701 PetscErrorCode MatDiagonalScale_MPIAIJ(Mat mat,Vec ll,Vec rr)
1702 {
1703   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
1704   Mat            a = aij->A,b = aij->B;
1705   PetscErrorCode ierr;
1706   PetscInt       s1,s2,s3;
1707 
1708   PetscFunctionBegin;
1709   ierr = MatGetLocalSize(mat,&s2,&s3);CHKERRQ(ierr);
1710   if (rr) {
1711     ierr = VecGetLocalSize(rr,&s1);CHKERRQ(ierr);
1712     if (s1!=s3) SETERRQ(PETSC_ERR_ARG_SIZ,"right vector non-conforming local size");
1713     /* Overlap communication with computation. */
1714     ierr = VecScatterBegin(aij->Mvctx,rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1715   }
1716   if (ll) {
1717     ierr = VecGetLocalSize(ll,&s1);CHKERRQ(ierr);
1718     if (s1!=s2) SETERRQ(PETSC_ERR_ARG_SIZ,"left vector non-conforming local size");
1719     ierr = (*b->ops->diagonalscale)(b,ll,0);CHKERRQ(ierr);
1720   }
1721   /* scale  the diagonal block */
1722   ierr = (*a->ops->diagonalscale)(a,ll,rr);CHKERRQ(ierr);
1723 
1724   if (rr) {
1725     /* Do a scatter end and then right scale the off-diagonal block */
1726     ierr = VecScatterEnd(aij->Mvctx,rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
1727     ierr = (*b->ops->diagonalscale)(b,0,aij->lvec);CHKERRQ(ierr);
1728   }
1729 
1730   PetscFunctionReturn(0);
1731 }
1732 
1733 #undef __FUNCT__
1734 #define __FUNCT__ "MatSetBlockSize_MPIAIJ"
1735 PetscErrorCode MatSetBlockSize_MPIAIJ(Mat A,PetscInt bs)
1736 {
1737   Mat_MPIAIJ     *a   = (Mat_MPIAIJ*)A->data;
1738   PetscErrorCode ierr;
1739 
1740   PetscFunctionBegin;
1741   ierr = MatSetBlockSize(a->A,bs);CHKERRQ(ierr);
1742   ierr = MatSetBlockSize(a->B,bs);CHKERRQ(ierr);
1743   PetscFunctionReturn(0);
1744 }
1745 #undef __FUNCT__
1746 #define __FUNCT__ "MatSetUnfactored_MPIAIJ"
1747 PetscErrorCode MatSetUnfactored_MPIAIJ(Mat A)
1748 {
1749   Mat_MPIAIJ     *a   = (Mat_MPIAIJ*)A->data;
1750   PetscErrorCode ierr;
1751 
1752   PetscFunctionBegin;
1753   ierr = MatSetUnfactored(a->A);CHKERRQ(ierr);
1754   PetscFunctionReturn(0);
1755 }
1756 
1757 #undef __FUNCT__
1758 #define __FUNCT__ "MatEqual_MPIAIJ"
1759 PetscErrorCode MatEqual_MPIAIJ(Mat A,Mat B,PetscTruth *flag)
1760 {
1761   Mat_MPIAIJ     *matB = (Mat_MPIAIJ*)B->data,*matA = (Mat_MPIAIJ*)A->data;
1762   Mat            a,b,c,d;
1763   PetscTruth     flg;
1764   PetscErrorCode ierr;
1765 
1766   PetscFunctionBegin;
1767   a = matA->A; b = matA->B;
1768   c = matB->A; d = matB->B;
1769 
1770   ierr = MatEqual(a,c,&flg);CHKERRQ(ierr);
1771   if (flg) {
1772     ierr = MatEqual(b,d,&flg);CHKERRQ(ierr);
1773   }
1774   ierr = MPI_Allreduce(&flg,flag,1,MPI_INT,MPI_LAND,((PetscObject)A)->comm);CHKERRQ(ierr);
1775   PetscFunctionReturn(0);
1776 }
1777 
1778 #undef __FUNCT__
1779 #define __FUNCT__ "MatCopy_MPIAIJ"
1780 PetscErrorCode MatCopy_MPIAIJ(Mat A,Mat B,MatStructure str)
1781 {
1782   PetscErrorCode ierr;
1783   Mat_MPIAIJ     *a = (Mat_MPIAIJ *)A->data;
1784   Mat_MPIAIJ     *b = (Mat_MPIAIJ *)B->data;
1785 
1786   PetscFunctionBegin;
1787   /* If the two matrices don't have the same copy implementation, they aren't compatible for fast copy. */
1788   if ((str != SAME_NONZERO_PATTERN) || (A->ops->copy != B->ops->copy)) {
1789     /* because of the column compression in the off-processor part of the matrix a->B,
1790        the number of columns in a->B and b->B may be different, hence we cannot call
1791        the MatCopy() directly on the two parts. If need be, we can provide a more
1792        efficient copy than the MatCopy_Basic() by first uncompressing the a->B matrices
1793        then copying the submatrices */
1794     ierr = MatCopy_Basic(A,B,str);CHKERRQ(ierr);
1795   } else {
1796     ierr = MatCopy(a->A,b->A,str);CHKERRQ(ierr);
1797     ierr = MatCopy(a->B,b->B,str);CHKERRQ(ierr);
1798   }
1799   PetscFunctionReturn(0);
1800 }
1801 
1802 #undef __FUNCT__
1803 #define __FUNCT__ "MatSetUpPreallocation_MPIAIJ"
1804 PetscErrorCode MatSetUpPreallocation_MPIAIJ(Mat A)
1805 {
1806   PetscErrorCode ierr;
1807 
1808   PetscFunctionBegin;
1809   ierr =  MatMPIAIJSetPreallocation(A,PETSC_DEFAULT,0,PETSC_DEFAULT,0);CHKERRQ(ierr);
1810   PetscFunctionReturn(0);
1811 }
1812 
1813 #include "petscblaslapack.h"
1814 #undef __FUNCT__
1815 #define __FUNCT__ "MatAXPY_MPIAIJ"
1816 PetscErrorCode MatAXPY_MPIAIJ(Mat Y,PetscScalar a,Mat X,MatStructure str)
1817 {
1818   PetscErrorCode ierr;
1819   PetscInt       i;
1820   Mat_MPIAIJ     *xx = (Mat_MPIAIJ *)X->data,*yy = (Mat_MPIAIJ *)Y->data;
1821   PetscBLASInt   bnz,one=1;
1822   Mat_SeqAIJ     *x,*y;
1823 
1824   PetscFunctionBegin;
1825   if (str == SAME_NONZERO_PATTERN) {
1826     PetscScalar alpha = a;
1827     x = (Mat_SeqAIJ *)xx->A->data;
1828     y = (Mat_SeqAIJ *)yy->A->data;
1829     bnz = PetscBLASIntCast(x->nz);
1830     BLASaxpy_(&bnz,&alpha,x->a,&one,y->a,&one);
1831     x = (Mat_SeqAIJ *)xx->B->data;
1832     y = (Mat_SeqAIJ *)yy->B->data;
1833     bnz = PetscBLASIntCast(x->nz);
1834     BLASaxpy_(&bnz,&alpha,x->a,&one,y->a,&one);
1835   } else if (str == SUBSET_NONZERO_PATTERN) {
1836     ierr = MatAXPY_SeqAIJ(yy->A,a,xx->A,str);CHKERRQ(ierr);
1837 
1838     x = (Mat_SeqAIJ *)xx->B->data;
1839     y = (Mat_SeqAIJ *)yy->B->data;
1840     if (y->xtoy && y->XtoY != xx->B) {
1841       ierr = PetscFree(y->xtoy);CHKERRQ(ierr);
1842       ierr = MatDestroy(y->XtoY);CHKERRQ(ierr);
1843     }
1844     if (!y->xtoy) { /* get xtoy */
1845       ierr = MatAXPYGetxtoy_Private(xx->B->rmap->n,x->i,x->j,xx->garray,y->i,y->j,yy->garray,&y->xtoy);CHKERRQ(ierr);
1846       y->XtoY = xx->B;
1847       ierr = PetscObjectReference((PetscObject)xx->B);CHKERRQ(ierr);
1848     }
1849     for (i=0; i<x->nz; i++) y->a[y->xtoy[i]] += a*(x->a[i]);
1850   } else {
1851     ierr = MatAXPY_Basic(Y,a,X,str);CHKERRQ(ierr);
1852   }
1853   PetscFunctionReturn(0);
1854 }
1855 
1856 EXTERN PetscErrorCode PETSCMAT_DLLEXPORT MatConjugate_SeqAIJ(Mat);
1857 
1858 #undef __FUNCT__
1859 #define __FUNCT__ "MatConjugate_MPIAIJ"
1860 PetscErrorCode PETSCMAT_DLLEXPORT MatConjugate_MPIAIJ(Mat mat)
1861 {
1862 #if defined(PETSC_USE_COMPLEX)
1863   PetscErrorCode ierr;
1864   Mat_MPIAIJ     *aij = (Mat_MPIAIJ *)mat->data;
1865 
1866   PetscFunctionBegin;
1867   ierr = MatConjugate_SeqAIJ(aij->A);CHKERRQ(ierr);
1868   ierr = MatConjugate_SeqAIJ(aij->B);CHKERRQ(ierr);
1869 #else
1870   PetscFunctionBegin;
1871 #endif
1872   PetscFunctionReturn(0);
1873 }
1874 
1875 #undef __FUNCT__
1876 #define __FUNCT__ "MatRealPart_MPIAIJ"
1877 PetscErrorCode MatRealPart_MPIAIJ(Mat A)
1878 {
1879   Mat_MPIAIJ   *a = (Mat_MPIAIJ*)A->data;
1880   PetscErrorCode ierr;
1881 
1882   PetscFunctionBegin;
1883   ierr = MatRealPart(a->A);CHKERRQ(ierr);
1884   ierr = MatRealPart(a->B);CHKERRQ(ierr);
1885   PetscFunctionReturn(0);
1886 }
1887 
1888 #undef __FUNCT__
1889 #define __FUNCT__ "MatImaginaryPart_MPIAIJ"
1890 PetscErrorCode MatImaginaryPart_MPIAIJ(Mat A)
1891 {
1892   Mat_MPIAIJ   *a = (Mat_MPIAIJ*)A->data;
1893   PetscErrorCode ierr;
1894 
1895   PetscFunctionBegin;
1896   ierr = MatImaginaryPart(a->A);CHKERRQ(ierr);
1897   ierr = MatImaginaryPart(a->B);CHKERRQ(ierr);
1898   PetscFunctionReturn(0);
1899 }
1900 
1901 #ifdef PETSC_HAVE_PBGL
1902 
1903 #include <boost/parallel/mpi/bsp_process_group.hpp>
1904 #include <boost/graph/distributed/ilu_default_graph.hpp>
1905 #include <boost/graph/distributed/ilu_0_block.hpp>
1906 #include <boost/graph/distributed/ilu_preconditioner.hpp>
1907 #include <boost/graph/distributed/petsc/interface.hpp>
1908 #include <boost/multi_array.hpp>
1909 #include <boost/parallel/distributed_property_map->hpp>
1910 
1911 #undef __FUNCT__
1912 #define __FUNCT__ "MatILUFactorSymbolic_MPIAIJ"
1913 /*
1914   This uses the parallel ILU factorization of Peter Gottschling <pgottsch@osl.iu.edu>
1915 */
1916 PetscErrorCode MatILUFactorSymbolic_MPIAIJ(Mat fact,Mat A, IS isrow, IS iscol, const MatFactorInfo *info)
1917 {
1918   namespace petsc = boost::distributed::petsc;
1919 
1920   namespace graph_dist = boost::graph::distributed;
1921   using boost::graph::distributed::ilu_default::process_group_type;
1922   using boost::graph::ilu_permuted;
1923 
1924   PetscTruth      row_identity, col_identity;
1925   PetscContainer  c;
1926   PetscInt        m, n, M, N;
1927   PetscErrorCode  ierr;
1928 
1929   PetscFunctionBegin;
1930   if (info->levels != 0) SETERRQ(PETSC_ERR_SUP,"Only levels = 0 supported for parallel ilu");
1931   ierr = ISIdentity(isrow, &row_identity);CHKERRQ(ierr);
1932   ierr = ISIdentity(iscol, &col_identity);CHKERRQ(ierr);
1933   if (!row_identity || !col_identity) {
1934     SETERRQ(PETSC_ERR_ARG_WRONG,"Row and column permutations must be identity for parallel ILU");
1935   }
1936 
1937   process_group_type pg;
1938   typedef graph_dist::ilu_default::ilu_level_graph_type  lgraph_type;
1939   lgraph_type*   lgraph_p = new lgraph_type(petsc::num_global_vertices(A), pg, petsc::matrix_distribution(A, pg));
1940   lgraph_type&   level_graph = *lgraph_p;
1941   graph_dist::ilu_default::graph_type&            graph(level_graph.graph);
1942 
1943   petsc::read_matrix(A, graph, get(boost::edge_weight, graph));
1944   ilu_permuted(level_graph);
1945 
1946   /* put together the new matrix */
1947   ierr = MatCreate(((PetscObject)A)->comm, fact);CHKERRQ(ierr);
1948   ierr = MatGetLocalSize(A, &m, &n);CHKERRQ(ierr);
1949   ierr = MatGetSize(A, &M, &N);CHKERRQ(ierr);
1950   ierr = MatSetSizes(fact, m, n, M, N);CHKERRQ(ierr);
1951   ierr = MatSetType(fact, ((PetscObject)A)->type_name);CHKERRQ(ierr);
1952   ierr = MatAssemblyBegin(fact, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1953   ierr = MatAssemblyEnd(fact, MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1954 
1955   ierr = PetscContainerCreate(((PetscObject)A)->comm, &c);
1956   ierr = PetscContainerSetPointer(c, lgraph_p);
1957   ierr = PetscObjectCompose((PetscObject) (fact), "graph", (PetscObject) c);
1958   PetscFunctionReturn(0);
1959 }
1960 
1961 #undef __FUNCT__
1962 #define __FUNCT__ "MatLUFactorNumeric_MPIAIJ"
1963 PetscErrorCode MatLUFactorNumeric_MPIAIJ(Mat B,Mat A, const MatFactorInfo *info)
1964 {
1965   PetscFunctionBegin;
1966   PetscFunctionReturn(0);
1967 }
1968 
1969 #undef __FUNCT__
1970 #define __FUNCT__ "MatSolve_MPIAIJ"
1971 /*
1972   This uses the parallel ILU factorization of Peter Gottschling <pgottsch@osl.iu.edu>
1973 */
1974 PetscErrorCode MatSolve_MPIAIJ(Mat A, Vec b, Vec x)
1975 {
1976   namespace graph_dist = boost::graph::distributed;
1977 
1978   typedef graph_dist::ilu_default::ilu_level_graph_type  lgraph_type;
1979   lgraph_type*   lgraph_p;
1980   PetscContainer c;
1981   PetscErrorCode ierr;
1982 
1983   PetscFunctionBegin;
1984   ierr = PetscObjectQuery((PetscObject) A, "graph", (PetscObject *) &c);CHKERRQ(ierr);
1985   ierr = PetscContainerGetPointer(c, (void **) &lgraph_p);CHKERRQ(ierr);
1986   ierr = VecCopy(b, x);CHKERRQ(ierr);
1987 
1988   PetscScalar* array_x;
1989   ierr = VecGetArray(x, &array_x);CHKERRQ(ierr);
1990   PetscInt sx;
1991   ierr = VecGetSize(x, &sx);CHKERRQ(ierr);
1992 
1993   PetscScalar* array_b;
1994   ierr = VecGetArray(b, &array_b);CHKERRQ(ierr);
1995   PetscInt sb;
1996   ierr = VecGetSize(b, &sb);CHKERRQ(ierr);
1997 
1998   lgraph_type&   level_graph = *lgraph_p;
1999   graph_dist::ilu_default::graph_type&            graph(level_graph.graph);
2000 
2001   typedef boost::multi_array_ref<PetscScalar, 1> array_ref_type;
2002   array_ref_type                                 ref_b(array_b, boost::extents[num_vertices(graph)]),
2003                                                  ref_x(array_x, boost::extents[num_vertices(graph)]);
2004 
2005   typedef boost::iterator_property_map<array_ref_type::iterator,
2006                                 boost::property_map<graph_dist::ilu_default::graph_type, boost::vertex_index_t>::type>  gvector_type;
2007   gvector_type                                   vector_b(ref_b.begin(), get(boost::vertex_index, graph)),
2008                                                  vector_x(ref_x.begin(), get(boost::vertex_index, graph));
2009 
2010   ilu_set_solve(*lgraph_p, vector_b, vector_x);
2011 
2012   PetscFunctionReturn(0);
2013 }
2014 #endif
2015 
2016 typedef struct { /* used by MatGetRedundantMatrix() for reusing matredundant */
2017   PetscInt       nzlocal,nsends,nrecvs;
2018   PetscMPIInt    *send_rank;
2019   PetscInt       *sbuf_nz,*sbuf_j,**rbuf_j;
2020   PetscScalar    *sbuf_a,**rbuf_a;
2021   PetscErrorCode (*MatDestroy)(Mat);
2022 } Mat_Redundant;
2023 
2024 #undef __FUNCT__
2025 #define __FUNCT__ "PetscContainerDestroy_MatRedundant"
2026 PetscErrorCode PetscContainerDestroy_MatRedundant(void *ptr)
2027 {
2028   PetscErrorCode       ierr;
2029   Mat_Redundant        *redund=(Mat_Redundant*)ptr;
2030   PetscInt             i;
2031 
2032   PetscFunctionBegin;
2033   ierr = PetscFree(redund->send_rank);CHKERRQ(ierr);
2034   ierr = PetscFree(redund->sbuf_j);CHKERRQ(ierr);
2035   ierr = PetscFree(redund->sbuf_a);CHKERRQ(ierr);
2036   for (i=0; i<redund->nrecvs; i++){
2037     ierr = PetscFree(redund->rbuf_j[i]);CHKERRQ(ierr);
2038     ierr = PetscFree(redund->rbuf_a[i]);CHKERRQ(ierr);
2039   }
2040   ierr = PetscFree3(redund->sbuf_nz,redund->rbuf_j,redund->rbuf_a);CHKERRQ(ierr);
2041   ierr = PetscFree(redund);CHKERRQ(ierr);
2042   PetscFunctionReturn(0);
2043 }
2044 
2045 #undef __FUNCT__
2046 #define __FUNCT__ "MatDestroy_MatRedundant"
2047 PetscErrorCode MatDestroy_MatRedundant(Mat A)
2048 {
2049   PetscErrorCode  ierr;
2050   PetscContainer  container;
2051   Mat_Redundant   *redund=PETSC_NULL;
2052 
2053   PetscFunctionBegin;
2054   ierr = PetscObjectQuery((PetscObject)A,"Mat_Redundant",(PetscObject *)&container);CHKERRQ(ierr);
2055   if (container) {
2056     ierr = PetscContainerGetPointer(container,(void **)&redund);CHKERRQ(ierr);
2057   } else {
2058     SETERRQ(PETSC_ERR_PLIB,"Container does not exit");
2059   }
2060   A->ops->destroy = redund->MatDestroy;
2061   ierr = PetscObjectCompose((PetscObject)A,"Mat_Redundant",0);CHKERRQ(ierr);
2062   ierr = (*A->ops->destroy)(A);CHKERRQ(ierr);
2063   ierr = PetscContainerDestroy(container);CHKERRQ(ierr);
2064   PetscFunctionReturn(0);
2065 }
2066 
2067 #undef __FUNCT__
2068 #define __FUNCT__ "MatGetRedundantMatrix_MPIAIJ"
2069 PetscErrorCode MatGetRedundantMatrix_MPIAIJ(Mat mat,PetscInt nsubcomm,MPI_Comm subcomm,PetscInt mlocal_sub,MatReuse reuse,Mat *matredundant)
2070 {
2071   PetscMPIInt    rank,size;
2072   MPI_Comm       comm=((PetscObject)mat)->comm;
2073   PetscErrorCode ierr;
2074   PetscInt       nsends=0,nrecvs=0,i,rownz_max=0;
2075   PetscMPIInt    *send_rank=PETSC_NULL,*recv_rank=PETSC_NULL;
2076   PetscInt       *rowrange=mat->rmap->range;
2077   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
2078   Mat            A=aij->A,B=aij->B,C=*matredundant;
2079   Mat_SeqAIJ     *a=(Mat_SeqAIJ*)A->data,*b=(Mat_SeqAIJ*)B->data;
2080   PetscScalar    *sbuf_a;
2081   PetscInt       nzlocal=a->nz+b->nz;
2082   PetscInt       j,cstart=mat->cmap->rstart,cend=mat->cmap->rend,row,nzA,nzB,ncols,*cworkA,*cworkB;
2083   PetscInt       rstart=mat->rmap->rstart,rend=mat->rmap->rend,*bmap=aij->garray,M,N;
2084   PetscInt       *cols,ctmp,lwrite,*rptr,l,*sbuf_j;
2085   MatScalar      *aworkA,*aworkB;
2086   PetscScalar    *vals;
2087   PetscMPIInt    tag1,tag2,tag3,imdex;
2088   MPI_Request    *s_waits1=PETSC_NULL,*s_waits2=PETSC_NULL,*s_waits3=PETSC_NULL,
2089                  *r_waits1=PETSC_NULL,*r_waits2=PETSC_NULL,*r_waits3=PETSC_NULL;
2090   MPI_Status     recv_status,*send_status;
2091   PetscInt       *sbuf_nz=PETSC_NULL,*rbuf_nz=PETSC_NULL,count;
2092   PetscInt       **rbuf_j=PETSC_NULL;
2093   PetscScalar    **rbuf_a=PETSC_NULL;
2094   Mat_Redundant  *redund=PETSC_NULL;
2095   PetscContainer container;
2096 
2097   PetscFunctionBegin;
2098   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
2099   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2100 
2101   if (reuse == MAT_REUSE_MATRIX) {
2102     ierr = MatGetSize(C,&M,&N);CHKERRQ(ierr);
2103     if (M != N || M != mat->rmap->N) SETERRQ(PETSC_ERR_ARG_SIZ,"Cannot reuse matrix. Wrong global size");
2104     ierr = MatGetLocalSize(C,&M,&N);CHKERRQ(ierr);
2105     if (M != N || M != mlocal_sub) SETERRQ(PETSC_ERR_ARG_SIZ,"Cannot reuse matrix. Wrong local size");
2106     ierr = PetscObjectQuery((PetscObject)C,"Mat_Redundant",(PetscObject *)&container);CHKERRQ(ierr);
2107     if (container) {
2108       ierr = PetscContainerGetPointer(container,(void **)&redund);CHKERRQ(ierr);
2109     } else {
2110       SETERRQ(PETSC_ERR_PLIB,"Container does not exit");
2111     }
2112     if (nzlocal != redund->nzlocal) SETERRQ(PETSC_ERR_ARG_SIZ,"Cannot reuse matrix. Wrong nzlocal");
2113 
2114     nsends    = redund->nsends;
2115     nrecvs    = redund->nrecvs;
2116     send_rank = redund->send_rank; recv_rank = send_rank + size;
2117     sbuf_nz   = redund->sbuf_nz;     rbuf_nz = sbuf_nz + nsends;
2118     sbuf_j    = redund->sbuf_j;
2119     sbuf_a    = redund->sbuf_a;
2120     rbuf_j    = redund->rbuf_j;
2121     rbuf_a    = redund->rbuf_a;
2122   }
2123 
2124   if (reuse == MAT_INITIAL_MATRIX){
2125     PetscMPIInt  subrank,subsize;
2126     PetscInt     nleftover,np_subcomm;
2127     /* get the destination processors' id send_rank, nsends and nrecvs */
2128     ierr = MPI_Comm_rank(subcomm,&subrank);CHKERRQ(ierr);
2129     ierr = MPI_Comm_size(subcomm,&subsize);CHKERRQ(ierr);
2130     ierr = PetscMalloc((2*size+1)*sizeof(PetscMPIInt),&send_rank);
2131     recv_rank = send_rank + size;
2132     np_subcomm = size/nsubcomm;
2133     nleftover  = size - nsubcomm*np_subcomm;
2134     nsends = 0; nrecvs = 0;
2135     for (i=0; i<size; i++){ /* i=rank*/
2136       if (subrank == i/nsubcomm && rank != i){ /* my_subrank == other's subrank */
2137         send_rank[nsends] = i; nsends++;
2138         recv_rank[nrecvs++] = i;
2139       }
2140     }
2141     if (rank >= size - nleftover){/* this proc is a leftover processor */
2142       i = size-nleftover-1;
2143       j = 0;
2144       while (j < nsubcomm - nleftover){
2145         send_rank[nsends++] = i;
2146         i--; j++;
2147       }
2148     }
2149 
2150     if (nleftover && subsize == size/nsubcomm && subrank==subsize-1){ /* this proc recvs from leftover processors */
2151       for (i=0; i<nleftover; i++){
2152         recv_rank[nrecvs++] = size-nleftover+i;
2153       }
2154     }
2155 
2156     /* allocate sbuf_j, sbuf_a */
