xref: /petsc/src/mat/impls/aij/mpi/mpiaij.c (revision cd0089b03c240696c596d4fef40bc47e257771ec)
1 /*$Id: mpiaij.c,v 1.344 2001/08/10 03:30:48 bsmith Exp $*/
2 
3 #include "src/mat/impls/aij/mpi/mpiaij.h"
4 #include "src/vec/vecimpl.h"
5 #include "src/inline/spops.h"
6 
7 /*
8   Local utility routine that creates a mapping from the global column
9 number to the local number in the off-diagonal part of the local
10 storage of the matrix.  When PETSC_USE_CTABLE is used this is scalable at
11 a slightly higher hash table cost; without it it is not scalable (each processor
12 has an order N integer array but is fast to acess.
13 */
14 #undef __FUNCT__
15 #define __FUNCT__ "CreateColmap_MPIAIJ_Private"
16 int CreateColmap_MPIAIJ_Private(Mat mat)
17 {
18   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
19   int        n = aij->B->n,i,ierr;
20 
21   PetscFunctionBegin;
22 #if defined (PETSC_USE_CTABLE)
23   ierr = PetscTableCreate(n,&aij->colmap);CHKERRQ(ierr);
24   for (i=0; i<n; i++){
25     ierr = PetscTableAdd(aij->colmap,aij->garray[i]+1,i+1);CHKERRQ(ierr);
26   }
27 #else
28   ierr = PetscMalloc((mat->N+1)*sizeof(int),&aij->colmap);CHKERRQ(ierr);
29   PetscLogObjectMemory(mat,mat->N*sizeof(int));
30   ierr = PetscMemzero(aij->colmap,mat->N*sizeof(int));CHKERRQ(ierr);
31   for (i=0; i<n; i++) aij->colmap[aij->garray[i]] = i+1;
32 #endif
33   PetscFunctionReturn(0);
34 }
35 
36 #define CHUNKSIZE   15
37 #define MatSetValues_SeqAIJ_A_Private(row,col,value,addv) \
38 { \
39  \
40     rp   = aj + ai[row] + shift; ap = aa + ai[row] + shift; \
41     rmax = aimax[row]; nrow = ailen[row];  \
42     col1 = col - shift; \
43      \
44     low = 0; high = nrow; \
45     while (high-low > 5) { \
46       t = (low+high)/2; \
47       if (rp[t] > col) high = t; \
48       else             low  = t; \
49     } \
50       for (_i=low; _i<high; _i++) { \
51         if (rp[_i] > col1) break; \
52         if (rp[_i] == col1) { \
53           if (addv == ADD_VALUES) ap[_i] += value;   \
54           else                  ap[_i] = value; \
55           goto a_noinsert; \
56         } \
57       }  \
58       if (nonew == 1) goto a_noinsert; \
59       else if (nonew == -1) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) into matrix", row, col); \
60       if (nrow >= rmax) { \
61         /* there is no extra room in row, therefore enlarge */ \
62         int    new_nz = ai[am] + CHUNKSIZE,len,*new_i,*new_j; \
63         PetscScalar *new_a; \
64  \
65         if (nonew == -2) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) in the matrix", row, col); \
66  \
67         /* malloc new storage space */ \
68         len     = new_nz*(sizeof(int)+sizeof(PetscScalar))+(am+1)*sizeof(int); \
69         ierr    = PetscMalloc(len,&new_a);CHKERRQ(ierr); \
70         new_j   = (int*)(new_a + new_nz); \
71         new_i   = new_j + new_nz; \
72  \
73         /* copy over old data into new slots */ \
74         for (ii=0; ii<row+1; ii++) {new_i[ii] = ai[ii];} \
75         for (ii=row+1; ii<am+1; ii++) {new_i[ii] = ai[ii]+CHUNKSIZE;} \
76         ierr = PetscMemcpy(new_j,aj,(ai[row]+nrow+shift)*sizeof(int));CHKERRQ(ierr); \
77         len = (new_nz - CHUNKSIZE - ai[row] - nrow - shift); \
78         ierr = PetscMemcpy(new_j+ai[row]+shift+nrow+CHUNKSIZE,aj+ai[row]+shift+nrow, \
79                                                            len*sizeof(int));CHKERRQ(ierr); \
80         ierr = PetscMemcpy(new_a,aa,(ai[row]+nrow+shift)*sizeof(PetscScalar));CHKERRQ(ierr); \
81         ierr = PetscMemcpy(new_a+ai[row]+shift+nrow+CHUNKSIZE,aa+ai[row]+shift+nrow, \
82                                                            len*sizeof(PetscScalar));CHKERRQ(ierr);  \
83         /* free up old matrix storage */ \
84  \
85         ierr = PetscFree(a->a);CHKERRQ(ierr);  \
86         if (!a->singlemalloc) { \
87            ierr = PetscFree(a->i);CHKERRQ(ierr); \
88            ierr = PetscFree(a->j);CHKERRQ(ierr); \
89         } \
90         aa = a->a = new_a; ai = a->i = new_i; aj = a->j = new_j;  \
91         a->singlemalloc = PETSC_TRUE; \
92  \
93         rp   = aj + ai[row] + shift; ap = aa + ai[row] + shift; \
94         rmax = aimax[row] = aimax[row] + CHUNKSIZE; \
95         PetscLogObjectMemory(A,CHUNKSIZE*(sizeof(int) + sizeof(PetscScalar))); \
96         a->maxnz += CHUNKSIZE; \
97         a->reallocs++; \
98       } \
99       N = nrow++ - 1; a->nz++; \
100       /* shift up all the later entries in this row */ \
101       for (ii=N; ii>=_i; ii--) { \
102         rp[ii+1] = rp[ii]; \
103         ap[ii+1] = ap[ii]; \
104       } \
105       rp[_i] = col1;  \
106       ap[_i] = value;  \
107       a_noinsert: ; \
108       ailen[row] = nrow; \
109 }
110 
111 #define MatSetValues_SeqAIJ_B_Private(row,col,value,addv) \
112 { \
113  \
114     rp   = bj + bi[row] + shift; ap = ba + bi[row] + shift; \
115     rmax = bimax[row]; nrow = bilen[row];  \
116     col1 = col - shift; \
117      \
118     low = 0; high = nrow; \
119     while (high-low > 5) { \
120       t = (low+high)/2; \
121       if (rp[t] > col) high = t; \
122       else             low  = t; \
123     } \
124        for (_i=low; _i<high; _i++) { \
125         if (rp[_i] > col1) break; \
126         if (rp[_i] == col1) { \
127           if (addv == ADD_VALUES) ap[_i] += value;   \
128           else                  ap[_i] = value; \
129           goto b_noinsert; \
130         } \
131       }  \
132       if (nonew == 1) goto b_noinsert; \
133       else if (nonew == -1) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) into matrix", row, col); \
134       if (nrow >= rmax) { \
135         /* there is no extra room in row, therefore enlarge */ \
136         int    new_nz = bi[bm] + CHUNKSIZE,len,*new_i,*new_j; \
137         PetscScalar *new_a; \
138  \
139         if (nonew == -2) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) in the matrix", row, col); \
140  \
141         /* malloc new storage space */ \
142         len     = new_nz*(sizeof(int)+sizeof(PetscScalar))+(bm+1)*sizeof(int); \
143         ierr    = PetscMalloc(len,&new_a);CHKERRQ(ierr); \
144         new_j   = (int*)(new_a + new_nz); \
145         new_i   = new_j + new_nz; \
146  \
147         /* copy over old data into new slots */ \
148         for (ii=0; ii<row+1; ii++) {new_i[ii] = bi[ii];} \
149         for (ii=row+1; ii<bm+1; ii++) {new_i[ii] = bi[ii]+CHUNKSIZE;} \
150         ierr = PetscMemcpy(new_j,bj,(bi[row]+nrow+shift)*sizeof(int));CHKERRQ(ierr); \
151         len = (new_nz - CHUNKSIZE - bi[row] - nrow - shift); \
152         ierr = PetscMemcpy(new_j+bi[row]+shift+nrow+CHUNKSIZE,bj+bi[row]+shift+nrow, \
153                                                            len*sizeof(int));CHKERRQ(ierr); \
154         ierr = PetscMemcpy(new_a,ba,(bi[row]+nrow+shift)*sizeof(PetscScalar));CHKERRQ(ierr); \
155         ierr = PetscMemcpy(new_a+bi[row]+shift+nrow+CHUNKSIZE,ba+bi[row]+shift+nrow, \
156                                                            len*sizeof(PetscScalar));CHKERRQ(ierr);  \
157         /* free up old matrix storage */ \
158  \
159         ierr = PetscFree(b->a);CHKERRQ(ierr);  \
160         if (!b->singlemalloc) { \
161           ierr = PetscFree(b->i);CHKERRQ(ierr); \
162           ierr = PetscFree(b->j);CHKERRQ(ierr); \
163         } \
164         ba = b->a = new_a; bi = b->i = new_i; bj = b->j = new_j;  \
165         b->singlemalloc = PETSC_TRUE; \
166  \
167         rp   = bj + bi[row] + shift; ap = ba + bi[row] + shift; \
168         rmax = bimax[row] = bimax[row] + CHUNKSIZE; \
169         PetscLogObjectMemory(B,CHUNKSIZE*(sizeof(int) + sizeof(PetscScalar))); \
170         b->maxnz += CHUNKSIZE; \
171         b->reallocs++; \
172       } \
173       N = nrow++ - 1; b->nz++; \
174       /* shift up all the later entries in this row */ \
175       for (ii=N; ii>=_i; ii--) { \
176         rp[ii+1] = rp[ii]; \
177         ap[ii+1] = ap[ii]; \
178       } \
179       rp[_i] = col1;  \
180       ap[_i] = value;  \
181       b_noinsert: ; \
182       bilen[row] = nrow; \
183 }
184 
185 #undef __FUNCT__
186 #define __FUNCT__ "MatSetValues_MPIAIJ"
187 int MatSetValues_MPIAIJ(Mat mat,int m,const int im[],int n,const int in[],const PetscScalar v[],InsertMode addv)
188 {
189   Mat_MPIAIJ   *aij = (Mat_MPIAIJ*)mat->data;
190   PetscScalar  value;
191   int          ierr,i,j,rstart = aij->rstart,rend = aij->rend;
192   int          cstart = aij->cstart,cend = aij->cend,row,col;
193   PetscTruth   roworiented = aij->roworiented;
194 
195   /* Some Variables required in the macro */
196   Mat          A = aij->A;
197   Mat_SeqAIJ   *a = (Mat_SeqAIJ*)A->data;
198   int          *aimax = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
199   PetscScalar  *aa = a->a;
200   PetscTruth   ignorezeroentries = (((a->ignorezeroentries)&&(addv==ADD_VALUES))?PETSC_TRUE:PETSC_FALSE);
201   Mat          B = aij->B;
202   Mat_SeqAIJ   *b = (Mat_SeqAIJ*)B->data;
203   int          *bimax = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->m,am = aij->A->m;
204   PetscScalar  *ba = b->a;
205 
206   int          *rp,ii,nrow,_i,rmax,N,col1,low,high,t;
207   int          nonew = a->nonew,shift=0;
208   PetscScalar  *ap;
209 
210   PetscFunctionBegin;
211   for (i=0; i<m; i++) {
212     if (im[i] < 0) continue;
213 #if defined(PETSC_USE_BOPT_g)
214     if (im[i] >= mat->M) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %d max %d",im[i],mat->M-1);
215 #endif
216     if (im[i] >= rstart && im[i] < rend) {
217       row = im[i] - rstart;
218       for (j=0; j<n; j++) {
219         if (in[j] >= cstart && in[j] < cend){
220           col = in[j] - cstart;
221           if (roworiented) value = v[i*n+j]; else value = v[i+j*m];
222           if (ignorezeroentries && value == 0.0) continue;
223           MatSetValues_SeqAIJ_A_Private(row,col,value,addv);
224           /* ierr = MatSetValues_SeqAIJ(aij->A,1,&row,1,&col,&value,addv);CHKERRQ(ierr); */
225         } else if (in[j] < 0) continue;
226 #if defined(PETSC_USE_BOPT_g)
227         else if (in[j] >= mat->N) {SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %d max %d",in[j],mat->N-1);}
228 #endif
229         else {
230           if (mat->was_assembled) {
231             if (!aij->colmap) {
232               ierr = CreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
233             }
234 #if defined (PETSC_USE_CTABLE)
235             ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
236 	    col--;
237 #else
238             col = aij->colmap[in[j]] - 1;
239 #endif
240             if (col < 0 && !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
241               ierr = DisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
242               col =  in[j];
243               /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
244               B = aij->B;
245               b = (Mat_SeqAIJ*)B->data;
246               bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j;
247               ba = b->a;
248             }
249           } else col = in[j];
250           if (roworiented) value = v[i*n+j]; else value = v[i+j*m];
251           if (ignorezeroentries && value == 0.0) continue;
252           MatSetValues_SeqAIJ_B_Private(row,col,value,addv);
253           /* ierr = MatSetValues_SeqAIJ(aij->B,1,&row,1,&col,&value,addv);CHKERRQ(ierr); */
254         }
255       }
256     } else {
257       if (!aij->donotstash) {
258         if (roworiented) {
259           if (ignorezeroentries && v[i*n] == 0.0) continue;
260           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n);CHKERRQ(ierr);
261         } else {
262           if (ignorezeroentries && v[i] == 0.0) continue;
263           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m);CHKERRQ(ierr);
264         }
265       }
266     }
267   }
268   PetscFunctionReturn(0);
269 }
270 
271 #undef __FUNCT__
272 #define __FUNCT__ "MatGetValues_MPIAIJ"
273 int MatGetValues_MPIAIJ(Mat mat,int m,const int idxm[],int n,const int idxn[],PetscScalar v[])
274 {
275   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
276   int        ierr,i,j,rstart = aij->rstart,rend = aij->rend;
277   int        cstart = aij->cstart,cend = aij->cend,row,col;
278 
279   PetscFunctionBegin;
280   for (i=0; i<m; i++) {
281     if (idxm[i] < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Negative row: %d",idxm[i]);
282     if (idxm[i] >= mat->M) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %d max %d",idxm[i],mat->M-1);
283     if (idxm[i] >= rstart && idxm[i] < rend) {
284       row = idxm[i] - rstart;
285       for (j=0; j<n; j++) {
286         if (idxn[j] < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Negative column: %d",idxn[j]);
287         if (idxn[j] >= mat->N) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %d max %d",idxn[j],mat->N-1);
288         if (idxn[j] >= cstart && idxn[j] < cend){
289           col = idxn[j] - cstart;
290           ierr = MatGetValues(aij->A,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
291         } else {
292           if (!aij->colmap) {
293             ierr = CreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
294           }
295 #if defined (PETSC_USE_CTABLE)
296           ierr = PetscTableFind(aij->colmap,idxn[j]+1,&col);CHKERRQ(ierr);
297           col --;
298 #else
299           col = aij->colmap[idxn[j]] - 1;
300 #endif
301           if ((col < 0) || (aij->garray[col] != idxn[j])) *(v+i*n+j) = 0.0;
302           else {
303             ierr = MatGetValues(aij->B,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
304           }
305         }
306       }
307     } else {
308       SETERRQ(PETSC_ERR_SUP,"Only local values currently supported");
309     }
310   }
311   PetscFunctionReturn(0);
