xref: /petsc/src/mat/impls/aij/mpi/mpiaij.c (revision d5058c763de0077e1c2d63aecbdb635e3d260d53)
1 
2 #include "src/mat/impls/aij/mpi/mpiaij.h"
3 #include "src/inline/spops.h"
4 
5 /*
6   Local utility routine that creates a mapping from the global column
7 number to the local number in the off-diagonal part of the local
8 storage of the matrix.  When PETSC_USE_CTABLE is used this is scalable at
9 a slightly higher hash table cost; without it it is not scalable (each processor
10 has an order N integer array but is fast to acess.
11 */
12 #undef __FUNCT__
13 #define __FUNCT__ "CreateColmap_MPIAIJ_Private"
14 int CreateColmap_MPIAIJ_Private(Mat mat)
15 {
16   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
17   int        n = aij->B->n,i,ierr;
18 
19   PetscFunctionBegin;
20 #if defined (PETSC_USE_CTABLE)
21   ierr = PetscTableCreate(n,&aij->colmap);CHKERRQ(ierr);
22   for (i=0; i<n; i++){
23     ierr = PetscTableAdd(aij->colmap,aij->garray[i]+1,i+1);CHKERRQ(ierr);
24   }
25 #else
26   ierr = PetscMalloc((mat->N+1)*sizeof(int),&aij->colmap);CHKERRQ(ierr);
27   PetscLogObjectMemory(mat,mat->N*sizeof(int));
28   ierr = PetscMemzero(aij->colmap,mat->N*sizeof(int));CHKERRQ(ierr);
29   for (i=0; i<n; i++) aij->colmap[aij->garray[i]] = i+1;
30 #endif
31   PetscFunctionReturn(0);
32 }
33 
34 #define CHUNKSIZE   15
35 #define MatSetValues_SeqAIJ_A_Private(row,col,value,addv) \
36 { \
37  \
38     rp   = aj + ai[row] + shift; ap = aa + ai[row] + shift; \
39     rmax = aimax[row]; nrow = ailen[row];  \
40     col1 = col - shift; \
41      \
42     low = 0; high = nrow; \
43     while (high-low > 5) { \
44       t = (low+high)/2; \
45       if (rp[t] > col) high = t; \
46       else             low  = t; \
47     } \
48       for (_i=low; _i<high; _i++) { \
49         if (rp[_i] > col1) break; \
50         if (rp[_i] == col1) { \
51           if (addv == ADD_VALUES) ap[_i] += value;   \
52           else                  ap[_i] = value; \
53           goto a_noinsert; \
54         } \
55       }  \
56       if (nonew == 1) goto a_noinsert; \
57       else if (nonew == -1) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) into matrix", row, col); \
58       if (nrow >= rmax) { \
59         /* there is no extra room in row, therefore enlarge */ \
60         int    new_nz = ai[am] + CHUNKSIZE,len,*new_i,*new_j; \
61         PetscScalar *new_a; \
62  \
63         if (nonew == -2) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) in the matrix", row, col); \
64  \
65         /* malloc new storage space */ \
66         len     = new_nz*(sizeof(int)+sizeof(PetscScalar))+(am+1)*sizeof(int); \
67         ierr    = PetscMalloc(len,&new_a);CHKERRQ(ierr); \
68         new_j   = (int*)(new_a + new_nz); \
69         new_i   = new_j + new_nz; \
70  \
71         /* copy over old data into new slots */ \
72         for (ii=0; ii<row+1; ii++) {new_i[ii] = ai[ii];} \
73         for (ii=row+1; ii<am+1; ii++) {new_i[ii] = ai[ii]+CHUNKSIZE;} \
74         ierr = PetscMemcpy(new_j,aj,(ai[row]+nrow+shift)*sizeof(int));CHKERRQ(ierr); \
75         len = (new_nz - CHUNKSIZE - ai[row] - nrow - shift); \
76         ierr = PetscMemcpy(new_j+ai[row]+shift+nrow+CHUNKSIZE,aj+ai[row]+shift+nrow, \
77                                                            len*sizeof(int));CHKERRQ(ierr); \
78         ierr = PetscMemcpy(new_a,aa,(ai[row]+nrow+shift)*sizeof(PetscScalar));CHKERRQ(ierr); \
79         ierr = PetscMemcpy(new_a+ai[row]+shift+nrow+CHUNKSIZE,aa+ai[row]+shift+nrow, \
80                                                            len*sizeof(PetscScalar));CHKERRQ(ierr);  \
81         /* free up old matrix storage */ \
82  \
83         ierr = PetscFree(a->a);CHKERRQ(ierr);  \
84         if (!a->singlemalloc) { \
85            ierr = PetscFree(a->i);CHKERRQ(ierr); \
86            ierr = PetscFree(a->j);CHKERRQ(ierr); \
87         } \
88         aa = a->a = new_a; ai = a->i = new_i; aj = a->j = new_j;  \
89         a->singlemalloc = PETSC_TRUE; \
90  \
91         rp   = aj + ai[row] + shift; ap = aa + ai[row] + shift; \
92         rmax = aimax[row] = aimax[row] + CHUNKSIZE; \
93         PetscLogObjectMemory(A,CHUNKSIZE*(sizeof(int) + sizeof(PetscScalar))); \
94         a->maxnz += CHUNKSIZE; \
95         a->reallocs++; \
96       } \
97       N = nrow++ - 1; a->nz++; \
98       /* shift up all the later entries in this row */ \
99       for (ii=N; ii>=_i; ii--) { \
100         rp[ii+1] = rp[ii]; \
101         ap[ii+1] = ap[ii]; \
102       } \
103       rp[_i] = col1;  \
104       ap[_i] = value;  \
105       a_noinsert: ; \
106       ailen[row] = nrow; \
107 }
108 
109 #define MatSetValues_SeqAIJ_B_Private(row,col,value,addv) \
110 { \
111  \
112     rp   = bj + bi[row] + shift; ap = ba + bi[row] + shift; \
113     rmax = bimax[row]; nrow = bilen[row];  \
114     col1 = col - shift; \
115      \
116     low = 0; high = nrow; \
117     while (high-low > 5) { \
118       t = (low+high)/2; \
119       if (rp[t] > col) high = t; \
120       else             low  = t; \
121     } \
122        for (_i=low; _i<high; _i++) { \
123         if (rp[_i] > col1) break; \
124         if (rp[_i] == col1) { \
125           if (addv == ADD_VALUES) ap[_i] += value;   \
126           else                  ap[_i] = value; \
127           goto b_noinsert; \
128         } \
129       }  \
130       if (nonew == 1) goto b_noinsert; \
131       else if (nonew == -1) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) into matrix", row, col); \
132       if (nrow >= rmax) { \
133         /* there is no extra room in row, therefore enlarge */ \
134         int    new_nz = bi[bm] + CHUNKSIZE,len,*new_i,*new_j; \
135         PetscScalar *new_a; \
136  \
137         if (nonew == -2) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Inserting a new nonzero (%d, %d) in the matrix", row, col); \
138  \
139         /* malloc new storage space */ \
140         len     = new_nz*(sizeof(int)+sizeof(PetscScalar))+(bm+1)*sizeof(int); \
141         ierr    = PetscMalloc(len,&new_a);CHKERRQ(ierr); \
142         new_j   = (int*)(new_a + new_nz); \
143         new_i   = new_j + new_nz; \
144  \
145         /* copy over old data into new slots */ \
146         for (ii=0; ii<row+1; ii++) {new_i[ii] = bi[ii];} \
147         for (ii=row+1; ii<bm+1; ii++) {new_i[ii] = bi[ii]+CHUNKSIZE;} \
148         ierr = PetscMemcpy(new_j,bj,(bi[row]+nrow+shift)*sizeof(int));CHKERRQ(ierr); \
149         len = (new_nz - CHUNKSIZE - bi[row] - nrow - shift); \
150         ierr = PetscMemcpy(new_j+bi[row]+shift+nrow+CHUNKSIZE,bj+bi[row]+shift+nrow, \
151                                                            len*sizeof(int));CHKERRQ(ierr); \
152         ierr = PetscMemcpy(new_a,ba,(bi[row]+nrow+shift)*sizeof(PetscScalar));CHKERRQ(ierr); \
153         ierr = PetscMemcpy(new_a+bi[row]+shift+nrow+CHUNKSIZE,ba+bi[row]+shift+nrow, \
154                                                            len*sizeof(PetscScalar));CHKERRQ(ierr);  \
155         /* free up old matrix storage */ \
156  \
157         ierr = PetscFree(b->a);CHKERRQ(ierr);  \
158         if (!b->singlemalloc) { \
159           ierr = PetscFree(b->i);CHKERRQ(ierr); \
160           ierr = PetscFree(b->j);CHKERRQ(ierr); \
161         } \
162         ba = b->a = new_a; bi = b->i = new_i; bj = b->j = new_j;  \
163         b->singlemalloc = PETSC_TRUE; \
164  \