2157     i = nzlocal + rowrange[rank+1] - rowrange[rank] + 2;
2158     ierr = PetscMalloc(i*sizeof(PetscInt),&sbuf_j);CHKERRQ(ierr);
2159     ierr = PetscMalloc((nzlocal+1)*sizeof(PetscScalar),&sbuf_a);CHKERRQ(ierr);
2160   } /* endof if (reuse == MAT_INITIAL_MATRIX) */
2161 
2162   /* copy mat's local entries into the buffers */
2163   if (reuse == MAT_INITIAL_MATRIX){
2164     rownz_max = 0;
2165     rptr = sbuf_j;
2166     cols = sbuf_j + rend-rstart + 1;
2167     vals = sbuf_a;
2168     rptr[0] = 0;
2169     for (i=0; i<rend-rstart; i++){
2170       row = i + rstart;
2171       nzA    = a->i[i+1] - a->i[i]; nzB = b->i[i+1] - b->i[i];
2172       ncols  = nzA + nzB;
2173       cworkA = a->j + a->i[i]; cworkB = b->j + b->i[i];
2174       aworkA = a->a + a->i[i]; aworkB = b->a + b->i[i];
2175       /* load the column indices for this row into cols */
2176       lwrite = 0;
2177       for (l=0; l<nzB; l++) {
2178         if ((ctmp = bmap[cworkB[l]]) < cstart){
2179           vals[lwrite]   = aworkB[l];
2180           cols[lwrite++] = ctmp;
2181         }
2182       }
2183       for (l=0; l<nzA; l++){
2184         vals[lwrite]   = aworkA[l];
2185         cols[lwrite++] = cstart + cworkA[l];
2186       }
2187       for (l=0; l<nzB; l++) {
2188         if ((ctmp = bmap[cworkB[l]]) >= cend){
2189           vals[lwrite]   = aworkB[l];
2190           cols[lwrite++] = ctmp;
2191         }
2192       }
2193       vals += ncols;
2194       cols += ncols;
2195       rptr[i+1] = rptr[i] + ncols;
2196       if (rownz_max < ncols) rownz_max = ncols;
2197     }
2198     if (rptr[rend-rstart] != a->nz + b->nz) SETERRQ4(1, "rptr[%d] %d != %d + %d",rend-rstart,rptr[rend-rstart+1],a->nz,b->nz);
2199   } else { /* only copy matrix values into sbuf_a */
2200     rptr = sbuf_j;
2201     vals = sbuf_a;
2202     rptr[0] = 0;
2203     for (i=0; i<rend-rstart; i++){
2204       row = i + rstart;
2205       nzA    = a->i[i+1] - a->i[i]; nzB = b->i[i+1] - b->i[i];
2206       ncols  = nzA + nzB;
2207       cworkA = a->j + a->i[i]; cworkB = b->j + b->i[i];
2208       aworkA = a->a + a->i[i]; aworkB = b->a + b->i[i];
2209       lwrite = 0;
2210       for (l=0; l<nzB; l++) {
2211         if ((ctmp = bmap[cworkB[l]]) < cstart) vals[lwrite++] = aworkB[l];
2212       }
2213       for (l=0; l<nzA; l++) vals[lwrite++] = aworkA[l];
2214       for (l=0; l<nzB; l++) {
2215         if ((ctmp = bmap[cworkB[l]]) >= cend) vals[lwrite++] = aworkB[l];
2216       }
2217       vals += ncols;
2218       rptr[i+1] = rptr[i] + ncols;
2219     }
2220   } /* endof if (reuse == MAT_INITIAL_MATRIX) */
2221 
2222   /* send nzlocal to others, and recv other's nzlocal */
2223   /*--------------------------------------------------*/
2224   if (reuse == MAT_INITIAL_MATRIX){
2225     ierr = PetscMalloc2(3*(nsends + nrecvs)+1,MPI_Request,&s_waits3,nsends+1,MPI_Status,&send_status);CHKERRQ(ierr);
2226     s_waits2 = s_waits3 + nsends;
2227     s_waits1 = s_waits2 + nsends;
2228     r_waits1 = s_waits1 + nsends;
2229     r_waits2 = r_waits1 + nrecvs;
2230     r_waits3 = r_waits2 + nrecvs;
2231   } else {
2232     ierr = PetscMalloc2(nsends + nrecvs +1,MPI_Request,&s_waits3,nsends+1,MPI_Status,&send_status);CHKERRQ(ierr);
2233     r_waits3 = s_waits3 + nsends;
2234   }
2235 
2236   ierr = PetscObjectGetNewTag((PetscObject)mat,&tag3);CHKERRQ(ierr);
2237   if (reuse == MAT_INITIAL_MATRIX){
2238     /* get new tags to keep the communication clean */
2239     ierr = PetscObjectGetNewTag((PetscObject)mat,&tag1);CHKERRQ(ierr);
2240     ierr = PetscObjectGetNewTag((PetscObject)mat,&tag2);CHKERRQ(ierr);
2241     ierr = PetscMalloc3(nsends+nrecvs+1,PetscInt,&sbuf_nz,nrecvs,PetscInt*,&rbuf_j,nrecvs,PetscScalar*,&rbuf_a);CHKERRQ(ierr);
2242     rbuf_nz = sbuf_nz + nsends;
2243 
2244     /* post receives of other's nzlocal */
2245     for (i=0; i<nrecvs; i++){
2246       ierr = MPI_Irecv(rbuf_nz+i,1,MPIU_INT,MPI_ANY_SOURCE,tag1,comm,r_waits1+i);CHKERRQ(ierr);
2247     }
2248     /* send nzlocal to others */
2249     for (i=0; i<nsends; i++){
2250       sbuf_nz[i] = nzlocal;
2251       ierr = MPI_Isend(sbuf_nz+i,1,MPIU_INT,send_rank[i],tag1,comm,s_waits1+i);CHKERRQ(ierr);
2252     }
2253     /* wait on receives of nzlocal; allocate space for rbuf_j, rbuf_a */
2254     count = nrecvs;
2255     while (count) {
2256       ierr = MPI_Waitany(nrecvs,r_waits1,&imdex,&recv_status);CHKERRQ(ierr);
2257       recv_rank[imdex] = recv_status.MPI_SOURCE;
2258       /* allocate rbuf_a and rbuf_j; then post receives of rbuf_j */
2259       ierr = PetscMalloc((rbuf_nz[imdex]+1)*sizeof(PetscScalar),&rbuf_a[imdex]);CHKERRQ(ierr);
2260 
2261       i = rowrange[recv_status.MPI_SOURCE+1] - rowrange[recv_status.MPI_SOURCE]; /* number of expected mat->i */
2262       rbuf_nz[imdex] += i + 2;
2263       ierr = PetscMalloc(rbuf_nz[imdex]*sizeof(PetscInt),&rbuf_j[imdex]);CHKERRQ(ierr);
2264       ierr = MPI_Irecv(rbuf_j[imdex],rbuf_nz[imdex],MPIU_INT,recv_status.MPI_SOURCE,tag2,comm,r_waits2+imdex);CHKERRQ(ierr);
2265       count--;
2266     }
2267     /* wait on sends of nzlocal */
2268     if (nsends) {ierr = MPI_Waitall(nsends,s_waits1,send_status);CHKERRQ(ierr);}
2269     /* send mat->i,j to others, and recv from other's */
2270     /*------------------------------------------------*/
2271     for (i=0; i<nsends; i++){
2272       j = nzlocal + rowrange[rank+1] - rowrange[rank] + 1;
2273       ierr = MPI_Isend(sbuf_j,j,MPIU_INT,send_rank[i],tag2,comm,s_waits2+i);CHKERRQ(ierr);
2274     }
2275     /* wait on receives of mat->i,j */
2276     /*------------------------------*/
2277     count = nrecvs;
2278     while (count) {
2279       ierr = MPI_Waitany(nrecvs,r_waits2,&imdex,&recv_status);CHKERRQ(ierr);
2280       if (recv_rank[imdex] != recv_status.MPI_SOURCE) SETERRQ2(1, "recv_rank %d != MPI_SOURCE %d",recv_rank[imdex],recv_status.MPI_SOURCE);
2281       count--;
2282     }
2283     /* wait on sends of mat->i,j */
2284     /*---------------------------*/
2285     if (nsends) {
2286       ierr = MPI_Waitall(nsends,s_waits2,send_status);CHKERRQ(ierr);
2287     }
2288   } /* endof if (reuse == MAT_INITIAL_MATRIX) */
2289 
2290   /* post receives, send and receive mat->a */
2291   /*----------------------------------------*/
2292   for (imdex=0; imdex<nrecvs; imdex++) {
2293     ierr = MPI_Irecv(rbuf_a[imdex],rbuf_nz[imdex],MPIU_SCALAR,recv_rank[imdex],tag3,comm,r_waits3+imdex);CHKERRQ(ierr);
2294   }
2295   for (i=0; i<nsends; i++){
2296     ierr = MPI_Isend(sbuf_a,nzlocal,MPIU_SCALAR,send_rank[i],tag3,comm,s_waits3+i);CHKERRQ(ierr);
2297   }
2298   count = nrecvs;
2299   while (count) {
2300     ierr = MPI_Waitany(nrecvs,r_waits3,&imdex,&recv_status);CHKERRQ(ierr);
2301     if (recv_rank[imdex] != recv_status.MPI_SOURCE) SETERRQ2(1, "recv_rank %d != MPI_SOURCE %d",recv_rank[imdex],recv_status.MPI_SOURCE);
2302     count--;
2303   }
2304   if (nsends) {
2305     ierr = MPI_Waitall(nsends,s_waits3,send_status);CHKERRQ(ierr);
2306   }
2307 
2308   ierr = PetscFree2(s_waits3,send_status);CHKERRQ(ierr);
2309 
2310   /* create redundant matrix */
2311   /*-------------------------*/
2312   if (reuse == MAT_INITIAL_MATRIX){
2313     /* compute rownz_max for preallocation */
2314     for (imdex=0; imdex<nrecvs; imdex++){
2315       j = rowrange[recv_rank[imdex]+1] - rowrange[recv_rank[imdex]];
2316       rptr = rbuf_j[imdex];
2317       for (i=0; i<j; i++){
2318         ncols = rptr[i+1] - rptr[i];
2319         if (rownz_max < ncols) rownz_max = ncols;
2320       }
2321     }
2322 
2323     ierr = MatCreate(subcomm,&C);CHKERRQ(ierr);
2324     ierr = MatSetSizes(C,mlocal_sub,mlocal_sub,PETSC_DECIDE,PETSC_DECIDE);CHKERRQ(ierr);
2325     ierr = MatSetFromOptions(C);CHKERRQ(ierr);
2326     ierr = MatSeqAIJSetPreallocation(C,rownz_max,PETSC_NULL);CHKERRQ(ierr);
2327     ierr = MatMPIAIJSetPreallocation(C,rownz_max,PETSC_NULL,rownz_max,PETSC_NULL);CHKERRQ(ierr);
2328   } else {
2329     C = *matredundant;
2330   }
2331 
2332   /* insert local matrix entries */
2333   rptr = sbuf_j;
2334   cols = sbuf_j + rend-rstart + 1;
2335   vals = sbuf_a;
2336   for (i=0; i<rend-rstart; i++){
2337     row   = i + rstart;
2338     ncols = rptr[i+1] - rptr[i];
2339     ierr = MatSetValues(C,1,&row,ncols,cols,vals,INSERT_VALUES);CHKERRQ(ierr);
2340     vals += ncols;
2341     cols += ncols;
2342   }
2343   /* insert received matrix entries */
2344   for (imdex=0; imdex<nrecvs; imdex++){
2345     rstart = rowrange[recv_rank[imdex]];
2346     rend   = rowrange[recv_rank[imdex]+1];
2347     rptr = rbuf_j[imdex];
2348     cols = rbuf_j[imdex] + rend-rstart + 1;
2349     vals = rbuf_a[imdex];
2350     for (i=0; i<rend-rstart; i++){
2351       row   = i + rstart;
2352       ncols = rptr[i+1] - rptr[i];
2353       ierr = MatSetValues(C,1,&row,ncols,cols,vals,INSERT_VALUES);CHKERRQ(ierr);
2354       vals += ncols;
2355       cols += ncols;
2356     }
2357   }
2358   ierr = MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2359   ierr = MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2360   ierr = MatGetSize(C,&M,&N);CHKERRQ(ierr);
2361   if (M != mat->rmap->N || N != mat->cmap->N) SETERRQ2(PETSC_ERR_ARG_INCOMP,"redundant mat size %d != input mat size %d",M,mat->rmap->N);
2362   if (reuse == MAT_INITIAL_MATRIX){
2363     PetscContainer container;
2364     *matredundant = C;
2365     /* create a supporting struct and attach it to C for reuse */
2366     ierr = PetscNewLog(C,Mat_Redundant,&redund);CHKERRQ(ierr);
2367     ierr = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
2368     ierr = PetscContainerSetPointer(container,redund);CHKERRQ(ierr);
2369     ierr = PetscObjectCompose((PetscObject)C,"Mat_Redundant",(PetscObject)container);CHKERRQ(ierr);
2370     ierr = PetscContainerSetUserDestroy(container,PetscContainerDestroy_MatRedundant);CHKERRQ(ierr);
2371 
2372     redund->nzlocal = nzlocal;
2373     redund->nsends  = nsends;
2374     redund->nrecvs  = nrecvs;
2375     redund->send_rank = send_rank;
2376     redund->sbuf_nz = sbuf_nz;
2377     redund->sbuf_j  = sbuf_j;
2378     redund->sbuf_a  = sbuf_a;
2379     redund->rbuf_j  = rbuf_j;
2380     redund->rbuf_a  = rbuf_a;
2381 
2382     redund->MatDestroy = C->ops->destroy;
2383     C->ops->destroy    = MatDestroy_MatRedundant;
2384   }
2385   PetscFunctionReturn(0);
2386 }
2387 
2388 #undef __FUNCT__
2389 #define __FUNCT__ "MatGetRowMaxAbs_MPIAIJ"
2390 PetscErrorCode MatGetRowMaxAbs_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2391 {
2392   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2393   PetscErrorCode ierr;
2394   PetscInt       i,*idxb = 0;
2395   PetscScalar    *va,*vb;
2396   Vec            vtmp;
2397 
2398   PetscFunctionBegin;
2399   ierr = MatGetRowMaxAbs(a->A,v,idx);CHKERRQ(ierr);
2400   ierr = VecGetArray(v,&va);CHKERRQ(ierr);
2401   if (idx) {
2402     for (i=0; i<A->rmap->n; i++) {
2403       if (PetscAbsScalar(va[i])) idx[i] += A->cmap->rstart;
2404     }
2405   }
2406 
2407   ierr = VecCreateSeq(PETSC_COMM_SELF,A->rmap->n,&vtmp);CHKERRQ(ierr);
2408   if (idx) {
2409     ierr = PetscMalloc(A->rmap->n*sizeof(PetscInt),&idxb);CHKERRQ(ierr);
2410   }
2411   ierr = MatGetRowMaxAbs(a->B,vtmp,idxb);CHKERRQ(ierr);
2412   ierr = VecGetArray(vtmp,&vb);CHKERRQ(ierr);
2413 
2414   for (i=0; i<A->rmap->n; i++){
2415     if (PetscAbsScalar(va[i]) < PetscAbsScalar(vb[i])) {
2416       va[i] = vb[i];
2417       if (idx) idx[i] = a->garray[idxb[i]];
2418     }
2419   }
2420 
2421   ierr = VecRestoreArray(v,&va);CHKERRQ(ierr);
2422   ierr = VecRestoreArray(vtmp,&vb);CHKERRQ(ierr);
2423   if (idxb) {
2424     ierr = PetscFree(idxb);CHKERRQ(ierr);
2425   }
2426   ierr = VecDestroy(vtmp);CHKERRQ(ierr);
2427   PetscFunctionReturn(0);
2428 }
2429 
2430 #undef __FUNCT__
2431 #define __FUNCT__ "MatGetRowMinAbs_MPIAIJ"
2432 PetscErrorCode MatGetRowMinAbs_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2433 {
2434   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
2435   PetscErrorCode ierr;
2436   PetscInt       i,*idxb = 0;
2437   PetscScalar    *va,*vb;
2438   Vec            vtmp;
2439 
2440   PetscFunctionBegin;
2441   ierr = MatGetRowMinAbs(a->A,v,idx);CHKERRQ(ierr);
2442   ierr = VecGetArray(v,&va);CHKERRQ(ierr);
2443   if (idx) {
2444     for (i=0; i<A->cmap->n; i++) {
2445       if (PetscAbsScalar(va[i])) idx[i] += A->cmap->rstart;
2446     }
2447   }
2448 
2449   ierr = VecCreateSeq(PETSC_COMM_SELF,A->rmap->n,&vtmp);CHKERRQ(ierr);
2450   if (idx) {
2451     ierr = PetscMalloc(A->rmap->n*sizeof(PetscInt),&idxb);CHKERRQ(ierr);
2452   }
2453   ierr = MatGetRowMinAbs(a->B,vtmp,idxb);CHKERRQ(ierr);
2454   ierr = VecGetArray(vtmp,&vb);CHKERRQ(ierr);
2455 
2456   for (i=0; i<A->rmap->n; i++){
2457     if (PetscAbsScalar(va[i]) > PetscAbsScalar(vb[i])) {
2458       va[i] = vb[i];
2459       if (idx) idx[i] = a->garray[idxb[i]];
2460     }
2461   }
2462 
2463   ierr = VecRestoreArray(v,&va);CHKERRQ(ierr);
2464   ierr = VecRestoreArray(vtmp,&vb);CHKERRQ(ierr);
2465   if (idxb) {
2466     ierr = PetscFree(idxb);CHKERRQ(ierr);
2467   }
2468   ierr = VecDestroy(vtmp);CHKERRQ(ierr);
2469   PetscFunctionReturn(0);
2470 }
2471 
2472 #undef __FUNCT__
2473 #define __FUNCT__ "MatGetRowMin_MPIAIJ"
2474 PetscErrorCode MatGetRowMin_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2475 {
2476   Mat_MPIAIJ    *mat    = (Mat_MPIAIJ *) A->data;
2477   PetscInt       n      = A->rmap->n;
2478   PetscInt       cstart = A->cmap->rstart;
2479   PetscInt      *cmap   = mat->garray;
2480   PetscInt      *diagIdx, *offdiagIdx;
2481   Vec            diagV, offdiagV;
2482   PetscScalar   *a, *diagA, *offdiagA;
2483   PetscInt       r;
2484   PetscErrorCode ierr;
2485 
2486   PetscFunctionBegin;
2487   ierr = PetscMalloc2(n,PetscInt,&diagIdx,n,PetscInt,&offdiagIdx);CHKERRQ(ierr);
2488   ierr = VecCreateSeq(((PetscObject)A)->comm, n, &diagV);CHKERRQ(ierr);
2489   ierr = VecCreateSeq(((PetscObject)A)->comm, n, &offdiagV);CHKERRQ(ierr);
2490   ierr = MatGetRowMin(mat->A, diagV,    diagIdx);CHKERRQ(ierr);
2491   ierr = MatGetRowMin(mat->B, offdiagV, offdiagIdx);CHKERRQ(ierr);
2492   ierr = VecGetArray(v,        &a);CHKERRQ(ierr);
2493   ierr = VecGetArray(diagV,    &diagA);CHKERRQ(ierr);
2494   ierr = VecGetArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2495   for(r = 0; r < n; ++r) {
2496     if (PetscAbsScalar(diagA[r]) <= PetscAbsScalar(offdiagA[r])) {
2497       a[r]   = diagA[r];
2498       idx[r] = cstart + diagIdx[r];
2499     } else {
2500       a[r]   = offdiagA[r];
2501       idx[r] = cmap[offdiagIdx[r]];
2502     }
2503   }
2504   ierr = VecRestoreArray(v,        &a);CHKERRQ(ierr);
2505   ierr = VecRestoreArray(diagV,    &diagA);CHKERRQ(ierr);
2506   ierr = VecRestoreArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2507   ierr = VecDestroy(diagV);CHKERRQ(ierr);
2508   ierr = VecDestroy(offdiagV);CHKERRQ(ierr);
2509   ierr = PetscFree2(diagIdx, offdiagIdx);CHKERRQ(ierr);
2510   PetscFunctionReturn(0);
2511 }
2512 
2513 #undef __FUNCT__
2514 #define __FUNCT__ "MatGetRowMax_MPIAIJ"
2515 PetscErrorCode MatGetRowMax_MPIAIJ(Mat A, Vec v, PetscInt idx[])
2516 {
2517   Mat_MPIAIJ    *mat    = (Mat_MPIAIJ *) A->data;
2518   PetscInt       n      = A->rmap->n;
2519   PetscInt       cstart = A->cmap->rstart;
2520   PetscInt      *cmap   = mat->garray;
2521   PetscInt      *diagIdx, *offdiagIdx;
2522   Vec            diagV, offdiagV;
2523   PetscScalar   *a, *diagA, *offdiagA;
2524   PetscInt       r;
2525   PetscErrorCode ierr;
2526 
2527   PetscFunctionBegin;
2528   ierr = PetscMalloc2(n,PetscInt,&diagIdx,n,PetscInt,&offdiagIdx);CHKERRQ(ierr);
2529   ierr = VecCreateSeq(((PetscObject)A)->comm, n, &diagV);CHKERRQ(ierr);
2530   ierr = VecCreateSeq(((PetscObject)A)->comm, n, &offdiagV);CHKERRQ(ierr);
2531   ierr = MatGetRowMax(mat->A, diagV,    diagIdx);CHKERRQ(ierr);
2532   ierr = MatGetRowMax(mat->B, offdiagV, offdiagIdx);CHKERRQ(ierr);
2533   ierr = VecGetArray(v,        &a);CHKERRQ(ierr);
2534   ierr = VecGetArray(diagV,    &diagA);CHKERRQ(ierr);
2535   ierr = VecGetArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2536   for(r = 0; r < n; ++r) {
2537     if (PetscAbsScalar(diagA[r]) >= PetscAbsScalar(offdiagA[r])) {
2538       a[r]   = diagA[r];
2539       idx[r] = cstart + diagIdx[r];
2540     } else {
2541       a[r]   = offdiagA[r];
2542       idx[r] = cmap[offdiagIdx[r]];
2543     }
2544   }
2545   ierr = VecRestoreArray(v,        &a);CHKERRQ(ierr);
2546   ierr = VecRestoreArray(diagV,    &diagA);CHKERRQ(ierr);
2547   ierr = VecRestoreArray(offdiagV, &offdiagA);CHKERRQ(ierr);
2548   ierr = VecDestroy(diagV);CHKERRQ(ierr);
2549   ierr = VecDestroy(offdiagV);CHKERRQ(ierr);
2550   ierr = PetscFree2(diagIdx, offdiagIdx);CHKERRQ(ierr);
2551   PetscFunctionReturn(0);
2552 }
2553 
2554 #undef __FUNCT__
2555 #define __FUNCT__ "MatGetSeqNonzerostructure_MPIAIJ"
2556 PetscErrorCode MatGetSeqNonzerostructure_MPIAIJ(Mat mat,Mat *newmat[])
2557 {
2558   PetscErrorCode ierr;
2559 
2560   PetscFunctionBegin;
2561   ierr = MatGetSubMatrix_MPIAIJ_All(mat,MAT_DO_NOT_GET_VALUES,MAT_INITIAL_MATRIX,newmat);CHKERRQ(ierr);
2562   PetscFunctionReturn(0);
2563 }
2564 
2565 /* -------------------------------------------------------------------*/
2566 static struct _MatOps MatOps_Values = {MatSetValues_MPIAIJ,
2567        MatGetRow_MPIAIJ,
2568        MatRestoreRow_MPIAIJ,
2569        MatMult_MPIAIJ,
2570 /* 4*/ MatMultAdd_MPIAIJ,
2571        MatMultTranspose_MPIAIJ,
2572        MatMultTransposeAdd_MPIAIJ,
2573 #ifdef PETSC_HAVE_PBGL
2574        MatSolve_MPIAIJ,
2575 #else
2576        0,
2577 #endif
2578        0,
2579        0,
2580 /*10*/ 0,
2581        0,
2582        0,
2583        MatRelax_MPIAIJ,
2584        MatTranspose_MPIAIJ,
2585 /*15*/ MatGetInfo_MPIAIJ,
2586        MatEqual_MPIAIJ,
2587        MatGetDiagonal_MPIAIJ,
2588        MatDiagonalScale_MPIAIJ,
2589        MatNorm_MPIAIJ,
2590 /*20*/ MatAssemblyBegin_MPIAIJ,
2591        MatAssemblyEnd_MPIAIJ,
2592        MatSetOption_MPIAIJ,
2593        MatZeroEntries_MPIAIJ,
2594 /*24*/ MatZeroRows_MPIAIJ,
2595        0,
2596 #ifdef PETSC_HAVE_PBGL
2597        0,
2598 #else
2599        0,
2600 #endif
2601        0,
2602        0,
2603 /*29*/ MatSetUpPreallocation_MPIAIJ,
2604 #ifdef PETSC_HAVE_PBGL
2605        0,
2606 #else
2607        0,
2608 #endif
2609        0,
2610        0,
2611        0,
2612 /*34*/ MatDuplicate_MPIAIJ,
2613        0,
2614        0,
2615        0,
2616        0,