312 }
313 
314 #undef __FUNCT__
315 #define __FUNCT__ "MatAssemblyBegin_MPIAIJ"
316 int MatAssemblyBegin_MPIAIJ(Mat mat,MatAssemblyType mode)
317 {
318   Mat_MPIAIJ  *aij = (Mat_MPIAIJ*)mat->data;
319   int         ierr,nstash,reallocs;
320   InsertMode  addv;
321 
322   PetscFunctionBegin;
323   if (aij->donotstash) {
324     PetscFunctionReturn(0);
325   }
326 
327   /* make sure all processors are either in INSERTMODE or ADDMODE */
328   ierr = MPI_Allreduce(&mat->insertmode,&addv,1,MPI_INT,MPI_BOR,mat->comm);CHKERRQ(ierr);
329   if (addv == (ADD_VALUES|INSERT_VALUES)) {
330     SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Some processors inserted others added");
331   }
332   mat->insertmode = addv; /* in case this processor had no cache */
333 
334   ierr = MatStashScatterBegin_Private(&mat->stash,aij->rowners);CHKERRQ(ierr);
335   ierr = MatStashGetInfo_Private(&mat->stash,&nstash,&reallocs);CHKERRQ(ierr);
336   PetscLogInfo(aij->A,"MatAssemblyBegin_MPIAIJ:Stash has %d entries, uses %d mallocs.\n",nstash,reallocs);
337   PetscFunctionReturn(0);
338 }
339 
340 
341 #undef __FUNCT__
342 #define __FUNCT__ "MatAssemblyEnd_MPIAIJ"
343 int MatAssemblyEnd_MPIAIJ(Mat mat,MatAssemblyType mode)
344 {
345   Mat_MPIAIJ  *aij = (Mat_MPIAIJ*)mat->data;
346   Mat_SeqAIJ  *a=(Mat_SeqAIJ *)aij->A->data,*b= (Mat_SeqAIJ *)aij->B->data;
347   int         i,j,rstart,ncols,n,ierr,flg;
348   int         *row,*col,other_disassembled;
349   PetscScalar *val;
350   InsertMode  addv = mat->insertmode;
351 
352   PetscFunctionBegin;
353   if (!aij->donotstash) {
354     while (1) {
355       ierr = MatStashScatterGetMesg_Private(&mat->stash,&n,&row,&col,&val,&flg);CHKERRQ(ierr);
356       if (!flg) break;
357 
358       for (i=0; i<n;) {
359         /* Now identify the consecutive vals belonging to the same row */
360         for (j=i,rstart=row[j]; j<n; j++) { if (row[j] != rstart) break; }
361         if (j < n) ncols = j-i;
362         else       ncols = n-i;
363         /* Now assemble all these values with a single function call */
364         ierr = MatSetValues_MPIAIJ(mat,1,row+i,ncols,col+i,val+i,addv);CHKERRQ(ierr);
365         i = j;
366       }
367     }
368     ierr = MatStashScatterEnd_Private(&mat->stash);CHKERRQ(ierr);
369   }
370 
371   ierr = MatAssemblyBegin(aij->A,mode);CHKERRQ(ierr);
372   ierr = MatAssemblyEnd(aij->A,mode);CHKERRQ(ierr);
373 
374   /* determine if any processor has disassembled, if so we must
375      also disassemble ourselfs, in order that we may reassemble. */
376   /*
377      if nonzero structure of submatrix B cannot change then we know that
378      no processor disassembled thus we can skip this stuff
379   */
380   if (!((Mat_SeqAIJ*)aij->B->data)->nonew)  {
381     ierr = MPI_Allreduce(&mat->was_assembled,&other_disassembled,1,MPI_INT,MPI_PROD,mat->comm);CHKERRQ(ierr);
382     if (mat->was_assembled && !other_disassembled) {
383       ierr = DisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
384     }
385   }
386 
387   if (!mat->was_assembled && mode == MAT_FINAL_ASSEMBLY) {
388     ierr = MatSetUpMultiply_MPIAIJ(mat);CHKERRQ(ierr);
389   }
390   ierr = MatAssemblyBegin(aij->B,mode);CHKERRQ(ierr);
391   ierr = MatAssemblyEnd(aij->B,mode);CHKERRQ(ierr);
392 
393   if (aij->rowvalues) {
394     ierr = PetscFree(aij->rowvalues);CHKERRQ(ierr);
395     aij->rowvalues = 0;
396   }
397 
398   /* used by MatAXPY() */
399   a->xtoy = 0; b->xtoy = 0;
400   a->XtoY = 0; b->XtoY = 0;
401 
402   PetscFunctionReturn(0);
403 }
404 
405 #undef __FUNCT__
406 #define __FUNCT__ "MatZeroEntries_MPIAIJ"
407 int MatZeroEntries_MPIAIJ(Mat A)
408 {
409   Mat_MPIAIJ *l = (Mat_MPIAIJ*)A->data;
410   int        ierr;
411 
412   PetscFunctionBegin;
413   ierr = MatZeroEntries(l->A);CHKERRQ(ierr);
414   ierr = MatZeroEntries(l->B);CHKERRQ(ierr);
415   PetscFunctionReturn(0);
416 }
417 
418 #undef __FUNCT__
419 #define __FUNCT__ "MatZeroRows_MPIAIJ"
420 int MatZeroRows_MPIAIJ(Mat A,IS is,const PetscScalar *diag)
421 {
422   Mat_MPIAIJ     *l = (Mat_MPIAIJ*)A->data;
423   int            i,ierr,N,*rows,*owners = l->rowners,size = l->size;
424   int            *nprocs,j,idx,nsends,row;
425   int            nmax,*svalues,*starts,*owner,nrecvs,rank = l->rank;
426   int            *rvalues,tag = A->tag,count,base,slen,n,*source;
427   int            *lens,imdex,*lrows,*values,rstart=l->rstart;
428   MPI_Comm       comm = A->comm;
429   MPI_Request    *send_waits,*recv_waits;
430   MPI_Status     recv_status,*send_status;
431   IS             istmp;
432   PetscTruth     found;
433 
434   PetscFunctionBegin;
435   ierr = ISGetLocalSize(is,&N);CHKERRQ(ierr);
436   ierr = ISGetIndices(is,&rows);CHKERRQ(ierr);
437 
438   /*  first count number of contributors to each processor */
439   ierr = PetscMalloc(2*size*sizeof(int),&nprocs);CHKERRQ(ierr);
440   ierr   = PetscMemzero(nprocs,2*size*sizeof(int));CHKERRQ(ierr);
441   ierr = PetscMalloc((N+1)*sizeof(int),&owner);CHKERRQ(ierr); /* see note*/
442   for (i=0; i<N; i++) {
443     idx = rows[i];
444     found = PETSC_FALSE;
445     for (j=0; j<size; j++) {
446       if (idx >= owners[j] && idx < owners[j+1]) {
447         nprocs[2*j]++; nprocs[2*j+1] = 1; owner[i] = j; found = PETSC_TRUE; break;
448       }
449     }
450     if (!found) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Index out of range");
451   }
452   nsends = 0;  for (i=0; i<size; i++) { nsends += nprocs[2*i+1];}
453 
454   /* inform other processors of number of messages and max length*/
455   ierr = PetscMaxSum(comm,nprocs,&nmax,&nrecvs);CHKERRQ(ierr);
456 
457   /* post receives:   */
458   ierr = PetscMalloc((nrecvs+1)*(nmax+1)*sizeof(int),&rvalues);CHKERRQ(ierr);
459   ierr = PetscMalloc((nrecvs+1)*sizeof(MPI_Request),&recv_waits);CHKERRQ(ierr);
460   for (i=0; i<nrecvs; i++) {
461     ierr = MPI_Irecv(rvalues+nmax*i,nmax,MPI_INT,MPI_ANY_SOURCE,tag,comm,recv_waits+i);CHKERRQ(ierr);
462   }
463 
464   /* do sends:
465       1) starts[i] gives the starting index in svalues for stuff going to
466          the ith processor
467   */
468   ierr = PetscMalloc((N+1)*sizeof(int),&svalues);CHKERRQ(ierr);
469   ierr = PetscMalloc((nsends+1)*sizeof(MPI_Request),&send_waits);CHKERRQ(ierr);
470   ierr = PetscMalloc((size+1)*sizeof(int),&starts);CHKERRQ(ierr);
471   starts[0] = 0;
472   for (i=1; i<size; i++) { starts[i] = starts[i-1] + nprocs[2*i-2];}
473   for (i=0; i<N; i++) {
474     svalues[starts[owner[i]]++] = rows[i];
475   }
476   ierr = ISRestoreIndices(is,&rows);CHKERRQ(ierr);
477 
478   starts[0] = 0;
479   for (i=1; i<size+1; i++) { starts[i] = starts[i-1] + nprocs[2*i-2];}
480   count = 0;
481   for (i=0; i<size; i++) {
482     if (nprocs[2*i+1]) {
483       ierr = MPI_Isend(svalues+starts[i],nprocs[2*i],MPI_INT,i,tag,comm,send_waits+count++);CHKERRQ(ierr);
484     }
485   }
486   ierr = PetscFree(starts);CHKERRQ(ierr);
487 
488   base = owners[rank];
489 
490   /*  wait on receives */
491   ierr   = PetscMalloc(2*(nrecvs+1)*sizeof(int),&lens);CHKERRQ(ierr);
492   source = lens + nrecvs;
493   count  = nrecvs; slen = 0;
494   while (count) {
495     ierr = MPI_Waitany(nrecvs,recv_waits,&imdex,&recv_status);CHKERRQ(ierr);
496     /* unpack receives into our local space */
497     ierr = MPI_Get_count(&recv_status,MPI_INT,&n);CHKERRQ(ierr);
498     source[imdex]  = recv_status.MPI_SOURCE;
499     lens[imdex]    = n;
500     slen          += n;
501     count--;
502   }
503   ierr = PetscFree(recv_waits);CHKERRQ(ierr);
504 
505   /* move the data into the send scatter */
506   ierr = PetscMalloc((slen+1)*sizeof(int),&lrows);CHKERRQ(ierr);
507   count = 0;
508   for (i=0; i<nrecvs; i++) {
509     values = rvalues + i*nmax;
510     for (j=0; j<lens[i]; j++) {
511       lrows[count++] = values[j] - base;
512     }
513   }
514   ierr = PetscFree(rvalues);CHKERRQ(ierr);
515   ierr = PetscFree(lens);CHKERRQ(ierr);
516   ierr = PetscFree(owner);CHKERRQ(ierr);
517   ierr = PetscFree(nprocs);CHKERRQ(ierr);
518 
519   /* actually zap the local rows */
520   ierr = ISCreateGeneral(PETSC_COMM_SELF,slen,lrows,&istmp);CHKERRQ(ierr);
521   PetscLogObjectParent(A,istmp);
522 
523   /*
524         Zero the required rows. If the "diagonal block" of the matrix
525      is square and the user wishes to set the diagonal we use seperate
526      code so that MatSetValues() is not called for each diagonal allocating
527      new memory, thus calling lots of mallocs and slowing things down.
528 
529        Contributed by: Mathew Knepley
530   */
531   /* must zero l->B before l->A because the (diag) case below may put values into l->B*/
532   ierr = MatZeroRows(l->B,istmp,0);CHKERRQ(ierr);
533   if (diag && (l->A->M == l->A->N)) {
534     ierr      = MatZeroRows(l->A,istmp,diag);CHKERRQ(ierr);
535   } else if (diag) {
536     ierr = MatZeroRows(l->A,istmp,0);CHKERRQ(ierr);
537     if (((Mat_SeqAIJ*)l->A->data)->nonew) {
538       SETERRQ(PETSC_ERR_SUP,"MatZeroRows() on rectangular matrices cannot be used with the Mat options\n\
539 MAT_NO_NEW_NONZERO_LOCATIONS,MAT_NEW_NONZERO_LOCATION_ERR,MAT_NEW_NONZERO_ALLOCATION_ERR");
540     }
541     for (i = 0; i < slen; i++) {
542       row  = lrows[i] + rstart;
543       ierr = MatSetValues(A,1,&row,1,&row,diag,INSERT_VALUES);CHKERRQ(ierr);
544     }
545     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
546     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
547   } else {
548     ierr = MatZeroRows(l->A,istmp,0);CHKERRQ(ierr);
549   }
550   ierr = ISDestroy(istmp);CHKERRQ(ierr);
551   ierr = PetscFree(lrows);CHKERRQ(ierr);
552 
553   /* wait on sends */
554   if (nsends) {
555     ierr = PetscMalloc(nsends*sizeof(MPI_Status),&send_status);CHKERRQ(ierr);
556     ierr = MPI_Waitall(nsends,send_waits,send_status);CHKERRQ(ierr);
557     ierr = PetscFree(send_status);CHKERRQ(ierr);
558   }
559   ierr = PetscFree(send_waits);CHKERRQ(ierr);
560   ierr = PetscFree(svalues);CHKERRQ(ierr);
561 
562   PetscFunctionReturn(0);
563 }
564 
565 #undef __FUNCT__
566 #define __FUNCT__ "MatMult_MPIAIJ"
567 int MatMult_MPIAIJ(Mat A,Vec xx,Vec yy)
568 {
569   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
570   int        ierr,nt;
571 
572   PetscFunctionBegin;
573   ierr = VecGetLocalSize(xx,&nt);CHKERRQ(ierr);
574   if (nt != A->n) {
575     SETERRQ2(PETSC_ERR_ARG_SIZ,"Incompatible partition of A (%d) and xx (%d)",A->n,nt);
576   }
577   ierr = VecScatterBegin(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
578   ierr = (*a->A->ops->mult)(a->A,xx,yy);CHKERRQ(ierr);
579   ierr = VecScatterEnd(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
580   ierr = (*a->B->ops->multadd)(a->B,a->lvec,yy,yy);CHKERRQ(ierr);
581   PetscFunctionReturn(0);
582 }
583 
584 #undef __FUNCT__
585 #define __FUNCT__ "MatMultAdd_MPIAIJ"
586 int MatMultAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
587 {
588   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
589   int        ierr;
590 
591   PetscFunctionBegin;
592   ierr = VecScatterBegin(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
593   ierr = (*a->A->ops->multadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
594   ierr = VecScatterEnd(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
595   ierr = (*a->B->ops->multadd)(a->B,a->lvec,zz,zz);CHKERRQ(ierr);
596   PetscFunctionReturn(0);
597 }
598 
599 #undef __FUNCT__
600 #define __FUNCT__ "MatMultTranspose_MPIAIJ"
601 int MatMultTranspose_MPIAIJ(Mat A,Vec xx,Vec yy)
602 {
603   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
604   int        ierr;
605 
606   PetscFunctionBegin;
607   /* do nondiagonal part */
608   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
609   /* send it on its way */
610   ierr = VecScatterBegin(a->lvec,yy,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
611   /* do local part */
612   ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
613   /* receive remote parts: note this assumes the values are not actually */
614   /* inserted in yy until the next line, which is true for my implementation*/
615   /* but is not perhaps always true. */
616   ierr = VecScatterEnd(a->lvec,yy,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
617   PetscFunctionReturn(0);
618 }
619 
620 EXTERN_C_BEGIN
621 #undef __FUNCT__
622 #define __FUNCT__ "MatIsTranspose_MPIAIJ"
623 int MatIsTranspose_MPIAIJ(Mat Amat,Mat Bmat,PetscTruth *f)
624 {
625   MPI_Comm comm;
626   Mat_MPIAIJ *Aij = (Mat_MPIAIJ *) Amat->data, *Bij;
627   Mat        Adia = Aij->A, Bdia, Aoff,Boff,*Aoffs,*Boffs;
628   IS         Me,Notme;
629   int        M,N,first,last,*notme,ntids,i, ierr;
630 
631   PetscFunctionBegin;
632 
633   /* Easy test: symmetric diagonal block */
634   Bij = (Mat_MPIAIJ *) Bmat->data; Bdia = Bij->A;
635   ierr = MatIsTranspose(Adia,Bdia,f); CHKERRQ(ierr);
636   if (!*f) PetscFunctionReturn(0);
637   ierr = PetscObjectGetComm((PetscObject)Amat,&comm); CHKERRQ(ierr);
638   ierr = MPI_Comm_size(comm,&ntids); CHKERRQ(ierr);
639   if (ntids==1) PetscFunctionReturn(0);
640 
641   /* Hard test: off-diagonal block. This takes a MatGetSubMatrix. */
642   ierr = MatGetSize(Amat,&M,&N); CHKERRQ(ierr);
643   ierr = MatGetOwnershipRange(Amat,&first,&last); CHKERRQ(ierr);
644   ierr = PetscMalloc((N-last+first)*sizeof(int),&notme); CHKERRQ(ierr);
645   for (i=0; i<first; i++) notme[i] = i;
646   for (i=last; i<M; i++) notme[i-last+first] = i;
647   ierr = ISCreateGeneral(MPI_COMM_SELF,N-last+first,notme,&Notme); CHKERRQ(ierr);
648   ierr = ISCreateStride(MPI_COMM_SELF,last-first,first,1,&Me); CHKERRQ(ierr);
649   ierr = MatGetSubMatrices(Amat,1,&Me,&Notme,MAT_INITIAL_MATRIX,&Aoffs); CHKERRQ(ierr);
650   Aoff = Aoffs[0];
651   ierr = MatGetSubMatrices(Bmat,1,&Notme,&Me,MAT_INITIAL_MATRIX,&Boffs); CHKERRQ(ierr);