165         rp   = bj + bi[row] + shift; ap = ba + bi[row] + shift; \
166         rmax = bimax[row] = bimax[row] + CHUNKSIZE; \
167         PetscLogObjectMemory(B,CHUNKSIZE*(sizeof(int) + sizeof(PetscScalar))); \
168         b->maxnz += CHUNKSIZE; \
169         b->reallocs++; \
170       } \
171       N = nrow++ - 1; b->nz++; \
172       /* shift up all the later entries in this row */ \
173       for (ii=N; ii>=_i; ii--) { \
174         rp[ii+1] = rp[ii]; \
175         ap[ii+1] = ap[ii]; \
176       } \
177       rp[_i] = col1;  \
178       ap[_i] = value;  \
179       b_noinsert: ; \
180       bilen[row] = nrow; \
181 }
182 
183 #undef __FUNCT__
184 #define __FUNCT__ "MatSetValues_MPIAIJ"
185 int MatSetValues_MPIAIJ(Mat mat,int m,const int im[],int n,const int in[],const PetscScalar v[],InsertMode addv)
186 {
187   Mat_MPIAIJ   *aij = (Mat_MPIAIJ*)mat->data;
188   PetscScalar  value;
189   int          ierr,i,j,rstart = aij->rstart,rend = aij->rend;
190   int          cstart = aij->cstart,cend = aij->cend,row,col;
191   PetscTruth   roworiented = aij->roworiented;
192 
193   /* Some Variables required in the macro */
194   Mat          A = aij->A;
195   Mat_SeqAIJ   *a = (Mat_SeqAIJ*)A->data;
196   int          *aimax = a->imax,*ai = a->i,*ailen = a->ilen,*aj = a->j;
197   PetscScalar  *aa = a->a;
198   PetscTruth   ignorezeroentries = (((a->ignorezeroentries)&&(addv==ADD_VALUES))?PETSC_TRUE:PETSC_FALSE);
199   Mat          B = aij->B;
200   Mat_SeqAIJ   *b = (Mat_SeqAIJ*)B->data;
201   int          *bimax = b->imax,*bi = b->i,*bilen = b->ilen,*bj = b->j,bm = aij->B->m,am = aij->A->m;
202   PetscScalar  *ba = b->a;
203 
204   int          *rp,ii,nrow,_i,rmax,N,col1,low,high,t;
205   int          nonew = a->nonew,shift=0;
206   PetscScalar  *ap;
207 
208   PetscFunctionBegin;
209   for (i=0; i<m; i++) {
210     if (im[i] < 0) continue;
211 #if defined(PETSC_USE_BOPT_g)
212     if (im[i] >= mat->M) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %d max %d",im[i],mat->M-1);
213 #endif
214     if (im[i] >= rstart && im[i] < rend) {
215       row = im[i] - rstart;
216       for (j=0; j<n; j++) {
217         if (in[j] >= cstart && in[j] < cend){
218           col = in[j] - cstart;
219           if (roworiented) value = v[i*n+j]; else value = v[i+j*m];
220           if (ignorezeroentries && value == 0.0) continue;
221           MatSetValues_SeqAIJ_A_Private(row,col,value,addv);
222           /* ierr = MatSetValues_SeqAIJ(aij->A,1,&row,1,&col,&value,addv);CHKERRQ(ierr); */
223         } else if (in[j] < 0) continue;
224 #if defined(PETSC_USE_BOPT_g)
225         else if (in[j] >= mat->N) {SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %d max %d",in[j],mat->N-1);}
226 #endif
227         else {
228           if (mat->was_assembled) {
229             if (!aij->colmap) {
230               ierr = CreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
231             }
232 #if defined (PETSC_USE_CTABLE)
233             ierr = PetscTableFind(aij->colmap,in[j]+1,&col);CHKERRQ(ierr);
234 	    col--;
235 #else
236             col = aij->colmap[in[j]] - 1;
237 #endif
238             if (col < 0 && !((Mat_SeqAIJ*)(aij->A->data))->nonew) {
239               ierr = DisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
240               col =  in[j];
241               /* Reinitialize the variables required by MatSetValues_SeqAIJ_B_Private() */
242               B = aij->B;
243               b = (Mat_SeqAIJ*)B->data;
244               bimax = b->imax; bi = b->i; bilen = b->ilen; bj = b->j;
245               ba = b->a;
246             }
247           } else col = in[j];
248           if (roworiented) value = v[i*n+j]; else value = v[i+j*m];
249           if (ignorezeroentries && value == 0.0) continue;
250           MatSetValues_SeqAIJ_B_Private(row,col,value,addv);
251           /* ierr = MatSetValues_SeqAIJ(aij->B,1,&row,1,&col,&value,addv);CHKERRQ(ierr); */
252         }
253       }
254     } else {
255       if (!aij->donotstash) {
256         if (roworiented) {
257           if (ignorezeroentries && v[i*n] == 0.0) continue;
258           ierr = MatStashValuesRow_Private(&mat->stash,im[i],n,in,v+i*n);CHKERRQ(ierr);
259         } else {
260           if (ignorezeroentries && v[i] == 0.0) continue;
261           ierr = MatStashValuesCol_Private(&mat->stash,im[i],n,in,v+i,m);CHKERRQ(ierr);
262         }
263       }
264     }
265   }
266   PetscFunctionReturn(0);
267 }
268 
269 #undef __FUNCT__
270 #define __FUNCT__ "MatGetValues_MPIAIJ"
271 int MatGetValues_MPIAIJ(Mat mat,int m,const int idxm[],int n,const int idxn[],PetscScalar v[])
272 {
273   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
274   int        ierr,i,j,rstart = aij->rstart,rend = aij->rend;
275   int        cstart = aij->cstart,cend = aij->cend,row,col;
276 
277   PetscFunctionBegin;
278   for (i=0; i<m; i++) {
279     if (idxm[i] < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Negative row: %d",idxm[i]);
280     if (idxm[i] >= mat->M) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Row too large: row %d max %d",idxm[i],mat->M-1);
281     if (idxm[i] >= rstart && idxm[i] < rend) {
282       row = idxm[i] - rstart;
283       for (j=0; j<n; j++) {
284         if (idxn[j] < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"Negative column: %d",idxn[j]);
285         if (idxn[j] >= mat->N) SETERRQ2(PETSC_ERR_ARG_OUTOFRANGE,"Column too large: col %d max %d",idxn[j],mat->N-1);
286         if (idxn[j] >= cstart && idxn[j] < cend){
287           col = idxn[j] - cstart;
288           ierr = MatGetValues(aij->A,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
289         } else {
290           if (!aij->colmap) {
291             ierr = CreateColmap_MPIAIJ_Private(mat);CHKERRQ(ierr);
292           }
293 #if defined (PETSC_USE_CTABLE)
294           ierr = PetscTableFind(aij->colmap,idxn[j]+1,&col);CHKERRQ(ierr);
295           col --;
296 #else
297           col = aij->colmap[idxn[j]] - 1;
298 #endif
299           if ((col < 0) || (aij->garray[col] != idxn[j])) *(v+i*n+j) = 0.0;
300           else {
301             ierr = MatGetValues(aij->B,1,&row,1,&col,v+i*n+j);CHKERRQ(ierr);
302           }
303         }
304       }
305     } else {
306       SETERRQ(PETSC_ERR_SUP,"Only local values currently supported");
307     }
308   }
309   PetscFunctionReturn(0);
310 }
311 
312 #undef __FUNCT__
313 #define __FUNCT__ "MatAssemblyBegin_MPIAIJ"
314 int MatAssemblyBegin_MPIAIJ(Mat mat,MatAssemblyType mode)
315 {
316   Mat_MPIAIJ  *aij = (Mat_MPIAIJ*)mat->data;
317   int         ierr,nstash,reallocs;
318   InsertMode  addv;
319 
320   PetscFunctionBegin;
321   if (aij->donotstash) {
322     PetscFunctionReturn(0);
323   }
324 
325   /* make sure all processors are either in INSERTMODE or ADDMODE */
326   ierr = MPI_Allreduce(&mat->insertmode,&addv,1,MPI_INT,MPI_BOR,mat->comm);CHKERRQ(ierr);
327   if (addv == (ADD_VALUES|INSERT_VALUES)) {
328     SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Some processors inserted others added");
329   }
330   mat->insertmode = addv; /* in case this processor had no cache */
331 
332   ierr = MatStashScatterBegin_Private(&mat->stash,aij->rowners);CHKERRQ(ierr);
333   ierr = MatStashGetInfo_Private(&mat->stash,&nstash,&reallocs);CHKERRQ(ierr);
334   PetscLogInfo(aij->A,"MatAssemblyBegin_MPIAIJ:Stash has %d entries, uses %d mallocs.\n",nstash,reallocs);