2617 /*39*/ MatAXPY_MPIAIJ,
2618        MatGetSubMatrices_MPIAIJ,
2619        MatIncreaseOverlap_MPIAIJ,
2620        MatGetValues_MPIAIJ,
2621        MatCopy_MPIAIJ,
2622 /*44*/ MatGetRowMax_MPIAIJ,
2623        MatScale_MPIAIJ,
2624        0,
2625        0,
2626        0,
2627 /*49*/ MatSetBlockSize_MPIAIJ,
2628        0,
2629        0,
2630        0,
2631        0,
2632 /*54*/ MatFDColoringCreate_MPIAIJ,
2633        0,
2634        MatSetUnfactored_MPIAIJ,
2635        MatPermute_MPIAIJ,
2636        0,
2637 /*59*/ MatGetSubMatrix_MPIAIJ,
2638        MatDestroy_MPIAIJ,
2639        MatView_MPIAIJ,
2640        0,
2641        0,
2642 /*64*/ 0,
2643        0,
2644        0,
2645        0,
2646        0,
2647 /*69*/ MatGetRowMaxAbs_MPIAIJ,
2648        MatGetRowMinAbs_MPIAIJ,
2649        0,
2650        MatSetColoring_MPIAIJ,
2651 #if defined(PETSC_HAVE_ADIC)
2652        MatSetValuesAdic_MPIAIJ,
2653 #else
2654        0,
2655 #endif
2656        MatSetValuesAdifor_MPIAIJ,
2657 /*75*/ 0,
2658        0,
2659        0,
2660        0,
2661        0,
2662 /*80*/ 0,
2663        0,
2664        0,
2665 /*83*/ MatLoad_MPIAIJ,
2666        0,
2667        0,
2668        0,
2669        0,
2670        0,
2671 /*89*/ MatMatMult_MPIAIJ_MPIAIJ,
2672        MatMatMultSymbolic_MPIAIJ_MPIAIJ,
2673        MatMatMultNumeric_MPIAIJ_MPIAIJ,
2674        MatPtAP_Basic,
2675        MatPtAPSymbolic_MPIAIJ,
2676 /*94*/ MatPtAPNumeric_MPIAIJ,
2677        0,
2678        0,
2679        0,
2680        0,
2681 /*99*/ 0,
2682        MatPtAPSymbolic_MPIAIJ_MPIAIJ,
2683        MatPtAPNumeric_MPIAIJ_MPIAIJ,
2684        MatConjugate_MPIAIJ,
2685        0,
2686 /*104*/MatSetValuesRow_MPIAIJ,
2687        MatRealPart_MPIAIJ,
2688        MatImaginaryPart_MPIAIJ,
2689        0,
2690        0,
2691 /*109*/0,
2692        MatGetRedundantMatrix_MPIAIJ,
2693        MatGetRowMin_MPIAIJ,
2694        0,
2695        0,
2696 /*114*/MatGetSeqNonzerostructure_MPIAIJ,
2697        0,
2698        0,
2699        0,
2700        0,
2701        0
2702 };
2703 
2704 /* ----------------------------------------------------------------------------------------*/
2705 
2706 EXTERN_C_BEGIN
2707 #undef __FUNCT__
2708 #define __FUNCT__ "MatStoreValues_MPIAIJ"
2709 PetscErrorCode PETSCMAT_DLLEXPORT MatStoreValues_MPIAIJ(Mat mat)
2710 {
2711   Mat_MPIAIJ     *aij = (Mat_MPIAIJ *)mat->data;
2712   PetscErrorCode ierr;
2713 
2714   PetscFunctionBegin;
2715   ierr = MatStoreValues(aij->A);CHKERRQ(ierr);
2716   ierr = MatStoreValues(aij->B);CHKERRQ(ierr);
2717   PetscFunctionReturn(0);
2718 }
2719 EXTERN_C_END
2720 
2721 EXTERN_C_BEGIN
2722 #undef __FUNCT__
2723 #define __FUNCT__ "MatRetrieveValues_MPIAIJ"
2724 PetscErrorCode PETSCMAT_DLLEXPORT MatRetrieveValues_MPIAIJ(Mat mat)
2725 {
2726   Mat_MPIAIJ     *aij = (Mat_MPIAIJ *)mat->data;
2727   PetscErrorCode ierr;
2728 
2729   PetscFunctionBegin;
2730   ierr = MatRetrieveValues(aij->A);CHKERRQ(ierr);
2731   ierr = MatRetrieveValues(aij->B);CHKERRQ(ierr);
2732   PetscFunctionReturn(0);
2733 }
2734 EXTERN_C_END
2735 
2736 #include "petscpc.h"
2737 EXTERN_C_BEGIN
2738 #undef __FUNCT__
2739 #define __FUNCT__ "MatMPIAIJSetPreallocation_MPIAIJ"
2740 PetscErrorCode PETSCMAT_DLLEXPORT MatMPIAIJSetPreallocation_MPIAIJ(Mat B,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[])
2741 {
2742   Mat_MPIAIJ     *b;
2743   PetscErrorCode ierr;
2744   PetscInt       i;
2745 
2746   PetscFunctionBegin;
2747   if (d_nz == PETSC_DEFAULT || d_nz == PETSC_DECIDE) d_nz = 5;
2748   if (o_nz == PETSC_DEFAULT || o_nz == PETSC_DECIDE) o_nz = 2;
2749   if (d_nz < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"d_nz cannot be less than 0: value %D",d_nz);
2750   if (o_nz < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"o_nz cannot be less than 0: value %D",o_nz);
2751 
2752   ierr = PetscMapSetBlockSize(B->rmap,1);CHKERRQ(ierr);
2753   ierr = PetscMapSetBlockSize(B->cmap,1);CHKERRQ(ierr);
2754   ierr = PetscMapSetUp(B->rmap);CHKERRQ(ierr);
2755   ierr = PetscMapSetUp(B->cmap);CHKERRQ(ierr);
2756   if (d_nnz) {
2757     for (i=0; i<B->rmap->n; i++) {
2758       if (d_nnz[i] < 0) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"d_nnz cannot be less than 0: local row %D value %D",i,d_nnz[i]);
2759     }
2760   }
2761   if (o_nnz) {
2762     for (i=0; i<B->rmap->n; i++) {
2763       if (o_nnz[i] < 0) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"o_nnz cannot be less than 0: local row %D value %D",i,o_nnz[i]);
2764     }
2765   }
2766   b = (Mat_MPIAIJ*)B->data;
2767 
2768   if (!B->preallocated) {
2769     /* Explicitly create 2 MATSEQAIJ matrices. */
2770     ierr = MatCreate(PETSC_COMM_SELF,&b->A);CHKERRQ(ierr);
2771     ierr = MatSetSizes(b->A,B->rmap->n,B->cmap->n,B->rmap->n,B->cmap->n);CHKERRQ(ierr);
2772     ierr = MatSetType(b->A,MATSEQAIJ);CHKERRQ(ierr);
2773     ierr = PetscLogObjectParent(B,b->A);CHKERRQ(ierr);
2774     ierr = MatCreate(PETSC_COMM_SELF,&b->B);CHKERRQ(ierr);
2775     ierr = MatSetSizes(b->B,B->rmap->n,B->cmap->N,B->rmap->n,B->cmap->N);CHKERRQ(ierr);
2776     ierr = MatSetType(b->B,MATSEQAIJ);CHKERRQ(ierr);
2777     ierr = PetscLogObjectParent(B,b->B);CHKERRQ(ierr);
2778   }
2779 
2780   ierr = MatSeqAIJSetPreallocation(b->A,d_nz,d_nnz);CHKERRQ(ierr);
2781   ierr = MatSeqAIJSetPreallocation(b->B,o_nz,o_nnz);CHKERRQ(ierr);
2782   B->preallocated = PETSC_TRUE;
2783   PetscFunctionReturn(0);
2784 }
2785 EXTERN_C_END
2786 
2787 #undef __FUNCT__
2788 #define __FUNCT__ "MatDuplicate_MPIAIJ"
2789 PetscErrorCode MatDuplicate_MPIAIJ(Mat matin,MatDuplicateOption cpvalues,Mat *newmat)
2790 {
2791   Mat            mat;
2792   Mat_MPIAIJ     *a,*oldmat = (Mat_MPIAIJ*)matin->data;
2793   PetscErrorCode ierr;
2794 
2795   PetscFunctionBegin;
2796   *newmat       = 0;
2797   ierr = MatCreate(((PetscObject)matin)->comm,&mat);CHKERRQ(ierr);
2798   ierr = MatSetSizes(mat,matin->rmap->n,matin->cmap->n,matin->rmap->N,matin->cmap->N);CHKERRQ(ierr);
2799   ierr = MatSetType(mat,((PetscObject)matin)->type_name);CHKERRQ(ierr);
2800   ierr = PetscMemcpy(mat->ops,matin->ops,sizeof(struct _MatOps));CHKERRQ(ierr);
2801   a    = (Mat_MPIAIJ*)mat->data;
2802 
2803   mat->factor       = matin->factor;
2804   mat->rmap->bs      = matin->rmap->bs;
2805   mat->assembled    = PETSC_TRUE;
2806   mat->insertmode   = NOT_SET_VALUES;
2807   mat->preallocated = PETSC_TRUE;
2808 
2809   a->size           = oldmat->size;
2810   a->rank           = oldmat->rank;
2811   a->donotstash     = oldmat->donotstash;
2812   a->roworiented    = oldmat->roworiented;
2813   a->rowindices     = 0;
2814   a->rowvalues      = 0;
2815   a->getrowactive   = PETSC_FALSE;
2816 
2817   ierr = PetscMapCopy(((PetscObject)mat)->comm,matin->rmap,mat->rmap);CHKERRQ(ierr);
2818   ierr = PetscMapCopy(((PetscObject)mat)->comm,matin->cmap,mat->cmap);CHKERRQ(ierr);
2819 
2820   ierr = MatStashCreate_Private(((PetscObject)matin)->comm,1,&mat->stash);CHKERRQ(ierr);
2821   if (oldmat->colmap) {
2822 #if defined (PETSC_USE_CTABLE)
2823     ierr = PetscTableCreateCopy(oldmat->colmap,&a->colmap);CHKERRQ(ierr);
2824 #else
2825     ierr = PetscMalloc((mat->cmap->N)*sizeof(PetscInt),&a->colmap);CHKERRQ(ierr);
2826     ierr = PetscLogObjectMemory(mat,(mat->cmap->N)*sizeof(PetscInt));CHKERRQ(ierr);
2827     ierr = PetscMemcpy(a->colmap,oldmat->colmap,(mat->cmap->N)*sizeof(PetscInt));CHKERRQ(ierr);
2828 #endif
2829   } else a->colmap = 0;
2830   if (oldmat->garray) {
2831     PetscInt len;
2832     len  = oldmat->B->cmap->n;
2833     ierr = PetscMalloc((len+1)*sizeof(PetscInt),&a->garray);CHKERRQ(ierr);
2834     ierr = PetscLogObjectMemory(mat,len*sizeof(PetscInt));CHKERRQ(ierr);
2835     if (len) { ierr = PetscMemcpy(a->garray,oldmat->garray,len*sizeof(PetscInt));CHKERRQ(ierr); }
2836   } else a->garray = 0;
2837 
2838   ierr = VecDuplicate(oldmat->lvec,&a->lvec);CHKERRQ(ierr);
2839   ierr = PetscLogObjectParent(mat,a->lvec);CHKERRQ(ierr);
2840   ierr = VecScatterCopy(oldmat->Mvctx,&a->Mvctx);CHKERRQ(ierr);
2841   ierr = PetscLogObjectParent(mat,a->Mvctx);CHKERRQ(ierr);
2842   ierr = MatDuplicate(oldmat->A,cpvalues,&a->A);CHKERRQ(ierr);
2843   ierr = PetscLogObjectParent(mat,a->A);CHKERRQ(ierr);
2844   ierr = MatDuplicate(oldmat->B,cpvalues,&a->B);CHKERRQ(ierr);
2845   ierr = PetscLogObjectParent(mat,a->B);CHKERRQ(ierr);
2846   ierr = PetscFListDuplicate(((PetscObject)matin)->qlist,&((PetscObject)mat)->qlist);CHKERRQ(ierr);
2847   *newmat = mat;
2848   PetscFunctionReturn(0);
2849 }
2850 
2851 #include "petscsys.h"
2852 
2853 #undef __FUNCT__
2854 #define __FUNCT__ "MatLoad_MPIAIJ"
2855 PetscErrorCode MatLoad_MPIAIJ(PetscViewer viewer, const MatType type,Mat *newmat)
2856 {
2857   Mat            A;
2858   PetscScalar    *vals,*svals;
2859   MPI_Comm       comm = ((PetscObject)viewer)->comm;
2860   MPI_Status     status;
2861   PetscErrorCode ierr;
2862   PetscMPIInt    rank,size,tag = ((PetscObject)viewer)->tag,mpicnt,mpimaxnz;
2863   PetscInt       i,nz,j,rstart,rend,mmax,maxnz = 0;
2864   PetscInt       header[4],*rowlengths = 0,M,N,m,*cols;
2865   PetscInt       *ourlens = PETSC_NULL,*procsnz = PETSC_NULL,*offlens = PETSC_NULL,jj,*mycols,*smycols;
2866   PetscInt       cend,cstart,n,*rowners;
2867   int            fd;
2868 
2869   PetscFunctionBegin;
2870   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2871   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
2872   if (!rank) {
2873     ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
2874     ierr = PetscBinaryRead(fd,(char *)header,4,PETSC_INT);CHKERRQ(ierr);
2875     if (header[0] != MAT_FILE_COOKIE) SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"not matrix object");
2876   }
2877 
2878   ierr = MPI_Bcast(header+1,3,MPIU_INT,0,comm);CHKERRQ(ierr);
2879   M = header[1]; N = header[2];
2880   /* determine ownership of all rows */
2881   m    = M/size + ((M % size) > rank);
2882   ierr = PetscMalloc((size+1)*sizeof(PetscInt),&rowners);CHKERRQ(ierr);
2883   ierr = MPI_Allgather(&m,1,MPIU_INT,rowners+1,1,MPIU_INT,comm);CHKERRQ(ierr);
2884 
2885   /* First process needs enough room for process with most rows */
2886   if (!rank) {
2887     mmax       = rowners[1];
2888     for (i=2; i<size; i++) {
2889       mmax = PetscMax(mmax,rowners[i]);
2890     }
2891   } else mmax = m;
2892 
2893   rowners[0] = 0;
2894   for (i=2; i<=size; i++) {
2895     rowners[i] += rowners[i-1];
2896   }
2897   rstart = rowners[rank];
2898   rend   = rowners[rank+1];
2899 
2900   /* distribute row lengths to all processors */
2901   ierr    = PetscMalloc2(mmax,PetscInt,&ourlens,mmax,PetscInt,&offlens);CHKERRQ(ierr);
2902   if (!rank) {
2903     ierr = PetscBinaryRead(fd,ourlens,m,PETSC_INT);CHKERRQ(ierr);
2904     ierr = PetscMalloc(m*sizeof(PetscInt),&rowlengths);CHKERRQ(ierr);
2905     ierr = PetscMalloc(size*sizeof(PetscInt),&procsnz);CHKERRQ(ierr);
2906     ierr = PetscMemzero(procsnz,size*sizeof(PetscInt));CHKERRQ(ierr);
2907     for (j=0; j<m; j++) {
2908       procsnz[0] += ourlens[j];
2909     }
2910     for (i=1; i<size; i++) {
2911       ierr = PetscBinaryRead(fd,rowlengths,rowners[i+1]-rowners[i],PETSC_INT);CHKERRQ(ierr);
2912       /* calculate the number of nonzeros on each processor */
2913       for (j=0; j<rowners[i+1]-rowners[i]; j++) {
2914         procsnz[i] += rowlengths[j];
2915       }
2916       mpicnt = PetscMPIIntCast(rowners[i+1]-rowners[i]);
2917       ierr   = MPI_Send(rowlengths,mpicnt,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
2918     }
2919     ierr = PetscFree(rowlengths);CHKERRQ(ierr);
2920   } else {
2921     mpicnt = PetscMPIIntCast(m);CHKERRQ(ierr);
2922     ierr   = MPI_Recv(ourlens,mpicnt,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
2923   }
2924 
2925   if (!rank) {
2926     /* determine max buffer needed and allocate it */
2927     maxnz = 0;
2928     for (i=0; i<size; i++) {
2929       maxnz = PetscMax(maxnz,procsnz[i]);
2930     }
2931     ierr = PetscMalloc(maxnz*sizeof(PetscInt),&cols);CHKERRQ(ierr);
2932 
2933     /* read in my part of the matrix column indices  */
2934     nz   = procsnz[0];
2935     ierr = PetscMalloc(nz*sizeof(PetscInt),&mycols);CHKERRQ(ierr);
2936     ierr = PetscBinaryRead(fd,mycols,nz,PETSC_INT);CHKERRQ(ierr);
2937 
2938     /* read in every one elses and ship off */
2939     for (i=1; i<size; i++) {
2940       nz     = procsnz[i];
2941       ierr   = PetscBinaryRead(fd,cols,nz,PETSC_INT);CHKERRQ(ierr);
2942       mpicnt = PetscMPIIntCast(nz);
2943       ierr   = MPI_Send(cols,mpicnt,MPIU_INT,i,tag,comm);CHKERRQ(ierr);
2944     }
2945     ierr = PetscFree(cols);CHKERRQ(ierr);
2946   } else {
2947     /* determine buffer space needed for message */
2948     nz = 0;
2949     for (i=0; i<m; i++) {
2950       nz += ourlens[i];
2951     }
2952     ierr = PetscMalloc(nz*sizeof(PetscInt),&mycols);CHKERRQ(ierr);
2953 
2954     /* receive message of column indices*/
2955     mpicnt = PetscMPIIntCast(nz);CHKERRQ(ierr);
2956     ierr = MPI_Recv(mycols,mpicnt,MPIU_INT,0,tag,comm,&status);CHKERRQ(ierr);
2957     ierr = MPI_Get_count(&status,MPIU_INT,&mpimaxnz);CHKERRQ(ierr);
2958     if (mpimaxnz == MPI_UNDEFINED) {SETERRQ1(PETSC_ERR_LIB,"MPI_Get_count() returned MPI_UNDEFINED, expected %d",mpicnt);}
2959     else if (mpimaxnz < 0) {SETERRQ2(PETSC_ERR_LIB,"MPI_Get_count() returned impossible negative value %d, expected %d",mpimaxnz,mpicnt);}
2960     else if (mpimaxnz != mpicnt) {SETERRQ2(PETSC_ERR_FILE_UNEXPECTED,"something is wrong with file: expected %d received %d",mpicnt,mpimaxnz);}
2961   }
2962 
2963   /* determine column ownership if matrix is not square */
2964   if (N != M) {
2965     n      = N/size + ((N % size) > rank);
2966     ierr   = MPI_Scan(&n,&cend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
2967     cstart = cend - n;
2968   } else {
2969     cstart = rstart;
2970     cend   = rend;
2971     n      = cend - cstart;
2972   }
2973 
2974   /* loop over local rows, determining number of off diagonal entries */
2975   ierr = PetscMemzero(offlens,m*sizeof(PetscInt));CHKERRQ(ierr);
2976   jj = 0;
2977   for (i=0; i<m; i++) {
2978     for (j=0; j<ourlens[i]; j++) {
2979       if (mycols[jj] < cstart || mycols[jj] >= cend) offlens[i]++;
2980       jj++;
2981     }
2982   }
2983 
2984   /* create our matrix */
2985   for (i=0; i<m; i++) {
2986     ourlens[i] -= offlens[i];
2987   }
2988   ierr = MatCreate(comm,&A);CHKERRQ(ierr);
2989   ierr = MatSetSizes(A,m,n,M,N);CHKERRQ(ierr);
2990   ierr = MatSetType(A,type);CHKERRQ(ierr);
2991   ierr = MatMPIAIJSetPreallocation(A,0,ourlens,0,offlens);CHKERRQ(ierr);
2992 
2993   for (i=0; i<m; i++) {
2994     ourlens[i] += offlens[i];
2995   }
2996 
2997   if (!rank) {
2998     ierr = PetscMalloc((maxnz+1)*sizeof(PetscScalar),&vals);CHKERRQ(ierr);
2999 
3000     /* read in my part of the matrix numerical values  */
3001     nz   = procsnz[0];
3002     ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
3003 
3004     /* insert into matrix */
3005     jj      = rstart;
3006     smycols = mycols;
3007     svals   = vals;
3008     for (i=0; i<m; i++) {
3009       ierr = MatSetValues_MPIAIJ(A,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
3010       smycols += ourlens[i];
3011       svals   += ourlens[i];
3012       jj++;
3013     }
3014 
3015     /* read in other processors and ship out */
3016     for (i=1; i<size; i++) {
3017       nz     = procsnz[i];
3018       ierr   = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
3019       mpicnt = PetscMPIIntCast(nz);
3020       ierr   = MPI_Send(vals,mpicnt,MPIU_SCALAR,i,((PetscObject)A)->tag,comm);CHKERRQ(ierr);
3021     }
3022     ierr = PetscFree(procsnz);CHKERRQ(ierr);
3023   } else {
3024     /* receive numeric values */
3025     ierr = PetscMalloc((nz+1)*sizeof(PetscScalar),&vals);CHKERRQ(ierr);
3026 
3027     /* receive message of values*/
3028     mpicnt = PetscMPIIntCast(nz);
3029     ierr   = MPI_Recv(vals,mpicnt,MPIU_SCALAR,0,((PetscObject)A)->tag,comm,&status);CHKERRQ(ierr);
3030     ierr   = MPI_Get_count(&status,MPIU_SCALAR,&mpimaxnz);CHKERRQ(ierr);
3031     if (mpimaxnz == MPI_UNDEFINED) {SETERRQ1(PETSC_ERR_LIB,"MPI_Get_count() returned MPI_UNDEFINED, expected %d",mpicnt);}
3032     else if (mpimaxnz < 0) {SETERRQ2(PETSC_ERR_LIB,"MPI_Get_count() returned impossible negative value %d, expected %d",mpimaxnz,mpicnt);}
3033     else if (mpimaxnz != mpicnt) {SETERRQ2(PETSC_ERR_FILE_UNEXPECTED,"something is wrong with file: expected %d received %d",mpicnt,mpimaxnz);}
3034 
3035     /* insert into matrix */
3036     jj      = rstart;
3037     smycols = mycols;
3038     svals   = vals;
3039     for (i=0; i<m; i++) {
3040       ierr     = MatSetValues_MPIAIJ(A,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
3041       smycols += ourlens[i];
3042       svals   += ourlens[i];
3043       jj++;
3044     }
3045   }
3046   ierr = PetscFree2(ourlens,offlens);CHKERRQ(ierr);
3047   ierr = PetscFree(vals);CHKERRQ(ierr);
3048   ierr = PetscFree(mycols);CHKERRQ(ierr);
3049   ierr = PetscFree(rowners);CHKERRQ(ierr);
3050 
3051   ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3052   ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3053   *newmat = A;
3054   PetscFunctionReturn(0);
3055 }
3056 
3057 #undef __FUNCT__
3058 #define __FUNCT__ "MatGetSubMatrix_MPIAIJ"
3059 PetscErrorCode MatGetSubMatrix_MPIAIJ(Mat mat,IS isrow,IS iscol,MatReuse call,Mat *newmat)
3060 {
3061   PetscErrorCode ierr;
3062   IS             iscol_local;
3063   PetscInt       csize;
3064 
3065   PetscFunctionBegin;
3066   ierr = ISGetLocalSize(iscol,&csize);CHKERRQ(ierr);
3067   if (call == MAT_REUSE_MATRIX) {
3068     ierr = PetscObjectQuery((PetscObject)*newmat,"ISAllGather",(PetscObject*)&iscol_local);CHKERRQ(ierr);
3069     if (!iscol_local) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3070   } else {
3071     ierr = ISAllGather(iscol,&iscol_local);CHKERRQ(ierr);
3072   }
3073   ierr = MatGetSubMatrix_MPIAIJ_Private(mat,isrow,iscol_local,csize,call,newmat);CHKERRQ(ierr);
3074   if (call == MAT_INITIAL_MATRIX) {
3075     ierr = PetscObjectCompose((PetscObject)*newmat,"ISAllGather",(PetscObject)iscol_local);CHKERRQ(ierr);
3076     ierr = ISDestroy(iscol_local);CHKERRQ(ierr);
3077   }
3078   PetscFunctionReturn(0);
3079 }
3080 
3081 #undef __FUNCT__
3082 #define __FUNCT__ "MatGetSubMatrix_MPIAIJ_Private"
3083 /*
3084     Not great since it makes two copies of the submatrix, first an SeqAIJ
3085   in local and then by concatenating the local matrices the end result.