652   Boff = Boffs[0];
653   ierr = MatIsTranspose(Aoff,Boff,f); CHKERRQ(ierr);
654   ierr = MatDestroyMatrices(1,&Aoffs); CHKERRQ(ierr);
655   ierr = MatDestroyMatrices(1,&Boffs); CHKERRQ(ierr);
656   ierr = ISDestroy(Me); CHKERRQ(ierr);
657   ierr = ISDestroy(Notme); CHKERRQ(ierr);
658 
659   PetscFunctionReturn(0);
660 }
661 EXTERN_C_END
662 
663 #undef __FUNCT__
664 #define __FUNCT__ "MatMultTransposeAdd_MPIAIJ"
665 int MatMultTransposeAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
666 {
667   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
668   int        ierr;
669 
670   PetscFunctionBegin;
671   /* do nondiagonal part */
672   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
673   /* send it on its way */
674   ierr = VecScatterBegin(a->lvec,zz,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
675   /* do local part */
676   ierr = (*a->A->ops->multtransposeadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
677   /* receive remote parts: note this assumes the values are not actually */
678   /* inserted in yy until the next line, which is true for my implementation*/
679   /* but is not perhaps always true. */
680   ierr = VecScatterEnd(a->lvec,zz,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
681   PetscFunctionReturn(0);
682 }
683 
684 /*
685   This only works correctly for square matrices where the subblock A->A is the
686    diagonal block
687 */
688 #undef __FUNCT__
689 #define __FUNCT__ "MatGetDiagonal_MPIAIJ"
690 int MatGetDiagonal_MPIAIJ(Mat A,Vec v)
691 {
692   int        ierr;
693   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
694 
695   PetscFunctionBegin;
696   if (A->M != A->N) SETERRQ(PETSC_ERR_SUP,"Supports only square matrix where A->A is diag block");
697   if (a->rstart != a->cstart || a->rend != a->cend) {
698     SETERRQ(PETSC_ERR_ARG_SIZ,"row partition must equal col partition");
699   }
700   ierr = MatGetDiagonal(a->A,v);CHKERRQ(ierr);
701   PetscFunctionReturn(0);
702 }
703 
704 #undef __FUNCT__
705 #define __FUNCT__ "MatScale_MPIAIJ"
706 int MatScale_MPIAIJ(const PetscScalar aa[],Mat A)
707 {
708   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
709   int        ierr;
710 
711   PetscFunctionBegin;
712   ierr = MatScale(aa,a->A);CHKERRQ(ierr);
713   ierr = MatScale(aa,a->B);CHKERRQ(ierr);
714   PetscFunctionReturn(0);
715 }
716 
717 #undef __FUNCT__
718 #define __FUNCT__ "MatDestroy_MPIAIJ"
719 int MatDestroy_MPIAIJ(Mat mat)
720 {
721   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
722   int        ierr;
723 
724   PetscFunctionBegin;
725 #if defined(PETSC_USE_LOG)
726   PetscLogObjectState((PetscObject)mat,"Rows=%d, Cols=%d",mat->M,mat->N);
727 #endif
728   ierr = MatStashDestroy_Private(&mat->stash);CHKERRQ(ierr);
729   ierr = PetscFree(aij->rowners);CHKERRQ(ierr);
730   ierr = MatDestroy(aij->A);CHKERRQ(ierr);
731   ierr = MatDestroy(aij->B);CHKERRQ(ierr);
732 #if defined (PETSC_USE_CTABLE)
733   if (aij->colmap) {ierr = PetscTableDelete(aij->colmap);CHKERRQ(ierr);}
734 #else
735   if (aij->colmap) {ierr = PetscFree(aij->colmap);CHKERRQ(ierr);}
736 #endif
737   if (aij->garray) {ierr = PetscFree(aij->garray);CHKERRQ(ierr);}
738   if (aij->lvec)   {ierr = VecDestroy(aij->lvec);CHKERRQ(ierr);}
739   if (aij->Mvctx)  {ierr = VecScatterDestroy(aij->Mvctx);CHKERRQ(ierr);}
740   if (aij->rowvalues) {ierr = PetscFree(aij->rowvalues);CHKERRQ(ierr);}
741   ierr = PetscFree(aij);CHKERRQ(ierr);
742   PetscFunctionReturn(0);
743 }
744 
745 #undef __FUNCT__
746 #define __FUNCT__ "MatView_MPIAIJ_Binary"
747 int MatView_MPIAIJ_Binary(Mat mat,PetscViewer viewer)
748 {
749   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
750   Mat_SeqAIJ*       A = (Mat_SeqAIJ*)aij->A->data;
751   Mat_SeqAIJ*       B = (Mat_SeqAIJ*)aij->B->data;
752   int               nz,fd,ierr,header[4],rank,size,*row_lengths,*range,rlen,i,tag = ((PetscObject)viewer)->tag;
753   int               nzmax,*column_indices,j,k,col,*garray = aij->garray,cnt,cstart = aij->cstart,rnz;
754   PetscScalar       *column_values;
755 
756   PetscFunctionBegin;
757   ierr = MPI_Comm_rank(mat->comm,&rank);CHKERRQ(ierr);
758   ierr = MPI_Comm_size(mat->comm,&size);CHKERRQ(ierr);
759   nz   = A->nz + B->nz;
760   if (rank == 0) {
761     header[0] = MAT_FILE_COOKIE;
762     header[1] = mat->M;
763     header[2] = mat->N;
764     ierr = MPI_Reduce(&nz,&header[3],1,MPI_INT,MPI_SUM,0,mat->comm);CHKERRQ(ierr);
765     ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
766     ierr = PetscBinaryWrite(fd,header,4,PETSC_INT,1);CHKERRQ(ierr);
767     /* get largest number of rows any processor has */
768     rlen = mat->m;
769     ierr = PetscMapGetGlobalRange(mat->rmap,&range);CHKERRQ(ierr);
770     for (i=1; i<size; i++) {
771       rlen = PetscMax(rlen,range[i+1] - range[i]);
772     }
773   } else {
774     ierr = MPI_Reduce(&nz,0,1,MPI_INT,MPI_SUM,0,mat->comm);CHKERRQ(ierr);
775     rlen = mat->m;
776   }
777 
778   /* load up the local row counts */
779   ierr = PetscMalloc((rlen+1)*sizeof(int),&row_lengths);CHKERRQ(ierr);
780   for (i=0; i<mat->m; i++) {
781     row_lengths[i] = A->i[i+1] - A->i[i] + B->i[i+1] - B->i[i];
782   }
783 
784   /* store the row lengths to the file */
785   if (rank == 0) {
786     MPI_Status status;
787     ierr = PetscBinaryWrite(fd,row_lengths,mat->m,PETSC_INT,1);CHKERRQ(ierr);
788     for (i=1; i<size; i++) {
789       rlen = range[i+1] - range[i];
790       ierr = MPI_Recv(row_lengths,rlen,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
791       ierr = PetscBinaryWrite(fd,row_lengths,rlen,PETSC_INT,1);CHKERRQ(ierr);
792     }
793   } else {
794     ierr = MPI_Send(row_lengths,mat->m,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
795   }
796   ierr = PetscFree(row_lengths);CHKERRQ(ierr);
797 
798   /* load up the local column indices */
799   nzmax = nz; /* )th processor needs space a largest processor needs */
800   ierr = MPI_Reduce(&nz,&nzmax,1,MPI_INT,MPI_MAX,0,mat->comm);CHKERRQ(ierr);
801   ierr = PetscMalloc((nzmax+1)*sizeof(int),&column_indices);CHKERRQ(ierr);
802   cnt  = 0;
803   for (i=0; i<mat->m; i++) {
804     for (j=B->i[i]; j<B->i[i+1]; j++) {
805       if ( (col = garray[B->j[j]]) > cstart) break;
806       column_indices[cnt++] = col;
807     }
808     for (k=A->i[i]; k<A->i[i+1]; k++) {
809       column_indices[cnt++] = A->j[k] + cstart;
810     }
811     for (; j<B->i[i+1]; j++) {
812       column_indices[cnt++] = garray[B->j[j]];
813     }
814   }
815   if (cnt != A->nz + B->nz) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: cnt = %d nz = %d",cnt,A->nz+B->nz);
816 
817   /* store the column indices to the file */
818   if (rank == 0) {
819     MPI_Status status;
820     ierr = PetscBinaryWrite(fd,column_indices,nz,PETSC_INT,1);CHKERRQ(ierr);
821     for (i=1; i<size; i++) {
822       ierr = MPI_Recv(&rnz,1,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
823       if (rnz > nzmax) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: nz = %d nzmax = %d",nz,nzmax);
824       ierr = MPI_Recv(column_indices,rnz,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
825       ierr = PetscBinaryWrite(fd,column_indices,rnz,PETSC_INT,1);CHKERRQ(ierr);
826     }
827   } else {
828     ierr = MPI_Send(&nz,1,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
829     ierr = MPI_Send(column_indices,nz,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
830   }
831   ierr = PetscFree(column_indices);CHKERRQ(ierr);
832 
833   /* load up the local column values */
834   ierr = PetscMalloc((nzmax+1)*sizeof(PetscScalar),&column_values);CHKERRQ(ierr);
835   cnt  = 0;
836   for (i=0; i<mat->m; i++) {
837     for (j=B->i[i]; j<B->i[i+1]; j++) {
838       if ( garray[B->j[j]] > cstart) break;
839       column_values[cnt++] = B->a[j];
840     }
841     for (k=A->i[i]; k<A->i[i+1]; k++) {
842       column_values[cnt++] = A->a[k];
843     }
844     for (; j<B->i[i+1]; j++) {
845       column_values[cnt++] = B->a[j];
846     }
847   }
848   if (cnt != A->nz + B->nz) SETERRQ2(1,"Internal PETSc error: cnt = %d nz = %d",cnt,A->nz+B->nz);
849 
850   /* store the column values to the file */
851   if (rank == 0) {
852     MPI_Status status;
853     ierr = PetscBinaryWrite(fd,column_values,nz,PETSC_SCALAR,1);CHKERRQ(ierr);
854     for (i=1; i<size; i++) {
855       ierr = MPI_Recv(&rnz,1,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
856       if (rnz > nzmax) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: nz = %d nzmax = %d",nz,nzmax);
857       ierr = MPI_Recv(column_values,rnz,MPIU_SCALAR,i,tag,mat->comm,&status);CHKERRQ(ierr);
858       ierr = PetscBinaryWrite(fd,column_values,rnz,PETSC_SCALAR,1);CHKERRQ(ierr);
859     }
860   } else {
861     ierr = MPI_Send(&nz,1,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
862     ierr = MPI_Send(column_values,nz,MPIU_SCALAR,0,tag,mat->comm);CHKERRQ(ierr);
863   }
864   ierr = PetscFree(column_values);CHKERRQ(ierr);
865   PetscFunctionReturn(0);
866 }
867 
868 #undef __FUNCT__
869 #define __FUNCT__ "MatView_MPIAIJ_ASCIIorDraworSocket"
870 int MatView_MPIAIJ_ASCIIorDraworSocket(Mat mat,PetscViewer viewer)
871 {
872   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
873   int               ierr,rank = aij->rank,size = aij->size;
874   PetscTruth        isdraw,isascii,flg,isbinary;
875   PetscViewer       sviewer;
876   PetscViewerFormat format;
877 
878   PetscFunctionBegin;
879   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_DRAW,&isdraw);CHKERRQ(ierr);
880   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&isascii);CHKERRQ(ierr);
881   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_BINARY,&isbinary);CHKERRQ(ierr);
882   if (isascii) {
883     ierr = PetscViewerGetFormat(viewer,&format);CHKERRQ(ierr);
884     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
885       MatInfo info;
886       ierr = MPI_Comm_rank(mat->comm,&rank);CHKERRQ(ierr);
887       ierr = MatGetInfo(mat,MAT_LOCAL,&info);CHKERRQ(ierr);
888       ierr = PetscOptionsHasName(PETSC_NULL,"-mat_aij_no_inode",&flg);CHKERRQ(ierr);
889       if (flg) {
890         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %d nz %d nz alloced %d mem %d, not using I-node routines\n",
891 					      rank,mat->m,(int)info.nz_used,(int)info.nz_allocated,(int)info.memory);CHKERRQ(ierr);
892       } else {
893         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %d nz %d nz alloced %d mem %d, using I-node routines\n",
894 		    rank,mat->m,(int)info.nz_used,(int)info.nz_allocated,(int)info.memory);CHKERRQ(ierr);
895       }
896       ierr = MatGetInfo(aij->A,MAT_LOCAL,&info);CHKERRQ(ierr);
897       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] on-diagonal part: nz %d \n",rank,(int)info.nz_used);CHKERRQ(ierr);
898       ierr = MatGetInfo(aij->B,MAT_LOCAL,&info);CHKERRQ(ierr);
899       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] off-diagonal part: nz %d \n",rank,(int)info.nz_used);CHKERRQ(ierr);
900       ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
901       ierr = VecScatterView(aij->Mvctx,viewer);CHKERRQ(ierr);
902       PetscFunctionReturn(0);
903     } else if (format == PETSC_VIEWER_ASCII_INFO) {
904       PetscFunctionReturn(0);
905     } else if (format == PETSC_VIEWER_ASCII_FACTOR_INFO) {
906       PetscFunctionReturn(0);
907     }
908   } else if (isbinary) {
909     if (size == 1) {
910       ierr = PetscObjectSetName((PetscObject)aij->A,mat->name);CHKERRQ(ierr);
911       ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
912     } else {
913       ierr = MatView_MPIAIJ_Binary(mat,viewer);CHKERRQ(ierr);
914     }
915     PetscFunctionReturn(0);
916   } else if (isdraw) {
917     PetscDraw  draw;
918     PetscTruth isnull;
919     ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
920     ierr = PetscDrawIsNull(draw,&isnull);CHKERRQ(ierr); if (isnull) PetscFunctionReturn(0);
921   }
922 
923   if (size == 1) {
924     ierr = PetscObjectSetName((PetscObject)aij->A,mat->name);CHKERRQ(ierr);
925     ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
926   } else {
927     /* assemble the entire matrix onto first processor. */
928     Mat         A;
929     Mat_SeqAIJ *Aloc;
930     int         M = mat->M,N = mat->N,m,*ai,*aj,row,*cols,i,*ct;
931     PetscScalar *a;
932 
933     if (!rank) {
934       ierr = MatCreateMPIAIJ(mat->comm,M,N,M,N,0,PETSC_NULL,0,PETSC_NULL,&A);CHKERRQ(ierr);
935     } else {
936       ierr = MatCreateMPIAIJ(mat->comm,0,0,M,N,0,PETSC_NULL,0,PETSC_NULL,&A);CHKERRQ(ierr);
937     }
938     PetscLogObjectParent(mat,A);
939 
940     /* copy over the A part */
941     Aloc = (Mat_SeqAIJ*)aij->A->data;
942     m = aij->A->m; ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
943     row = aij->rstart;
944     for (i=0; i<ai[m]; i++) {aj[i] += aij->cstart ;}
945     for (i=0; i<m; i++) {
946       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],aj,a,INSERT_VALUES);CHKERRQ(ierr);
947       row++; a += ai[i+1]-ai[i]; aj += ai[i+1]-ai[i];
948     }
949     aj = Aloc->j;
950     for (i=0; i<ai[m]; i++) {aj[i] -= aij->cstart;}
951 
952     /* copy over the B part */
953     Aloc = (Mat_SeqAIJ*)aij->B->data;
954     m    = aij->B->m;  ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
955     row  = aij->rstart;
956     ierr = PetscMalloc((ai[m]+1)*sizeof(int),&cols);CHKERRQ(ierr);
957     ct   = cols;
958     for (i=0; i<ai[m]; i++) {cols[i] = aij->garray[aj[i]];}
959     for (i=0; i<m; i++) {
960       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],cols,a,INSERT_VALUES);CHKERRQ(ierr);
961       row++; a += ai[i+1]-ai[i]; cols += ai[i+1]-ai[i];
962     }
963     ierr = PetscFree(ct);CHKERRQ(ierr);
964     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