335   PetscFunctionReturn(0);
336 }
337 
338 
339 #undef __FUNCT__
340 #define __FUNCT__ "MatAssemblyEnd_MPIAIJ"
341 int MatAssemblyEnd_MPIAIJ(Mat mat,MatAssemblyType mode)
342 {
343   Mat_MPIAIJ  *aij = (Mat_MPIAIJ*)mat->data;
344   Mat_SeqAIJ  *a=(Mat_SeqAIJ *)aij->A->data,*b= (Mat_SeqAIJ *)aij->B->data;
345   int         i,j,rstart,ncols,n,ierr,flg;
346   int         *row,*col,other_disassembled;
347   PetscScalar *val;
348   InsertMode  addv = mat->insertmode;
349 
350   PetscFunctionBegin;
351   if (!aij->donotstash) {
352     while (1) {
353       ierr = MatStashScatterGetMesg_Private(&mat->stash,&n,&row,&col,&val,&flg);CHKERRQ(ierr);
354       if (!flg) break;
355 
356       for (i=0; i<n;) {
357         /* Now identify the consecutive vals belonging to the same row */
358         for (j=i,rstart=row[j]; j<n; j++) { if (row[j] != rstart) break; }
359         if (j < n) ncols = j-i;
360         else       ncols = n-i;
361         /* Now assemble all these values with a single function call */
362         ierr = MatSetValues_MPIAIJ(mat,1,row+i,ncols,col+i,val+i,addv);CHKERRQ(ierr);
363         i = j;
364       }
365     }
366     ierr = MatStashScatterEnd_Private(&mat->stash);CHKERRQ(ierr);
367   }
368 
369   ierr = MatAssemblyBegin(aij->A,mode);CHKERRQ(ierr);
370   ierr = MatAssemblyEnd(aij->A,mode);CHKERRQ(ierr);
371 
372   /* determine if any processor has disassembled, if so we must
373      also disassemble ourselfs, in order that we may reassemble. */
374   /*
375      if nonzero structure of submatrix B cannot change then we know that
376      no processor disassembled thus we can skip this stuff
377   */
378   if (!((Mat_SeqAIJ*)aij->B->data)->nonew)  {
379     ierr = MPI_Allreduce(&mat->was_assembled,&other_disassembled,1,MPI_INT,MPI_PROD,mat->comm);CHKERRQ(ierr);
380     if (mat->was_assembled && !other_disassembled) {
381       ierr = DisAssemble_MPIAIJ(mat);CHKERRQ(ierr);
382     }
383   }
384 
385   if (!mat->was_assembled && mode == MAT_FINAL_ASSEMBLY) {
386     ierr = MatSetUpMultiply_MPIAIJ(mat);CHKERRQ(ierr);
387   }
388   ierr = MatAssemblyBegin(aij->B,mode);CHKERRQ(ierr);
389   ierr = MatAssemblyEnd(aij->B,mode);CHKERRQ(ierr);
390 
391   if (aij->rowvalues) {
392     ierr = PetscFree(aij->rowvalues);CHKERRQ(ierr);
393     aij->rowvalues = 0;
394   }
395 
396   /* used by MatAXPY() */
397   a->xtoy = 0; b->xtoy = 0;
398   a->XtoY = 0; b->XtoY = 0;
399 
400   PetscFunctionReturn(0);
401 }
402 
403 #undef __FUNCT__
404 #define __FUNCT__ "MatZeroEntries_MPIAIJ"
405 int MatZeroEntries_MPIAIJ(Mat A)
406 {
407   Mat_MPIAIJ *l = (Mat_MPIAIJ*)A->data;
408   int        ierr;
409 
410   PetscFunctionBegin;
411   ierr = MatZeroEntries(l->A);CHKERRQ(ierr);
412   ierr = MatZeroEntries(l->B);CHKERRQ(ierr);
413   PetscFunctionReturn(0);
414 }
415 
416 #undef __FUNCT__
417 #define __FUNCT__ "MatZeroRows_MPIAIJ"
418 int MatZeroRows_MPIAIJ(Mat A,IS is,const PetscScalar *diag)
419 {
420   Mat_MPIAIJ     *l = (Mat_MPIAIJ*)A->data;
421   int            i,ierr,N,*rows,*owners = l->rowners,size = l->size;
422   int            *nprocs,j,idx,nsends,row;
423   int            nmax,*svalues,*starts,*owner,nrecvs,rank = l->rank;
424   int            *rvalues,tag = A->tag,count,base,slen,n,*source;
425   int            *lens,imdex,*lrows,*values,rstart=l->rstart;
426   MPI_Comm       comm = A->comm;
427   MPI_Request    *send_waits,*recv_waits;
428   MPI_Status     recv_status,*send_status;
429   IS             istmp;
430   PetscTruth     found;
431 
432   PetscFunctionBegin;
433   ierr = ISGetLocalSize(is,&N);CHKERRQ(ierr);
434   ierr = ISGetIndices(is,&rows);CHKERRQ(ierr);
435 
436   /*  first count number of contributors to each processor */
437   ierr = PetscMalloc(2*size*sizeof(int),&nprocs);CHKERRQ(ierr);
438   ierr   = PetscMemzero(nprocs,2*size*sizeof(int));CHKERRQ(ierr);
439   ierr = PetscMalloc((N+1)*sizeof(int),&owner);CHKERRQ(ierr); /* see note*/
440   for (i=0; i<N; i++) {
441     idx = rows[i];
442     found = PETSC_FALSE;
443     for (j=0; j<size; j++) {
444       if (idx >= owners[j] && idx < owners[j+1]) {
445         nprocs[2*j]++; nprocs[2*j+1] = 1; owner[i] = j; found = PETSC_TRUE; break;
446       }
447     }
448     if (!found) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Index out of range");
449   }
450   nsends = 0;  for (i=0; i<size; i++) { nsends += nprocs[2*i+1];}
451 
452   /* inform other processors of number of messages and max length*/
453   ierr = PetscMaxSum(comm,nprocs,&nmax,&nrecvs);CHKERRQ(ierr);
454 
455   /* post receives:   */
456   ierr = PetscMalloc((nrecvs+1)*(nmax+1)*sizeof(int),&rvalues);CHKERRQ(ierr);
457   ierr = PetscMalloc((nrecvs+1)*sizeof(MPI_Request),&recv_waits);CHKERRQ(ierr);
458   for (i=0; i<nrecvs; i++) {
459     ierr = MPI_Irecv(rvalues+nmax*i,nmax,MPI_INT,MPI_ANY_SOURCE,tag,comm,recv_waits+i);CHKERRQ(ierr);
460   }
461 
462   /* do sends:
463       1) starts[i] gives the starting index in svalues for stuff going to
464          the ith processor
465   */
466   ierr = PetscMalloc((N+1)*sizeof(int),&svalues);CHKERRQ(ierr);
467   ierr = PetscMalloc((nsends+1)*sizeof(MPI_Request),&send_waits);CHKERRQ(ierr);
468   ierr = PetscMalloc((size+1)*sizeof(int),&starts);CHKERRQ(ierr);
469   starts[0] = 0;
470   for (i=1; i<size; i++) { starts[i] = starts[i-1] + nprocs[2*i-2];}
471   for (i=0; i<N; i++) {
472     svalues[starts[owner[i]]++] = rows[i];
473   }
474   ierr = ISRestoreIndices(is,&rows);CHKERRQ(ierr);
475 
476   starts[0] = 0;
477   for (i=1; i<size+1; i++) { starts[i] = starts[i-1] + nprocs[2*i-2];}
478   count = 0;
479   for (i=0; i<size; i++) {
480     if (nprocs[2*i+1]) {
481       ierr = MPI_Isend(svalues+starts[i],nprocs[2*i],MPI_INT,i,tag,comm,send_waits+count++);CHKERRQ(ierr);
482     }
483   }
484   ierr = PetscFree(starts);CHKERRQ(ierr);
485 
486   base = owners[rank];
487 
488   /*  wait on receives */
489   ierr   = PetscMalloc(2*(nrecvs+1)*sizeof(int),&lens);CHKERRQ(ierr);
490   source = lens + nrecvs;
491   count  = nrecvs; slen = 0;
492   while (count) {
493     ierr = MPI_Waitany(nrecvs,recv_waits,&imdex,&recv_status);CHKERRQ(ierr);
494     /* unpack receives into our local space */
495     ierr = MPI_Get_count(&recv_status,MPI_INT,&n);CHKERRQ(ierr);
496     source[imdex]  = recv_status.MPI_SOURCE;
497     lens[imdex]    = n;
498     slen          += n;
499     count--;
500   }
501   ierr = PetscFree(recv_waits);CHKERRQ(ierr);
502 
503   /* move the data into the send scatter */
504   ierr = PetscMalloc((slen+1)*sizeof(int),&lrows);CHKERRQ(ierr);
505   count = 0;
506   for (i=0; i<nrecvs; i++) {
507     values = rvalues + i*nmax;
508     for (j=0; j<lens[i]; j++) {
509       lrows[count++] = values[j] - base;
510     }
511   }
512   ierr = PetscFree(rvalues);CHKERRQ(ierr);
513   ierr = PetscFree(lens);CHKERRQ(ierr);
514   ierr = PetscFree(owner);CHKERRQ(ierr);
515   ierr = PetscFree(nprocs);CHKERRQ(ierr);
516 
517   /* actually zap the local rows */
518   ierr = ISCreateGeneral(PETSC_COMM_SELF,slen,lrows,&istmp);CHKERRQ(ierr);
519   PetscLogObjectParent(A,istmp);
520 
521   /*
522         Zero the required rows. If the "diagonal block" of the matrix
523      is square and the user wishes to set the diagonal we use seperate
524      code so that MatSetValues() is not called for each diagonal allocating
525      new memory, thus calling lots of mallocs and slowing things down.