3086   Writing it directly would be much like MatGetSubMatrices_MPIAIJ()
3087 
3088   Note: This requires a sequential iscol with all indices.
3089 */
3090 PetscErrorCode MatGetSubMatrix_MPIAIJ_Private(Mat mat,IS isrow,IS iscol,PetscInt csize,MatReuse call,Mat *newmat)
3091 {
3092   PetscErrorCode ierr;
3093   PetscMPIInt    rank,size;
3094   PetscInt       i,m,n,rstart,row,rend,nz,*cwork,j;
3095   PetscInt       *ii,*jj,nlocal,*dlens,*olens,dlen,olen,jend,mglobal;
3096   Mat            *local,M,Mreuse;
3097   MatScalar      *vwork,*aa;
3098   MPI_Comm       comm = ((PetscObject)mat)->comm;
3099   Mat_SeqAIJ     *aij;
3100 
3101 
3102   PetscFunctionBegin;
3103   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
3104   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3105 
3106   if (call ==  MAT_REUSE_MATRIX) {
3107     ierr = PetscObjectQuery((PetscObject)*newmat,"SubMatrix",(PetscObject *)&Mreuse);CHKERRQ(ierr);
3108     if (!Mreuse) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Submatrix passed in was not used before, cannot reuse");
3109     local = &Mreuse;
3110     ierr  = MatGetSubMatrices(mat,1,&isrow,&iscol,MAT_REUSE_MATRIX,&local);CHKERRQ(ierr);
3111   } else {
3112     ierr   = MatGetSubMatrices(mat,1,&isrow,&iscol,MAT_INITIAL_MATRIX,&local);CHKERRQ(ierr);
3113     Mreuse = *local;
3114     ierr   = PetscFree(local);CHKERRQ(ierr);
3115   }
3116 
3117   /*
3118       m - number of local rows
3119       n - number of columns (same on all processors)
3120       rstart - first row in new global matrix generated
3121   */
3122   ierr = MatGetSize(Mreuse,&m,&n);CHKERRQ(ierr);
3123   if (call == MAT_INITIAL_MATRIX) {
3124     aij = (Mat_SeqAIJ*)(Mreuse)->data;
3125     ii  = aij->i;
3126     jj  = aij->j;
3127 
3128     /*
3129         Determine the number of non-zeros in the diagonal and off-diagonal
3130         portions of the matrix in order to do correct preallocation
3131     */
3132 
3133     /* first get start and end of "diagonal" columns */
3134     if (csize == PETSC_DECIDE) {
3135       ierr = ISGetSize(isrow,&mglobal);CHKERRQ(ierr);
3136       if (mglobal == n) { /* square matrix */
3137 	nlocal = m;
3138       } else {
3139         nlocal = n/size + ((n % size) > rank);
3140       }
3141     } else {
3142       nlocal = csize;
3143     }
3144     ierr   = MPI_Scan(&nlocal,&rend,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3145     rstart = rend - nlocal;
3146     if (rank == size - 1 && rend != n) {
3147       SETERRQ2(PETSC_ERR_ARG_SIZ,"Local column sizes %D do not add up to total number of columns %D",rend,n);
3148     }
3149 
3150     /* next, compute all the lengths */
3151     ierr  = PetscMalloc((2*m+1)*sizeof(PetscInt),&dlens);CHKERRQ(ierr);
3152     olens = dlens + m;
3153     for (i=0; i<m; i++) {
3154       jend = ii[i+1] - ii[i];
3155       olen = 0;
3156       dlen = 0;
3157       for (j=0; j<jend; j++) {
3158         if (*jj < rstart || *jj >= rend) olen++;
3159         else dlen++;
3160         jj++;
3161       }
3162       olens[i] = olen;
3163       dlens[i] = dlen;
3164     }
3165     ierr = MatCreate(comm,&M);CHKERRQ(ierr);
3166     ierr = MatSetSizes(M,m,nlocal,PETSC_DECIDE,n);CHKERRQ(ierr);
3167     ierr = MatSetType(M,((PetscObject)mat)->type_name);CHKERRQ(ierr);
3168     ierr = MatMPIAIJSetPreallocation(M,0,dlens,0,olens);CHKERRQ(ierr);
3169     ierr = PetscFree(dlens);CHKERRQ(ierr);
3170   } else {
3171     PetscInt ml,nl;
3172 
3173     M = *newmat;
3174     ierr = MatGetLocalSize(M,&ml,&nl);CHKERRQ(ierr);
3175     if (ml != m) SETERRQ(PETSC_ERR_ARG_SIZ,"Previous matrix must be same size/layout as request");
3176     ierr = MatZeroEntries(M);CHKERRQ(ierr);
3177     /*
3178          The next two lines are needed so we may call MatSetValues_MPIAIJ() below directly,
3179        rather than the slower MatSetValues().
3180     */
3181     M->was_assembled = PETSC_TRUE;
3182     M->assembled     = PETSC_FALSE;
3183   }
3184   ierr = MatGetOwnershipRange(M,&rstart,&rend);CHKERRQ(ierr);
3185   aij = (Mat_SeqAIJ*)(Mreuse)->data;
3186   ii  = aij->i;
3187   jj  = aij->j;
3188   aa  = aij->a;
3189   for (i=0; i<m; i++) {
3190     row   = rstart + i;
3191     nz    = ii[i+1] - ii[i];
3192     cwork = jj;     jj += nz;
3193     vwork = aa;     aa += nz;
3194     ierr = MatSetValues_MPIAIJ(M,1,&row,nz,cwork,vwork,INSERT_VALUES);CHKERRQ(ierr);
3195   }
3196 
3197   ierr = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3198   ierr = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3199   *newmat = M;
3200 
3201   /* save submatrix used in processor for next request */
3202   if (call ==  MAT_INITIAL_MATRIX) {
3203     ierr = PetscObjectCompose((PetscObject)M,"SubMatrix",(PetscObject)Mreuse);CHKERRQ(ierr);
3204     ierr = PetscObjectDereference((PetscObject)Mreuse);CHKERRQ(ierr);
3205   }
3206 
3207   PetscFunctionReturn(0);
3208 }
3209 
3210 EXTERN_C_BEGIN
3211 #undef __FUNCT__
3212 #define __FUNCT__ "MatMPIAIJSetPreallocationCSR_MPIAIJ"
3213 PetscErrorCode PETSCMAT_DLLEXPORT MatMPIAIJSetPreallocationCSR_MPIAIJ(Mat B,const PetscInt Ii[],const PetscInt J[],const PetscScalar v[])
3214 {
3215   PetscInt       m,cstart, cend,j,nnz,i,d;
3216   PetscInt       *d_nnz,*o_nnz,nnz_max = 0,rstart,ii;
3217   const PetscInt *JJ;
3218   PetscScalar    *values;
3219   PetscErrorCode ierr;
3220 
3221   PetscFunctionBegin;
3222   if (Ii[0]) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Ii[0] must be 0 it is %D",Ii[0]);
3223 
3224   ierr = PetscMapSetBlockSize(B->rmap,1);CHKERRQ(ierr);
3225   ierr = PetscMapSetBlockSize(B->cmap,1);CHKERRQ(ierr);
3226   ierr = PetscMapSetUp(B->rmap);CHKERRQ(ierr);
3227   ierr = PetscMapSetUp(B->cmap);CHKERRQ(ierr);
3228   m      = B->rmap->n;
3229   cstart = B->cmap->rstart;
3230   cend   = B->cmap->rend;
3231   rstart = B->rmap->rstart;
3232 
3233   ierr  = PetscMalloc((2*m+1)*sizeof(PetscInt),&d_nnz);CHKERRQ(ierr);
3234   o_nnz = d_nnz + m;
3235 
3236 #if defined(PETSC_USE_DEBUGGING)
3237   for (i=0; i<m; i++) {
3238     nnz     = Ii[i+1]- Ii[i];
3239     JJ      = J + Ii[i];
3240     if (nnz < 0) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Local row %D has a negative %D number of columns",i,nnz);
3241     if (nnz && (JJ[0] < 0)) SETERRRQ1(PETSC_ERR_ARG_WRONGSTATE,"Row %D starts with negative column index",i,j);
3242     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);
3243     for (j=1; j<nnz; j++) {
3244       if (JJ[i] <= JJ[i-1]) SETERRRQ(PETSC_ERR_ARG_WRONGSTATE,"Row %D has unsorted column index at %D location in column indices",i,j);
3245     }
3246   }
3247 #endif
3248 
3249   for (i=0; i<m; i++) {
3250     nnz     = Ii[i+1]- Ii[i];
3251     JJ      = J + Ii[i];
3252     nnz_max = PetscMax(nnz_max,nnz);
3253     for (j=0; j<nnz; j++) {
3254       if (*JJ >= cstart) break;
3255       JJ++;
3256     }
3257     d = 0;
3258     for (; j<nnz; j++) {
3259       if (*JJ++ >= cend) break;
3260       d++;
3261     }
3262     d_nnz[i] = d;
3263     o_nnz[i] = nnz - d;
3264   }
3265   ierr = MatMPIAIJSetPreallocation(B,0,d_nnz,0,o_nnz);CHKERRQ(ierr);
3266   ierr = PetscFree(d_nnz);CHKERRQ(ierr);
3267 
3268   if (v) values = (PetscScalar*)v;
3269   else {
3270     ierr = PetscMalloc((nnz_max+1)*sizeof(PetscScalar),&values);CHKERRQ(ierr);
3271     ierr = PetscMemzero(values,nnz_max*sizeof(PetscScalar));CHKERRQ(ierr);
3272   }
3273 
3274   for (i=0; i<m; i++) {
3275     ii   = i + rstart;
3276     nnz  = Ii[i+1]- Ii[i];
3277     ierr = MatSetValues_MPIAIJ(B,1,&ii,nnz,J+Ii[i],values+(v ? Ii[i] : 0),INSERT_VALUES);CHKERRQ(ierr);
3278   }
3279   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3280   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3281 
3282   if (!v) {
3283     ierr = PetscFree(values);CHKERRQ(ierr);
3284   }
3285   PetscFunctionReturn(0);
3286 }
3287 EXTERN_C_END
3288 
3289 #undef __FUNCT__
3290 #define __FUNCT__ "MatMPIAIJSetPreallocationCSR"
3291 /*@
3292    MatMPIAIJSetPreallocationCSR - Allocates memory for a sparse parallel matrix in AIJ format
3293    (the default parallel PETSc format).
3294 
3295    Collective on MPI_Comm
3296 
3297    Input Parameters:
3298 +  B - the matrix
3299 .  i - the indices into j for the start of each local row (starts with zero)
3300 .  j - the column indices for each local row (starts with zero) these must be sorted for each row
3301 -  v - optional values in the matrix
3302 
3303    Level: developer
3304 
3305    Notes:
3306        The i, j, and a arrays ARE copied by this routine into the internal format used by PETSc;
3307      thus you CANNOT change the matrix entries by changing the values of a[] after you have
3308      called this routine. Use MatCreateMPIAIJWithSplitArrays() to avoid needing to copy the arrays.
3309 
3310        The i and j indices are 0 based, and i indices are indices corresponding to the local j array.
3311 
3312        The format which is used for the sparse matrix input, is equivalent to a
3313     row-major ordering.. i.e for the following matrix, the input data expected is
3314     as shown:
3315 
3316         1 0 0
3317         2 0 3     P0
3318        -------
3319         4 5 6     P1
3320 
3321      Process0 [P0]: rows_owned=[0,1]
3322         i =  {0,1,3}  [size = nrow+1  = 2+1]
3323         j =  {0,0,2}  [size = nz = 6]
3324         v =  {1,2,3}  [size = nz = 6]
3325 
3326      Process1 [P1]: rows_owned=[2]
3327         i =  {0,3}    [size = nrow+1  = 1+1]
3328         j =  {0,1,2}  [size = nz = 6]
3329         v =  {4,5,6}  [size = nz = 6]
3330 
3331       The column indices for each row MUST be sorted.
3332 
3333 .keywords: matrix, aij, compressed row, sparse, parallel
3334 
3335 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatCreateMPIAIJ(), MPIAIJ,
3336           MatCreateSeqAIJWithArrays(), MatCreateMPIAIJWithSplitArrays()
3337 @*/
3338 PetscErrorCode PETSCMAT_DLLEXPORT MatMPIAIJSetPreallocationCSR(Mat B,const PetscInt i[],const PetscInt j[], const PetscScalar v[])
3339 {
3340   PetscErrorCode ierr,(*f)(Mat,const PetscInt[],const PetscInt[],const PetscScalar[]);
3341 
3342   PetscFunctionBegin;
3343   ierr = PetscObjectQueryFunction((PetscObject)B,"MatMPIAIJSetPreallocationCSR_C",(void (**)(void))&f);CHKERRQ(ierr);
3344   if (f) {
3345     ierr = (*f)(B,i,j,v);CHKERRQ(ierr);
3346   }
3347   PetscFunctionReturn(0);
3348 }
3349 
3350 #undef __FUNCT__
3351 #define __FUNCT__ "MatMPIAIJSetPreallocation"
3352 /*@C
3353    MatMPIAIJSetPreallocation - Preallocates memory for a sparse parallel matrix in AIJ format
3354    (the default parallel PETSc format).  For good matrix assembly performance
3355    the user should preallocate the matrix storage by setting the parameters
3356    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
3357    performance can be increased by more than a factor of 50.
3358 
3359    Collective on MPI_Comm
3360 
3361    Input Parameters:
3362 +  A - the matrix
3363 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
3364            (same value is used for all local rows)
3365 .  d_nnz - array containing the number of nonzeros in the various rows of the
3366            DIAGONAL portion of the local submatrix (possibly different for each row)
3367            or PETSC_NULL, if d_nz is used to specify the nonzero structure.
3368            The size of this array is equal to the number of local rows, i.e 'm'.
3369            You must leave room for the diagonal entry even if it is zero.
3370 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
3371            submatrix (same value is used for all local rows).
3372 -  o_nnz - array containing the number of nonzeros in the various rows of the
3373            OFF-DIAGONAL portion of the local submatrix (possibly different for
3374            each row) or PETSC_NULL, if o_nz is used to specify the nonzero
3375            structure. The size of this array is equal to the number
3376            of local rows, i.e 'm'.
3377 
3378    If the *_nnz parameter is given then the *_nz parameter is ignored
3379 
3380    The AIJ format (also called the Yale sparse matrix format or
3381    compressed row storage (CSR)), is fully compatible with standard Fortran 77
3382    storage.  The stored row and column indices begin with zero.  See the users manual for details.
3383 
3384    The parallel matrix is partitioned such that the first m0 rows belong to
3385    process 0, the next m1 rows belong to process 1, the next m2 rows belong
3386    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.
3387 
3388    The DIAGONAL portion of the local submatrix of a processor can be defined
3389    as the submatrix which is obtained by extraction the part corresponding
3390    to the rows r1-r2 and columns r1-r2 of the global matrix, where r1 is the
3391    first row that belongs to the processor, and r2 is the last row belonging
3392    to the this processor. This is a square mxm matrix. The remaining portion
3393    of the local submatrix (mxN) constitute the OFF-DIAGONAL portion.
3394 
3395    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
3396 
3397    You can call MatGetInfo() to get information on how effective the preallocation was;
3398    for example the fields mallocs,nz_allocated,nz_used,nz_unneeded;
3399    You can also run with the option -info and look for messages with the string
3400    malloc in them to see if additional memory allocation was needed.
3401 
3402    Example usage:
3403 
3404    Consider the following 8x8 matrix with 34 non-zero values, that is
3405    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
3406    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
3407    as follows:
3408 
3409 .vb
3410             1  2  0  |  0  3  0  |  0  4
3411     Proc0   0  5  6  |  7  0  0  |  8  0
3412             9  0 10  | 11  0  0  | 12  0
3413     -------------------------------------
3414            13  0 14  | 15 16 17  |  0  0
3415     Proc1   0 18  0  | 19 20 21  |  0  0
3416             0  0  0  | 22 23  0  | 24  0
3417     -------------------------------------
3418     Proc2  25 26 27  |  0  0 28  | 29  0
3419            30  0  0  | 31 32 33  |  0 34
3420 .ve
3421 
3422    This can be represented as a collection of submatrices as:
3423 
3424 .vb
3425       A B C
3426       D E F
3427       G H I
3428 .ve
3429 
3430    Where the submatrices A,B,C are owned by proc0, D,E,F are
3431    owned by proc1, G,H,I are owned by proc2.
3432 
3433    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3434    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3435    The 'M','N' parameters are 8,8, and have the same values on all procs.
3436 
3437    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
3438    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
3439    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
3440    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
3441    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
3442    matrix, ans [DF] as another SeqAIJ matrix.
3443 
3444    When d_nz, o_nz parameters are specified, d_nz storage elements are
3445    allocated for every row of the local diagonal submatrix, and o_nz
3446    storage locations are allocated for every row of the OFF-DIAGONAL submat.
3447    One way to choose d_nz and o_nz is to use the max nonzerors per local
3448    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
3449    In this case, the values of d_nz,o_nz are:
3450 .vb
3451      proc0 : dnz = 2, o_nz = 2
3452      proc1 : dnz = 3, o_nz = 2
3453      proc2 : dnz = 1, o_nz = 4
3454 .ve
3455    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
3456    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
3457    for proc3. i.e we are using 12+15+10=37 storage locations to store
3458    34 values.
3459 
3460    When d_nnz, o_nnz parameters are specified, the storage is specified
3461    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
3462    In the above case the values for d_nnz,o_nnz are:
3463 .vb
3464      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
3465      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
3466      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
3467 .ve
3468    Here the space allocated is sum of all the above values i.e 34, and
3469    hence pre-allocation is perfect.
3470 
3471    Level: intermediate
3472 
3473 .keywords: matrix, aij, compressed row, sparse, parallel
3474 
3475 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatCreateMPIAIJ(), MatMPIAIJSetPreallocationCSR(),
3476           MPIAIJ, MatGetInfo()
3477 @*/
3478 PetscErrorCode PETSCMAT_DLLEXPORT MatMPIAIJSetPreallocation(Mat B,PetscInt d_nz,const PetscInt d_nnz[],PetscInt o_nz,const PetscInt o_nnz[])
3479 {
3480   PetscErrorCode ierr,(*f)(Mat,PetscInt,const PetscInt[],PetscInt,const PetscInt[]);
3481 
3482   PetscFunctionBegin;
3483   ierr = PetscObjectQueryFunction((PetscObject)B,"MatMPIAIJSetPreallocation_C",(void (**)(void))&f);CHKERRQ(ierr);
3484   if (f) {
3485     ierr = (*f)(B,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
3486   }
3487   PetscFunctionReturn(0);
3488 }
3489 
3490 #undef __FUNCT__
3491 #define __FUNCT__ "MatCreateMPIAIJWithArrays"
3492 /*@
3493      MatCreateMPIAIJWithArrays - creates a MPI AIJ matrix using arrays that contain in standard
3494          CSR format the local rows.
3495 
3496    Collective on MPI_Comm
3497 
3498    Input Parameters:
3499 +  comm - MPI communicator
3500 .  m - number of local rows (Cannot be PETSC_DECIDE)
3501 .  n - This value should be the same as the local size used in creating the
3502        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
3503        calculated if N is given) For square matrices n is almost always m.