965     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
966     /*
967        Everyone has to call to draw the matrix since the graphics waits are
968        synchronized across all processors that share the PetscDraw object
969     */
970     ierr = PetscViewerGetSingleton(viewer,&sviewer);CHKERRQ(ierr);
971     if (!rank) {
972       ierr = PetscObjectSetName((PetscObject)((Mat_MPIAIJ*)(A->data))->A,mat->name);CHKERRQ(ierr);
973       ierr = MatView(((Mat_MPIAIJ*)(A->data))->A,sviewer);CHKERRQ(ierr);
974     }
975     ierr = PetscViewerRestoreSingleton(viewer,&sviewer);CHKERRQ(ierr);
976     ierr = MatDestroy(A);CHKERRQ(ierr);
977   }
978   PetscFunctionReturn(0);
979 }
980 
981 #undef __FUNCT__
982 #define __FUNCT__ "MatView_MPIAIJ"
983 int MatView_MPIAIJ(Mat mat,PetscViewer viewer)
984 {
985   int        ierr;
986   PetscTruth isascii,isdraw,issocket,isbinary;
987 
988   PetscFunctionBegin;
989   ierr  = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&isascii);CHKERRQ(ierr);
990   ierr  = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_DRAW,&isdraw);CHKERRQ(ierr);
991   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_BINARY,&isbinary);CHKERRQ(ierr);
992   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_SOCKET,&issocket);CHKERRQ(ierr);
993   if (isascii || isdraw || isbinary || issocket) {
994     ierr = MatView_MPIAIJ_ASCIIorDraworSocket(mat,viewer);CHKERRQ(ierr);
995   } else {
996     SETERRQ1(1,"Viewer type %s not supported by MPIAIJ matrices",((PetscObject)viewer)->type_name);
997   }
998   PetscFunctionReturn(0);
999 }
1000 
1001 
1002 
1003 #undef __FUNCT__
1004 #define __FUNCT__ "MatRelax_MPIAIJ"
1005 int MatRelax_MPIAIJ(Mat matin,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,int its,int lits,Vec xx)
1006 {
1007   Mat_MPIAIJ   *mat = (Mat_MPIAIJ*)matin->data;
1008   int          ierr;
1009   Vec          bb1;
1010   PetscScalar  mone=-1.0;
1011 
1012   PetscFunctionBegin;
1013   if (its <= 0 || lits <= 0) SETERRQ2(PETSC_ERR_ARG_WRONG,"Relaxation requires global its %d and local its %d both positive",its,lits);
1014 
1015   ierr = VecDuplicate(bb,&bb1);CHKERRQ(ierr);
1016 
1017   if ((flag & SOR_LOCAL_SYMMETRIC_SWEEP) == SOR_LOCAL_SYMMETRIC_SWEEP){
1018     if (flag & SOR_ZERO_INITIAL_GUESS) {
1019       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,lits,xx);CHKERRQ(ierr);
1020       its--;
1021     }
1022 
1023     while (its--) {
1024       ierr = VecScatterBegin(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1025       ierr = VecScatterEnd(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1026 
1027       /* update rhs: bb1 = bb - B*x */
1028       ierr = VecScale(&mone,mat->lvec);CHKERRQ(ierr);
1029       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1030 
1031       /* local sweep */
1032       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_SYMMETRIC_SWEEP,fshift,lits,lits,xx);
1033       CHKERRQ(ierr);
1034     }
1035   } else if (flag & SOR_LOCAL_FORWARD_SWEEP){
1036     if (flag & SOR_ZERO_INITIAL_GUESS) {
1037       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,PETSC_NULL,xx);CHKERRQ(ierr);
1038       its--;
1039     }
1040     while (its--) {
1041       ierr = VecScatterBegin(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1042       ierr = VecScatterEnd(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1043 
1044       /* update rhs: bb1 = bb - B*x */
1045       ierr = VecScale(&mone,mat->lvec);CHKERRQ(ierr);
1046       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1047 
1048       /* local sweep */
1049       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_FORWARD_SWEEP,fshift,lits,PETSC_NULL,xx);
1050       CHKERRQ(ierr);
1051     }
1052   } else if (flag & SOR_LOCAL_BACKWARD_SWEEP){
1053     if (flag & SOR_ZERO_INITIAL_GUESS) {
1054       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,PETSC_NULL,xx);CHKERRQ(ierr);
1055       its--;
1056     }
1057     while (its--) {
1058       ierr = VecScatterBegin(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1059       ierr = VecScatterEnd(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1060 
1061       /* update rhs: bb1 = bb - B*x */
1062       ierr = VecScale(&mone,mat->lvec);CHKERRQ(ierr);
1063       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1064 
1065       /* local sweep */
1066       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_BACKWARD_SWEEP,fshift,lits,PETSC_NULL,xx);
1067       CHKERRQ(ierr);
1068     }
1069   } else {
1070     SETERRQ(PETSC_ERR_SUP,"Parallel SOR not supported");
1071   }
1072 
1073   ierr = VecDestroy(bb1);CHKERRQ(ierr);
1074   PetscFunctionReturn(0);
1075 }
1076 
1077 #undef __FUNCT__
1078 #define __FUNCT__ "MatGetInfo_MPIAIJ"
1079 int MatGetInfo_MPIAIJ(Mat matin,MatInfoType flag,MatInfo *info)
1080 {
1081   Mat_MPIAIJ *mat = (Mat_MPIAIJ*)matin->data;
1082   Mat        A = mat->A,B = mat->B;
1083   int        ierr;
1084   PetscReal  isend[5],irecv[5];
1085 
1086   PetscFunctionBegin;
1087   info->block_size     = 1.0;
1088   ierr = MatGetInfo(A,MAT_LOCAL,info);CHKERRQ(ierr);
1089   isend[0] = info->nz_used; isend[1] = info->nz_allocated; isend[2] = info->nz_unneeded;
1090   isend[3] = info->memory;  isend[4] = info->mallocs;
1091   ierr = MatGetInfo(B,MAT_LOCAL,info);CHKERRQ(ierr);
1092   isend[0] += info->nz_used; isend[1] += info->nz_allocated; isend[2] += info->nz_unneeded;
1093   isend[3] += info->memory;  isend[4] += info->mallocs;
1094   if (flag == MAT_LOCAL) {
1095     info->nz_used      = isend[0];
1096     info->nz_allocated = isend[1];
1097     info->nz_unneeded  = isend[2];
1098     info->memory       = isend[3];
1099     info->mallocs      = isend[4];
1100   } else if (flag == MAT_GLOBAL_MAX) {
1101     ierr = MPI_Allreduce(isend,irecv,5,MPIU_REAL,MPI_MAX,matin->comm);CHKERRQ(ierr);
1102     info->nz_used      = irecv[0];
1103     info->nz_allocated = irecv[1];
1104     info->nz_unneeded  = irecv[2];
1105     info->memory       = irecv[3];
1106     info->mallocs      = irecv[4];
1107   } else if (flag == MAT_GLOBAL_SUM) {
1108     ierr = MPI_Allreduce(isend,irecv,5,MPIU_REAL,MPI_SUM,matin->comm);CHKERRQ(ierr);
1109     info->nz_used      = irecv[0];
1110     info->nz_allocated = irecv[1];
1111     info->nz_unneeded  = irecv[2];
1112     info->memory       = irecv[3];
1113     info->mallocs      = irecv[4];
1114   }
1115   info->fill_ratio_given  = 0; /* no parallel LU/ILU/Cholesky */
1116   info->fill_ratio_needed = 0;
1117   info->factor_mallocs    = 0;
1118   info->rows_global       = (double)matin->M;
1119   info->columns_global    = (double)matin->N;
1120   info->rows_local        = (double)matin->m;
1121   info->columns_local     = (double)matin->N;
1122 
1123   PetscFunctionReturn(0);
1124 }
1125 
1126 #undef __FUNCT__
1127 #define __FUNCT__ "MatSetOption_MPIAIJ"
1128 int MatSetOption_MPIAIJ(Mat A,MatOption op)
1129 {
1130   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
1131   int        ierr;
1132 
1133   PetscFunctionBegin;
1134   switch (op) {
1135   case MAT_NO_NEW_NONZERO_LOCATIONS:
1136   case MAT_YES_NEW_NONZERO_LOCATIONS:
1137   case MAT_COLUMNS_UNSORTED:
1138   case MAT_COLUMNS_SORTED:
1139   case MAT_NEW_NONZERO_ALLOCATION_ERR:
1140   case MAT_KEEP_ZEROED_ROWS:
1141   case MAT_NEW_NONZERO_LOCATION_ERR:
1142   case MAT_USE_INODES:
1143   case MAT_DO_NOT_USE_INODES:
1144   case MAT_IGNORE_ZERO_ENTRIES:
1145     ierr = MatSetOption(a->A,op);CHKERRQ(ierr);
1146     ierr = MatSetOption(a->B,op);CHKERRQ(ierr);
1147     break;
1148   case MAT_ROW_ORIENTED:
1149     a->roworiented = PETSC_TRUE;
1150     ierr = MatSetOption(a->A,op);CHKERRQ(ierr);
1151     ierr = MatSetOption(a->B,op);CHKERRQ(ierr);
1152     break;
1153   case MAT_ROWS_SORTED:
1154   case MAT_ROWS_UNSORTED:
1155   case MAT_YES_NEW_DIAGONALS:
1156     PetscLogInfo(A,"MatSetOption_MPIAIJ:Option ignored\n");
1157     break;
1158   case MAT_COLUMN_ORIENTED:
1159     a->roworiented = PETSC_FALSE;
1160     ierr = MatSetOption(a->A,op);CHKERRQ(ierr);
1161     ierr = MatSetOption(a->B,op);CHKERRQ(ierr);
1162     break;
1163   case MAT_IGNORE_OFF_PROC_ENTRIES:
1164     a->donotstash = PETSC_TRUE;
1165     break;
1166   case MAT_NO_NEW_DIAGONALS:
1167     SETERRQ(PETSC_ERR_SUP,"MAT_NO_NEW_DIAGONALS");
1168   case MAT_SYMMETRIC:
1169   case MAT_STRUCTURALLY_SYMMETRIC:
1170   case MAT_NOT_SYMMETRIC:
1171   case MAT_NOT_STRUCTURALLY_SYMMETRIC:
1172   case MAT_HERMITIAN:
1173   case MAT_NOT_HERMITIAN:
1174   case MAT_SYMMETRY_ETERNAL:
1175   case MAT_NOT_SYMMETRY_ETERNAL:
1176     break;
1177   default:
1178     SETERRQ(PETSC_ERR_SUP,"unknown option");
1179   }
1180   PetscFunctionReturn(0);
1181 }
1182 
1183 #undef __FUNCT__
1184 #define __FUNCT__ "MatGetRow_MPIAIJ"
1185 int MatGetRow_MPIAIJ(Mat matin,int row,int *nz,int **idx,PetscScalar **v)
1186 {
1187   Mat_MPIAIJ   *mat = (Mat_MPIAIJ*)matin->data;
1188   PetscScalar  *vworkA,*vworkB,**pvA,**pvB,*v_p;
1189   int          i,ierr,*cworkA,*cworkB,**pcA,**pcB,cstart = mat->cstart;
1190   int          nztot,nzA,nzB,lrow,rstart = mat->rstart,rend = mat->rend;
1191   int          *cmap,*idx_p;
1192 
1193   PetscFunctionBegin;
1194   if (mat->getrowactive == PETSC_TRUE) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Already active");
1195   mat->getrowactive = PETSC_TRUE;
1196 
1197   if (!mat->rowvalues && (idx || v)) {
1198     /*
1199         allocate enough space to hold information from the longest row.
1200     */
1201     Mat_SeqAIJ *Aa = (Mat_SeqAIJ*)mat->A->data,*Ba = (Mat_SeqAIJ*)mat->B->data;
1202     int     max = 1,tmp;
1203     for (i=0; i<matin->m; i++) {
1204       tmp = Aa->i[i+1] - Aa->i[i] + Ba->i[i+1] - Ba->i[i];
1205       if (max < tmp) { max = tmp; }
1206     }
1207     ierr = PetscMalloc(max*(sizeof(int)+sizeof(PetscScalar)),&mat->rowvalues);CHKERRQ(ierr);
1208     mat->rowindices = (int*)(mat->rowvalues + max);
1209   }
1210 
1211   if (row < rstart || row >= rend) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Only local rows")
1212   lrow = row - rstart;
1213 
1214   pvA = &vworkA; pcA = &cworkA; pvB = &vworkB; pcB = &cworkB;
1215   if (!v)   {pvA = 0; pvB = 0;}
1216   if (!idx) {pcA = 0; if (!v) pcB = 0;}
1217   ierr = (*mat->A->ops->getrow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1218   ierr = (*mat->B->ops->getrow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1219   nztot = nzA + nzB;
1220 
1221   cmap  = mat->garray;
1222   if (v  || idx) {
1223     if (nztot) {
1224       /* Sort by increasing column numbers, assuming A and B already sorted */
1225       int imark = -1;
1226       if (v) {
1227         *v = v_p = mat->rowvalues;
1228         for (i=0; i<nzB; i++) {
1229           if (cmap[cworkB[i]] < cstart)   v_p[i] = vworkB[i];
1230           else break;
1231         }
1232         imark = i;
1233         for (i=0; i<nzA; i++)     v_p[imark+i] = vworkA[i];
1234         for (i=imark; i<nzB; i++) v_p[nzA+i]   = vworkB[i];
1235       }
1236       if (idx) {
1237         *idx = idx_p = mat->rowindices;
1238         if (imark > -1) {
1239           for (i=0; i<imark; i++) {
1240             idx_p[i] = cmap[cworkB[i]];
1241           }
1242         } else {
1243           for (i=0; i<nzB; i++) {
1244             if (cmap[cworkB[i]] < cstart)   idx_p[i] = cmap[cworkB[i]];
1245             else break;
1246           }
1247           imark = i;
1248         }
1249         for (i=0; i<nzA; i++)     idx_p[imark+i] = cstart + cworkA[i];
1250         for (i=imark; i<nzB; i++) idx_p[nzA+i]   = cmap[cworkB[i]];
1251       }
1252     } else {
1253       if (idx) *idx = 0;
1254       if (v)   *v   = 0;
1255     }
1256   }
1257   *nz = nztot;
1258   ierr = (*mat->A->ops->restorerow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1259   ierr = (*mat->B->ops->restorerow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1260   PetscFunctionReturn(0);
1261 }
1262 
1263 #undef __FUNCT__
1264 #define __FUNCT__ "MatRestoreRow_MPIAIJ"
1265 int MatRestoreRow_MPIAIJ(Mat mat,int row,int *nz,int **idx,PetscScalar **v)
1266 {
1267   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1268 
1269   PetscFunctionBegin;
1270   if (aij->getrowactive == PETSC_FALSE) {
1271     SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"MatGetRow not called");
1272   }
1273   aij->getrowactive = PETSC_FALSE;
1274   PetscFunctionReturn(0);
1275 }
1276 
1277 #undef __FUNCT__
1278 #define __FUNCT__ "MatNorm_MPIAIJ"
1279 int MatNorm_MPIAIJ(Mat mat,NormType type,PetscReal *norm)
1280 {
1281   Mat_MPIAIJ   *aij = (Mat_MPIAIJ*)mat->data;
1282   Mat_SeqAIJ   *amat = (Mat_SeqAIJ*)aij->A->data,*bmat = (Mat_SeqAIJ*)aij->B->data;
1283   int          ierr,i,j,cstart = aij->cstart;
1284   PetscReal    sum = 0.0;
1285   PetscScalar  *v;
1286 
1287   PetscFunctionBegin;
1288   if (aij->size == 1) {
1289     ierr =  MatNorm(aij->A,type,norm);CHKERRQ(ierr);
1290   } else {
1291     if (type == NORM_FROBENIUS) {
1292       v = amat->a;
1293       for (i=0; i<amat->nz; i++) {
1294 #if defined(PETSC_USE_COMPLEX)
1295         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1296 #else
1297         sum += (*v)*(*v); v++;
1298 #endif
1299       }
1300       v = bmat->a;
1301       for (i=0; i<bmat->nz; i++) {
1302 #if defined(PETSC_USE_COMPLEX)
1303         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1304 #else
1305         sum += (*v)*(*v); v++;
1306 #endif
1307       }
1308       ierr = MPI_Allreduce(&sum,norm,1,MPIU_REAL,MPI_SUM,mat->comm);CHKERRQ(ierr);
1309       *norm = sqrt(*norm);
1310     } else if (type == NORM_1) { /* max column norm */
1311       PetscReal *tmp,*tmp2;
1312       int    *jj,*garray = aij->garray;
1313       ierr = PetscMalloc((mat->N+1)*sizeof(PetscReal),&tmp);CHKERRQ(ierr);