526 
527        Contributed by: Mathew Knepley
528   */
529   /* must zero l->B before l->A because the (diag) case below may put values into l->B*/
530   ierr = MatZeroRows(l->B,istmp,0);CHKERRQ(ierr);
531   if (diag && (l->A->M == l->A->N)) {
532     ierr      = MatZeroRows(l->A,istmp,diag);CHKERRQ(ierr);
533   } else if (diag) {
534     ierr = MatZeroRows(l->A,istmp,0);CHKERRQ(ierr);
535     if (((Mat_SeqAIJ*)l->A->data)->nonew) {
536       SETERRQ(PETSC_ERR_SUP,"MatZeroRows() on rectangular matrices cannot be used with the Mat options\n\
537 MAT_NO_NEW_NONZERO_LOCATIONS,MAT_NEW_NONZERO_LOCATION_ERR,MAT_NEW_NONZERO_ALLOCATION_ERR");
538     }
539     for (i = 0; i < slen; i++) {
540       row  = lrows[i] + rstart;
541       ierr = MatSetValues(A,1,&row,1,&row,diag,INSERT_VALUES);CHKERRQ(ierr);
542     }
543     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
544     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
545   } else {
546     ierr = MatZeroRows(l->A,istmp,0);CHKERRQ(ierr);
547   }
548   ierr = ISDestroy(istmp);CHKERRQ(ierr);
549   ierr = PetscFree(lrows);CHKERRQ(ierr);
550 
551   /* wait on sends */
552   if (nsends) {
553     ierr = PetscMalloc(nsends*sizeof(MPI_Status),&send_status);CHKERRQ(ierr);
554     ierr = MPI_Waitall(nsends,send_waits,send_status);CHKERRQ(ierr);
555     ierr = PetscFree(send_status);CHKERRQ(ierr);
556   }
557   ierr = PetscFree(send_waits);CHKERRQ(ierr);
558   ierr = PetscFree(svalues);CHKERRQ(ierr);
559 
560   PetscFunctionReturn(0);
561 }
562 
563 #undef __FUNCT__
564 #define __FUNCT__ "MatMult_MPIAIJ"
565 int MatMult_MPIAIJ(Mat A,Vec xx,Vec yy)
566 {
567   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
568   int        ierr,nt;
569 
570   PetscFunctionBegin;
571   ierr = VecGetLocalSize(xx,&nt);CHKERRQ(ierr);
572   if (nt != A->n) {
573     SETERRQ2(PETSC_ERR_ARG_SIZ,"Incompatible partition of A (%d) and xx (%d)",A->n,nt);
574   }
575   ierr = VecScatterBegin(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
576   ierr = (*a->A->ops->mult)(a->A,xx,yy);CHKERRQ(ierr);
577   ierr = VecScatterEnd(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
578   ierr = (*a->B->ops->multadd)(a->B,a->lvec,yy,yy);CHKERRQ(ierr);
579   PetscFunctionReturn(0);
580 }
581 
582 #undef __FUNCT__
583 #define __FUNCT__ "MatMultAdd_MPIAIJ"
584 int MatMultAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
585 {
586   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
587   int        ierr;
588 
589   PetscFunctionBegin;
590   ierr = VecScatterBegin(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
591   ierr = (*a->A->ops->multadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
592   ierr = VecScatterEnd(xx,a->lvec,INSERT_VALUES,SCATTER_FORWARD,a->Mvctx);CHKERRQ(ierr);
593   ierr = (*a->B->ops->multadd)(a->B,a->lvec,zz,zz);CHKERRQ(ierr);
594   PetscFunctionReturn(0);
595 }
596 
597 #undef __FUNCT__
598 #define __FUNCT__ "MatMultTranspose_MPIAIJ"
599 int MatMultTranspose_MPIAIJ(Mat A,Vec xx,Vec yy)
600 {
601   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
602   int        ierr;
603 
604   PetscFunctionBegin;
605   /* do nondiagonal part */
606   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
607   /* send it on its way */
608   ierr = VecScatterBegin(a->lvec,yy,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
609   /* do local part */
610   ierr = (*a->A->ops->multtranspose)(a->A,xx,yy);CHKERRQ(ierr);
611   /* receive remote parts: note this assumes the values are not actually */
612   /* inserted in yy until the next line, which is true for my implementation*/
613   /* but is not perhaps always true. */
614   ierr = VecScatterEnd(a->lvec,yy,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
615   PetscFunctionReturn(0);
616 }
617 
618 EXTERN_C_BEGIN
619 #undef __FUNCT__
620 #define __FUNCT__ "MatIsTranspose_MPIAIJ"
621 int MatIsTranspose_MPIAIJ(Mat Amat,Mat Bmat,PetscTruth *f)
622 {
623   MPI_Comm comm;
624   Mat_MPIAIJ *Aij = (Mat_MPIAIJ *) Amat->data, *Bij;
625   Mat        Adia = Aij->A, Bdia, Aoff,Boff,*Aoffs,*Boffs;
626   IS         Me,Notme;
627   int        M,N,first,last,*notme,ntids,i, ierr;
628 
629   PetscFunctionBegin;
630 
631   /* Easy test: symmetric diagonal block */
632   Bij = (Mat_MPIAIJ *) Bmat->data; Bdia = Bij->A;
633   ierr = MatIsTranspose(Adia,Bdia,f);CHKERRQ(ierr);
634   if (!*f) PetscFunctionReturn(0);
635   ierr = PetscObjectGetComm((PetscObject)Amat,&comm);CHKERRQ(ierr);
636   ierr = MPI_Comm_size(comm,&ntids);CHKERRQ(ierr);
637   if (ntids==1) PetscFunctionReturn(0);
638 
639   /* Hard test: off-diagonal block. This takes a MatGetSubMatrix. */
640   ierr = MatGetSize(Amat,&M,&N);CHKERRQ(ierr);
641   ierr = MatGetOwnershipRange(Amat,&first,&last);CHKERRQ(ierr);
642   ierr = PetscMalloc((N-last+first)*sizeof(int),&notme);CHKERRQ(ierr);
643   for (i=0; i<first; i++) notme[i] = i;
644   for (i=last; i<M; i++) notme[i-last+first] = i;
645   ierr = ISCreateGeneral(MPI_COMM_SELF,N-last+first,notme,&Notme);CHKERRQ(ierr);
646   ierr = ISCreateStride(MPI_COMM_SELF,last-first,first,1,&Me);CHKERRQ(ierr);
647   ierr = MatGetSubMatrices(Amat,1,&Me,&Notme,MAT_INITIAL_MATRIX,&Aoffs);CHKERRQ(ierr);
648   Aoff = Aoffs[0];
649   ierr = MatGetSubMatrices(Bmat,1,&Notme,&Me,MAT_INITIAL_MATRIX,&Boffs);CHKERRQ(ierr);
650   Boff = Boffs[0];
651   ierr = MatIsTranspose(Aoff,Boff,f);CHKERRQ(ierr);
652   ierr = MatDestroyMatrices(1,&Aoffs);CHKERRQ(ierr);
653   ierr = MatDestroyMatrices(1,&Boffs);CHKERRQ(ierr);
654   ierr = ISDestroy(Me);CHKERRQ(ierr);
655   ierr = ISDestroy(Notme);CHKERRQ(ierr);
656 
657   PetscFunctionReturn(0);
658 }
659 EXTERN_C_END
660 
661 #undef __FUNCT__
662 #define __FUNCT__ "MatMultTransposeAdd_MPIAIJ"
663 int MatMultTransposeAdd_MPIAIJ(Mat A,Vec xx,Vec yy,Vec zz)
664 {
665   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
666   int        ierr;
667 
668   PetscFunctionBegin;
669   /* do nondiagonal part */
670   ierr = (*a->B->ops->multtranspose)(a->B,xx,a->lvec);CHKERRQ(ierr);
671   /* send it on its way */
672   ierr = VecScatterBegin(a->lvec,zz,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
673   /* do local part */
674   ierr = (*a->A->ops->multtransposeadd)(a->A,xx,yy,zz);CHKERRQ(ierr);