3504 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
3505 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
3506 .   i - row indices
3507 .   j - column indices
3508 -   a - matrix values
3509 
3510    Output Parameter:
3511 .   mat - the matrix
3512 
3513    Level: intermediate
3514 
3515    Notes:
3516        The i, j, and a arrays ARE copied by this routine into the internal format used by PETSc;
3517      thus you CANNOT change the matrix entries by changing the values of a[] after you have
3518      called this routine. Use MatCreateMPIAIJWithSplitArrays() to avoid needing to copy the arrays.
3519 
3520        The i and j indices are 0 based, and i indices are indices corresponding to the local j array.
3521 
3522        The format which is used for the sparse matrix input, is equivalent to a
3523     row-major ordering.. i.e for the following matrix, the input data expected is
3524     as shown:
3525 
3526         1 0 0
3527         2 0 3     P0
3528        -------
3529         4 5 6     P1
3530 
3531      Process0 [P0]: rows_owned=[0,1]
3532         i =  {0,1,3}  [size = nrow+1  = 2+1]
3533         j =  {0,0,2}  [size = nz = 6]
3534         v =  {1,2,3}  [size = nz = 6]
3535 
3536      Process1 [P1]: rows_owned=[2]
3537         i =  {0,3}    [size = nrow+1  = 1+1]
3538         j =  {0,1,2}  [size = nz = 6]
3539         v =  {4,5,6}  [size = nz = 6]
3540 
3541 .keywords: matrix, aij, compressed row, sparse, parallel
3542 
3543 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
3544           MPIAIJ, MatCreateMPIAIJ(), MatCreateMPIAIJWithSplitArrays()
3545 @*/
3546 PetscErrorCode PETSCMAT_DLLEXPORT MatCreateMPIAIJWithArrays(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,const PetscInt i[],const PetscInt j[],const PetscScalar a[],Mat *mat)
3547 {
3548   PetscErrorCode ierr;
3549 
3550  PetscFunctionBegin;
3551   if (i[0]) {
3552     SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"i (row indices) must start with 0");
3553   }
3554   if (m < 0) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"local number of rows (m) cannot be PETSC_DECIDE, or negative");
3555   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
3556   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
3557   ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
3558   ierr = MatMPIAIJSetPreallocationCSR(*mat,i,j,a);CHKERRQ(ierr);
3559   PetscFunctionReturn(0);
3560 }
3561 
3562 #undef __FUNCT__
3563 #define __FUNCT__ "MatCreateMPIAIJ"
3564 /*@C
3565    MatCreateMPIAIJ - Creates a sparse parallel matrix in AIJ format
3566    (the default parallel PETSc format).  For good matrix assembly performance
3567    the user should preallocate the matrix storage by setting the parameters
3568    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
3569    performance can be increased by more than a factor of 50.
3570 
3571    Collective on MPI_Comm
3572 
3573    Input Parameters:
3574 +  comm - MPI communicator
3575 .  m - number of local rows (or PETSC_DECIDE to have calculated if M is given)
3576            This value should be the same as the local size used in creating the
3577            y vector for the matrix-vector product y = Ax.
3578 .  n - This value should be the same as the local size used in creating the
3579        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
3580        calculated if N is given) For square matrices n is almost always m.
3581 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
3582 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
3583 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
3584            (same value is used for all local rows)
3585 .  d_nnz - array containing the number of nonzeros in the various rows of the
3586            DIAGONAL portion of the local submatrix (possibly different for each row)
3587            or PETSC_NULL, if d_nz is used to specify the nonzero structure.
3588            The size of this array is equal to the number of local rows, i.e 'm'.
3589            You must leave room for the diagonal entry even if it is zero.
3590 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
3591            submatrix (same value is used for all local rows).
3592 -  o_nnz - array containing the number of nonzeros in the various rows of the
3593            OFF-DIAGONAL portion of the local submatrix (possibly different for
3594            each row) or PETSC_NULL, if o_nz is used to specify the nonzero
3595            structure. The size of this array is equal to the number
3596            of local rows, i.e 'm'.
3597 
3598    Output Parameter:
3599 .  A - the matrix
3600 
3601    It is recommended that one use the MatCreate(), MatSetType() and/or MatSetFromOptions(),
3602    MatXXXXSetPreallocation() paradgm instead of this routine directly.
3603    [MatXXXXSetPreallocation() is, for example, MatSeqAIJSetPreallocation]
3604 
3605    Notes:
3606    If the *_nnz parameter is given then the *_nz parameter is ignored
3607 
3608    m,n,M,N parameters specify the size of the matrix, and its partitioning across
3609    processors, while d_nz,d_nnz,o_nz,o_nnz parameters specify the approximate
3610    storage requirements for this matrix.
3611 
3612    If PETSC_DECIDE or  PETSC_DETERMINE is used for a particular argument on one
3613    processor than it must be used on all processors that share the object for
3614    that argument.
3615 
3616    The user MUST specify either the local or global matrix dimensions
3617    (possibly both).
3618 
3619    The parallel matrix is partitioned across processors such that the
3620    first m0 rows belong to process 0, the next m1 rows belong to
3621    process 1, the next m2 rows belong to process 2 etc.. where
3622    m0,m1,m2,.. are the input parameter 'm'. i.e each processor stores
3623    values corresponding to [m x N] submatrix.
3624 
3625    The columns are logically partitioned with the n0 columns belonging
3626    to 0th partition, the next n1 columns belonging to the next
3627    partition etc.. where n0,n1,n2... are the the input parameter 'n'.
3628 
3629    The DIAGONAL portion of the local submatrix on any given processor
3630    is the submatrix corresponding to the rows and columns m,n
3631    corresponding to the given processor. i.e diagonal matrix on
3632    process 0 is [m0 x n0], diagonal matrix on process 1 is [m1 x n1]
3633    etc. The remaining portion of the local submatrix [m x (N-n)]
3634    constitute the OFF-DIAGONAL portion. The example below better
3635    illustrates this concept.
3636 
3637    For a square global matrix we define each processor's diagonal portion
3638    to be its local rows and the corresponding columns (a square submatrix);
3639    each processor's off-diagonal portion encompasses the remainder of the
3640    local matrix (a rectangular submatrix).
3641 
3642    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
3643 
3644    When calling this routine with a single process communicator, a matrix of
3645    type SEQAIJ is returned.  If a matrix of type MPIAIJ is desired for this
3646    type of communicator, use the construction mechanism:
3647      MatCreate(...,&A); MatSetType(A,MATMPIAIJ); MatSetSizes(A, m,n,M,N); MatMPIAIJSetPreallocation(A,...);
3648 
3649    By default, this format uses inodes (identical nodes) when possible.
3650    We search for consecutive rows with the same nonzero structure, thereby
3651    reusing matrix information to achieve increased efficiency.
3652 
3653    Options Database Keys:
3654 +  -mat_no_inode  - Do not use inodes
3655 .  -mat_inode_limit <limit> - Sets inode limit (max limit=5)
3656 -  -mat_aij_oneindex - Internally use indexing starting at 1
3657         rather than 0.  Note that when calling MatSetValues(),
3658         the user still MUST index entries starting at 0!
3659 
3660 
3661    Example usage:
3662 
3663    Consider the following 8x8 matrix with 34 non-zero values, that is
3664    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
3665    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
3666    as follows:
3667 
3668 .vb
3669             1  2  0  |  0  3  0  |  0  4
3670     Proc0   0  5  6  |  7  0  0  |  8  0
3671             9  0 10  | 11  0  0  | 12  0
3672     -------------------------------------
3673            13  0 14  | 15 16 17  |  0  0
3674     Proc1   0 18  0  | 19 20 21  |  0  0
3675             0  0  0  | 22 23  0  | 24  0
3676     -------------------------------------
3677     Proc2  25 26 27  |  0  0 28  | 29  0
3678            30  0  0  | 31 32 33  |  0 34
3679 .ve
3680 
3681    This can be represented as a collection of submatrices as:
3682 
3683 .vb
3684       A B C
3685       D E F
3686       G H I
3687 .ve
3688 
3689    Where the submatrices A,B,C are owned by proc0, D,E,F are
3690    owned by proc1, G,H,I are owned by proc2.
3691 
3692    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3693    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
3694    The 'M','N' parameters are 8,8, and have the same values on all procs.
3695 
3696    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
3697    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
3698    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
3699    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
3700    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
3701    matrix, ans [DF] as another SeqAIJ matrix.
3702 
3703    When d_nz, o_nz parameters are specified, d_nz storage elements are
3704    allocated for every row of the local diagonal submatrix, and o_nz
3705    storage locations are allocated for every row of the OFF-DIAGONAL submat.
3706    One way to choose d_nz and o_nz is to use the max nonzerors per local
3707    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
3708    In this case, the values of d_nz,o_nz are:
3709 .vb
3710      proc0 : dnz = 2, o_nz = 2
3711      proc1 : dnz = 3, o_nz = 2
3712      proc2 : dnz = 1, o_nz = 4
3713 .ve
3714    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
3715    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
3716    for proc3. i.e we are using 12+15+10=37 storage locations to store
3717    34 values.
3718 
3719    When d_nnz, o_nnz parameters are specified, the storage is specified
3720    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
3721    In the above case the values for d_nnz,o_nnz are:
3722 .vb
3723      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
3724      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
3725      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
3726 .ve
3727    Here the space allocated is sum of all the above values i.e 34, and
3728    hence pre-allocation is perfect.
3729 
3730    Level: intermediate
3731 
3732 .keywords: matrix, aij, compressed row, sparse, parallel
3733 
3734 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
3735           MPIAIJ, MatCreateMPIAIJWithArrays()
3736 @*/
3737 PetscErrorCode PETSCMAT_DLLEXPORT MatCreateMPIAIJ(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)
3738 {
3739   PetscErrorCode ierr;
3740   PetscMPIInt    size;
3741 
3742   PetscFunctionBegin;
3743   ierr = MatCreate(comm,A);CHKERRQ(ierr);
3744   ierr = MatSetSizes(*A,m,n,M,N);CHKERRQ(ierr);
3745   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
3746   if (size > 1) {
3747     ierr = MatSetType(*A,MATMPIAIJ);CHKERRQ(ierr);
3748     ierr = MatMPIAIJSetPreallocation(*A,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
3749   } else {
3750     ierr = MatSetType(*A,MATSEQAIJ);CHKERRQ(ierr);
3751     ierr = MatSeqAIJSetPreallocation(*A,d_nz,d_nnz);CHKERRQ(ierr);
3752   }
3753   PetscFunctionReturn(0);
3754 }
3755 
3756 #undef __FUNCT__
3757 #define __FUNCT__ "MatMPIAIJGetSeqAIJ"
3758 PetscErrorCode PETSCMAT_DLLEXPORT MatMPIAIJGetSeqAIJ(Mat A,Mat *Ad,Mat *Ao,PetscInt *colmap[])
3759 {
3760   Mat_MPIAIJ *a = (Mat_MPIAIJ *)A->data;
3761 
3762   PetscFunctionBegin;
3763   *Ad     = a->A;
3764   *Ao     = a->B;
3765   *colmap = a->garray;
3766   PetscFunctionReturn(0);
3767 }
3768 
3769 #undef __FUNCT__
3770 #define __FUNCT__ "MatSetColoring_MPIAIJ"
3771 PetscErrorCode MatSetColoring_MPIAIJ(Mat A,ISColoring coloring)
3772 {
3773   PetscErrorCode ierr;
3774   PetscInt       i;
3775   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
3776 
3777   PetscFunctionBegin;
3778   if (coloring->ctype == IS_COLORING_GLOBAL) {
3779     ISColoringValue *allcolors,*colors;
3780     ISColoring      ocoloring;
3781 
3782     /* set coloring for diagonal portion */
3783     ierr = MatSetColoring_SeqAIJ(a->A,coloring);CHKERRQ(ierr);
3784 
3785     /* set coloring for off-diagonal portion */
3786     ierr = ISAllGatherColors(((PetscObject)A)->comm,coloring->n,coloring->colors,PETSC_NULL,&allcolors);CHKERRQ(ierr);
3787     ierr = PetscMalloc((a->B->cmap->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
3788     for (i=0; i<a->B->cmap->n; i++) {
3789       colors[i] = allcolors[a->garray[i]];
3790     }
3791     ierr = PetscFree(allcolors);CHKERRQ(ierr);
3792     ierr = ISColoringCreate(MPI_COMM_SELF,coloring->n,a->B->cmap->n,colors,&ocoloring);CHKERRQ(ierr);
3793     ierr = MatSetColoring_SeqAIJ(a->B,ocoloring);CHKERRQ(ierr);
3794     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
3795   } else if (coloring->ctype == IS_COLORING_GHOSTED) {
3796     ISColoringValue *colors;
3797     PetscInt        *larray;
3798     ISColoring      ocoloring;
3799 
3800     /* set coloring for diagonal portion */
3801     ierr = PetscMalloc((a->A->cmap->n+1)*sizeof(PetscInt),&larray);CHKERRQ(ierr);
3802     for (i=0; i<a->A->cmap->n; i++) {
3803       larray[i] = i + A->cmap->rstart;
3804     }
3805     ierr = ISGlobalToLocalMappingApply(A->mapping,IS_GTOLM_MASK,a->A->cmap->n,larray,PETSC_NULL,larray);CHKERRQ(ierr);
3806     ierr = PetscMalloc((a->A->cmap->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
3807     for (i=0; i<a->A->cmap->n; i++) {
3808       colors[i] = coloring->colors[larray[i]];
3809     }
3810     ierr = PetscFree(larray);CHKERRQ(ierr);
3811     ierr = ISColoringCreate(PETSC_COMM_SELF,coloring->n,a->A->cmap->n,colors,&ocoloring);CHKERRQ(ierr);
3812     ierr = MatSetColoring_SeqAIJ(a->A,ocoloring);CHKERRQ(ierr);
3813     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
3814 
3815     /* set coloring for off-diagonal portion */
3816     ierr = PetscMalloc((a->B->cmap->n+1)*sizeof(PetscInt),&larray);CHKERRQ(ierr);
3817     ierr = ISGlobalToLocalMappingApply(A->mapping,IS_GTOLM_MASK,a->B->cmap->n,a->garray,PETSC_NULL,larray);CHKERRQ(ierr);
3818     ierr = PetscMalloc((a->B->cmap->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
3819     for (i=0; i<a->B->cmap->n; i++) {
3820       colors[i] = coloring->colors[larray[i]];
3821     }
3822     ierr = PetscFree(larray);CHKERRQ(ierr);
3823     ierr = ISColoringCreate(MPI_COMM_SELF,coloring->n,a->B->cmap->n,colors,&ocoloring);CHKERRQ(ierr);
3824     ierr = MatSetColoring_SeqAIJ(a->B,ocoloring);CHKERRQ(ierr);
3825     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
3826   } else {
3827     SETERRQ1(PETSC_ERR_SUP,"No support ISColoringType %d",(int)coloring->ctype);
3828   }
3829 
3830   PetscFunctionReturn(0);
3831 }
3832 
3833 #if defined(PETSC_HAVE_ADIC)
3834 #undef __FUNCT__
3835 #define __FUNCT__ "MatSetValuesAdic_MPIAIJ"
3836 PetscErrorCode MatSetValuesAdic_MPIAIJ(Mat A,void *advalues)
3837 {
3838   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
3839   PetscErrorCode ierr;
3840 
3841   PetscFunctionBegin;
3842   ierr = MatSetValuesAdic_SeqAIJ(a->A,advalues);CHKERRQ(ierr);
3843   ierr = MatSetValuesAdic_SeqAIJ(a->B,advalues);CHKERRQ(ierr);
3844   PetscFunctionReturn(0);
3845 }
3846 #endif
3847 
3848 #undef __FUNCT__
3849 #define __FUNCT__ "MatSetValuesAdifor_MPIAIJ"
3850 PetscErrorCode MatSetValuesAdifor_MPIAIJ(Mat A,PetscInt nl,void *advalues)
3851 {
3852   Mat_MPIAIJ     *a = (Mat_MPIAIJ*)A->data;
3853   PetscErrorCode ierr;
3854 
3855   PetscFunctionBegin;
3856   ierr = MatSetValuesAdifor_SeqAIJ(a->A,nl,advalues);CHKERRQ(ierr);
3857   ierr = MatSetValuesAdifor_SeqAIJ(a->B,nl,advalues);CHKERRQ(ierr);
3858   PetscFunctionReturn(0);
3859 }
3860 
3861 #undef __FUNCT__
3862 #define __FUNCT__ "MatMerge"
3863 /*@
3864       MatMerge - Creates a single large PETSc matrix by concatinating sequential
3865                  matrices from each processor
3866 
3867     Collective on MPI_Comm
3868 
3869    Input Parameters:
3870 +    comm - the communicators the parallel matrix will live on
3871 .    inmat - the input sequential matrices
3872 .    n - number of local columns (or PETSC_DECIDE)
3873 -    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
3874 
3875    Output Parameter:
3876 .    outmat - the parallel matrix generated
3877 
3878     Level: advanced
3879 
3880    Notes: The number of columns of the matrix in EACH processor MUST be the same.
3881 
3882 @*/
3883 PetscErrorCode PETSCMAT_DLLEXPORT MatMerge(MPI_Comm comm,Mat inmat,PetscInt n,MatReuse scall,Mat *outmat)
3884 {
3885   PetscErrorCode ierr;
3886   PetscInt       m,N,i,rstart,nnz,Ii,*dnz,*onz;
3887   PetscInt       *indx;
3888   PetscScalar    *values;
3889 
3890   PetscFunctionBegin;
3891   ierr = MatGetSize(inmat,&m,&N);CHKERRQ(ierr);
3892   if (scall == MAT_INITIAL_MATRIX){
3893     /* count nonzeros in each row, for diagonal and off diagonal portion of matrix */
3894     if (n == PETSC_DECIDE){
3895       ierr = PetscSplitOwnership(comm,&n,&N);CHKERRQ(ierr);
3896     }
3897     ierr = MPI_Scan(&m, &rstart,1,MPIU_INT,MPI_SUM,comm);CHKERRQ(ierr);
3898     rstart -= m;
3899 
3900     ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
3901     for (i=0;i<m;i++) {
3902       ierr = MatGetRow_SeqAIJ(inmat,i,&nnz,&indx,PETSC_NULL);CHKERRQ(ierr);
3903       ierr = MatPreallocateSet(i+rstart,nnz,indx,dnz,onz);CHKERRQ(ierr);
3904       ierr = MatRestoreRow_SeqAIJ(inmat,i,&nnz,&indx,PETSC_NULL);CHKERRQ(ierr);
3905     }
3906     /* This routine will ONLY return MPIAIJ type matrix */
3907     ierr = MatCreate(comm,outmat);CHKERRQ(ierr);
3908     ierr = MatSetSizes(*outmat,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
3909     ierr = MatSetType(*outmat,MATMPIAIJ);CHKERRQ(ierr);
3910     ierr = MatMPIAIJSetPreallocation(*outmat,0,dnz,0,onz);CHKERRQ(ierr);
3911     ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
3912 
3913   } else if (scall == MAT_REUSE_MATRIX){
3914     ierr = MatGetOwnershipRange(*outmat,&rstart,PETSC_NULL);CHKERRQ(ierr);
3915   } else {
3916     SETERRQ1(PETSC_ERR_ARG_WRONG,"Invalid MatReuse %d",(int)scall);
3917   }
3918 
3919   for (i=0;i<m;i++) {
3920     ierr = MatGetRow_SeqAIJ(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
3921     Ii    = i + rstart;
3922     ierr = MatSetValues(*outmat,1,&Ii,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
3923     ierr = MatRestoreRow_SeqAIJ(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
3924   }
3925   ierr = MatDestroy(inmat);CHKERRQ(ierr);
3926   ierr = MatAssemblyBegin(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3927   ierr = MatAssemblyEnd(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3928 
3929   PetscFunctionReturn(0);
3930 }
3931 
3932 #undef __FUNCT__
3933 #define __FUNCT__ "MatFileSplit"
3934 PetscErrorCode MatFileSplit(Mat A,char *outfile)
3935 {
3936   PetscErrorCode    ierr;
3937   PetscMPIInt       rank;
3938   PetscInt          m,N,i,rstart,nnz;
3939   size_t            len;
3940   const PetscInt    *indx;
3941   PetscViewer       out;
3942   char              *name;
3943   Mat               B;
3944   const PetscScalar *values;
3945 
3946   PetscFunctionBegin;
3947   ierr = MatGetLocalSize(A,&m,0);CHKERRQ(ierr);
3948   ierr = MatGetSize(A,0,&N);CHKERRQ(ierr);
3949   /* Should this be the type of the diagonal block of A? */
3950   ierr = MatCreate(PETSC_COMM_SELF,&B);CHKERRQ(ierr);
3951   ierr = MatSetSizes(B,m,N,m,N);CHKERRQ(ierr);
3952   ierr = MatSetType(B,MATSEQAIJ);CHKERRQ(ierr);
3953   ierr = MatSeqAIJSetPreallocation(B,0,PETSC_NULL);CHKERRQ(ierr);
3954   ierr = MatGetOwnershipRange(A,&rstart,0);CHKERRQ(ierr);
3955   for (i=0;i<m;i++) {
3956     ierr = MatGetRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
3957     ierr = MatSetValues(B,1,&i,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
3958     ierr = MatRestoreRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
3959   }
3960   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3961   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
3962 
3963   ierr = MPI_Comm_rank(((PetscObject)A)->comm,&rank);CHKERRQ(ierr);
3964   ierr = PetscStrlen(outfile,&len);CHKERRQ(ierr);
3965   ierr = PetscMalloc((len+5)*sizeof(char),&name);CHKERRQ(ierr);
3966   sprintf(name,"%s.%d",outfile,rank);
3967   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,name,FILE_MODE_APPEND,&out);CHKERRQ(ierr);
3968   ierr = PetscFree(name);
3969   ierr = MatView(B,out);CHKERRQ(ierr);
3970   ierr = PetscViewerDestroy(out);CHKERRQ(ierr);
3971   ierr = MatDestroy(B);CHKERRQ(ierr);
3972   PetscFunctionReturn(0);
3973 }
3974 
3975 EXTERN PetscErrorCode MatDestroy_MPIAIJ(Mat);
3976 #undef __FUNCT__
3977 #define __FUNCT__ "MatDestroy_MPIAIJ_SeqsToMPI"
3978 PetscErrorCode PETSCMAT_DLLEXPORT MatDestroy_MPIAIJ_SeqsToMPI(Mat A)
3979 {
3980   PetscErrorCode       ierr;
3981   Mat_Merge_SeqsToMPI  *merge;
3982   PetscContainer       container;
3983 
3984   PetscFunctionBegin;
3985   ierr = PetscObjectQuery((PetscObject)A,"MatMergeSeqsToMPI",(PetscObject *)&container);CHKERRQ(ierr);
3986   if (container) {
3987     ierr = PetscContainerGetPointer(container,(void **)&merge);CHKERRQ(ierr);
3988     ierr = PetscFree(merge->id_r);CHKERRQ(ierr);
3989     ierr = PetscFree(merge->len_s);CHKERRQ(ierr);
3990     ierr = PetscFree(merge->len_r);CHKERRQ(ierr);
3991     ierr = PetscFree(merge->bi);CHKERRQ(ierr);
3992     ierr = PetscFree(merge->bj);CHKERRQ(ierr);
3993     ierr = PetscFree(merge->buf_ri);CHKERRQ(ierr);
3994     ierr = PetscFree(merge->buf_rj);CHKERRQ(ierr);
3995     ierr = PetscFree(merge->coi);CHKERRQ(ierr);
3996     ierr = PetscFree(merge->coj);CHKERRQ(ierr);
3997     ierr = PetscFree(merge->owners_co);CHKERRQ(ierr);
3998     ierr = PetscFree(merge->rowmap.range);CHKERRQ(ierr);
3999 
4000     ierr = PetscContainerDestroy(container);CHKERRQ(ierr);
4001     ierr = PetscObjectCompose((PetscObject)A,"MatMergeSeqsToMPI",0);CHKERRQ(ierr);
4002   }
4003   ierr = PetscFree(merge);CHKERRQ(ierr);
4004 
4005   ierr = MatDestroy_MPIAIJ(A);CHKERRQ(ierr);
4006   PetscFunctionReturn(0);
4007 }
4008 
4009 #include "../src/mat/utils/freespace.h"
4010 #include "petscbt.h"
4011 
4012 #undef __FUNCT__
4013 #define __FUNCT__ "MatMerge_SeqsToMPINumeric"
4014 /*@C
4015       MatMerge_SeqsToMPI - Creates a MPIAIJ matrix by adding sequential
4016                  matrices from each processor
4017 
4018     Collective on MPI_Comm
4019 
4020    Input Parameters:
4021 +    comm - the communicators the parallel matrix will live on
4022 .    seqmat - the input sequential matrices
4023 .    m - number of local rows (or PETSC_DECIDE)
4024 .    n - number of local columns (or PETSC_DECIDE)
4025 -    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4026 
4027    Output Parameter:
4028 .    mpimat - the parallel matrix generated
4029 
4030     Level: advanced
4031 
4032    Notes:
4033      The dimensions of the sequential matrix in each processor MUST be the same.
4034      The input seqmat is included into the container "Mat_Merge_SeqsToMPI", and will be
4035      destroyed when mpimat is destroyed. Call PetscObjectQuery() to access seqmat.