1314       ierr = PetscMalloc((mat->N+1)*sizeof(PetscReal),&tmp2);CHKERRQ(ierr);
1315       ierr = PetscMemzero(tmp,mat->N*sizeof(PetscReal));CHKERRQ(ierr);
1316       *norm = 0.0;
1317       v = amat->a; jj = amat->j;
1318       for (j=0; j<amat->nz; j++) {
1319         tmp[cstart + *jj++ ] += PetscAbsScalar(*v);  v++;
1320       }
1321       v = bmat->a; jj = bmat->j;
1322       for (j=0; j<bmat->nz; j++) {
1323         tmp[garray[*jj++]] += PetscAbsScalar(*v); v++;
1324       }
1325       ierr = MPI_Allreduce(tmp,tmp2,mat->N,MPIU_REAL,MPI_SUM,mat->comm);CHKERRQ(ierr);
1326       for (j=0; j<mat->N; j++) {
1327         if (tmp2[j] > *norm) *norm = tmp2[j];
1328       }
1329       ierr = PetscFree(tmp);CHKERRQ(ierr);
1330       ierr = PetscFree(tmp2);CHKERRQ(ierr);
1331     } else if (type == NORM_INFINITY) { /* max row norm */
1332       PetscReal ntemp = 0.0;
1333       for (j=0; j<aij->A->m; j++) {
1334         v = amat->a + amat->i[j];
1335         sum = 0.0;
1336         for (i=0; i<amat->i[j+1]-amat->i[j]; i++) {
1337           sum += PetscAbsScalar(*v); v++;
1338         }
1339         v = bmat->a + bmat->i[j];
1340         for (i=0; i<bmat->i[j+1]-bmat->i[j]; i++) {
1341           sum += PetscAbsScalar(*v); v++;
1342         }
1343         if (sum > ntemp) ntemp = sum;
1344       }
1345       ierr = MPI_Allreduce(&ntemp,norm,1,MPIU_REAL,MPI_MAX,mat->comm);CHKERRQ(ierr);
1346     } else {
1347       SETERRQ(PETSC_ERR_SUP,"No support for two norm");
1348     }
1349   }
1350   PetscFunctionReturn(0);
1351 }
1352 
1353 #undef __FUNCT__
1354 #define __FUNCT__ "MatTranspose_MPIAIJ"
1355 int MatTranspose_MPIAIJ(Mat A,Mat *matout)
1356 {
1357   Mat_MPIAIJ   *a = (Mat_MPIAIJ*)A->data;
1358   Mat_SeqAIJ   *Aloc = (Mat_SeqAIJ*)a->A->data;
1359   int          ierr;
1360   int          M = A->M,N = A->N,m,*ai,*aj,row,*cols,i,*ct;
1361   Mat          B;
1362   PetscScalar  *array;
1363 
1364   PetscFunctionBegin;
1365   if (!matout && M != N) {
1366     SETERRQ(PETSC_ERR_ARG_SIZ,"Square matrix only for in-place");
1367   }
1368 
1369   ierr = MatCreateMPIAIJ(A->comm,A->n,A->m,N,M,0,PETSC_NULL,0,PETSC_NULL,&B);CHKERRQ(ierr);
1370 
1371   /* copy over the A part */
1372   Aloc = (Mat_SeqAIJ*)a->A->data;
1373   m = a->A->m; ai = Aloc->i; aj = Aloc->j; array = Aloc->a;
1374   row = a->rstart;
1375   for (i=0; i<ai[m]; i++) {aj[i] += a->cstart ;}
1376   for (i=0; i<m; i++) {
1377     ierr = MatSetValues(B,ai[i+1]-ai[i],aj,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1378     row++; array += ai[i+1]-ai[i]; aj += ai[i+1]-ai[i];
1379   }
1380   aj = Aloc->j;
1381   for (i=0; i<ai[m]; i++) {aj[i] -= a->cstart ;}
1382 
1383   /* copy over the B part */
1384   Aloc = (Mat_SeqAIJ*)a->B->data;
1385   m = a->B->m;  ai = Aloc->i; aj = Aloc->j; array = Aloc->a;
1386   row  = a->rstart;
1387   ierr = PetscMalloc((1+ai[m])*sizeof(int),&cols);CHKERRQ(ierr);
1388   ct   = cols;
1389   for (i=0; i<ai[m]; i++) {cols[i] = a->garray[aj[i]];}
1390   for (i=0; i<m; i++) {
1391     ierr = MatSetValues(B,ai[i+1]-ai[i],cols,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1392     row++; array += ai[i+1]-ai[i]; cols += ai[i+1]-ai[i];
1393   }
1394   ierr = PetscFree(ct);CHKERRQ(ierr);
1395   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1396   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1397   if (matout) {
1398     *matout = B;
1399   } else {
1400     ierr = MatHeaderCopy(A,B);CHKERRQ(ierr);
1401   }
1402   PetscFunctionReturn(0);
1403 }
1404 
1405 #undef __FUNCT__
1406 #define __FUNCT__ "MatDiagonalScale_MPIAIJ"
1407 int MatDiagonalScale_MPIAIJ(Mat mat,Vec ll,Vec rr)
1408 {
1409   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1410   Mat        a = aij->A,b = aij->B;
1411   int        ierr,s1,s2,s3;
1412 
1413   PetscFunctionBegin;
1414   ierr = MatGetLocalSize(mat,&s2,&s3);CHKERRQ(ierr);
1415   if (rr) {
1416     ierr = VecGetLocalSize(rr,&s1);CHKERRQ(ierr);
1417     if (s1!=s3) SETERRQ(PETSC_ERR_ARG_SIZ,"right vector non-conforming local size");
1418     /* Overlap communication with computation. */
1419     ierr = VecScatterBegin(rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD,aij->Mvctx);CHKERRQ(ierr);
1420   }
1421   if (ll) {
1422     ierr = VecGetLocalSize(ll,&s1);CHKERRQ(ierr);
1423     if (s1!=s2) SETERRQ(PETSC_ERR_ARG_SIZ,"left vector non-conforming local size");
1424     ierr = (*b->ops->diagonalscale)(b,ll,0);CHKERRQ(ierr);
1425   }
1426   /* scale  the diagonal block */
1427   ierr = (*a->ops->diagonalscale)(a,ll,rr);CHKERRQ(ierr);
1428 
1429   if (rr) {
1430     /* Do a scatter end and then right scale the off-diagonal block */
1431     ierr = VecScatterEnd(rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD,aij->Mvctx);CHKERRQ(ierr);
1432     ierr = (*b->ops->diagonalscale)(b,0,aij->lvec);CHKERRQ(ierr);
1433   }
1434 
1435   PetscFunctionReturn(0);
1436 }
1437 
1438 
1439 #undef __FUNCT__
1440 #define __FUNCT__ "MatPrintHelp_MPIAIJ"
1441 int MatPrintHelp_MPIAIJ(Mat A)
1442 {
1443   Mat_MPIAIJ *a   = (Mat_MPIAIJ*)A->data;
1444   int        ierr;
1445 
1446   PetscFunctionBegin;
1447   if (!a->rank) {
1448     ierr = MatPrintHelp_SeqAIJ(a->A);CHKERRQ(ierr);
1449   }
1450   PetscFunctionReturn(0);
1451 }
1452 
1453 #undef __FUNCT__
1454 #define __FUNCT__ "MatGetBlockSize_MPIAIJ"
1455 int MatGetBlockSize_MPIAIJ(Mat A,int *bs)
1456 {
1457   PetscFunctionBegin;
1458   *bs = 1;
1459   PetscFunctionReturn(0);
1460 }
1461 #undef __FUNCT__
1462 #define __FUNCT__ "MatSetUnfactored_MPIAIJ"
1463 int MatSetUnfactored_MPIAIJ(Mat A)
1464 {
1465   Mat_MPIAIJ *a   = (Mat_MPIAIJ*)A->data;
1466   int        ierr;
1467 
1468   PetscFunctionBegin;
1469   ierr = MatSetUnfactored(a->A);CHKERRQ(ierr);
1470   PetscFunctionReturn(0);
1471 }
1472 
1473 #undef __FUNCT__
1474 #define __FUNCT__ "MatEqual_MPIAIJ"
1475 int MatEqual_MPIAIJ(Mat A,Mat B,PetscTruth *flag)
1476 {
1477   Mat_MPIAIJ *matB = (Mat_MPIAIJ*)B->data,*matA = (Mat_MPIAIJ*)A->data;
1478   Mat        a,b,c,d;
1479   PetscTruth flg;
1480   int        ierr;
1481 
1482   PetscFunctionBegin;
1483   a = matA->A; b = matA->B;
1484   c = matB->A; d = matB->B;
1485 
1486   ierr = MatEqual(a,c,&flg);CHKERRQ(ierr);
1487   if (flg == PETSC_TRUE) {
1488     ierr = MatEqual(b,d,&flg);CHKERRQ(ierr);
1489   }
1490   ierr = MPI_Allreduce(&flg,flag,1,MPI_INT,MPI_LAND,A->comm);CHKERRQ(ierr);
1491   PetscFunctionReturn(0);
1492 }
1493 
1494 #undef __FUNCT__
1495 #define __FUNCT__ "MatCopy_MPIAIJ"
1496 int MatCopy_MPIAIJ(Mat A,Mat B,MatStructure str)
1497 {
1498   int        ierr;
1499   Mat_MPIAIJ *a = (Mat_MPIAIJ *)A->data;
1500   Mat_MPIAIJ *b = (Mat_MPIAIJ *)B->data;
1501 
1502   PetscFunctionBegin;
1503   /* If the two matrices don't have the same copy implementation, they aren't compatible for fast copy. */
1504   if ((str != SAME_NONZERO_PATTERN) || (A->ops->copy != B->ops->copy)) {
1505     /* because of the column compression in the off-processor part of the matrix a->B,
1506        the number of columns in a->B and b->B may be different, hence we cannot call
1507        the MatCopy() directly on the two parts. If need be, we can provide a more
1508        efficient copy than the MatCopy_Basic() by first uncompressing the a->B matrices
1509        then copying the submatrices */
1510     ierr = MatCopy_Basic(A,B,str);CHKERRQ(ierr);
1511   } else {
1512     ierr = MatCopy(a->A,b->A,str);CHKERRQ(ierr);
1513     ierr = MatCopy(a->B,b->B,str);CHKERRQ(ierr);
1514   }
1515   PetscFunctionReturn(0);
1516 }
1517 
1518 #undef __FUNCT__
1519 #define __FUNCT__ "MatSetUpPreallocation_MPIAIJ"
1520 int MatSetUpPreallocation_MPIAIJ(Mat A)
1521 {
1522   int        ierr;
1523 
1524   PetscFunctionBegin;
1525   ierr =  MatMPIAIJSetPreallocation(A,PETSC_DEFAULT,0,PETSC_DEFAULT,0);CHKERRQ(ierr);
1526   PetscFunctionReturn(0);
1527 }
1528 
1529 #include "petscblaslapack.h"
1530 #undef __FUNCT__
1531 #define __FUNCT__ "MatAXPY_MPIAIJ"
1532 int MatAXPY_MPIAIJ(const PetscScalar a[],Mat X,Mat Y,MatStructure str)
1533 {
1534   int        ierr,one=1,i;
1535   Mat_MPIAIJ *xx = (Mat_MPIAIJ *)X->data,*yy = (Mat_MPIAIJ *)Y->data;
1536   Mat_SeqAIJ *x,*y;
1537 
1538   PetscFunctionBegin;
1539   if (str == SAME_NONZERO_PATTERN) {
1540     x = (Mat_SeqAIJ *)xx->A->data;
1541     y = (Mat_SeqAIJ *)yy->A->data;
1542     BLaxpy_(&x->nz,(PetscScalar*)a,x->a,&one,y->a,&one);
1543     x = (Mat_SeqAIJ *)xx->B->data;
1544     y = (Mat_SeqAIJ *)yy->B->data;
1545     BLaxpy_(&x->nz,(PetscScalar*)a,x->a,&one,y->a,&one);
1546   } else if (str == SUBSET_NONZERO_PATTERN) {
1547     ierr = MatAXPY_SeqAIJ(a,xx->A,yy->A,str);CHKERRQ(ierr);
1548 
1549     x = (Mat_SeqAIJ *)xx->B->data;
1550     y = (Mat_SeqAIJ *)yy->B->data;
1551     if (y->xtoy && y->XtoY != xx->B) {
1552       ierr = PetscFree(y->xtoy);CHKERRQ(ierr);
1553       ierr = MatDestroy(y->XtoY);CHKERRQ(ierr);
1554     }
1555     if (!y->xtoy) { /* get xtoy */
1556       ierr = MatAXPYGetxtoy_Private(xx->B->m,x->i,x->j,xx->garray,y->i,y->j,yy->garray,&y->xtoy);CHKERRQ(ierr);
1557       y->XtoY = xx->B;
1558     }
1559     for (i=0; i<x->nz; i++) y->a[y->xtoy[i]] += (*a)*(x->a[i]);
1560   } else {
1561     ierr = MatAXPY_Basic(a,X,Y,str);CHKERRQ(ierr);
1562   }
1563   PetscFunctionReturn(0);
1564 }
1565 
1566 /* -------------------------------------------------------------------*/
1567 static struct _MatOps MatOps_Values = {MatSetValues_MPIAIJ,
1568        MatGetRow_MPIAIJ,
1569        MatRestoreRow_MPIAIJ,
1570        MatMult_MPIAIJ,
1571 /* 4*/ MatMultAdd_MPIAIJ,
1572        MatMultTranspose_MPIAIJ,
1573        MatMultTransposeAdd_MPIAIJ,
1574        0,
1575        0,
1576        0,
1577 /*10*/ 0,
1578        0,
1579        0,
1580        MatRelax_MPIAIJ,
1581        MatTranspose_MPIAIJ,
1582 /*15*/ MatGetInfo_MPIAIJ,
1583        MatEqual_MPIAIJ,
1584        MatGetDiagonal_MPIAIJ,
1585        MatDiagonalScale_MPIAIJ,
1586        MatNorm_MPIAIJ,
1587 /*20*/ MatAssemblyBegin_MPIAIJ,
1588        MatAssemblyEnd_MPIAIJ,
1589        0,
1590        MatSetOption_MPIAIJ,
1591        MatZeroEntries_MPIAIJ,
1592 /*25*/ MatZeroRows_MPIAIJ,
1593 #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_SINGLE)
1594        MatLUFactorSymbolic_MPIAIJ_TFS,
1595 #else
1596        0,
1597 #endif
1598        0,
1599        0,
1600        0,
1601 /*30*/ MatSetUpPreallocation_MPIAIJ,
1602        0,
1603        0,
1604        0,
1605        0,
1606 /*35*/ MatDuplicate_MPIAIJ,
1607        0,
1608        0,
1609        0,
1610        0,
1611 /*40*/ MatAXPY_MPIAIJ,
1612        MatGetSubMatrices_MPIAIJ,
1613        MatIncreaseOverlap_MPIAIJ,
1614        MatGetValues_MPIAIJ,
1615        MatCopy_MPIAIJ,
1616 /*45*/ MatPrintHelp_MPIAIJ,
1617        MatScale_MPIAIJ,
1618        0,
1619        0,
1620        0,
1621 /*50*/ MatGetBlockSize_MPIAIJ,
1622        0,
1623        0,
1624        0,
1625        0,
1626 /*55*/ MatFDColoringCreate_MPIAIJ,
1627        0,
1628        MatSetUnfactored_MPIAIJ,
1629        0,
1630        0,
1631 /*60*/ MatGetSubMatrix_MPIAIJ,
1632        MatDestroy_MPIAIJ,
1633        MatView_MPIAIJ,
1634        MatGetPetscMaps_Petsc,
1635        0,
1636 /*65*/ 0,
1637        0,
1638        0,
1639        0,
1640        0,
1641 /*70*/ 0,
1642        0,
1643        MatSetColoring_MPIAIJ,
1644        MatSetValuesAdic_MPIAIJ,
1645        MatSetValuesAdifor_MPIAIJ,
1646 /*75*/ 0,
1647        0,
1648        0,
1649        0,
1650        0,
1651 /*80*/ 0,
1652        0,
1653        0,
1654        0,
1655 /*85*/ MatLoad_MPIAIJ};
1656 
1657 /* ----------------------------------------------------------------------------------------*/
1658 
1659 EXTERN_C_BEGIN
1660 #undef __FUNCT__
1661 #define __FUNCT__ "MatStoreValues_MPIAIJ"
1662 int MatStoreValues_MPIAIJ(Mat mat)
1663 {
1664   Mat_MPIAIJ *aij = (Mat_MPIAIJ *)mat->data;
1665   int        ierr;
1666 
1667   PetscFunctionBegin;
1668   ierr = MatStoreValues(aij->A);CHKERRQ(ierr);
1669   ierr = MatStoreValues(aij->B);CHKERRQ(ierr);
1670   PetscFunctionReturn(0);
1671 }
1672 EXTERN_C_END
1673 
1674 EXTERN_C_BEGIN
1675 #undef __FUNCT__
1676 #define __FUNCT__ "MatRetrieveValues_MPIAIJ"
1677 int MatRetrieveValues_MPIAIJ(Mat mat)
1678 {
1679   Mat_MPIAIJ *aij = (Mat_MPIAIJ *)mat->data;
1680   int        ierr;
1681 
1682   PetscFunctionBegin;
1683   ierr = MatRetrieveValues(aij->A);CHKERRQ(ierr);
1684   ierr = MatRetrieveValues(aij->B);CHKERRQ(ierr);
1685   PetscFunctionReturn(0);
1686 }
1687 EXTERN_C_END
1688 
1689 #include "petscpc.h"
1690 EXTERN_C_BEGIN
1691 #undef __FUNCT__
1692 #define __FUNCT__ "MatMPIAIJSetPreallocation_MPIAIJ"
1693 int MatMPIAIJSetPreallocation_MPIAIJ(Mat B,int d_nz,const int d_nnz[],int o_nz,const int o_nnz[])
1694 {
1695   Mat_MPIAIJ   *b;
1696   int          ierr,i;
1697 
1698   PetscFunctionBegin;
1699   B->preallocated = PETSC_TRUE;
1700   if (d_nz == PETSC_DEFAULT || d_nz == PETSC_DECIDE) d_nz = 5;
1701   if (o_nz == PETSC_DEFAULT || o_nz == PETSC_DECIDE) o_nz = 2;
1702   if (d_nz < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"d_nz cannot be less than 0: value %d",d_nz);
1703   if (o_nz < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"o_nz cannot be less than 0: value %d",o_nz);
1704   if (d_nnz) {
1705     for (i=0; i<B->m; i++) {
1706       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]);
1707     }
1708   }
1709   if (o_nnz) {
1710     for (i=0; i<B->m; i++) {
1711       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]);
1712     }
1713   }
1714   b = (Mat_MPIAIJ*)B->data;
1715 
1716   ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,B->m,B->n,d_nz,d_nnz,&b->A);CHKERRQ(ierr);
1717   PetscLogObjectParent(B,b->A);
1718   ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,B->m,B->N,o_nz,o_nnz,&b->B);CHKERRQ(ierr);