675   /* receive remote parts: note this assumes the values are not actually */
676   /* inserted in yy until the next line, which is true for my implementation*/
677   /* but is not perhaps always true. */
678   ierr = VecScatterEnd(a->lvec,zz,ADD_VALUES,SCATTER_REVERSE,a->Mvctx);CHKERRQ(ierr);
679   PetscFunctionReturn(0);
680 }
681 
682 /*
683   This only works correctly for square matrices where the subblock A->A is the
684    diagonal block
685 */
686 #undef __FUNCT__
687 #define __FUNCT__ "MatGetDiagonal_MPIAIJ"
688 int MatGetDiagonal_MPIAIJ(Mat A,Vec v)
689 {
690   int        ierr;
691   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
692 
693   PetscFunctionBegin;
694   if (A->M != A->N) SETERRQ(PETSC_ERR_SUP,"Supports only square matrix where A->A is diag block");
695   if (a->rstart != a->cstart || a->rend != a->cend) {
696     SETERRQ(PETSC_ERR_ARG_SIZ,"row partition must equal col partition");
697   }
698   ierr = MatGetDiagonal(a->A,v);CHKERRQ(ierr);
699   PetscFunctionReturn(0);
700 }
701 
702 #undef __FUNCT__
703 #define __FUNCT__ "MatScale_MPIAIJ"
704 int MatScale_MPIAIJ(const PetscScalar aa[],Mat A)
705 {
706   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
707   int        ierr;
708 
709   PetscFunctionBegin;
710   ierr = MatScale(aa,a->A);CHKERRQ(ierr);
711   ierr = MatScale(aa,a->B);CHKERRQ(ierr);
712   PetscFunctionReturn(0);
713 }
714 
715 #undef __FUNCT__
716 #define __FUNCT__ "MatDestroy_MPIAIJ"
717 int MatDestroy_MPIAIJ(Mat mat)
718 {
719   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
720   int        ierr;
721 
722   PetscFunctionBegin;
723 #if defined(PETSC_USE_LOG)
724   PetscLogObjectState((PetscObject)mat,"Rows=%d, Cols=%d",mat->M,mat->N);
725 #endif
726   ierr = MatStashDestroy_Private(&mat->stash);CHKERRQ(ierr);
727   ierr = PetscFree(aij->rowners);CHKERRQ(ierr);
728   ierr = MatDestroy(aij->A);CHKERRQ(ierr);
729   ierr = MatDestroy(aij->B);CHKERRQ(ierr);
730 #if defined (PETSC_USE_CTABLE)
731   if (aij->colmap) {ierr = PetscTableDelete(aij->colmap);CHKERRQ(ierr);}
732 #else
733   if (aij->colmap) {ierr = PetscFree(aij->colmap);CHKERRQ(ierr);}
734 #endif
735   if (aij->garray) {ierr = PetscFree(aij->garray);CHKERRQ(ierr);}
736   if (aij->lvec)   {ierr = VecDestroy(aij->lvec);CHKERRQ(ierr);}
737   if (aij->Mvctx)  {ierr = VecScatterDestroy(aij->Mvctx);CHKERRQ(ierr);}
738   if (aij->rowvalues) {ierr = PetscFree(aij->rowvalues);CHKERRQ(ierr);}
739   ierr = PetscFree(aij);CHKERRQ(ierr);
740   PetscFunctionReturn(0);
741 }
742 
743 #undef __FUNCT__
744 #define __FUNCT__ "MatView_MPIAIJ_Binary"
745 int MatView_MPIAIJ_Binary(Mat mat,PetscViewer viewer)
746 {
747   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
748   Mat_SeqAIJ*       A = (Mat_SeqAIJ*)aij->A->data;
749   Mat_SeqAIJ*       B = (Mat_SeqAIJ*)aij->B->data;
750   int               nz,fd,ierr,header[4],rank,size,*row_lengths,*range,rlen,i,tag = ((PetscObject)viewer)->tag;
751   int               nzmax,*column_indices,j,k,col,*garray = aij->garray,cnt,cstart = aij->cstart,rnz;
752   PetscScalar       *column_values;
753 
754   PetscFunctionBegin;
755   ierr = MPI_Comm_rank(mat->comm,&rank);CHKERRQ(ierr);
756   ierr = MPI_Comm_size(mat->comm,&size);CHKERRQ(ierr);
757   nz   = A->nz + B->nz;
758   if (rank == 0) {
759     header[0] = MAT_FILE_COOKIE;
760     header[1] = mat->M;
761     header[2] = mat->N;
762     ierr = MPI_Reduce(&nz,&header[3],1,MPI_INT,MPI_SUM,0,mat->comm);CHKERRQ(ierr);
763     ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
764     ierr = PetscBinaryWrite(fd,header,4,PETSC_INT,1);CHKERRQ(ierr);
765     /* get largest number of rows any processor has */
766     rlen = mat->m;
767     ierr = PetscMapGetGlobalRange(mat->rmap,&range);CHKERRQ(ierr);
768     for (i=1; i<size; i++) {
769       rlen = PetscMax(rlen,range[i+1] - range[i]);
770     }
771   } else {
772     ierr = MPI_Reduce(&nz,0,1,MPI_INT,MPI_SUM,0,mat->comm);CHKERRQ(ierr);
773     rlen = mat->m;
774   }
775 
776   /* load up the local row counts */
777   ierr = PetscMalloc((rlen+1)*sizeof(int),&row_lengths);CHKERRQ(ierr);
778   for (i=0; i<mat->m; i++) {
779     row_lengths[i] = A->i[i+1] - A->i[i] + B->i[i+1] - B->i[i];
780   }
781 
782   /* store the row lengths to the file */
783   if (rank == 0) {
784     MPI_Status status;
785     ierr = PetscBinaryWrite(fd,row_lengths,mat->m,PETSC_INT,1);CHKERRQ(ierr);
786     for (i=1; i<size; i++) {
787       rlen = range[i+1] - range[i];
788       ierr = MPI_Recv(row_lengths,rlen,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
789       ierr = PetscBinaryWrite(fd,row_lengths,rlen,PETSC_INT,1);CHKERRQ(ierr);
790     }
791   } else {
792     ierr = MPI_Send(row_lengths,mat->m,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
793   }
794   ierr = PetscFree(row_lengths);CHKERRQ(ierr);
795 
796   /* load up the local column indices */
797   nzmax = nz; /* )th processor needs space a largest processor needs */
798   ierr = MPI_Reduce(&nz,&nzmax,1,MPI_INT,MPI_MAX,0,mat->comm);CHKERRQ(ierr);
799   ierr = PetscMalloc((nzmax+1)*sizeof(int),&column_indices);CHKERRQ(ierr);
800   cnt  = 0;
801   for (i=0; i<mat->m; i++) {
802     for (j=B->i[i]; j<B->i[i+1]; j++) {
803       if ( (col = garray[B->j[j]]) > cstart) break;
804       column_indices[cnt++] = col;
805     }
806     for (k=A->i[i]; k<A->i[i+1]; k++) {
807       column_indices[cnt++] = A->j[k] + cstart;
808     }
809     for (; j<B->i[i+1]; j++) {
810       column_indices[cnt++] = garray[B->j[j]];
811     }
812   }
813   if (cnt != A->nz + B->nz) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: cnt = %d nz = %d",cnt,A->nz+B->nz);
814 
815   /* store the column indices to the file */
816   if (rank == 0) {
817     MPI_Status status;
818     ierr = PetscBinaryWrite(fd,column_indices,nz,PETSC_INT,1);CHKERRQ(ierr);
819     for (i=1; i<size; i++) {
820       ierr = MPI_Recv(&rnz,1,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
821       if (rnz > nzmax) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: nz = %d nzmax = %d",nz,nzmax);
822       ierr = MPI_Recv(column_indices,rnz,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
823       ierr = PetscBinaryWrite(fd,column_indices,rnz,PETSC_INT,1);CHKERRQ(ierr);
824     }
825   } else {