4036 @*/
4037 PetscErrorCode PETSCMAT_DLLEXPORT MatMerge_SeqsToMPINumeric(Mat seqmat,Mat mpimat)
4038 {
4039   PetscErrorCode       ierr;
4040   MPI_Comm             comm=((PetscObject)mpimat)->comm;
4041   Mat_SeqAIJ           *a=(Mat_SeqAIJ*)seqmat->data;
4042   PetscMPIInt          size,rank,taga,*len_s;
4043   PetscInt             N=mpimat->cmap->N,i,j,*owners,*ai=a->i,*aj=a->j;
4044   PetscInt             proc,m;
4045   PetscInt             **buf_ri,**buf_rj;
4046   PetscInt             k,anzi,*bj_i,*bi,*bj,arow,bnzi,nextaj;
4047   PetscInt             nrows,**buf_ri_k,**nextrow,**nextai;
4048   MPI_Request          *s_waits,*r_waits;
4049   MPI_Status           *status;
4050   MatScalar            *aa=a->a;
4051   MatScalar            **abuf_r,*ba_i;
4052   Mat_Merge_SeqsToMPI  *merge;
4053   PetscContainer       container;
4054 
4055   PetscFunctionBegin;
4056   ierr = PetscLogEventBegin(MAT_Seqstompinum,seqmat,0,0,0);CHKERRQ(ierr);
4057 
4058   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4059   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4060 
4061   ierr = PetscObjectQuery((PetscObject)mpimat,"MatMergeSeqsToMPI",(PetscObject *)&container);CHKERRQ(ierr);
4062   if (container) {
4063     ierr  = PetscContainerGetPointer(container,(void **)&merge);CHKERRQ(ierr);
4064   }
4065   bi     = merge->bi;
4066   bj     = merge->bj;
4067   buf_ri = merge->buf_ri;
4068   buf_rj = merge->buf_rj;
4069 
4070   ierr   = PetscMalloc(size*sizeof(MPI_Status),&status);CHKERRQ(ierr);
4071   owners = merge->rowmap.range;
4072   len_s  = merge->len_s;
4073 
4074   /* send and recv matrix values */
4075   /*-----------------------------*/
4076   ierr = PetscObjectGetNewTag((PetscObject)mpimat,&taga);CHKERRQ(ierr);
4077   ierr = PetscPostIrecvScalar(comm,taga,merge->nrecv,merge->id_r,merge->len_r,&abuf_r,&r_waits);CHKERRQ(ierr);
4078 
4079   ierr = PetscMalloc((merge->nsend+1)*sizeof(MPI_Request),&s_waits);CHKERRQ(ierr);
4080   for (proc=0,k=0; proc<size; proc++){
4081     if (!len_s[proc]) continue;
4082     i = owners[proc];
4083     ierr = MPI_Isend(aa+ai[i],len_s[proc],MPIU_MATSCALAR,proc,taga,comm,s_waits+k);CHKERRQ(ierr);
4084     k++;
4085   }
4086 
4087   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,r_waits,status);CHKERRQ(ierr);}
4088   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,s_waits,status);CHKERRQ(ierr);}
4089   ierr = PetscFree(status);CHKERRQ(ierr);
4090 
4091   ierr = PetscFree(s_waits);CHKERRQ(ierr);
4092   ierr = PetscFree(r_waits);CHKERRQ(ierr);
4093 
4094   /* insert mat values of mpimat */
4095   /*----------------------------*/
4096   ierr = PetscMalloc(N*sizeof(PetscScalar),&ba_i);CHKERRQ(ierr);
4097   ierr = PetscMalloc((3*merge->nrecv+1)*sizeof(PetscInt**),&buf_ri_k);CHKERRQ(ierr);
4098   nextrow = buf_ri_k + merge->nrecv;
4099   nextai  = nextrow + merge->nrecv;
4100 
4101   for (k=0; k<merge->nrecv; k++){
4102     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
4103     nrows = *(buf_ri_k[k]);
4104     nextrow[k]  = buf_ri_k[k]+1;  /* next row number of k-th recved i-structure */
4105     nextai[k]   = buf_ri_k[k] + (nrows + 1);/* poins to the next i-structure of k-th recved i-structure  */
4106   }
4107 
4108   /* set values of ba */
4109   m = merge->rowmap.n;
4110   for (i=0; i<m; i++) {
4111     arow = owners[rank] + i;
4112     bj_i = bj+bi[i];  /* col indices of the i-th row of mpimat */
4113     bnzi = bi[i+1] - bi[i];
4114     ierr = PetscMemzero(ba_i,bnzi*sizeof(PetscScalar));CHKERRQ(ierr);
4115 
4116     /* add local non-zero vals of this proc's seqmat into ba */
4117     anzi = ai[arow+1] - ai[arow];
4118     aj   = a->j + ai[arow];
4119     aa   = a->a + ai[arow];
4120     nextaj = 0;
4121     for (j=0; nextaj<anzi; j++){
4122       if (*(bj_i + j) == aj[nextaj]){ /* bcol == acol */
4123         ba_i[j] += aa[nextaj++];
4124       }
4125     }
4126 
4127     /* add received vals into ba */
4128     for (k=0; k<merge->nrecv; k++){ /* k-th received message */
4129       /* i-th row */
4130       if (i == *nextrow[k]) {
4131         anzi = *(nextai[k]+1) - *nextai[k];
4132         aj   = buf_rj[k] + *(nextai[k]);
4133         aa   = abuf_r[k] + *(nextai[k]);
4134         nextaj = 0;
4135         for (j=0; nextaj<anzi; j++){
4136           if (*(bj_i + j) == aj[nextaj]){ /* bcol == acol */
4137             ba_i[j] += aa[nextaj++];
4138           }
4139         }
4140         nextrow[k]++; nextai[k]++;
4141       }
4142     }
4143     ierr = MatSetValues(mpimat,1,&arow,bnzi,bj_i,ba_i,INSERT_VALUES);CHKERRQ(ierr);
4144   }
4145   ierr = MatAssemblyBegin(mpimat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4146   ierr = MatAssemblyEnd(mpimat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4147 
4148   ierr = PetscFree(abuf_r);CHKERRQ(ierr);
4149   ierr = PetscFree(ba_i);CHKERRQ(ierr);
4150   ierr = PetscFree(buf_ri_k);CHKERRQ(ierr);
4151   ierr = PetscLogEventEnd(MAT_Seqstompinum,seqmat,0,0,0);CHKERRQ(ierr);
4152   PetscFunctionReturn(0);
4153 }
4154 
4155 #undef __FUNCT__
4156 #define __FUNCT__ "MatMerge_SeqsToMPISymbolic"
4157 PetscErrorCode PETSCMAT_DLLEXPORT MatMerge_SeqsToMPISymbolic(MPI_Comm comm,Mat seqmat,PetscInt m,PetscInt n,Mat *mpimat)
4158 {
4159   PetscErrorCode       ierr;
4160   Mat                  B_mpi;
4161   Mat_SeqAIJ           *a=(Mat_SeqAIJ*)seqmat->data;
4162   PetscMPIInt          size,rank,tagi,tagj,*len_s,*len_si,*len_ri;
4163   PetscInt             **buf_rj,**buf_ri,**buf_ri_k;
4164   PetscInt             M=seqmat->rmap->n,N=seqmat->cmap->n,i,*owners,*ai=a->i,*aj=a->j;
4165   PetscInt             len,proc,*dnz,*onz;
4166   PetscInt             k,anzi,*bi,*bj,*lnk,nlnk,arow,bnzi,nspacedouble=0;
4167   PetscInt             nrows,*buf_s,*buf_si,*buf_si_i,**nextrow,**nextai;
4168   MPI_Request          *si_waits,*sj_waits,*ri_waits,*rj_waits;
4169   MPI_Status           *status;
4170   PetscFreeSpaceList   free_space=PETSC_NULL,current_space=PETSC_NULL;
4171   PetscBT              lnkbt;
4172   Mat_Merge_SeqsToMPI  *merge;
4173   PetscContainer       container;
4174 
4175   PetscFunctionBegin;
4176   ierr = PetscLogEventBegin(MAT_Seqstompisym,seqmat,0,0,0);CHKERRQ(ierr);
4177 
4178   /* make sure it is a PETSc comm */
4179   ierr = PetscCommDuplicate(comm,&comm,PETSC_NULL);CHKERRQ(ierr);
4180   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
4181   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4182 
4183   ierr = PetscNew(Mat_Merge_SeqsToMPI,&merge);CHKERRQ(ierr);
4184   ierr = PetscMalloc(size*sizeof(MPI_Status),&status);CHKERRQ(ierr);
4185 
4186   /* determine row ownership */
4187   /*---------------------------------------------------------*/
4188   ierr = PetscMapInitialize(comm,&merge->rowmap);CHKERRQ(ierr);
4189   merge->rowmap.n = m;
4190   merge->rowmap.N = M;
4191   merge->rowmap.bs = 1;
4192   ierr = PetscMapSetUp(&merge->rowmap);CHKERRQ(ierr);
4193   ierr = PetscMalloc(size*sizeof(PetscMPIInt),&len_si);CHKERRQ(ierr);
4194   ierr = PetscMalloc(size*sizeof(PetscMPIInt),&merge->len_s);CHKERRQ(ierr);
4195 
4196   m      = merge->rowmap.n;
4197   M      = merge->rowmap.N;
4198   owners = merge->rowmap.range;
4199 
4200   /* determine the number of messages to send, their lengths */
4201   /*---------------------------------------------------------*/
4202   len_s  = merge->len_s;
4203 
4204   len = 0;  /* length of buf_si[] */
4205   merge->nsend = 0;
4206   for (proc=0; proc<size; proc++){
4207     len_si[proc] = 0;
4208     if (proc == rank){
4209       len_s[proc] = 0;
4210     } else {
4211       len_si[proc] = owners[proc+1] - owners[proc] + 1;
4212       len_s[proc] = ai[owners[proc+1]] - ai[owners[proc]]; /* num of rows to be sent to [proc] */
4213     }
4214     if (len_s[proc]) {
4215       merge->nsend++;
4216       nrows = 0;
4217       for (i=owners[proc]; i<owners[proc+1]; i++){
4218         if (ai[i+1] > ai[i]) nrows++;
4219       }
4220       len_si[proc] = 2*(nrows+1);
4221       len += len_si[proc];
4222     }
4223   }
4224 
4225   /* determine the number and length of messages to receive for ij-structure */
4226   /*-------------------------------------------------------------------------*/
4227   ierr = PetscGatherNumberOfMessages(comm,PETSC_NULL,len_s,&merge->nrecv);CHKERRQ(ierr);
4228   ierr = PetscGatherMessageLengths2(comm,merge->nsend,merge->nrecv,len_s,len_si,&merge->id_r,&merge->len_r,&len_ri);CHKERRQ(ierr);
4229 
4230   /* post the Irecv of j-structure */
4231   /*-------------------------------*/
4232   ierr = PetscCommGetNewTag(comm,&tagj);CHKERRQ(ierr);
4233   ierr = PetscPostIrecvInt(comm,tagj,merge->nrecv,merge->id_r,merge->len_r,&buf_rj,&rj_waits);CHKERRQ(ierr);
4234 
4235   /* post the Isend of j-structure */
4236   /*--------------------------------*/
4237   ierr = PetscMalloc((2*merge->nsend+1)*sizeof(MPI_Request),&si_waits);CHKERRQ(ierr);
4238   sj_waits = si_waits + merge->nsend;
4239 
4240   for (proc=0, k=0; proc<size; proc++){
4241     if (!len_s[proc]) continue;
4242     i = owners[proc];
4243     ierr = MPI_Isend(aj+ai[i],len_s[proc],MPIU_INT,proc,tagj,comm,sj_waits+k);CHKERRQ(ierr);
4244     k++;
4245   }
4246 
4247   /* receives and sends of j-structure are complete */
4248   /*------------------------------------------------*/
4249   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,rj_waits,status);CHKERRQ(ierr);}
4250   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,sj_waits,status);CHKERRQ(ierr);}
4251 
4252   /* send and recv i-structure */
4253   /*---------------------------*/
4254   ierr = PetscCommGetNewTag(comm,&tagi);CHKERRQ(ierr);
4255   ierr = PetscPostIrecvInt(comm,tagi,merge->nrecv,merge->id_r,len_ri,&buf_ri,&ri_waits);CHKERRQ(ierr);
4256 
4257   ierr = PetscMalloc((len+1)*sizeof(PetscInt),&buf_s);CHKERRQ(ierr);
4258   buf_si = buf_s;  /* points to the beginning of k-th msg to be sent */
4259   for (proc=0,k=0; proc<size; proc++){
4260     if (!len_s[proc]) continue;
4261     /* form outgoing message for i-structure:
4262          buf_si[0]:                 nrows to be sent
4263                [1:nrows]:           row index (global)
4264                [nrows+1:2*nrows+1]: i-structure index
4265     */
4266     /*-------------------------------------------*/
4267     nrows = len_si[proc]/2 - 1;
4268     buf_si_i    = buf_si + nrows+1;
4269     buf_si[0]   = nrows;
4270     buf_si_i[0] = 0;
4271     nrows = 0;
4272     for (i=owners[proc]; i<owners[proc+1]; i++){
4273       anzi = ai[i+1] - ai[i];
4274       if (anzi) {
4275         buf_si_i[nrows+1] = buf_si_i[nrows] + anzi; /* i-structure */
4276         buf_si[nrows+1] = i-owners[proc]; /* local row index */
4277         nrows++;
4278       }
4279     }
4280     ierr = MPI_Isend(buf_si,len_si[proc],MPIU_INT,proc,tagi,comm,si_waits+k);CHKERRQ(ierr);
4281     k++;
4282     buf_si += len_si[proc];
4283   }
4284 
4285   if (merge->nrecv) {ierr = MPI_Waitall(merge->nrecv,ri_waits,status);CHKERRQ(ierr);}
4286   if (merge->nsend) {ierr = MPI_Waitall(merge->nsend,si_waits,status);CHKERRQ(ierr);}
4287 
4288   ierr = PetscInfo2(seqmat,"nsend: %D, nrecv: %D\n",merge->nsend,merge->nrecv);CHKERRQ(ierr);
4289   for (i=0; i<merge->nrecv; i++){
4290     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);
4291   }
4292 
4293   ierr = PetscFree(len_si);CHKERRQ(ierr);
4294   ierr = PetscFree(len_ri);CHKERRQ(ierr);
4295   ierr = PetscFree(rj_waits);CHKERRQ(ierr);
4296   ierr = PetscFree(si_waits);CHKERRQ(ierr);
4297   ierr = PetscFree(ri_waits);CHKERRQ(ierr);
4298   ierr = PetscFree(buf_s);CHKERRQ(ierr);
4299   ierr = PetscFree(status);CHKERRQ(ierr);
4300 
4301   /* compute a local seq matrix in each processor */
4302   /*----------------------------------------------*/
4303   /* allocate bi array and free space for accumulating nonzero column info */
4304   ierr = PetscMalloc((m+1)*sizeof(PetscInt),&bi);CHKERRQ(ierr);
4305   bi[0] = 0;
4306 
4307   /* create and initialize a linked list */
4308   nlnk = N+1;
4309   ierr = PetscLLCreate(N,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4310 
4311   /* initial FreeSpace size is 2*(num of local nnz(seqmat)) */
4312   len = 0;
4313   len  = ai[owners[rank+1]] - ai[owners[rank]];
4314   ierr = PetscFreeSpaceGet((PetscInt)(2*len+1),&free_space);CHKERRQ(ierr);
4315   current_space = free_space;
4316 
4317   /* determine symbolic info for each local row */
4318   ierr = PetscMalloc((3*merge->nrecv+1)*sizeof(PetscInt**),&buf_ri_k);CHKERRQ(ierr);
4319   nextrow = buf_ri_k + merge->nrecv;
4320   nextai  = nextrow + merge->nrecv;
4321   for (k=0; k<merge->nrecv; k++){
4322     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
4323     nrows = *buf_ri_k[k];
4324     nextrow[k]  = buf_ri_k[k] + 1;  /* next row number of k-th recved i-structure */
4325     nextai[k]   = buf_ri_k[k] + (nrows + 1);/* poins to the next i-structure of k-th recved i-structure  */
4326   }
4327 
4328   ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
4329   len = 0;
4330   for (i=0;i<m;i++) {
4331     bnzi   = 0;
4332     /* add local non-zero cols of this proc's seqmat into lnk */
4333     arow   = owners[rank] + i;
4334     anzi   = ai[arow+1] - ai[arow];
4335     aj     = a->j + ai[arow];
4336     ierr = PetscLLAdd(anzi,aj,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4337     bnzi += nlnk;
4338     /* add received col data into lnk */
4339     for (k=0; k<merge->nrecv; k++){ /* k-th received message */
4340       if (i == *nextrow[k]) { /* i-th row */
4341         anzi = *(nextai[k]+1) - *nextai[k];
4342         aj   = buf_rj[k] + *nextai[k];
4343         ierr = PetscLLAdd(anzi,aj,N,nlnk,lnk,lnkbt);CHKERRQ(ierr);
4344         bnzi += nlnk;
4345         nextrow[k]++; nextai[k]++;
4346       }
4347     }
4348     if (len < bnzi) len = bnzi;  /* =max(bnzi) */
4349 
4350     /* if free space is not available, make more free space */
4351     if (current_space->local_remaining<bnzi) {
4352       ierr = PetscFreeSpaceGet(bnzi+current_space->total_array_size,&current_space);CHKERRQ(ierr);
4353       nspacedouble++;
4354     }
4355     /* copy data into free space, then initialize lnk */
4356     ierr = PetscLLClean(N,N,bnzi,lnk,current_space->array,lnkbt);CHKERRQ(ierr);
4357     ierr = MatPreallocateSet(i+owners[rank],bnzi,current_space->array,dnz,onz);CHKERRQ(ierr);
4358 
4359     current_space->array           += bnzi;
4360     current_space->local_used      += bnzi;
4361     current_space->local_remaining -= bnzi;
4362 
4363     bi[i+1] = bi[i] + bnzi;
4364   }
4365 
4366   ierr = PetscFree(buf_ri_k);CHKERRQ(ierr);
4367 
4368   ierr = PetscMalloc((bi[m]+1)*sizeof(PetscInt),&bj);CHKERRQ(ierr);
4369   ierr = PetscFreeSpaceContiguous(&free_space,bj);CHKERRQ(ierr);
4370   ierr = PetscLLDestroy(lnk,lnkbt);CHKERRQ(ierr);
4371 
4372   /* create symbolic parallel matrix B_mpi */
4373   /*---------------------------------------*/
4374   ierr = MatCreate(comm,&B_mpi);CHKERRQ(ierr);
4375   if (n==PETSC_DECIDE) {
4376     ierr = MatSetSizes(B_mpi,m,n,PETSC_DETERMINE,N);CHKERRQ(ierr);
4377   } else {
4378     ierr = MatSetSizes(B_mpi,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
4379   }
4380   ierr = MatSetType(B_mpi,MATMPIAIJ);CHKERRQ(ierr);
4381   ierr = MatMPIAIJSetPreallocation(B_mpi,0,dnz,0,onz);CHKERRQ(ierr);
4382   ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
4383 
4384   /* B_mpi is not ready for use - assembly will be done by MatMerge_SeqsToMPINumeric() */
4385   B_mpi->assembled     = PETSC_FALSE;
4386   B_mpi->ops->destroy  = MatDestroy_MPIAIJ_SeqsToMPI;
4387   merge->bi            = bi;
4388   merge->bj            = bj;
4389   merge->buf_ri        = buf_ri;
4390   merge->buf_rj        = buf_rj;
4391   merge->coi           = PETSC_NULL;
4392   merge->coj           = PETSC_NULL;
4393   merge->owners_co     = PETSC_NULL;
4394 
4395   /* attach the supporting struct to B_mpi for reuse */
4396   ierr = PetscContainerCreate(PETSC_COMM_SELF,&container);CHKERRQ(ierr);
4397   ierr = PetscContainerSetPointer(container,merge);CHKERRQ(ierr);
4398   ierr = PetscObjectCompose((PetscObject)B_mpi,"MatMergeSeqsToMPI",(PetscObject)container);CHKERRQ(ierr);
4399   *mpimat = B_mpi;
4400 
4401   ierr = PetscCommDestroy(&comm);CHKERRQ(ierr);
4402   ierr = PetscLogEventEnd(MAT_Seqstompisym,seqmat,0,0,0);CHKERRQ(ierr);
4403   PetscFunctionReturn(0);
4404 }
4405 
4406 #undef __FUNCT__
4407 #define __FUNCT__ "MatMerge_SeqsToMPI"
4408 PetscErrorCode PETSCMAT_DLLEXPORT MatMerge_SeqsToMPI(MPI_Comm comm,Mat seqmat,PetscInt m,PetscInt n,MatReuse scall,Mat *mpimat)
4409 {
4410   PetscErrorCode   ierr;
4411 
4412   PetscFunctionBegin;
4413   ierr = PetscLogEventBegin(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4414   if (scall == MAT_INITIAL_MATRIX){
4415     ierr = MatMerge_SeqsToMPISymbolic(comm,seqmat,m,n,mpimat);CHKERRQ(ierr);
4416   }
4417   ierr = MatMerge_SeqsToMPINumeric(seqmat,*mpimat);CHKERRQ(ierr);
4418   ierr = PetscLogEventEnd(MAT_Seqstompi,seqmat,0,0,0);CHKERRQ(ierr);
4419   PetscFunctionReturn(0);
4420 }
4421 
4422 #undef __FUNCT__
4423 #define __FUNCT__ "MatGetLocalMat"
4424 /*@
4425      MatGetLocalMat - Creates a SeqAIJ matrix by taking all its local rows
4426 
4427     Not Collective
4428 
4429    Input Parameters:
4430 +    A - the matrix
4431 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4432 
4433    Output Parameter:
4434 .    A_loc - the local sequential matrix generated
4435 
4436     Level: developer
4437 
4438 @*/
4439 PetscErrorCode PETSCMAT_DLLEXPORT MatGetLocalMat(Mat A,MatReuse scall,Mat *A_loc)
4440 {
4441   PetscErrorCode  ierr;
4442   Mat_MPIAIJ      *mpimat=(Mat_MPIAIJ*)A->data;
4443   Mat_SeqAIJ      *mat,*a=(Mat_SeqAIJ*)(mpimat->A)->data,*b=(Mat_SeqAIJ*)(mpimat->B)->data;
4444   PetscInt        *ai=a->i,*aj=a->j,*bi=b->i,*bj=b->j,*cmap=mpimat->garray;
4445   MatScalar       *aa=a->a,*ba=b->a,*cam;
4446   PetscScalar     *ca;
4447   PetscInt        am=A->rmap->n,i,j,k,cstart=A->cmap->rstart;
4448   PetscInt        *ci,*cj,col,ncols_d,ncols_o,jo;
4449 
4450   PetscFunctionBegin;
4451   ierr = PetscLogEventBegin(MAT_Getlocalmat,A,0,0,0);CHKERRQ(ierr);