1719   PetscLogObjectParent(B,b->B);
1720 
1721   PetscFunctionReturn(0);
1722 }
1723 EXTERN_C_END
1724 
1725 /*MC
1726    MATMPIAIJ - MATMPIAIJ = "mpiaij" - A matrix type to be used for parallel sparse matrices.
1727 
1728    Options Database Keys:
1729 . -mat_type mpiaij - sets the matrix type to "mpiaij" during a call to MatSetFromOptions()
1730 
1731   Level: beginner
1732 
1733 .seealso: MatCreateMPIAIJ
1734 M*/
1735 
1736 EXTERN_C_BEGIN
1737 #undef __FUNCT__
1738 #define __FUNCT__ "MatCreate_MPIAIJ"
1739 int MatCreate_MPIAIJ(Mat B)
1740 {
1741   Mat_MPIAIJ *b;
1742   int        ierr,i,size;
1743 
1744   PetscFunctionBegin;
1745   ierr = MPI_Comm_size(B->comm,&size);CHKERRQ(ierr);
1746 
1747   ierr            = PetscNew(Mat_MPIAIJ,&b);CHKERRQ(ierr);
1748   B->data         = (void*)b;
1749   ierr            = PetscMemzero(b,sizeof(Mat_MPIAIJ));CHKERRQ(ierr);
1750   ierr            = PetscMemcpy(B->ops,&MatOps_Values,sizeof(struct _MatOps));CHKERRQ(ierr);
1751   B->factor       = 0;
1752   B->assembled    = PETSC_FALSE;
1753   B->mapping      = 0;
1754 
1755   B->insertmode      = NOT_SET_VALUES;
1756   b->size            = size;
1757   ierr = MPI_Comm_rank(B->comm,&b->rank);CHKERRQ(ierr);
1758 
1759   ierr = PetscSplitOwnership(B->comm,&B->m,&B->M);CHKERRQ(ierr);
1760   ierr = PetscSplitOwnership(B->comm,&B->n,&B->N);CHKERRQ(ierr);
1761 
1762   /* the information in the maps duplicates the information computed below, eventually
1763      we should remove the duplicate information that is not contained in the maps */
1764   ierr = PetscMapCreateMPI(B->comm,B->m,B->M,&B->rmap);CHKERRQ(ierr);
1765   ierr = PetscMapCreateMPI(B->comm,B->n,B->N,&B->cmap);CHKERRQ(ierr);
1766 
1767   /* build local table of row and column ownerships */
1768   ierr = PetscMalloc(2*(b->size+2)*sizeof(int),&b->rowners);CHKERRQ(ierr);
1769   PetscLogObjectMemory(B,2*(b->size+2)*sizeof(int)+sizeof(struct _p_Mat)+sizeof(Mat_MPIAIJ));
1770   b->cowners = b->rowners + b->size + 2;
1771   ierr = MPI_Allgather(&B->m,1,MPI_INT,b->rowners+1,1,MPI_INT,B->comm);CHKERRQ(ierr);
1772   b->rowners[0] = 0;
1773   for (i=2; i<=b->size; i++) {
1774     b->rowners[i] += b->rowners[i-1];
1775   }
1776   b->rstart = b->rowners[b->rank];
1777   b->rend   = b->rowners[b->rank+1];
1778   ierr = MPI_Allgather(&B->n,1,MPI_INT,b->cowners+1,1,MPI_INT,B->comm);CHKERRQ(ierr);
1779   b->cowners[0] = 0;
1780   for (i=2; i<=b->size; i++) {
1781     b->cowners[i] += b->cowners[i-1];
1782   }
1783   b->cstart = b->cowners[b->rank];
1784   b->cend   = b->cowners[b->rank+1];
1785 
1786   /* build cache for off array entries formed */
1787   ierr = MatStashCreate_Private(B->comm,1,&B->stash);CHKERRQ(ierr);
1788   b->donotstash  = PETSC_FALSE;
1789   b->colmap      = 0;
1790   b->garray      = 0;
1791   b->roworiented = PETSC_TRUE;
1792 
1793   /* stuff used for matrix vector multiply */
1794   b->lvec      = PETSC_NULL;
1795   b->Mvctx     = PETSC_NULL;
1796 
1797   /* stuff for MatGetRow() */
1798   b->rowindices   = 0;
1799   b->rowvalues    = 0;
1800   b->getrowactive = PETSC_FALSE;
1801 
1802   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatStoreValues_C",
1803                                      "MatStoreValues_MPIAIJ",
1804                                      MatStoreValues_MPIAIJ);CHKERRQ(ierr);
1805   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatRetrieveValues_C",
1806                                      "MatRetrieveValues_MPIAIJ",
1807                                      MatRetrieveValues_MPIAIJ);CHKERRQ(ierr);
1808   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatGetDiagonalBlock_C",
1809 				     "MatGetDiagonalBlock_MPIAIJ",
1810                                      MatGetDiagonalBlock_MPIAIJ);CHKERRQ(ierr);
1811   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatIsTranspose_C",
1812 				     "MatIsTranspose_MPIAIJ",
1813 				     MatIsTranspose_MPIAIJ); CHKERRQ(ierr);
1814   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatMPIAIJSetPreallocation_C",
1815 				     "MatMPIAIJSetPreallocation_MPIAIJ",
1816 				     MatMPIAIJSetPreallocation_MPIAIJ); CHKERRQ(ierr);
1817   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatDiagonalScaleLocal_C",
1818 				     "MatDiagonalScaleLocal_MPIAIJ",
1819 				     MatDiagonalScaleLocal_MPIAIJ); CHKERRQ(ierr);
1820   PetscFunctionReturn(0);
1821 }
1822 EXTERN_C_END
1823 
1824 /*MC
1825    MATAIJ - MATAIJ = "aij" - A matrix type to be used for sparse matrices.
1826 
1827    This matrix type is identical to MATSEQAIJ when constructed with a single process communicator,
1828    and MATMPIAIJ otherwise.
1829 
1830    Options Database Keys:
1831 . -mat_type aij - sets the matrix type to "aij" during a call to MatSetFromOptions()
1832 
1833   Level: beginner
1834 
1835 .seealso: MatCreateMPIAIJ,MATSEQAIJ,MATMPIAIJ
1836 M*/
1837 
1838 EXTERN_C_BEGIN
1839 #undef __FUNCT__
1840 #define __FUNCT__ "MatCreate_AIJ"
1841 int MatCreate_AIJ(Mat A) {
1842   int ierr,size;
1843 
1844   PetscFunctionBegin;
1845   ierr = PetscObjectChangeTypeName((PetscObject)A,MATAIJ);CHKERRQ(ierr);
1846   ierr = MPI_Comm_size(A->comm,&size);CHKERRQ(ierr);
1847   if (size == 1) {
1848     ierr = MatSetType(A,MATSEQAIJ);CHKERRQ(ierr);
1849   } else {
1850     ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
1851   }
1852   PetscFunctionReturn(0);
1853 }
1854 EXTERN_C_END
1855 
1856 #undef __FUNCT__
1857 #define __FUNCT__ "MatDuplicate_MPIAIJ"
1858 int MatDuplicate_MPIAIJ(Mat matin,MatDuplicateOption cpvalues,Mat *newmat)
1859 {
1860   Mat        mat;
1861   Mat_MPIAIJ *a,*oldmat = (Mat_MPIAIJ*)matin->data;
1862   int        ierr;
1863 
1864   PetscFunctionBegin;
1865   *newmat       = 0;
1866   ierr = MatCreate(matin->comm,matin->m,matin->n,matin->M,matin->N,&mat);CHKERRQ(ierr);
1867   ierr = MatSetType(mat,MATMPIAIJ);CHKERRQ(ierr);
1868   a    = (Mat_MPIAIJ*)mat->data;
1869   ierr              = PetscMemcpy(mat->ops,&MatOps_Values,sizeof(struct _MatOps));CHKERRQ(ierr);
1870   mat->factor       = matin->factor;
1871   mat->assembled    = PETSC_TRUE;
1872   mat->insertmode   = NOT_SET_VALUES;
1873   mat->preallocated = PETSC_TRUE;
1874 
1875   a->rstart       = oldmat->rstart;
1876   a->rend         = oldmat->rend;
1877   a->cstart       = oldmat->cstart;
1878   a->cend         = oldmat->cend;
1879   a->size         = oldmat->size;
1880   a->rank         = oldmat->rank;
1881   a->donotstash   = oldmat->donotstash;
1882   a->roworiented  = oldmat->roworiented;
1883   a->rowindices   = 0;
1884   a->rowvalues    = 0;
1885   a->getrowactive = PETSC_FALSE;
1886 
1887   ierr       = PetscMemcpy(a->rowners,oldmat->rowners,2*(a->size+2)*sizeof(int));CHKERRQ(ierr);
1888   ierr       = MatStashCreate_Private(matin->comm,1,&mat->stash);CHKERRQ(ierr);
1889   if (oldmat->colmap) {
1890 #if defined (PETSC_USE_CTABLE)
1891     ierr = PetscTableCreateCopy(oldmat->colmap,&a->colmap);CHKERRQ(ierr);
1892 #else
1893     ierr = PetscMalloc((mat->N)*sizeof(int),&a->colmap);CHKERRQ(ierr);
1894     PetscLogObjectMemory(mat,(mat->N)*sizeof(int));
1895     ierr      = PetscMemcpy(a->colmap,oldmat->colmap,(mat->N)*sizeof(int));CHKERRQ(ierr);
1896 #endif
1897   } else a->colmap = 0;
1898   if (oldmat->garray) {
1899     int len;
1900     len  = oldmat->B->n;
1901     ierr = PetscMalloc((len+1)*sizeof(int),&a->garray);CHKERRQ(ierr);
1902     PetscLogObjectMemory(mat,len*sizeof(int));
1903     if (len) { ierr = PetscMemcpy(a->garray,oldmat->garray,len*sizeof(int));CHKERRQ(ierr); }
1904   } else a->garray = 0;
1905 
1906   ierr =  VecDuplicate(oldmat->lvec,&a->lvec);CHKERRQ(ierr);
1907   PetscLogObjectParent(mat,a->lvec);
1908   ierr =  VecScatterCopy(oldmat->Mvctx,&a->Mvctx);CHKERRQ(ierr);
1909   PetscLogObjectParent(mat,a->Mvctx);
1910   ierr =  MatDuplicate(oldmat->A,cpvalues,&a->A);CHKERRQ(ierr);
1911   PetscLogObjectParent(mat,a->A);
1912   ierr =  MatDuplicate(oldmat->B,cpvalues,&a->B);CHKERRQ(ierr);
1913   PetscLogObjectParent(mat,a->B);
1914   ierr = PetscFListDuplicate(matin->qlist,&mat->qlist);CHKERRQ(ierr);
1915   *newmat = mat;
1916   PetscFunctionReturn(0);
1917 }
1918 
1919 #include "petscsys.h"
1920 
1921 #undef __FUNCT__
1922 #define __FUNCT__ "MatLoad_MPIAIJ"
1923 int MatLoad_MPIAIJ(PetscViewer viewer,const MatType type,Mat *newmat)
1924 {
1925   Mat          A;
1926   PetscScalar  *vals,*svals;
1927   MPI_Comm     comm = ((PetscObject)viewer)->comm;
1928   MPI_Status   status;
1929   int          i,nz,ierr,j,rstart,rend,fd;
1930   int          header[4],rank,size,*rowlengths = 0,M,N,m,*rowners,maxnz,*cols;
1931   int          *ourlens,*sndcounts = 0,*procsnz = 0,*offlens,jj,*mycols,*smycols;
1932   int          tag = ((PetscObject)viewer)->tag,cend,cstart,n;
1933 
1934   PetscFunctionBegin;
1935   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
1936   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
1937   if (!rank) {
1938     ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
1939     ierr = PetscBinaryRead(fd,(char *)header,4,PETSC_INT);CHKERRQ(ierr);
1940     if (header[0] != MAT_FILE_COOKIE) SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"not matrix object");
1941     if (header[3] < 0) {
1942       SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"Matrix in special format on disk, cannot load as MPIAIJ");
1943     }
1944   }
1945 
1946   ierr = MPI_Bcast(header+1,3,MPI_INT,0,comm);CHKERRQ(ierr);
1947   M = header[1]; N = header[2];
1948   /* determine ownership of all rows */
1949   m = M/size + ((M % size) > rank);
1950   ierr = PetscMalloc((size+2)*sizeof(int),&rowners);CHKERRQ(ierr);
1951   ierr = MPI_Allgather(&m,1,MPI_INT,rowners+1,1,MPI_INT,comm);CHKERRQ(ierr);
1952   rowners[0] = 0;
1953   for (i=2; i<=size; i++) {
1954     rowners[i] += rowners[i-1];
1955   }
1956   rstart = rowners[rank];
1957   rend   = rowners[rank+1];
1958 
1959   /* distribute row lengths to all processors */
1960   ierr    = PetscMalloc(2*(rend-rstart+1)*sizeof(int),&ourlens);CHKERRQ(ierr);
1961   offlens = ourlens + (rend-rstart);
1962   if (!rank) {
1963     ierr = PetscMalloc(M*sizeof(int),&rowlengths);CHKERRQ(ierr);
1964     ierr = PetscBinaryRead(fd,rowlengths,M,PETSC_INT);CHKERRQ(ierr);
1965     ierr = PetscMalloc(size*sizeof(int),&sndcounts);CHKERRQ(ierr);
1966     for (i=0; i<size; i++) sndcounts[i] = rowners[i+1] - rowners[i];
1967     ierr = MPI_Scatterv(rowlengths,sndcounts,rowners,MPI_INT,ourlens,rend-rstart,MPI_INT,0,comm);CHKERRQ(ierr);
1968     ierr = PetscFree(sndcounts);CHKERRQ(ierr);
1969   } else {
1970     ierr = MPI_Scatterv(0,0,0,MPI_INT,ourlens,rend-rstart,MPI_INT,0,comm);CHKERRQ(ierr);
1971   }
1972 
1973   if (!rank) {
1974     /* calculate the number of nonzeros on each processor */
1975     ierr = PetscMalloc(size*sizeof(int),&procsnz);CHKERRQ(ierr);
1976     ierr = PetscMemzero(procsnz,size*sizeof(int));CHKERRQ(ierr);
1977     for (i=0; i<size; i++) {
1978       for (j=rowners[i]; j< rowners[i+1]; j++) {
1979         procsnz[i] += rowlengths[j];
1980       }
1981     }
1982     ierr = PetscFree(rowlengths);CHKERRQ(ierr);
1983 
1984     /* determine max buffer needed and allocate it */
1985     maxnz = 0;
1986     for (i=0; i<size; i++) {
1987       maxnz = PetscMax(maxnz,procsnz[i]);
1988     }
1989     ierr = PetscMalloc(maxnz*sizeof(int),&cols);CHKERRQ(ierr);
1990 
1991     /* read in my part of the matrix column indices  */
1992     nz   = procsnz[0];
1993     ierr = PetscMalloc(nz*sizeof(int),&mycols);CHKERRQ(ierr);
1994     ierr = PetscBinaryRead(fd,mycols,nz,PETSC_INT);CHKERRQ(ierr);
1995 
1996     /* read in every one elses and ship off */
1997     for (i=1; i<size; i++) {
1998       nz   = procsnz[i];
1999       ierr = PetscBinaryRead(fd,cols,nz,PETSC_INT);CHKERRQ(ierr);
2000       ierr = MPI_Send(cols,nz,MPI_INT,i,tag,comm);CHKERRQ(ierr);
2001     }
2002     ierr = PetscFree(cols);CHKERRQ(ierr);
2003   } else {
2004     /* determine buffer space needed for message */
2005     nz = 0;
2006     for (i=0; i<m; i++) {
2007       nz += ourlens[i];
2008     }
2009     ierr = PetscMalloc((nz+1)*sizeof(int),&mycols);CHKERRQ(ierr);
2010 
2011     /* receive message of column indices*/
2012     ierr = MPI_Recv(mycols,nz,MPI_INT,0,tag,comm,&status);CHKERRQ(ierr);
2013     ierr = MPI_Get_count(&status,MPI_INT,&maxnz);CHKERRQ(ierr);
2014     if (maxnz != nz) SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"something is wrong with file");
2015   }
2016 
2017   /* determine column ownership if matrix is not square */
2018   if (N != M) {
2019     n      = N/size + ((N % size) > rank);
2020     ierr   = MPI_Scan(&n,&cend,1,MPI_INT,MPI_SUM,comm);CHKERRQ(ierr);
2021     cstart = cend - n;
2022   } else {
2023     cstart = rstart;
2024     cend   = rend;
2025     n      = cend - cstart;
2026   }
2027 
2028   /* loop over local rows, determining number of off diagonal entries */
2029   ierr = PetscMemzero(offlens,m*sizeof(int));CHKERRQ(ierr);
2030   jj = 0;
2031   for (i=0; i<m; i++) {
2032     for (j=0; j<ourlens[i]; j++) {
2033       if (mycols[jj] < cstart || mycols[jj] >= cend) offlens[i]++;
2034       jj++;
2035     }
2036   }
2037 
2038   /* create our matrix */
2039   for (i=0; i<m; i++) {
2040     ourlens[i] -= offlens[i];
2041   }
2042   ierr = MatCreate(comm,m,n,M,N,&A);CHKERRQ(ierr);
2043   ierr = MatSetType(A,type);CHKERRQ(ierr);
2044   ierr = MatMPIAIJSetPreallocation(A,0,ourlens,0,offlens);CHKERRQ(ierr);
2045 
2046   ierr = MatSetOption(A,MAT_COLUMNS_SORTED);CHKERRQ(ierr);
2047   for (i=0; i<m; i++) {
2048     ourlens[i] += offlens[i];
2049   }
2050 
2051   if (!rank) {
2052     ierr = PetscMalloc(maxnz*sizeof(PetscScalar),&vals);CHKERRQ(ierr);
2053 
2054     /* read in my part of the matrix numerical values  */
2055     nz   = procsnz[0];
2056     ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2057 
2058     /* insert into matrix */
2059     jj      = rstart;
2060     smycols = mycols;
2061     svals   = vals;
2062     for (i=0; i<m; i++) {
2063       ierr = MatSetValues(A,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2064       smycols += ourlens[i];
2065       svals   += ourlens[i];
2066       jj++;
2067     }
2068 
2069     /* read in other processors and ship out */
2070     for (i=1; i<size; i++) {
2071       nz   = procsnz[i];
2072       ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2073       ierr = MPI_Send(vals,nz,MPIU_SCALAR,i,A->tag,comm);CHKERRQ(ierr);
2074     }
2075     ierr = PetscFree(procsnz);CHKERRQ(ierr);
2076   } else {
2077     /* receive numeric values */
2078     ierr = PetscMalloc((nz+1)*sizeof(PetscScalar),&vals);CHKERRQ(ierr);
2079 
2080     /* receive message of values*/
2081     ierr = MPI_Recv(vals,nz,MPIU_SCALAR,0,A->tag,comm,&status);CHKERRQ(ierr);
2082     ierr = MPI_Get_count(&status,MPIU_SCALAR,&maxnz);CHKERRQ(ierr);
2083     if (maxnz != nz) SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"something is wrong with file");
2084 
2085     /* insert into matrix */
2086     jj      = rstart;
2087     smycols = mycols;
2088     svals   = vals;
2089     for (i=0; i<m; i++) {
2090       ierr     = MatSetValues(A,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2091       smycols += ourlens[i];
2092       svals   += ourlens[i];
2093       jj++;
2094     }
2095   }
2096   ierr = PetscFree(ourlens);CHKERRQ(ierr);
2097   ierr = PetscFree(vals);CHKERRQ(ierr);
2098   ierr = PetscFree(mycols);CHKERRQ(ierr);
2099   ierr = PetscFree(rowners);CHKERRQ(ierr);
2100 
2101   ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2102   ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2103   *newmat = A;
2104   PetscFunctionReturn(0);
2105 }
2106 
2107 #undef __FUNCT__
2108 #define __FUNCT__ "MatGetSubMatrix_MPIAIJ"
2109 /*
2110     Not great since it makes two copies of the submatrix, first an SeqAIJ
2111   in local and then by concatenating the local matrices the end result.