826     ierr = MPI_Send(&nz,1,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
827     ierr = MPI_Send(column_indices,nz,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
828   }
829   ierr = PetscFree(column_indices);CHKERRQ(ierr);
830 
831   /* load up the local column values */
832   ierr = PetscMalloc((nzmax+1)*sizeof(PetscScalar),&column_values);CHKERRQ(ierr);
833   cnt  = 0;
834   for (i=0; i<mat->m; i++) {
835     for (j=B->i[i]; j<B->i[i+1]; j++) {
836       if ( garray[B->j[j]] > cstart) break;
837       column_values[cnt++] = B->a[j];
838     }
839     for (k=A->i[i]; k<A->i[i+1]; k++) {
840       column_values[cnt++] = A->a[k];
841     }
842     for (; j<B->i[i+1]; j++) {
843       column_values[cnt++] = B->a[j];
844     }
845   }
846   if (cnt != A->nz + B->nz) SETERRQ2(1,"Internal PETSc error: cnt = %d nz = %d",cnt,A->nz+B->nz);
847 
848   /* store the column values to the file */
849   if (rank == 0) {
850     MPI_Status status;
851     ierr = PetscBinaryWrite(fd,column_values,nz,PETSC_SCALAR,1);CHKERRQ(ierr);
852     for (i=1; i<size; i++) {
853       ierr = MPI_Recv(&rnz,1,MPI_INT,i,tag,mat->comm,&status);CHKERRQ(ierr);
854       if (rnz > nzmax) SETERRQ2(PETSC_ERR_LIB,"Internal PETSc error: nz = %d nzmax = %d",nz,nzmax);
855       ierr = MPI_Recv(column_values,rnz,MPIU_SCALAR,i,tag,mat->comm,&status);CHKERRQ(ierr);
856       ierr = PetscBinaryWrite(fd,column_values,rnz,PETSC_SCALAR,1);CHKERRQ(ierr);
857     }
858   } else {
859     ierr = MPI_Send(&nz,1,MPI_INT,0,tag,mat->comm);CHKERRQ(ierr);
860     ierr = MPI_Send(column_values,nz,MPIU_SCALAR,0,tag,mat->comm);CHKERRQ(ierr);
861   }
862   ierr = PetscFree(column_values);CHKERRQ(ierr);
863   PetscFunctionReturn(0);
864 }
865 
866 #undef __FUNCT__
867 #define __FUNCT__ "MatView_MPIAIJ_ASCIIorDraworSocket"
868 int MatView_MPIAIJ_ASCIIorDraworSocket(Mat mat,PetscViewer viewer)
869 {
870   Mat_MPIAIJ        *aij = (Mat_MPIAIJ*)mat->data;
871   int               ierr,rank = aij->rank,size = aij->size;
872   PetscTruth        isdraw,isascii,flg,isbinary;
873   PetscViewer       sviewer;
874   PetscViewerFormat format;
875 
876   PetscFunctionBegin;
877   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_DRAW,&isdraw);CHKERRQ(ierr);
878   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&isascii);CHKERRQ(ierr);
879   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_BINARY,&isbinary);CHKERRQ(ierr);
880   if (isascii) {
881     ierr = PetscViewerGetFormat(viewer,&format);CHKERRQ(ierr);
882     if (format == PETSC_VIEWER_ASCII_INFO_DETAIL) {
883       MatInfo info;
884       ierr = MPI_Comm_rank(mat->comm,&rank);CHKERRQ(ierr);
885       ierr = MatGetInfo(mat,MAT_LOCAL,&info);CHKERRQ(ierr);
886       ierr = PetscOptionsHasName(PETSC_NULL,"-mat_aij_no_inode",&flg);CHKERRQ(ierr);
887       if (flg) {
888         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %d nz %d nz alloced %d mem %d, not using I-node routines\n",
889 					      rank,mat->m,(int)info.nz_used,(int)info.nz_allocated,(int)info.memory);CHKERRQ(ierr);
890       } else {
891         ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Local rows %d nz %d nz alloced %d mem %d, using I-node routines\n",
892 		    rank,mat->m,(int)info.nz_used,(int)info.nz_allocated,(int)info.memory);CHKERRQ(ierr);
893       }
894       ierr = MatGetInfo(aij->A,MAT_LOCAL,&info);CHKERRQ(ierr);
895       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] on-diagonal part: nz %d \n",rank,(int)info.nz_used);CHKERRQ(ierr);
896       ierr = MatGetInfo(aij->B,MAT_LOCAL,&info);CHKERRQ(ierr);
897       ierr = PetscViewerASCIISynchronizedPrintf(viewer,"[%d] off-diagonal part: nz %d \n",rank,(int)info.nz_used);CHKERRQ(ierr);
898       ierr = PetscViewerFlush(viewer);CHKERRQ(ierr);
899       ierr = VecScatterView(aij->Mvctx,viewer);CHKERRQ(ierr);
900       PetscFunctionReturn(0);
901     } else if (format == PETSC_VIEWER_ASCII_INFO) {
902       PetscFunctionReturn(0);
903     } else if (format == PETSC_VIEWER_ASCII_FACTOR_INFO) {
904       PetscFunctionReturn(0);
905     }
906   } else if (isbinary) {
907     if (size == 1) {
908       ierr = PetscObjectSetName((PetscObject)aij->A,mat->name);CHKERRQ(ierr);
909       ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
910     } else {
911       ierr = MatView_MPIAIJ_Binary(mat,viewer);CHKERRQ(ierr);
912     }
913     PetscFunctionReturn(0);
914   } else if (isdraw) {
915     PetscDraw  draw;
916     PetscTruth isnull;
917     ierr = PetscViewerDrawGetDraw(viewer,0,&draw);CHKERRQ(ierr);
918     ierr = PetscDrawIsNull(draw,&isnull);CHKERRQ(ierr); if (isnull) PetscFunctionReturn(0);
919   }
920 
921   if (size == 1) {
922     ierr = PetscObjectSetName((PetscObject)aij->A,mat->name);CHKERRQ(ierr);
923     ierr = MatView(aij->A,viewer);CHKERRQ(ierr);
924   } else {
925     /* assemble the entire matrix onto first processor. */
926     Mat         A;
927     Mat_SeqAIJ *Aloc;
928     int         M = mat->M,N = mat->N,m,*ai,*aj,row,*cols,i,*ct;
929     PetscScalar *a;
930 
931     if (!rank) {
932       ierr = MatCreate(mat->comm,M,N,M,N,&A);CHKERRQ(ierr);
933     } else {
934       ierr = MatCreate(mat->comm,0,0,M,N,&A);CHKERRQ(ierr);
935     }
936     /* This is just a temporary matrix, so explicitly using MATMPIAIJ is probably best */
937     ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
938     ierr = MatMPIAIJSetPreallocation(A,0,PETSC_NULL,0,PETSC_NULL);CHKERRQ(ierr);
939     PetscLogObjectParent(mat,A);
940 
941     /* copy over the A part */
942     Aloc = (Mat_SeqAIJ*)aij->A->data;
943     m = aij->A->m; ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
944     row = aij->rstart;
945     for (i=0; i<ai[m]; i++) {aj[i] += aij->cstart ;}
946     for (i=0; i<m; i++) {
947       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],aj,a,INSERT_VALUES);CHKERRQ(ierr);
948       row++; a += ai[i+1]-ai[i]; aj += ai[i+1]-ai[i];
949     }
950     aj = Aloc->j;
951     for (i=0; i<ai[m]; i++) {aj[i] -= aij->cstart;}
952 
953     /* copy over the B part */
954     Aloc = (Mat_SeqAIJ*)aij->B->data;
955     m    = aij->B->m;  ai = Aloc->i; aj = Aloc->j; a = Aloc->a;
956     row  = aij->rstart;
957     ierr = PetscMalloc((ai[m]+1)*sizeof(int),&cols);CHKERRQ(ierr);
958     ct   = cols;