4452   if (scall == MAT_INITIAL_MATRIX){
4453     ierr = PetscMalloc((1+am)*sizeof(PetscInt),&ci);CHKERRQ(ierr);
4454     ci[0] = 0;
4455     for (i=0; i<am; i++){
4456       ci[i+1] = ci[i] + (ai[i+1] - ai[i]) + (bi[i+1] - bi[i]);
4457     }
4458     ierr = PetscMalloc((1+ci[am])*sizeof(PetscInt),&cj);CHKERRQ(ierr);
4459     ierr = PetscMalloc((1+ci[am])*sizeof(PetscScalar),&ca);CHKERRQ(ierr);
4460     k = 0;
4461     for (i=0; i<am; i++) {
4462       ncols_o = bi[i+1] - bi[i];
4463       ncols_d = ai[i+1] - ai[i];
4464       /* off-diagonal portion of A */
4465       for (jo=0; jo<ncols_o; jo++) {
4466         col = cmap[*bj];
4467         if (col >= cstart) break;
4468         cj[k]   = col; bj++;
4469         ca[k++] = *ba++;
4470       }
4471       /* diagonal portion of A */
4472       for (j=0; j<ncols_d; j++) {
4473         cj[k]   = cstart + *aj++;
4474         ca[k++] = *aa++;
4475       }
4476       /* off-diagonal portion of A */
4477       for (j=jo; j<ncols_o; j++) {
4478         cj[k]   = cmap[*bj++];
4479         ca[k++] = *ba++;
4480       }
4481     }
4482     /* put together the new matrix */
4483     ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,am,A->cmap->N,ci,cj,ca,A_loc);CHKERRQ(ierr);
4484     /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
4485     /* Since these are PETSc arrays, change flags to free them as necessary. */
4486     mat          = (Mat_SeqAIJ*)(*A_loc)->data;
4487     mat->free_a  = PETSC_TRUE;
4488     mat->free_ij = PETSC_TRUE;
4489     mat->nonew   = 0;
4490   } else if (scall == MAT_REUSE_MATRIX){
4491     mat=(Mat_SeqAIJ*)(*A_loc)->data;
4492     ci = mat->i; cj = mat->j; cam = mat->a;
4493     for (i=0; i<am; i++) {
4494       /* off-diagonal portion of A */
4495       ncols_o = bi[i+1] - bi[i];
4496       for (jo=0; jo<ncols_o; jo++) {
4497         col = cmap[*bj];
4498         if (col >= cstart) break;
4499         *cam++ = *ba++; bj++;
4500       }
4501       /* diagonal portion of A */
4502       ncols_d = ai[i+1] - ai[i];
4503       for (j=0; j<ncols_d; j++) *cam++ = *aa++;
4504       /* off-diagonal portion of A */
4505       for (j=jo; j<ncols_o; j++) {
4506         *cam++ = *ba++; bj++;
4507       }
4508     }
4509   } else {
4510     SETERRQ1(PETSC_ERR_ARG_WRONG,"Invalid MatReuse %d",(int)scall);
4511   }
4512 
4513   ierr = PetscLogEventEnd(MAT_Getlocalmat,A,0,0,0);CHKERRQ(ierr);
4514   PetscFunctionReturn(0);
4515 }
4516 
4517 #undef __FUNCT__
4518 #define __FUNCT__ "MatGetLocalMatCondensed"
4519 /*@C
4520      MatGetLocalMatCondensed - Creates a SeqAIJ matrix by taking all its local rows and NON-ZERO columns
4521 
4522     Not Collective
4523 
4524    Input Parameters:
4525 +    A - the matrix
4526 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4527 -    row, col - index sets of rows and columns to extract (or PETSC_NULL)
4528 
4529    Output Parameter:
4530 .    A_loc - the local sequential matrix generated
4531 
4532     Level: developer
4533 
4534 @*/
4535 PetscErrorCode PETSCMAT_DLLEXPORT MatGetLocalMatCondensed(Mat A,MatReuse scall,IS *row,IS *col,Mat *A_loc)
4536 {
4537   Mat_MPIAIJ        *a=(Mat_MPIAIJ*)A->data;
4538   PetscErrorCode    ierr;
4539   PetscInt          i,start,end,ncols,nzA,nzB,*cmap,imark,*idx;
4540   IS                isrowa,iscola;
4541   Mat               *aloc;
4542 
4543   PetscFunctionBegin;
4544   ierr = PetscLogEventBegin(MAT_Getlocalmatcondensed,A,0,0,0);CHKERRQ(ierr);
4545   if (!row){
4546     start = A->rmap->rstart; end = A->rmap->rend;
4547     ierr = ISCreateStride(PETSC_COMM_SELF,end-start,start,1,&isrowa);CHKERRQ(ierr);
4548   } else {
4549     isrowa = *row;
4550   }
4551   if (!col){
4552     start = A->cmap->rstart;
4553     cmap  = a->garray;
4554     nzA   = a->A->cmap->n;
4555     nzB   = a->B->cmap->n;
4556     ierr  = PetscMalloc((nzA+nzB)*sizeof(PetscInt), &idx);CHKERRQ(ierr);
4557     ncols = 0;
4558     for (i=0; i<nzB; i++) {
4559       if (cmap[i] < start) idx[ncols++] = cmap[i];
4560       else break;
4561     }
4562     imark = i;
4563     for (i=0; i<nzA; i++) idx[ncols++] = start + i;
4564     for (i=imark; i<nzB; i++) idx[ncols++] = cmap[i];
4565     ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,&iscola);CHKERRQ(ierr);
4566     ierr = PetscFree(idx);CHKERRQ(ierr);
4567   } else {
4568     iscola = *col;
4569   }
4570   if (scall != MAT_INITIAL_MATRIX){
4571     ierr = PetscMalloc(sizeof(Mat),&aloc);CHKERRQ(ierr);
4572     aloc[0] = *A_loc;
4573   }
4574   ierr = MatGetSubMatrices(A,1,&isrowa,&iscola,scall,&aloc);CHKERRQ(ierr);
4575   *A_loc = aloc[0];
4576   ierr = PetscFree(aloc);CHKERRQ(ierr);
4577   if (!row){
4578     ierr = ISDestroy(isrowa);CHKERRQ(ierr);
4579   }
4580   if (!col){
4581     ierr = ISDestroy(iscola);CHKERRQ(ierr);
4582   }
4583   ierr = PetscLogEventEnd(MAT_Getlocalmatcondensed,A,0,0,0);CHKERRQ(ierr);
4584   PetscFunctionReturn(0);
4585 }
4586 
4587 #undef __FUNCT__
4588 #define __FUNCT__ "MatGetBrowsOfAcols"
4589 /*@C
4590     MatGetBrowsOfAcols - Creates a SeqAIJ matrix by taking rows of B that equal to nonzero columns of local A
4591 
4592     Collective on Mat
4593 
4594    Input Parameters:
4595 +    A,B - the matrices in mpiaij format
4596 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4597 -    rowb, colb - index sets of rows and columns of B to extract (or PETSC_NULL)
4598 
4599    Output Parameter:
4600 +    rowb, colb - index sets of rows and columns of B to extract
4601 .    brstart - row index of B_seq from which next B->rmap->n rows are taken from B's local rows
4602 -    B_seq - the sequential matrix generated
4603 
4604     Level: developer
4605 
4606 @*/
4607 PetscErrorCode PETSCMAT_DLLEXPORT MatGetBrowsOfAcols(Mat A,Mat B,MatReuse scall,IS *rowb,IS *colb,PetscInt *brstart,Mat *B_seq)
4608 {
4609   Mat_MPIAIJ        *a=(Mat_MPIAIJ*)A->data;
4610   PetscErrorCode    ierr;
4611   PetscInt          *idx,i,start,ncols,nzA,nzB,*cmap,imark;
4612   IS                isrowb,iscolb;
4613   Mat               *bseq;
4614 
4615   PetscFunctionBegin;
4616   if (A->cmap->rstart != B->rmap->rstart || A->cmap->rend != B->rmap->rend){
4617     SETERRQ4(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);
4618   }
4619   ierr = PetscLogEventBegin(MAT_GetBrowsOfAcols,A,B,0,0);CHKERRQ(ierr);
4620 
4621   if (scall == MAT_INITIAL_MATRIX){
4622     start = A->cmap->rstart;
4623     cmap  = a->garray;
4624     nzA   = a->A->cmap->n;
4625     nzB   = a->B->cmap->n;
4626     ierr  = PetscMalloc((nzA+nzB)*sizeof(PetscInt), &idx);CHKERRQ(ierr);
4627     ncols = 0;
4628     for (i=0; i<nzB; i++) {  /* row < local row index */
4629       if (cmap[i] < start) idx[ncols++] = cmap[i];
4630       else break;
4631     }
4632     imark = i;
4633     for (i=0; i<nzA; i++) idx[ncols++] = start + i;  /* local rows */
4634     for (i=imark; i<nzB; i++) idx[ncols++] = cmap[i]; /* row > local row index */
4635     ierr = ISCreateGeneral(PETSC_COMM_SELF,ncols,idx,&isrowb);CHKERRQ(ierr);
4636     ierr = PetscFree(idx);CHKERRQ(ierr);
4637     *brstart = imark;
4638     ierr = ISCreateStride(PETSC_COMM_SELF,B->cmap->N,0,1,&iscolb);CHKERRQ(ierr);
4639   } else {
4640     if (!rowb || !colb) SETERRQ(PETSC_ERR_SUP,"IS rowb and colb must be provided for MAT_REUSE_MATRIX");
4641     isrowb = *rowb; iscolb = *colb;
4642     ierr = PetscMalloc(sizeof(Mat),&bseq);CHKERRQ(ierr);
4643     bseq[0] = *B_seq;
4644   }
4645   ierr = MatGetSubMatrices(B,1,&isrowb,&iscolb,scall,&bseq);CHKERRQ(ierr);
4646   *B_seq = bseq[0];
4647   ierr = PetscFree(bseq);CHKERRQ(ierr);
4648   if (!rowb){
4649     ierr = ISDestroy(isrowb);CHKERRQ(ierr);
4650   } else {
4651     *rowb = isrowb;
4652   }
4653   if (!colb){
4654     ierr = ISDestroy(iscolb);CHKERRQ(ierr);
4655   } else {
4656     *colb = iscolb;
4657   }
4658   ierr = PetscLogEventEnd(MAT_GetBrowsOfAcols,A,B,0,0);CHKERRQ(ierr);
4659   PetscFunctionReturn(0);
4660 }
4661 
4662 #undef __FUNCT__
4663 #define __FUNCT__ "MatGetBrowsOfAoCols"
4664 /*@C
4665     MatGetBrowsOfAoCols - Creates a SeqAIJ matrix by taking rows of B that equal to nonzero columns
4666     of the OFF-DIAGONAL portion of local A
4667 
4668     Collective on Mat
4669 
4670    Input Parameters:
4671 +    A,B - the matrices in mpiaij format
4672 .    scall - either MAT_INITIAL_MATRIX or MAT_REUSE_MATRIX
4673 .    startsj - starting point in B's sending and receiving j-arrays, saved for MAT_REUSE (or PETSC_NULL)
4674 -    bufa_ptr - array for sending matrix values, saved for MAT_REUSE (or PETSC_NULL)
4675 
4676    Output Parameter:
4677 +    B_oth - the sequential matrix generated
4678 
4679     Level: developer
4680 
4681 @*/
4682 PetscErrorCode PETSCMAT_DLLEXPORT MatGetBrowsOfAoCols(Mat A,Mat B,MatReuse scall,PetscInt **startsj,MatScalar **bufa_ptr,Mat *B_oth)
4683 {
4684   VecScatter_MPI_General *gen_to,*gen_from;
4685   PetscErrorCode         ierr;
4686   Mat_MPIAIJ             *a=(Mat_MPIAIJ*)A->data;
4687   Mat_SeqAIJ             *b_oth;
4688   VecScatter             ctx=a->Mvctx;
4689   MPI_Comm               comm=((PetscObject)ctx)->comm;
4690   PetscMPIInt            *rprocs,*sprocs,tag=((PetscObject)ctx)->tag,rank;
4691   PetscInt               *rowlen,*bufj,*bufJ,ncols,aBn=a->B->cmap->n,row,*b_othi,*b_othj;
4692   PetscScalar            *rvalues,*svalues;
4693   MatScalar              *b_otha,*bufa,*bufA;
4694   PetscInt               i,j,k,l,ll,nrecvs,nsends,nrows,*srow,*rstarts,*rstartsj = 0,*sstarts,*sstartsj,len;
4695   MPI_Request            *rwaits = PETSC_NULL,*swaits = PETSC_NULL;
4696   MPI_Status             *sstatus,rstatus;
4697   PetscMPIInt            jj;
4698   PetscInt               *cols,sbs,rbs;
4699   PetscScalar            *vals;
4700 
4701   PetscFunctionBegin;
4702   if (A->cmap->rstart != B->rmap->rstart || A->cmap->rend != B->rmap->rend){
4703     SETERRQ4(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);
4704   }
4705   ierr = PetscLogEventBegin(MAT_GetBrowsOfAocols,A,B,0,0);CHKERRQ(ierr);
4706   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
4707 
4708   gen_to   = (VecScatter_MPI_General*)ctx->todata;
4709   gen_from = (VecScatter_MPI_General*)ctx->fromdata;
4710   rvalues  = gen_from->values; /* holds the length of receiving row */
4711   svalues  = gen_to->values;   /* holds the length of sending row */
4712   nrecvs   = gen_from->n;
4713   nsends   = gen_to->n;
4714 
4715   ierr = PetscMalloc2(nrecvs,MPI_Request,&rwaits,nsends,MPI_Request,&swaits);CHKERRQ(ierr);
4716   srow     = gen_to->indices;   /* local row index to be sent */
4717   sstarts  = gen_to->starts;
4718   sprocs   = gen_to->procs;
4719   sstatus  = gen_to->sstatus;
4720   sbs      = gen_to->bs;
4721   rstarts  = gen_from->starts;
4722   rprocs   = gen_from->procs;
4723   rbs      = gen_from->bs;
4724 
4725   if (!startsj || !bufa_ptr) scall = MAT_INITIAL_MATRIX;
4726   if (scall == MAT_INITIAL_MATRIX){
4727     /* i-array */
4728     /*---------*/
4729     /*  post receives */
4730     for (i=0; i<nrecvs; i++){
4731       rowlen = (PetscInt*)rvalues + rstarts[i]*rbs;
4732       nrows = (rstarts[i+1]-rstarts[i])*rbs; /* num of indices to be received */
4733       ierr = MPI_Irecv(rowlen,nrows,MPIU_INT,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
4734     }
4735 
4736     /* pack the outgoing message */
4737     ierr = PetscMalloc((nsends+nrecvs+3)*sizeof(PetscInt),&sstartsj);CHKERRQ(ierr);
4738     rstartsj = sstartsj + nsends +1;
4739     sstartsj[0] = 0;  rstartsj[0] = 0;
4740     len = 0; /* total length of j or a array to be sent */
4741     k = 0;
4742     for (i=0; i<nsends; i++){
4743       rowlen = (PetscInt*)svalues + sstarts[i]*sbs;
4744       nrows = sstarts[i+1]-sstarts[i]; /* num of block rows */
4745       for (j=0; j<nrows; j++) {
4746         row = srow[k] + B->rmap->range[rank]; /* global row idx */
4747         for (l=0; l<sbs; l++){
4748           ierr = MatGetRow_MPIAIJ(B,row+l,&ncols,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr); /* rowlength */
4749           rowlen[j*sbs+l] = ncols;
4750           len += ncols;
4751           ierr = MatRestoreRow_MPIAIJ(B,row+l,&ncols,PETSC_NULL,PETSC_NULL);CHKERRQ(ierr);
4752         }
4753         k++;
4754       }
4755       ierr = MPI_Isend(rowlen,nrows*sbs,MPIU_INT,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
4756       sstartsj[i+1] = len;  /* starting point of (i+1)-th outgoing msg in bufj and bufa */
4757     }
4758     /* recvs and sends of i-array are completed */
4759     i = nrecvs;
4760     while (i--) {
4761       ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
4762     }
4763     if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
4764 
4765     /* allocate buffers for sending j and a arrays */
4766     ierr = PetscMalloc((len+1)*sizeof(PetscInt),&bufj);CHKERRQ(ierr);
4767     ierr = PetscMalloc((len+1)*sizeof(PetscScalar),&bufa);CHKERRQ(ierr);
4768 
4769     /* create i-array of B_oth */
4770     ierr = PetscMalloc((aBn+2)*sizeof(PetscInt),&b_othi);CHKERRQ(ierr);
4771     b_othi[0] = 0;
4772     len = 0; /* total length of j or a array to be received */
4773     k = 0;
4774     for (i=0; i<nrecvs; i++){
4775       rowlen = (PetscInt*)rvalues + rstarts[i]*rbs;
4776       nrows = rbs*(rstarts[i+1]-rstarts[i]); /* num of rows to be recieved */
4777       for (j=0; j<nrows; j++) {
4778         b_othi[k+1] = b_othi[k] + rowlen[j];
4779         len += rowlen[j]; k++;
4780       }
4781       rstartsj[i+1] = len; /* starting point of (i+1)-th incoming msg in bufj and bufa */
4782     }
4783 
4784     /* allocate space for j and a arrrays of B_oth */
4785     ierr = PetscMalloc((b_othi[aBn]+1)*sizeof(PetscInt),&b_othj);CHKERRQ(ierr);
4786     ierr = PetscMalloc((b_othi[aBn]+1)*sizeof(MatScalar),&b_otha);CHKERRQ(ierr);
4787 
4788     /* j-array */
4789     /*---------*/
4790     /*  post receives of j-array */
4791     for (i=0; i<nrecvs; i++){
4792       nrows = rstartsj[i+1]-rstartsj[i]; /* length of the msg received */
4793       ierr = MPI_Irecv(b_othj+rstartsj[i],nrows,MPIU_INT,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
4794     }
4795 
4796     /* pack the outgoing message j-array */
4797     k = 0;
4798     for (i=0; i<nsends; i++){
4799       nrows = sstarts[i+1]-sstarts[i]; /* num of block rows */
4800       bufJ = bufj+sstartsj[i];
4801       for (j=0; j<nrows; j++) {
4802         row  = srow[k++] + B->rmap->range[rank]; /* global row idx */
4803         for (ll=0; ll<sbs; ll++){
4804           ierr = MatGetRow_MPIAIJ(B,row+ll,&ncols,&cols,PETSC_NULL);CHKERRQ(ierr);
4805           for (l=0; l<ncols; l++){
4806             *bufJ++ = cols[l];
4807           }
4808           ierr = MatRestoreRow_MPIAIJ(B,row+ll,&ncols,&cols,PETSC_NULL);CHKERRQ(ierr);
4809         }
4810       }
4811       ierr = MPI_Isend(bufj+sstartsj[i],sstartsj[i+1]-sstartsj[i],MPIU_INT,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
4812     }
4813 
4814     /* recvs and sends of j-array are completed */
4815     i = nrecvs;
4816     while (i--) {
4817       ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
4818     }
4819     if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
4820   } else if (scall == MAT_REUSE_MATRIX){
4821     sstartsj = *startsj;
4822     rstartsj = sstartsj + nsends +1;
4823     bufa     = *bufa_ptr;
4824     b_oth    = (Mat_SeqAIJ*)(*B_oth)->data;
4825     b_otha   = b_oth->a;
4826   } else {
4827     SETERRQ(PETSC_ERR_ARG_WRONGSTATE, "Matrix P does not posses an object container");
4828   }
4829 
4830   /* a-array */
4831   /*---------*/
4832   /*  post receives of a-array */
4833   for (i=0; i<nrecvs; i++){
4834     nrows = rstartsj[i+1]-rstartsj[i]; /* length of the msg received */
4835     ierr = MPI_Irecv(b_otha+rstartsj[i],nrows,MPIU_SCALAR,rprocs[i],tag,comm,rwaits+i);CHKERRQ(ierr);
4836   }
4837 
4838   /* pack the outgoing message a-array */
4839   k = 0;
4840   for (i=0; i<nsends; i++){
4841     nrows = sstarts[i+1]-sstarts[i]; /* num of block rows */
4842     bufA = bufa+sstartsj[i];
4843     for (j=0; j<nrows; j++) {
4844       row  = srow[k++] + B->rmap->range[rank]; /* global row idx */
4845       for (ll=0; ll<sbs; ll++){
4846         ierr = MatGetRow_MPIAIJ(B,row+ll,&ncols,PETSC_NULL,&vals);CHKERRQ(ierr);
4847         for (l=0; l<ncols; l++){
4848           *bufA++ = vals[l];
4849         }
4850         ierr = MatRestoreRow_MPIAIJ(B,row+ll,&ncols,PETSC_NULL,&vals);CHKERRQ(ierr);
4851       }
4852     }
4853     ierr = MPI_Isend(bufa+sstartsj[i],sstartsj[i+1]-sstartsj[i],MPIU_SCALAR,sprocs[i],tag,comm,swaits+i);CHKERRQ(ierr);
4854   }
4855   /* recvs and sends of a-array are completed */
4856   i = nrecvs;
4857   while (i--) {
4858     ierr = MPI_Waitany(nrecvs,rwaits,&jj,&rstatus);CHKERRQ(ierr);
4859   }
4860   if (nsends) {ierr = MPI_Waitall(nsends,swaits,sstatus);CHKERRQ(ierr);}
4861   ierr = PetscFree2(rwaits,swaits);CHKERRQ(ierr);
4862 
4863   if (scall == MAT_INITIAL_MATRIX){
4864     /* put together the new matrix */
4865     ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,aBn,B->cmap->N,b_othi,b_othj,b_otha,B_oth);CHKERRQ(ierr);
4866 
4867     /* MatCreateSeqAIJWithArrays flags matrix so PETSc doesn't free the user's arrays. */
4868     /* Since these are PETSc arrays, change flags to free them as necessary. */
4869     b_oth          = (Mat_SeqAIJ *)(*B_oth)->data;
4870     b_oth->free_a  = PETSC_TRUE;
4871     b_oth->free_ij = PETSC_TRUE;
4872     b_oth->nonew   = 0;
4873 
4874     ierr = PetscFree(bufj);CHKERRQ(ierr);
4875     if (!startsj || !bufa_ptr){
4876       ierr = PetscFree(sstartsj);CHKERRQ(ierr);
4877       ierr = PetscFree(bufa_ptr);CHKERRQ(ierr);
4878     } else {
4879       *startsj  = sstartsj;
4880       *bufa_ptr = bufa;
4881     }
4882   }
4883   ierr = PetscLogEventEnd(MAT_GetBrowsOfAocols,A,B,0,0);CHKERRQ(ierr);
4884   PetscFunctionReturn(0);
4885 }
4886 
4887 #undef __FUNCT__
4888 #define __FUNCT__ "MatGetCommunicationStructs"
4889 /*@C
4890   MatGetCommunicationStructs - Provides access to the communication structures used in matrix-vector multiplication.