2112   Writing it directly would be much like MatGetSubMatrices_MPIAIJ()
2113 */
2114 int MatGetSubMatrix_MPIAIJ(Mat mat,IS isrow,IS iscol,int csize,MatReuse call,Mat *newmat)
2115 {
2116   int          ierr,i,m,n,rstart,row,rend,nz,*cwork,size,rank,j;
2117   int          *ii,*jj,nlocal,*dlens,*olens,dlen,olen,jend,mglobal;
2118   Mat          *local,M,Mreuse;
2119   PetscScalar  *vwork,*aa;
2120   MPI_Comm     comm = mat->comm;
2121   Mat_SeqAIJ   *aij;
2122 
2123 
2124   PetscFunctionBegin;
2125   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
2126   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2127 
2128   if (call ==  MAT_REUSE_MATRIX) {
2129     ierr = PetscObjectQuery((PetscObject)*newmat,"SubMatrix",(PetscObject *)&Mreuse);CHKERRQ(ierr);
2130     if (!Mreuse) SETERRQ(1,"Submatrix passed in was not used before, cannot reuse");
2131     local = &Mreuse;
2132     ierr  = MatGetSubMatrices(mat,1,&isrow,&iscol,MAT_REUSE_MATRIX,&local);CHKERRQ(ierr);
2133   } else {
2134     ierr   = MatGetSubMatrices(mat,1,&isrow,&iscol,MAT_INITIAL_MATRIX,&local);CHKERRQ(ierr);
2135     Mreuse = *local;
2136     ierr   = PetscFree(local);CHKERRQ(ierr);
2137   }
2138 
2139   /*
2140       m - number of local rows
2141       n - number of columns (same on all processors)
2142       rstart - first row in new global matrix generated
2143   */
2144   ierr = MatGetSize(Mreuse,&m,&n);CHKERRQ(ierr);
2145   if (call == MAT_INITIAL_MATRIX) {
2146     aij = (Mat_SeqAIJ*)(Mreuse)->data;
2147     ii  = aij->i;
2148     jj  = aij->j;
2149 
2150     /*
2151         Determine the number of non-zeros in the diagonal and off-diagonal
2152         portions of the matrix in order to do correct preallocation
2153     */
2154 
2155     /* first get start and end of "diagonal" columns */
2156     if (csize == PETSC_DECIDE) {
2157       ierr = ISGetSize(isrow,&mglobal);CHKERRQ(ierr);
2158       if (mglobal == n) { /* square matrix */
2159 	nlocal = m;
2160       } else {
2161         nlocal = n/size + ((n % size) > rank);
2162       }
2163     } else {
2164       nlocal = csize;
2165     }
2166     ierr   = MPI_Scan(&nlocal,&rend,1,MPI_INT,MPI_SUM,comm);CHKERRQ(ierr);
2167     rstart = rend - nlocal;
2168     if (rank == size - 1 && rend != n) {
2169       SETERRQ2(1,"Local column sizes %d do not add up to total number of columns %d",rend,n);
2170     }
2171 
2172     /* next, compute all the lengths */
2173     ierr  = PetscMalloc((2*m+1)*sizeof(int),&dlens);CHKERRQ(ierr);
2174     olens = dlens + m;
2175     for (i=0; i<m; i++) {
2176       jend = ii[i+1] - ii[i];
2177       olen = 0;
2178       dlen = 0;
2179       for (j=0; j<jend; j++) {
2180         if (*jj < rstart || *jj >= rend) olen++;
2181         else dlen++;
2182         jj++;
2183       }
2184       olens[i] = olen;
2185       dlens[i] = dlen;
2186     }
2187     ierr = MatCreateMPIAIJ(comm,m,nlocal,PETSC_DECIDE,n,0,dlens,0,olens,&M);CHKERRQ(ierr);
2188     ierr = PetscFree(dlens);CHKERRQ(ierr);
2189   } else {
2190     int ml,nl;
2191 
2192     M = *newmat;
2193     ierr = MatGetLocalSize(M,&ml,&nl);CHKERRQ(ierr);
2194     if (ml != m) SETERRQ(PETSC_ERR_ARG_SIZ,"Previous matrix must be same size/layout as request");
2195     ierr = MatZeroEntries(M);CHKERRQ(ierr);
2196     /*
2197          The next two lines are needed so we may call MatSetValues_MPIAIJ() below directly,
2198        rather than the slower MatSetValues().
2199     */
2200     M->was_assembled = PETSC_TRUE;
2201     M->assembled     = PETSC_FALSE;
2202   }
2203   ierr = MatGetOwnershipRange(M,&rstart,&rend);CHKERRQ(ierr);
2204   aij = (Mat_SeqAIJ*)(Mreuse)->data;
2205   ii  = aij->i;
2206   jj  = aij->j;
2207   aa  = aij->a;
2208   for (i=0; i<m; i++) {
2209     row   = rstart + i;
2210     nz    = ii[i+1] - ii[i];
2211     cwork = jj;     jj += nz;
2212     vwork = aa;     aa += nz;
2213     ierr = MatSetValues_MPIAIJ(M,1,&row,nz,cwork,vwork,INSERT_VALUES);CHKERRQ(ierr);
2214   }
2215 
2216   ierr = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2217   ierr = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2218   *newmat = M;
2219 
2220   /* save submatrix used in processor for next request */
2221   if (call ==  MAT_INITIAL_MATRIX) {
2222     ierr = PetscObjectCompose((PetscObject)M,"SubMatrix",(PetscObject)Mreuse);CHKERRQ(ierr);
2223     ierr = PetscObjectDereference((PetscObject)Mreuse);CHKERRQ(ierr);
2224   }
2225 
2226   PetscFunctionReturn(0);
2227 }
2228 
2229 #undef __FUNCT__
2230 #define __FUNCT__ "MatMPIAIJSetPreallocation"
2231 /*@C
2232    MatMPIAIJSetPreallocation - Creates a sparse parallel matrix in AIJ format
2233    (the default parallel PETSc format).  For good matrix assembly performance
2234    the user should preallocate the matrix storage by setting the parameters
2235    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
2236    performance can be increased by more than a factor of 50.
2237 
2238    Collective on MPI_Comm
2239 
2240    Input Parameters:
2241 +  A - the matrix
2242 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
2243            (same value is used for all local rows)
2244 .  d_nnz - array containing the number of nonzeros in the various rows of the
2245            DIAGONAL portion of the local submatrix (possibly different for each row)
2246            or PETSC_NULL, if d_nz is used to specify the nonzero structure.
2247            The size of this array is equal to the number of local rows, i.e 'm'.
2248            You must leave room for the diagonal entry even if it is zero.
2249 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
2250            submatrix (same value is used for all local rows).
2251 -  o_nnz - array containing the number of nonzeros in the various rows of the
2252            OFF-DIAGONAL portion of the local submatrix (possibly different for
2253            each row) or PETSC_NULL, if o_nz is used to specify the nonzero
2254            structure. The size of this array is equal to the number
2255            of local rows, i.e 'm'.
2256 
2257    The AIJ format (also called the Yale sparse matrix format or
2258    compressed row storage), is fully compatible with standard Fortran 77
2259    storage.  That is, the stored row and column indices can begin at
2260    either one (as in Fortran) or zero.  See the users manual for details.
2261 
2262    The user MUST specify either the local or global matrix dimensions
2263    (possibly both).
2264 
2265    The parallel matrix is partitioned such that the first m0 rows belong to
2266    process 0, the next m1 rows belong to process 1, the next m2 rows belong
2267    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.
2268 
2269    The DIAGONAL portion of the local submatrix of a processor can be defined
2270    as the submatrix which is obtained by extraction the part corresponding
2271    to the rows r1-r2 and columns r1-r2 of the global matrix, where r1 is the
2272    first row that belongs to the processor, and r2 is the last row belonging
2273    to the this processor. This is a square mxm matrix. The remaining portion
2274    of the local submatrix (mxN) constitute the OFF-DIAGONAL portion.
2275 
2276    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
2277 
2278    By default, this format uses inodes (identical nodes) when possible.
2279    We search for consecutive rows with the same nonzero structure, thereby
2280    reusing matrix information to achieve increased efficiency.
2281 
2282    Options Database Keys:
2283 +  -mat_aij_no_inode  - Do not use inodes
2284 .  -mat_aij_inode_limit <limit> - Sets inode limit (max limit=5)
2285 -  -mat_aij_oneindex - Internally use indexing starting at 1
2286         rather than 0.  Note that when calling MatSetValues(),
2287         the user still MUST index entries starting at 0!
2288 
2289    Example usage:
2290 
2291    Consider the following 8x8 matrix with 34 non-zero values, that is
2292    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
2293    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
2294    as follows:
2295 
2296 .vb
2297             1  2  0  |  0  3  0  |  0  4
2298     Proc0   0  5  6  |  7  0  0  |  8  0
2299             9  0 10  | 11  0  0  | 12  0
2300     -------------------------------------
2301            13  0 14  | 15 16 17  |  0  0
2302     Proc1   0 18  0  | 19 20 21  |  0  0
2303             0  0  0  | 22 23  0  | 24  0
2304     -------------------------------------
2305     Proc2  25 26 27  |  0  0 28  | 29  0
2306            30  0  0  | 31 32 33  |  0 34
2307 .ve
2308 
2309    This can be represented as a collection of submatrices as:
2310 
2311 .vb
2312       A B C
2313       D E F
2314       G H I
2315 .ve
2316 
2317    Where the submatrices A,B,C are owned by proc0, D,E,F are
2318    owned by proc1, G,H,I are owned by proc2.
2319 
2320    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2321    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2322    The 'M','N' parameters are 8,8, and have the same values on all procs.
2323 
2324    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
2325    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
2326    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
2327    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
2328    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
2329    matrix, ans [DF] as another SeqAIJ matrix.
2330 
2331    When d_nz, o_nz parameters are specified, d_nz storage elements are
2332    allocated for every row of the local diagonal submatrix, and o_nz
2333    storage locations are allocated for every row of the OFF-DIAGONAL submat.
2334    One way to choose d_nz and o_nz is to use the max nonzerors per local
2335    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
2336    In this case, the values of d_nz,o_nz are:
2337 .vb
2338      proc0 : dnz = 2, o_nz = 2
2339      proc1 : dnz = 3, o_nz = 2
2340      proc2 : dnz = 1, o_nz = 4
2341 .ve
2342    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
2343    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
2344    for proc3. i.e we are using 12+15+10=37 storage locations to store
2345    34 values.
2346 
2347    When d_nnz, o_nnz parameters are specified, the storage is specified
2348    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
2349    In the above case the values for d_nnz,o_nnz are:
2350 .vb
2351      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
2352      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
2353      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
2354 .ve
2355    Here the space allocated is sum of all the above values i.e 34, and
2356    hence pre-allocation is perfect.
2357 
2358    Level: intermediate
2359 
2360 .keywords: matrix, aij, compressed row, sparse, parallel
2361 
2362 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues()
2363 @*/
2364 int MatMPIAIJSetPreallocation(Mat B,int d_nz,const int d_nnz[],int o_nz,const int o_nnz[])
2365 {
2366   int ierr,(*f)(Mat,int,const int[],int,const int[]);
2367 
2368   PetscFunctionBegin;
2369   ierr = PetscObjectQueryFunction((PetscObject)B,"MatMPIAIJSetPreallocation_C",(void (**)(void))&f);CHKERRQ(ierr);
2370   if (f) {
2371     ierr = (*f)(B,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
2372   }
2373   PetscFunctionReturn(0);
2374 }
2375 
2376 #undef __FUNCT__
2377 #define __FUNCT__ "MatCreateMPIAIJ"
2378 /*@C
2379    MatCreateMPIAIJ - Creates a sparse parallel matrix in AIJ format
2380    (the default parallel PETSc format).  For good matrix assembly performance
2381    the user should preallocate the matrix storage by setting the parameters
2382    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
2383    performance can be increased by more than a factor of 50.
2384 
2385    Collective on MPI_Comm
2386 
2387    Input Parameters:
2388 +  comm - MPI communicator
2389 .  m - number of local rows (or PETSC_DECIDE to have calculated if M is given)
2390            This value should be the same as the local size used in creating the
2391            y vector for the matrix-vector product y = Ax.