959     for (i=0; i<ai[m]; i++) {cols[i] = aij->garray[aj[i]];}
960     for (i=0; i<m; i++) {
961       ierr = MatSetValues(A,1,&row,ai[i+1]-ai[i],cols,a,INSERT_VALUES);CHKERRQ(ierr);
962       row++; a += ai[i+1]-ai[i]; cols += ai[i+1]-ai[i];
963     }
964     ierr = PetscFree(ct);CHKERRQ(ierr);
965     ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
966     ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
967     /*
968        Everyone has to call to draw the matrix since the graphics waits are
969        synchronized across all processors that share the PetscDraw object
970     */
971     ierr = PetscViewerGetSingleton(viewer,&sviewer);CHKERRQ(ierr);
972     if (!rank) {
973       ierr = PetscObjectSetName((PetscObject)((Mat_MPIAIJ*)(A->data))->A,mat->name);CHKERRQ(ierr);
974       ierr = MatView(((Mat_MPIAIJ*)(A->data))->A,sviewer);CHKERRQ(ierr);
975     }
976     ierr = PetscViewerRestoreSingleton(viewer,&sviewer);CHKERRQ(ierr);
977     ierr = MatDestroy(A);CHKERRQ(ierr);
978   }
979   PetscFunctionReturn(0);
980 }
981 
982 #undef __FUNCT__
983 #define __FUNCT__ "MatView_MPIAIJ"
984 int MatView_MPIAIJ(Mat mat,PetscViewer viewer)
985 {
986   int        ierr;
987   PetscTruth isascii,isdraw,issocket,isbinary;
988 
989   PetscFunctionBegin;
990   ierr  = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&isascii);CHKERRQ(ierr);
991   ierr  = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_DRAW,&isdraw);CHKERRQ(ierr);
992   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_BINARY,&isbinary);CHKERRQ(ierr);
993   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_SOCKET,&issocket);CHKERRQ(ierr);
994   if (isascii || isdraw || isbinary || issocket) {
995     ierr = MatView_MPIAIJ_ASCIIorDraworSocket(mat,viewer);CHKERRQ(ierr);
996   } else {
997     SETERRQ1(1,"Viewer type %s not supported by MPIAIJ matrices",((PetscObject)viewer)->type_name);
998   }
999   PetscFunctionReturn(0);
1000 }
1001 
1002 
1003 
1004 #undef __FUNCT__
1005 #define __FUNCT__ "MatRelax_MPIAIJ"
1006 int MatRelax_MPIAIJ(Mat matin,Vec bb,PetscReal omega,MatSORType flag,PetscReal fshift,int its,int lits,Vec xx)
1007 {
1008   Mat_MPIAIJ   *mat = (Mat_MPIAIJ*)matin->data;
1009   int          ierr;
1010   Vec          bb1;
1011   PetscScalar  mone=-1.0;
1012 
1013   PetscFunctionBegin;
1014   if (its <= 0 || lits <= 0) SETERRQ2(PETSC_ERR_ARG_WRONG,"Relaxation requires global its %d and local its %d both positive",its,lits);
1015 
1016   ierr = VecDuplicate(bb,&bb1);CHKERRQ(ierr);
1017 
1018   if ((flag & SOR_LOCAL_SYMMETRIC_SWEEP) == SOR_LOCAL_SYMMETRIC_SWEEP){
1019     if (flag & SOR_ZERO_INITIAL_GUESS) {
1020       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,lits,xx);CHKERRQ(ierr);
1021       its--;
1022     }
1023 
1024     while (its--) {
1025       ierr = VecScatterBegin(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1026       ierr = VecScatterEnd(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1027 
1028       /* update rhs: bb1 = bb - B*x */
1029       ierr = VecScale(&mone,mat->lvec);CHKERRQ(ierr);
1030       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1031 
1032       /* local sweep */
1033       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_SYMMETRIC_SWEEP,fshift,lits,lits,xx);
1034       CHKERRQ(ierr);
1035     }
1036   } else if (flag & SOR_LOCAL_FORWARD_SWEEP){
1037     if (flag & SOR_ZERO_INITIAL_GUESS) {
1038       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,PETSC_NULL,xx);CHKERRQ(ierr);
1039       its--;
1040     }
1041     while (its--) {
1042       ierr = VecScatterBegin(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1043       ierr = VecScatterEnd(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1044 
1045       /* update rhs: bb1 = bb - B*x */
1046       ierr = VecScale(&mone,mat->lvec);CHKERRQ(ierr);
1047       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1048 
1049       /* local sweep */
1050       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_FORWARD_SWEEP,fshift,lits,PETSC_NULL,xx);
1051       CHKERRQ(ierr);
1052     }
1053   } else if (flag & SOR_LOCAL_BACKWARD_SWEEP){
1054     if (flag & SOR_ZERO_INITIAL_GUESS) {
1055       ierr = (*mat->A->ops->relax)(mat->A,bb,omega,flag,fshift,lits,PETSC_NULL,xx);CHKERRQ(ierr);
1056       its--;
1057     }
1058     while (its--) {
1059       ierr = VecScatterBegin(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1060       ierr = VecScatterEnd(xx,mat->lvec,INSERT_VALUES,SCATTER_FORWARD,mat->Mvctx);CHKERRQ(ierr);
1061 
1062       /* update rhs: bb1 = bb - B*x */
1063       ierr = VecScale(&mone,mat->lvec);CHKERRQ(ierr);
1064       ierr = (*mat->B->ops->multadd)(mat->B,mat->lvec,bb,bb1);CHKERRQ(ierr);
1065 
1066       /* local sweep */
1067       ierr = (*mat->A->ops->relax)(mat->A,bb1,omega,SOR_BACKWARD_SWEEP,fshift,lits,PETSC_NULL,xx);
1068       CHKERRQ(ierr);
1069     }
1070   } else {
1071     SETERRQ(PETSC_ERR_SUP,"Parallel SOR not supported");
1072   }
1073 
1074   ierr = VecDestroy(bb1);CHKERRQ(ierr);
1075   PetscFunctionReturn(0);
1076 }
1077 
1078 #undef __FUNCT__
1079 #define __FUNCT__ "MatGetInfo_MPIAIJ"
1080 int MatGetInfo_MPIAIJ(Mat matin,MatInfoType flag,MatInfo *info)
1081 {
1082   Mat_MPIAIJ *mat = (Mat_MPIAIJ*)matin->data;
1083   Mat        A = mat->A,B = mat->B;
1084   int        ierr;
1085   PetscReal  isend[5],irecv[5];
1086 
1087   PetscFunctionBegin;
1088   info->block_size     = 1.0;
1089   ierr = MatGetInfo(A,MAT_LOCAL,info);CHKERRQ(ierr);
1090   isend[0] = info->nz_used; isend[1] = info->nz_allocated; isend[2] = info->nz_unneeded;
1091   isend[3] = info->memory;  isend[4] = info->mallocs;
1092   ierr = MatGetInfo(B,MAT_LOCAL,info);CHKERRQ(ierr);
1093   isend[0] += info->nz_used; isend[1] += info->nz_allocated; isend[2] += info->nz_unneeded;
1094   isend[3] += info->memory;  isend[4] += info->mallocs;
1095   if (flag == MAT_LOCAL) {
1096     info->nz_used      = isend[0];
1097     info->nz_allocated = isend[1];
1098     info->nz_unneeded  = isend[2];
1099     info->memory       = isend[3];
1100     info->mallocs      = isend[4];
1101   } else if (flag == MAT_GLOBAL_MAX) {
1102     ierr = MPI_Allreduce(isend,irecv,5,MPIU_REAL,MPI_MAX,matin->comm);CHKERRQ(ierr);
1103     info->nz_used      = irecv[0];