4891 
4892   Not Collective
4893 
4894   Input Parameters:
4895 . A - The matrix in mpiaij format
4896 
4897   Output Parameter:
4898 + lvec - The local vector holding off-process values from the argument to a matrix-vector product
4899 . colmap - A map from global column index to local index into lvec
4900 - multScatter - A scatter from the argument of a matrix-vector product to lvec
4901 
4902   Level: developer
4903 
4904 @*/
4905 #if defined (PETSC_USE_CTABLE)
4906 PetscErrorCode PETSCMAT_DLLEXPORT MatGetCommunicationStructs(Mat A, Vec *lvec, PetscTable *colmap, VecScatter *multScatter)
4907 #else
4908 PetscErrorCode PETSCMAT_DLLEXPORT MatGetCommunicationStructs(Mat A, Vec *lvec, PetscInt *colmap[], VecScatter *multScatter)
4909 #endif
4910 {
4911   Mat_MPIAIJ *a;
4912 
4913   PetscFunctionBegin;
4914   PetscValidHeaderSpecific(A, MAT_COOKIE, 1);
4915   PetscValidPointer(lvec, 2)
4916   PetscValidPointer(colmap, 3)
4917   PetscValidPointer(multScatter, 4)
4918   a = (Mat_MPIAIJ *) A->data;
4919   if (lvec) *lvec = a->lvec;
4920   if (colmap) *colmap = a->colmap;
4921   if (multScatter) *multScatter = a->Mvctx;
4922   PetscFunctionReturn(0);
4923 }
4924 
4925 EXTERN_C_BEGIN
4926 extern PetscErrorCode PETSCMAT_DLLEXPORT MatConvert_MPIAIJ_MPICRL(Mat,const MatType,MatReuse,Mat*);
4927 extern PetscErrorCode PETSCMAT_DLLEXPORT MatConvert_MPIAIJ_MPICSRPERM(Mat,const MatType,MatReuse,Mat*);
4928 EXTERN_C_END
4929 
4930 #include "../src/mat/impls/dense/mpi/mpidense.h"
4931 
4932 #undef __FUNCT__
4933 #define __FUNCT__ "MatMatMultNumeric_MPIDense_MPIAIJ"
4934 /*
4935     Computes (B'*A')' since computing B*A directly is untenable
4936 
4937                n                       p                          p
4938         (              )       (              )         (                  )
4939       m (      A       )  *  n (       B      )   =   m (         C        )
4940         (              )       (              )         (                  )
4941 
4942 */
4943 PetscErrorCode MatMatMultNumeric_MPIDense_MPIAIJ(Mat A,Mat B,Mat C)
4944 {
4945   PetscErrorCode     ierr;
4946   Mat                At,Bt,Ct;
4947 
4948   PetscFunctionBegin;
4949   ierr = MatTranspose(A,MAT_INITIAL_MATRIX,&At);CHKERRQ(ierr);
4950   ierr = MatTranspose(B,MAT_INITIAL_MATRIX,&Bt);CHKERRQ(ierr);
4951   ierr = MatMatMult(Bt,At,MAT_INITIAL_MATRIX,1.0,&Ct);CHKERRQ(ierr);
4952   ierr = MatDestroy(At);CHKERRQ(ierr);
4953   ierr = MatDestroy(Bt);CHKERRQ(ierr);
4954   ierr = MatTranspose(Ct,MAT_REUSE_MATRIX,&C);CHKERRQ(ierr);
4955   ierr = MatDestroy(Ct);CHKERRQ(ierr);
4956   PetscFunctionReturn(0);
4957 }
4958 
4959 #undef __FUNCT__
4960 #define __FUNCT__ "MatMatMultSymbolic_MPIDense_MPIAIJ"
4961 PetscErrorCode MatMatMultSymbolic_MPIDense_MPIAIJ(Mat A,Mat B,PetscReal fill,Mat *C)
4962 {
4963   PetscErrorCode ierr;
4964   PetscInt       m=A->rmap->n,n=B->cmap->n;
4965   Mat            Cmat;
4966 
4967   PetscFunctionBegin;
4968   if (A->cmap->n != B->rmap->n) SETERRQ2(PETSC_ERR_ARG_SIZ,"A->cmap->n %d != B->rmap->n %d\n",A->cmap->n,B->rmap->n);
4969   ierr = MatCreate(((PetscObject)A)->comm,&Cmat);CHKERRQ(ierr);
4970   ierr = MatSetSizes(Cmat,m,n,PETSC_DETERMINE,PETSC_DETERMINE);CHKERRQ(ierr);
4971   ierr = MatSetType(Cmat,MATMPIDENSE);CHKERRQ(ierr);
4972   ierr = MatMPIDenseSetPreallocation(Cmat,PETSC_NULL);CHKERRQ(ierr);
4973   ierr = MatAssemblyBegin(Cmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4974   ierr = MatAssemblyEnd(Cmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
4975   *C   = Cmat;
4976   PetscFunctionReturn(0);
4977 }
4978 
4979 /* ----------------------------------------------------------------*/
4980 #undef __FUNCT__
4981 #define __FUNCT__ "MatMatMult_MPIDense_MPIAIJ"
4982 PetscErrorCode MatMatMult_MPIDense_MPIAIJ(Mat A,Mat B,MatReuse scall,PetscReal fill,Mat *C)
4983 {
4984   PetscErrorCode ierr;
4985 
4986   PetscFunctionBegin;
4987   if (scall == MAT_INITIAL_MATRIX){
4988     ierr = MatMatMultSymbolic_MPIDense_MPIAIJ(A,B,fill,C);CHKERRQ(ierr);
4989   }
4990   ierr = MatMatMultNumeric_MPIDense_MPIAIJ(A,B,*C);CHKERRQ(ierr);
4991   PetscFunctionReturn(0);
4992 }
4993 
4994 EXTERN_C_BEGIN
4995 #if defined(PETSC_HAVE_MUMPS)
4996 extern PetscErrorCode MatGetFactor_mpiaij_mumps(Mat,MatFactorType,Mat*);
4997 #endif
4998 #if defined(PETSC_HAVE_PASTIX)
4999 extern PetscErrorCode MatGetFactor_mpiaij_pastix(Mat,MatFactorType,Mat*);
5000 #endif
5001 #if defined(PETSC_HAVE_SUPERLU_DIST)
5002 extern PetscErrorCode MatGetFactor_mpiaij_superlu_dist(Mat,MatFactorType,Mat*);
5003 #endif
5004 #if defined(PETSC_HAVE_SPOOLES)
5005 extern PetscErrorCode MatGetFactor_mpiaij_spooles(Mat,MatFactorType,Mat*);
5006 #endif
5007 EXTERN_C_END
5008 
5009 /*MC
5010    MATMPIAIJ - MATMPIAIJ = "mpiaij" - A matrix type to be used for parallel sparse matrices.
5011 
5012    Options Database Keys:
5013 . -mat_type mpiaij - sets the matrix type to "mpiaij" during a call to MatSetFromOptions()
5014 
5015   Level: beginner
5016 
5017 .seealso: MatCreateMPIAIJ()
5018 M*/
5019 
5020 EXTERN_C_BEGIN
5021 #undef __FUNCT__
5022 #define __FUNCT__ "MatCreate_MPIAIJ"
5023 PetscErrorCode PETSCMAT_DLLEXPORT MatCreate_MPIAIJ(Mat B)
5024 {
5025   Mat_MPIAIJ     *b;
5026   PetscErrorCode ierr;
5027   PetscMPIInt    size;
5028 
5029   PetscFunctionBegin;
5030   ierr = MPI_Comm_size(((PetscObject)B)->comm,&size);CHKERRQ(ierr);
5031 
5032   ierr            = PetscNewLog(B,Mat_MPIAIJ,&b);CHKERRQ(ierr);
5033   B->data         = (void*)b;
5034   ierr            = PetscMemcpy(B->ops,&MatOps_Values,sizeof(struct _MatOps));CHKERRQ(ierr);
5035   B->rmap->bs      = 1;
5036   B->assembled    = PETSC_FALSE;
5037   B->mapping      = 0;
5038 
5039   B->insertmode      = NOT_SET_VALUES;
5040   b->size            = size;
5041   ierr = MPI_Comm_rank(((PetscObject)B)->comm,&b->rank);CHKERRQ(ierr);
5042 
5043   /* build cache for off array entries formed */
5044   ierr = MatStashCreate_Private(((PetscObject)B)->comm,1,&B->stash);CHKERRQ(ierr);
5045   b->donotstash  = PETSC_FALSE;
5046   b->colmap      = 0;
5047   b->garray      = 0;
5048   b->roworiented = PETSC_TRUE;
5049 
5050   /* stuff used for matrix vector multiply */
5051   b->lvec      = PETSC_NULL;
5052   b->Mvctx     = PETSC_NULL;
5053 
5054   /* stuff for MatGetRow() */
5055   b->rowindices   = 0;
5056   b->rowvalues    = 0;
5057   b->getrowactive = PETSC_FALSE;
5058 
5059 #if defined(PETSC_HAVE_SPOOLES)
5060   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatGetFactor_mpiaij_spooles_C",
5061                                      "MatGetFactor_mpiaij_spooles",
5062                                      MatGetFactor_mpiaij_spooles);CHKERRQ(ierr);
5063 #endif
5064 #if defined(PETSC_HAVE_MUMPS)
5065   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatGetFactor_mpiaij_mumps_C",
5066                                      "MatGetFactor_mpiaij_mumps",
5067                                      MatGetFactor_mpiaij_mumps);CHKERRQ(ierr);
5068 #endif
5069 #if defined(PETSC_HAVE_PASTIX)
5070   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatGetFactor_mpiaij_pastix_C",
5071 					   "MatGetFactor_mpiaij_pastix",
5072 					   MatGetFactor_mpiaij_pastix);CHKERRQ(ierr);
5073 #endif
5074 #if defined(PETSC_HAVE_SUPERLU_DIST)
5075   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatGetFactor_mpiaij_superlu_dist_C",
5076                                      "MatGetFactor_mpiaij_superlu_dist",
5077                                      MatGetFactor_mpiaij_superlu_dist);CHKERRQ(ierr);
5078 #endif
5079   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatStoreValues_C",
5080                                      "MatStoreValues_MPIAIJ",
5081                                      MatStoreValues_MPIAIJ);CHKERRQ(ierr);
5082   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatRetrieveValues_C",
5083                                      "MatRetrieveValues_MPIAIJ",
5084                                      MatRetrieveValues_MPIAIJ);CHKERRQ(ierr);
5085   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatGetDiagonalBlock_C",
5086 				     "MatGetDiagonalBlock_MPIAIJ",
5087                                      MatGetDiagonalBlock_MPIAIJ);CHKERRQ(ierr);
5088   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatIsTranspose_C",
5089 				     "MatIsTranspose_MPIAIJ",
5090 				     MatIsTranspose_MPIAIJ);CHKERRQ(ierr);
5091   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatMPIAIJSetPreallocation_C",
5092 				     "MatMPIAIJSetPreallocation_MPIAIJ",
5093 				     MatMPIAIJSetPreallocation_MPIAIJ);CHKERRQ(ierr);
5094   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatMPIAIJSetPreallocationCSR_C",
5095 				     "MatMPIAIJSetPreallocationCSR_MPIAIJ",
5096 				     MatMPIAIJSetPreallocationCSR_MPIAIJ);CHKERRQ(ierr);
5097   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatDiagonalScaleLocal_C",
5098 				     "MatDiagonalScaleLocal_MPIAIJ",
5099 				     MatDiagonalScaleLocal_MPIAIJ);CHKERRQ(ierr);
5100   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatConvert_mpiaij_mpicsrperm_C",
5101                                      "MatConvert_MPIAIJ_MPICSRPERM",
5102                                       MatConvert_MPIAIJ_MPICSRPERM);CHKERRQ(ierr);
5103   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatConvert_mpiaij_mpicrl_C",
5104                                      "MatConvert_MPIAIJ_MPICRL",
5105                                       MatConvert_MPIAIJ_MPICRL);CHKERRQ(ierr);
5106   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatMatMult_mpidense_mpiaij_C",
5107                                      "MatMatMult_MPIDense_MPIAIJ",
5108                                       MatMatMult_MPIDense_MPIAIJ);CHKERRQ(ierr);
5109   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatMatMultSymbolic_mpidense_mpiaij_C",
5110                                      "MatMatMultSymbolic_MPIDense_MPIAIJ",
5111                                       MatMatMultSymbolic_MPIDense_MPIAIJ);CHKERRQ(ierr);
5112   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatMatMultNumeric_mpidense_mpiaij_C",
5113                                      "MatMatMultNumeric_MPIDense_MPIAIJ",
5114                                       MatMatMultNumeric_MPIDense_MPIAIJ);CHKERRQ(ierr);
5115   ierr = PetscObjectChangeTypeName((PetscObject)B,MATMPIAIJ);CHKERRQ(ierr);
5116   PetscFunctionReturn(0);
5117 }
5118 EXTERN_C_END
5119 
5120 #undef __FUNCT__
5121 #define __FUNCT__ "MatCreateMPIAIJWithSplitArrays"
5122 /*@
5123      MatCreateMPIAIJWithSplitArrays - creates a MPI AIJ matrix using arrays that contain the "diagonal"
5124          and "off-diagonal" part of the matrix in CSR format.
5125 
5126    Collective on MPI_Comm
5127 
5128    Input Parameters:
5129 +  comm - MPI communicator
5130 .  m - number of local rows (Cannot be PETSC_DECIDE)
5131 .  n - This value should be the same as the local size used in creating the
5132        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
5133        calculated if N is given) For square matrices n is almost always m.
5134 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
5135 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
5136 .   i - row indices for "diagonal" portion of matrix
5137 .   j - column indices
5138 .   a - matrix values
5139 .   oi - row indices for "off-diagonal" portion of matrix
5140 .   oj - column indices
5141 -   oa - matrix values
5142 
5143    Output Parameter:
5144 .   mat - the matrix
5145 
5146    Level: advanced
5147 
5148    Notes:
5149        The i, j, and a arrays ARE NOT copied by this routine into the internal format used by PETSc.
5150 
5151        The i and j indices are 0 based
5152 
5153        See MatCreateMPIAIJ() for the definition of "diagonal" and "off-diagonal" portion of the matrix
5154 
5155 
5156 .keywords: matrix, aij, compressed row, sparse, parallel
5157 
5158 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues(), MatMPIAIJSetPreallocation(), MatMPIAIJSetPreallocationCSR(),
5159           MPIAIJ, MatCreateMPIAIJ(), MatCreateMPIAIJWithArrays()
5160 @*/
5161 PetscErrorCode PETSCMAT_DLLEXPORT MatCreateMPIAIJWithSplitArrays(MPI_Comm comm,PetscInt m,PetscInt n,PetscInt M,PetscInt N,PetscInt i[],PetscInt j[],PetscScalar a[],
5162 								PetscInt oi[], PetscInt oj[],PetscScalar oa[],Mat *mat)
5163 {
5164   PetscErrorCode ierr;
5165   Mat_MPIAIJ     *maij;
5166 
5167  PetscFunctionBegin;
5168   if (m < 0) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"local number of rows (m) cannot be PETSC_DECIDE, or negative");
5169   if (i[0]) {
5170     SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"i (row indices) must start with 0");
5171   }
5172   if (oi[0]) {
5173     SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"oi (row indices) must start with 0");
5174   }
5175   ierr = MatCreate(comm,mat);CHKERRQ(ierr);
5176   ierr = MatSetSizes(*mat,m,n,M,N);CHKERRQ(ierr);
5177   ierr = MatSetType(*mat,MATMPIAIJ);CHKERRQ(ierr);
5178   maij = (Mat_MPIAIJ*) (*mat)->data;
5179   maij->donotstash     = PETSC_TRUE;
5180   (*mat)->preallocated = PETSC_TRUE;
5181 
5182   ierr = PetscMapSetBlockSize((*mat)->rmap,1);CHKERRQ(ierr);
5183   ierr = PetscMapSetBlockSize((*mat)->cmap,1);CHKERRQ(ierr);
5184   ierr = PetscMapSetUp((*mat)->rmap);CHKERRQ(ierr);
5185   ierr = PetscMapSetUp((*mat)->cmap);CHKERRQ(ierr);
5186 
5187   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,m,n,i,j,a,&maij->A);CHKERRQ(ierr);
5188   ierr = MatCreateSeqAIJWithArrays(PETSC_COMM_SELF,m,(*mat)->cmap->N,oi,oj,oa,&maij->B);CHKERRQ(ierr);
5189 
5190   ierr = MatAssemblyBegin(maij->A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5191   ierr = MatAssemblyEnd(maij->A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5192   ierr = MatAssemblyBegin(maij->B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5193   ierr = MatAssemblyEnd(maij->B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5194 
5195   ierr = MatAssemblyBegin(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5196   ierr = MatAssemblyEnd(*mat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
5197   PetscFunctionReturn(0);
5198 }
5199 
5200 /*
5201     Special version for direct calls from Fortran
5202 */
5203 #if defined(PETSC_HAVE_FORTRAN_CAPS)
5204 #define matsetvaluesmpiaij_ MATSETVALUESMPIAIJ
5205 #elif !defined(PETSC_HAVE_FORTRAN_UNDERSCORE)
5206 #define matsetvaluesmpiaij_ matsetvaluesmpiaij
5207 #endif
5208 
5209 /* Change these macros so can be used in void function */
5210 #undef CHKERRQ
5211 #define CHKERRQ(ierr) CHKERRABORT(((PetscObject)mat)->comm,ierr)
5212 #undef SETERRQ2
5213 #define SETERRQ2(ierr,b,c,d) CHKERRABORT(((PetscObject)mat)->comm,ierr)
5214 #undef SETERRQ
5215 #define SETERRQ(ierr,b) CHKERRABORT(((PetscObject)mat)->comm,ierr)
5216 
5217 EXTERN_C_BEGIN
5218 #undef __FUNCT__
5219 #define __FUNCT__ "matsetvaluesmpiaij_"
5220 void PETSC_STDCALL matsetvaluesmpiaij_(Mat *mmat,PetscInt *mm,const PetscInt im[],PetscInt *mn,const PetscInt in[],const PetscScalar v[],InsertMode *maddv,PetscErrorCode *_ierr)
5221 {
5222   Mat             mat = *mmat;
5223   PetscInt        m = *mm, n = *mn;
5224   InsertMode      addv = *maddv;
5225   Mat_MPIAIJ      *aij = (Mat_MPIAIJ*)mat->data;
5226   PetscScalar     value;
5227   PetscErrorCode  ierr;
5228 
5229   ierr = MatPreallocated(mat);CHKERRQ(ierr);
5230   if (mat->insertmode == NOT_SET_VALUES) {
5231     mat->insertmode = addv;
5232   }
5233 #if defined(PETSC_USE_DEBUG)
5234   else if (mat->insertmode != addv) {
5235     SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Cannot mix add values and insert values");
5236   }
5237 #endif
5238   {
5239   PetscInt        i,j,rstart = mat->rmap->rstart,rend = mat->rmap->rend;
5240   PetscInt        cstart = mat->cmap->rstart,cend = mat->cmap->rend,row,col;
5241   PetscTruth      roworiented = aij->roworiented;
5242 
5243   /* Some Variables required in the macro */
5244   Mat             A = aij->A;
5245   Mat_SeqAIJ      *a = (Mat_SeqAIJ*)A->data;
5246   PetscInt        *aimax = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
5247   MatScalar       *aa = a->a;
5248   PetscTruth      ignorezeroentries = (((a->ignorezeroentries)&&(addv==ADD_VALUES))?PETSC_TRUE:PETSC_FALSE);
5249   Mat             B = aij->B;
5250   Mat_SeqAIJ      *b = (Mat_SeqAIJ*)B->data;
5251   PetscInt        *bimax = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->rmap->n,am = aij->A->rmap->n;
5252   MatScalar       *ba = b->a;
5253 
5254   PetscInt        *rp1,*rp2,ii,nrow1,nrow2,_i,rmax1,rmax2,N,low1,high1,low2,high2,t,lastcol1,lastcol2;
5255   PetscInt        nonew = a->nonew;
5256   MatScalar       *ap1,*ap2;
5257 
5258   PetscFunctionBegin;
5259   for (i=0; i<m; i++) {
5260     if (im[i] < 0) continue;
5261 #if defined(PETSC_USE_DEBUG)
5262     if (im[i] >= mat->rmap->N) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %D max %D",im[i],mat->rmap->N-1);
5263 #endif
5264     if (im[i] >= rstart && im[i] < rend) {
5265       row      = im[i] - rstart;
5266       lastcol1 = -1;
5267       rp1      = aj + ai[row];
5268       ap1      = aa + ai[row];
5269       rmax1    = aimax[row];
5270       nrow1    = ailen[row];
5271       low1     = 0;
5272       high1    = nrow1;
5273       lastcol2 = -1;
5274       rp2      = bj + bi[row];
5275       ap2      = ba + bi[row];
5276       rmax2    = bimax[row];
5277       nrow2    = bilen[row];
5278       low2     = 0;
5279       high2    = nrow2;
5280 
5281       for (j=0; j<n; j++) {
5282         if (roworiented) value = v[i*n+j]; else value = v[i+j*m];
5283         if (ignorezeroentries && value == 0.0 && (addv == ADD_VALUES)) continue;
5284         if (in[j] >= cstart && in[j] < cend){
5285           col = in[j] - cstart;
5286           MatSetValues_SeqAIJ_A_Private(row,col,value,addv);
5287         } else if (in[j] < 0) continue;
5288 #if defined(PETSC_USE_DEBUG)
5289         else if (in[j] >= mat->cmap->N) {SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %D max %D",in[j],mat->cmap->N-1);}
5290 #endif
5291         else {
5292           if (mat->was_assembled) {
5293             if (!aij->colmap) {
5294               ierr = CreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
5295             }
5296 #if defined (PETSC_USE_CTABLE)
5297             ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
5298 	    col--;
5299 #else
5300             col = aij->colmap[in[j]] - 1;
5301 #endif
5302             if (col < 0 && !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
5303               ierr = DisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
5304               col =  in[j];
5305               /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
5306               B = aij->B;
5307               b = (Mat_SeqAIJ*)B->data;
5308               bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j;
5309               rp2      = bj + bi[row];
5310               ap2      = ba + bi[row];
5311               rmax2    = bimax[row];
5312               nrow2    = bilen[row];
5313               low2     = 0;
5314               high2    = nrow2;
5315               bm       = aij->B->rmap->n;
5316               ba = b->a;
5317             }
5318           } else col = in[j];
5319           MatSetValues_SeqAIJ_B_Private(row,col,value,addv);
5320         }
5321       }
5322     } else {
5323       if (!aij->donotstash) {
5324         if (roworiented) {
5325           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n,ignorezeroentries && (addv == ADD_VALUES));CHKERRQ(ierr);
5326         } else {
5327           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m,ignorezeroentries && (addv == ADD_VALUES));CHKERRQ(ierr);
5328         }
5329       }
5330     }
5331   }}
5332   PetscFunctionReturnVoid();
5333 }
5334 EXTERN_C_END
5335 
5336