2392 .  n - This value should be the same as the local size used in creating the
2393        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
2394        calculated if N is given) For square matrices n is almost always m.
2395 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
2396 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
2397 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
2398            (same value is used for all local rows)
2399 .  d_nnz - array containing the number of nonzeros in the various rows of the
2400            DIAGONAL portion of the local submatrix (possibly different for each row)
2401            or PETSC_NULL, if d_nz is used to specify the nonzero structure.
2402            The size of this array is equal to the number of local rows, i.e 'm'.
2403            You must leave room for the diagonal entry even if it is zero.
2404 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
2405            submatrix (same value is used for all local rows).
2406 -  o_nnz - array containing the number of nonzeros in the various rows of the
2407            OFF-DIAGONAL portion of the local submatrix (possibly different for
2408            each row) or PETSC_NULL, if o_nz is used to specify the nonzero
2409            structure. The size of this array is equal to the number
2410            of local rows, i.e 'm'.
2411 
2412    Output Parameter:
2413 .  A - the matrix
2414 
2415    Notes:
2416    m,n,M,N parameters specify the size of the matrix, and its partitioning across
2417    processors, while d_nz,d_nnz,o_nz,o_nnz parameters specify the approximate
2418    storage requirements for this matrix.
2419 
2420    If PETSC_DECIDE or  PETSC_DETERMINE is used for a particular argument on one
2421    processor than it must be used on all processors that share the object for
2422    that argument.
2423 
2424    The AIJ format (also called the Yale sparse matrix format or
2425    compressed row storage), is fully compatible with standard Fortran 77
2426    storage.  That is, the stored row and column indices can begin at
2427    either one (as in Fortran) or zero.  See the users manual for details.
2428 
2429    The user MUST specify either the local or global matrix dimensions
2430    (possibly both).
2431 
2432    The parallel matrix is partitioned such that the first m0 rows belong to
2433    process 0, the next m1 rows belong to process 1, the next m2 rows belong
2434    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.
2435 
2436    The DIAGONAL portion of the local submatrix of a processor can be defined
2437    as the submatrix which is obtained by extraction the part corresponding
2438    to the rows r1-r2 and columns r1-r2 of the global matrix, where r1 is the
2439    first row that belongs to the processor, and r2 is the last row belonging
2440    to the this processor. This is a square mxm matrix. The remaining portion
2441    of the local submatrix (mxN) constitute the OFF-DIAGONAL portion.
2442 
2443    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
2444 
2445    When calling this routine with a single process communicator, a matrix of
2446    type SEQAIJ is returned.  If a matrix of type MPIAIJ is desired for this
2447    type of communicator, use the construction mechanism:
2448      MatCreate(...,&A); MatSetType(A,MPIAIJ); MatMPIAIJSetPreallocation(A,...);
2449 
2450    By default, this format uses inodes (identical nodes) when possible.
2451    We search for consecutive rows with the same nonzero structure, thereby
2452    reusing matrix information to achieve increased efficiency.
2453 
2454    Options Database Keys:
2455 +  -mat_aij_no_inode  - Do not use inodes
2456 .  -mat_aij_inode_limit <limit> - Sets inode limit (max limit=5)
2457 -  -mat_aij_oneindex - Internally use indexing starting at 1
2458         rather than 0.  Note that when calling MatSetValues(),
2459         the user still MUST index entries starting at 0!
2460 
2461 
2462    Example usage:
2463 
2464    Consider the following 8x8 matrix with 34 non-zero values, that is
2465    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
2466    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
2467    as follows:
2468 
2469 .vb
2470             1  2  0  |  0  3  0  |  0  4
2471     Proc0   0  5  6  |  7  0  0  |  8  0
2472             9  0 10  | 11  0  0  | 12  0
2473     -------------------------------------
2474            13  0 14  | 15 16 17  |  0  0
2475     Proc1   0 18  0  | 19 20 21  |  0  0
2476             0  0  0  | 22 23  0  | 24  0
2477     -------------------------------------
2478     Proc2  25 26 27  |  0  0 28  | 29  0
2479            30  0  0  | 31 32 33  |  0 34
2480 .ve
2481 
2482    This can be represented as a collection of submatrices as:
2483 
2484 .vb
2485       A B C
2486       D E F
2487       G H I
2488 .ve
2489 
2490    Where the submatrices A,B,C are owned by proc0, D,E,F are
2491    owned by proc1, G,H,I are owned by proc2.
2492 
2493    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2494    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2495    The 'M','N' parameters are 8,8, and have the same values on all procs.
2496 
2497    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
2498    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
2499    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
2500    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
2501    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
2502    matrix, ans [DF] as another SeqAIJ matrix.
2503 
2504    When d_nz, o_nz parameters are specified, d_nz storage elements are
2505    allocated for every row of the local diagonal submatrix, and o_nz
2506    storage locations are allocated for every row of the OFF-DIAGONAL submat.
2507    One way to choose d_nz and o_nz is to use the max nonzerors per local
2508    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
2509    In this case, the values of d_nz,o_nz are:
2510 .vb
2511      proc0 : dnz = 2, o_nz = 2
2512      proc1 : dnz = 3, o_nz = 2
2513      proc2 : dnz = 1, o_nz = 4
2514 .ve
2515    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
2516    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
2517    for proc3. i.e we are using 12+15+10=37 storage locations to store
2518    34 values.
2519 
2520    When d_nnz, o_nnz parameters are specified, the storage is specified
2521    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
2522    In the above case the values for d_nnz,o_nnz are:
2523 .vb
2524      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
2525      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
2526      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
2527 .ve
2528    Here the space allocated is sum of all the above values i.e 34, and
2529    hence pre-allocation is perfect.
2530 
2531    Level: intermediate
2532 
2533 .keywords: matrix, aij, compressed row, sparse, parallel
2534 
2535 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues()
2536 @*/
2537 int MatCreateMPIAIJ(MPI_Comm comm,int m,int n,int M,int N,int d_nz,const int d_nnz[],int o_nz,const int o_nnz[],Mat *A)
2538 {
2539   int ierr,size;
2540 
2541   PetscFunctionBegin;
2542   ierr = MatCreate(comm,m,n,M,N,A);CHKERRQ(ierr);
2543   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2544   if (size > 1) {
2545     ierr = MatSetType(*A,MATMPIAIJ);CHKERRQ(ierr);
2546     ierr = MatMPIAIJSetPreallocation(*A,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
2547   } else {
2548     ierr = MatSetType(*A,MATSEQAIJ);CHKERRQ(ierr);
2549     ierr = MatSeqAIJSetPreallocation(*A,d_nz,d_nnz);CHKERRQ(ierr);
2550   }
2551   PetscFunctionReturn(0);
2552 }
2553 
2554 #undef __FUNCT__
2555 #define __FUNCT__ "MatMPIAIJGetSeqAIJ"
2556 int MatMPIAIJGetSeqAIJ(Mat A,Mat *Ad,Mat *Ao,int *colmap[])
2557 {
2558   Mat_MPIAIJ *a = (Mat_MPIAIJ *)A->data;
2559   PetscFunctionBegin;
2560   *Ad     = a->A;
2561   *Ao     = a->B;
2562   *colmap = a->garray;
2563   PetscFunctionReturn(0);
2564 }
2565 
2566 #undef __FUNCT__
2567 #define __FUNCT__ "MatSetColoring_MPIAIJ"
2568 int MatSetColoring_MPIAIJ(Mat A,ISColoring coloring)
2569 {
2570   int        ierr,i;
2571   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
2572 
2573   PetscFunctionBegin;
2574   if (coloring->ctype == IS_COLORING_LOCAL) {
2575     ISColoringValue *allcolors,*colors;
2576     ISColoring      ocoloring;
2577 
2578     /* set coloring for diagonal portion */
2579     ierr = MatSetColoring_SeqAIJ(a->A,coloring);CHKERRQ(ierr);
2580 
2581     /* set coloring for off-diagonal portion */
2582     ierr = ISAllGatherColors(A->comm,coloring->n,coloring->colors,PETSC_NULL,&allcolors);CHKERRQ(ierr);
2583     ierr = PetscMalloc((a->B->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
2584     for (i=0; i<a->B->n; i++) {
2585       colors[i] = allcolors[a->garray[i]];
2586     }
2587     ierr = PetscFree(allcolors);CHKERRQ(ierr);
2588     ierr = ISColoringCreate(MPI_COMM_SELF,a->B->n,colors,&ocoloring);CHKERRQ(ierr);
2589     ierr = MatSetColoring_SeqAIJ(a->B,ocoloring);CHKERRQ(ierr);
2590     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
2591   } else if (coloring->ctype == IS_COLORING_GHOSTED) {
2592     ISColoringValue *colors;
2593     int             *larray;
2594     ISColoring      ocoloring;
2595 
2596     /* set coloring for diagonal portion */
2597     ierr = PetscMalloc((a->A->n+1)*sizeof(int),&larray);CHKERRQ(ierr);
2598     for (i=0; i<a->A->n; i++) {
2599       larray[i] = i + a->cstart;
2600     }
2601     ierr = ISGlobalToLocalMappingApply(A->mapping,IS_GTOLM_MASK,a->A->n,larray,PETSC_NULL,larray);CHKERRQ(ierr);
2602     ierr = PetscMalloc((a->A->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
2603     for (i=0; i<a->A->n; i++) {
2604       colors[i] = coloring->colors[larray[i]];
2605     }
2606     ierr = PetscFree(larray);CHKERRQ(ierr);
2607     ierr = ISColoringCreate(PETSC_COMM_SELF,a->A->n,colors,&ocoloring);CHKERRQ(ierr);
2608     ierr = MatSetColoring_SeqAIJ(a->A,ocoloring);CHKERRQ(ierr);
2609     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
2610 
2611     /* set coloring for off-diagonal portion */
2612     ierr = PetscMalloc((a->B->n+1)*sizeof(int),&larray);CHKERRQ(ierr);
2613     ierr = ISGlobalToLocalMappingApply(A->mapping,IS_GTOLM_MASK,a->B->n,a->garray,PETSC_NULL,larray);CHKERRQ(ierr);
2614     ierr = PetscMalloc((a->B->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
2615     for (i=0; i<a->B->n; i++) {
2616       colors[i] = coloring->colors[larray[i]];
2617     }
2618     ierr = PetscFree(larray);CHKERRQ(ierr);
2619     ierr = ISColoringCreate(MPI_COMM_SELF,a->B->n,colors,&ocoloring);CHKERRQ(ierr);
2620     ierr = MatSetColoring_SeqAIJ(a->B,ocoloring);CHKERRQ(ierr);
2621     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
2622   } else {
2623     SETERRQ1(1,"No support ISColoringType %d",coloring->ctype);
2624   }
2625 
2626   PetscFunctionReturn(0);
2627 }
2628 
2629 #undef __FUNCT__
2630 #define __FUNCT__ "MatSetValuesAdic_MPIAIJ"
2631 int MatSetValuesAdic_MPIAIJ(Mat A,void *advalues)
2632 {
2633   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
2634   int        ierr;
2635 
2636   PetscFunctionBegin;
2637   ierr = MatSetValuesAdic_SeqAIJ(a->A,advalues);CHKERRQ(ierr);
2638   ierr = MatSetValuesAdic_SeqAIJ(a->B,advalues);CHKERRQ(ierr);
2639   PetscFunctionReturn(0);
2640 }
2641 
2642 #undef __FUNCT__
2643 #define __FUNCT__ "MatSetValuesAdifor_MPIAIJ"
2644 int MatSetValuesAdifor_MPIAIJ(Mat A,int nl,void *advalues)
2645 {
2646   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
2647   int        ierr;
2648 
2649   PetscFunctionBegin;
2650   ierr = MatSetValuesAdifor_SeqAIJ(a->A,nl,advalues);CHKERRQ(ierr);
2651   ierr = MatSetValuesAdifor_SeqAIJ(a->B,nl,advalues);CHKERRQ(ierr);
2652   PetscFunctionReturn(0);
2653 }
2654 
2655 #undef __FUNCT__
2656 #define __FUNCT__ "MatMerge"
2657 /*@C
2658       MatMerge - Creates a single large PETSc matrix by concatinating sequential
2659                  matrices from each processor
2660 
2661     Collective on MPI_Comm
2662 
2663    Input Parameters:
2664 +    comm - the communicators the parallel matrix will live on
2665 -    inmat - the input sequential matrices
2666 
2667    Output Parameter:
2668 .    outmat - the parallel matrix generated
2669 
2670     Level: advanced
2671 
2672    Notes: The number of columns of the matrix in EACH of the seperate files
2673       MUST be the same.
2674 
2675 @*/
2676 int MatMerge(MPI_Comm comm,Mat inmat, Mat *outmat)
2677 {
2678   int         ierr,m,n,i,rstart,*indx,nnz,I,*dnz,*onz;
2679   PetscScalar *values;
2680   PetscMap    columnmap,rowmap;
2681 
2682   PetscFunctionBegin;
2683 
2684   ierr = MatGetSize(inmat,&m,&n);CHKERRQ(ierr);
2685 
2686   /* count nonzeros in each row, for diagonal and off diagonal portion of matrix */
2687   ierr = PetscMapCreate(comm,&columnmap);CHKERRQ(ierr);
2688   ierr = PetscMapSetSize(columnmap,n);CHKERRQ(ierr);
2689   ierr = PetscMapSetType(columnmap,MAP_MPI);CHKERRQ(ierr);
2690   ierr = PetscMapGetLocalSize(columnmap,&n);CHKERRQ(ierr);
2691   ierr = PetscMapDestroy(columnmap);CHKERRQ(ierr);
2692 
2693   ierr = PetscMapCreate(comm,&rowmap);CHKERRQ(ierr);
2694   ierr = PetscMapSetLocalSize(rowmap,m);CHKERRQ(ierr);
2695   ierr = PetscMapSetType(rowmap,MAP_MPI);CHKERRQ(ierr);
2696   ierr = PetscMapGetLocalRange(rowmap,&rstart,0);CHKERRQ(ierr);
2697   ierr = PetscMapDestroy(rowmap);CHKERRQ(ierr);
2698 
2699   ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
2700   for (i=0;i<m;i++) {
2701     ierr = MatGetRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2702     ierr = MatPreallocateSet(i+rstart,nnz,indx,dnz,onz);CHKERRQ(ierr);
2703     ierr = MatRestoreRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2704   }
2705   ierr = MatCreateMPIAIJ(comm,m,n,PETSC_DETERMINE,PETSC_DETERMINE,0,dnz,0,onz,outmat);CHKERRQ(ierr);
2706   ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
2707 
2708   for (i=0;i<m;i++) {
2709     ierr = MatGetRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2710     I    = i + rstart;
2711     ierr = MatSetValues(*outmat,1,&I,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
2712     ierr = MatRestoreRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2713   }
2714   ierr = MatDestroy(inmat);CHKERRQ(ierr);
2715   ierr = MatAssemblyBegin(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2716   ierr = MatAssemblyEnd(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2717 
2718   PetscFunctionReturn(0);
2719 }
2720 
2721 #undef __FUNCT__
2722 #define __FUNCT__ "MatFileSplit"
2723 int MatFileSplit(Mat A,char *outfile)
2724 {
2725   int         ierr,rank,len,m,N,i,rstart,*indx,nnz;
2726   PetscViewer out;
2727   char        *name;
2728   Mat         B;
2729   PetscScalar *values;
2730 
2731   PetscFunctionBegin;
2732 
2733   ierr = MatGetLocalSize(A,&m,0);CHKERRQ(ierr);
2734   ierr = MatGetSize(A,0,&N);CHKERRQ(ierr);
2735   ierr = MatCreateSeqAIJ(PETSC_COMM_SELF,m,N,0,0,&B);CHKERRQ(ierr);
2736   ierr = MatGetOwnershipRange(A,&rstart,0);CHKERRQ(ierr);
2737   for (i=0;i<m;i++) {
2738     ierr = MatGetRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
2739     ierr = MatSetValues(B,1,&i,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
2740     ierr = MatRestoreRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
2741   }
2742   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2743   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2744 
2745   ierr = MPI_Comm_rank(A->comm,&rank);CHKERRQ(ierr);
2746   ierr = PetscStrlen(outfile,&len);CHKERRQ(ierr);
2747   ierr = PetscMalloc((len+5)*sizeof(char),&name);CHKERRQ(ierr);
2748   sprintf(name,"%s.%d",outfile,rank);
2749   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,name,PETSC_FILE_CREATE,&out);CHKERRQ(ierr);
2750   ierr = PetscFree(name);
2751   ierr = MatView(B,out);CHKERRQ(ierr);
2752   ierr = PetscViewerDestroy(out);CHKERRQ(ierr);
2753   ierr = MatDestroy(B);CHKERRQ(ierr);
2754   PetscFunctionReturn(0);
2755 }
2756