1104     info->nz_allocated = irecv[1];
1105     info->nz_unneeded  = irecv[2];
1106     info->memory       = irecv[3];
1107     info->mallocs      = irecv[4];
1108   } else if (flag == MAT_GLOBAL_SUM) {
1109     ierr = MPI_Allreduce(isend,irecv,5,MPIU_REAL,MPI_SUM,matin->comm);CHKERRQ(ierr);
1110     info->nz_used      = irecv[0];
1111     info->nz_allocated = irecv[1];
1112     info->nz_unneeded  = irecv[2];
1113     info->memory       = irecv[3];
1114     info->mallocs      = irecv[4];
1115   }
1116   info->fill_ratio_given  = 0; /* no parallel LU/ILU/Cholesky */
1117   info->fill_ratio_needed = 0;
1118   info->factor_mallocs    = 0;
1119   info->rows_global       = (double)matin->M;
1120   info->columns_global    = (double)matin->N;
1121   info->rows_local        = (double)matin->m;
1122   info->columns_local     = (double)matin->N;
1123 
1124   PetscFunctionReturn(0);
1125 }
1126 
1127 #undef __FUNCT__
1128 #define __FUNCT__ "MatSetOption_MPIAIJ"
1129 int MatSetOption_MPIAIJ(Mat A,MatOption op)
1130 {
1131   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
1132   int        ierr;
1133 
1134   PetscFunctionBegin;
1135   switch (op) {
1136   case MAT_NO_NEW_NONZERO_LOCATIONS:
1137   case MAT_YES_NEW_NONZERO_LOCATIONS:
1138   case MAT_COLUMNS_UNSORTED:
1139   case MAT_COLUMNS_SORTED:
1140   case MAT_NEW_NONZERO_ALLOCATION_ERR:
1141   case MAT_KEEP_ZEROED_ROWS:
1142   case MAT_NEW_NONZERO_LOCATION_ERR:
1143   case MAT_USE_INODES:
1144   case MAT_DO_NOT_USE_INODES:
1145   case MAT_IGNORE_ZERO_ENTRIES:
1146     ierr = MatSetOption(a->A,op);CHKERRQ(ierr);
1147     ierr = MatSetOption(a->B,op);CHKERRQ(ierr);
1148     break;
1149   case MAT_ROW_ORIENTED:
1150     a->roworiented = PETSC_TRUE;
1151     ierr = MatSetOption(a->A,op);CHKERRQ(ierr);
1152     ierr = MatSetOption(a->B,op);CHKERRQ(ierr);
1153     break;
1154   case MAT_ROWS_SORTED:
1155   case MAT_ROWS_UNSORTED:
1156   case MAT_YES_NEW_DIAGONALS:
1157     PetscLogInfo(A,"MatSetOption_MPIAIJ:Option ignored\n");
1158     break;
1159   case MAT_COLUMN_ORIENTED:
1160     a->roworiented = PETSC_FALSE;
1161     ierr = MatSetOption(a->A,op);CHKERRQ(ierr);
1162     ierr = MatSetOption(a->B,op);CHKERRQ(ierr);
1163     break;
1164   case MAT_IGNORE_OFF_PROC_ENTRIES:
1165     a->donotstash = PETSC_TRUE;
1166     break;
1167   case MAT_NO_NEW_DIAGONALS:
1168     SETERRQ(PETSC_ERR_SUP,"MAT_NO_NEW_DIAGONALS");
1169   case MAT_SYMMETRIC:
1170   case MAT_STRUCTURALLY_SYMMETRIC:
1171   case MAT_HERMITIAN:
1172   case MAT_SYMMETRY_ETERNAL:
1173     ierr = MatSetOption(a->A,op);CHKERRQ(ierr);
1174     break;
1175   case MAT_NOT_SYMMETRIC:
1176   case MAT_NOT_STRUCTURALLY_SYMMETRIC:
1177   case MAT_NOT_HERMITIAN:
1178   case MAT_NOT_SYMMETRY_ETERNAL:
1179     break;
1180   default:
1181     SETERRQ(PETSC_ERR_SUP,"unknown option");
1182   }
1183   PetscFunctionReturn(0);
1184 }
1185 
1186 #undef __FUNCT__
1187 #define __FUNCT__ "MatGetRow_MPIAIJ"
1188 int MatGetRow_MPIAIJ(Mat matin,int row,int *nz,int **idx,PetscScalar **v)
1189 {
1190   Mat_MPIAIJ   *mat = (Mat_MPIAIJ*)matin->data;
1191   PetscScalar  *vworkA,*vworkB,**pvA,**pvB,*v_p;
1192   int          i,ierr,*cworkA,*cworkB,**pcA,**pcB,cstart = mat->cstart;
1193   int          nztot,nzA,nzB,lrow,rstart = mat->rstart,rend = mat->rend;
1194   int          *cmap,*idx_p;
1195 
1196   PetscFunctionBegin;
1197   if (mat->getrowactive == PETSC_TRUE) SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"Already active");
1198   mat->getrowactive = PETSC_TRUE;
1199 
1200   if (!mat->rowvalues && (idx || v)) {
1201     /*
1202         allocate enough space to hold information from the longest row.
1203     */
1204     Mat_SeqAIJ *Aa = (Mat_SeqAIJ*)mat->A->data,*Ba = (Mat_SeqAIJ*)mat->B->data;
1205     int     max = 1,tmp;
1206     for (i=0; i<matin->m; i++) {
1207       tmp = Aa->i[i+1] - Aa->i[i] + Ba->i[i+1] - Ba->i[i];
1208       if (max < tmp) { max = tmp; }
1209     }
1210     ierr = PetscMalloc(max*(sizeof(int)+sizeof(PetscScalar)),&mat->rowvalues);CHKERRQ(ierr);
1211     mat->rowindices = (int*)(mat->rowvalues + max);
1212   }
1213 
1214   if (row < rstart || row >= rend) SETERRQ(PETSC_ERR_ARG_OUTOFRANGE,"Only local rows")
1215   lrow = row - rstart;
1216 
1217   pvA = &vworkA; pcA = &cworkA; pvB = &vworkB; pcB = &cworkB;
1218   if (!v)   {pvA = 0; pvB = 0;}
1219   if (!idx) {pcA = 0; if (!v) pcB = 0;}
1220   ierr = (*mat->A->ops->getrow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1221   ierr = (*mat->B->ops->getrow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1222   nztot = nzA + nzB;
1223 
1224   cmap  = mat->garray;
1225   if (v  || idx) {
1226     if (nztot) {
1227       /* Sort by increasing column numbers, assuming A and B already sorted */
1228       int imark = -1;
1229       if (v) {
1230         *v = v_p = mat->rowvalues;
1231         for (i=0; i<nzB; i++) {
1232           if (cmap[cworkB[i]] < cstart)   v_p[i] = vworkB[i];
1233           else break;
1234         }
1235         imark = i;
1236         for (i=0; i<nzA; i++)     v_p[imark+i] = vworkA[i];
1237         for (i=imark; i<nzB; i++) v_p[nzA+i]   = vworkB[i];
1238       }
1239       if (idx) {
1240         *idx = idx_p = mat->rowindices;
1241         if (imark > -1) {
1242           for (i=0; i<imark; i++) {
1243             idx_p[i] = cmap[cworkB[i]];
1244           }
1245         } else {
1246           for (i=0; i<nzB; i++) {
1247             if (cmap[cworkB[i]] < cstart)   idx_p[i] = cmap[cworkB[i]];
1248             else break;
1249           }
1250           imark = i;
1251         }
1252         for (i=0; i<nzA; i++)     idx_p[imark+i] = cstart + cworkA[i];
1253         for (i=imark; i<nzB; i++) idx_p[nzA+i]   = cmap[cworkB[i]];
1254       }
1255     } else {
1256       if (idx) *idx = 0;
1257       if (v)   *v   = 0;
1258     }
1259   }
1260   *nz = nztot;
1261   ierr = (*mat->A->ops->restorerow)(mat->A,lrow,&nzA,pcA,pvA);CHKERRQ(ierr);
1262   ierr = (*mat->B->ops->restorerow)(mat->B,lrow,&nzB,pcB,pvB);CHKERRQ(ierr);
1263   PetscFunctionReturn(0);
1264 }
1265 
1266 #undef __FUNCT__
1267 #define __FUNCT__ "MatRestoreRow_MPIAIJ"
1268 int MatRestoreRow_MPIAIJ(Mat mat,int row,int *nz,int **idx,PetscScalar **v)
1269 {
1270   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1271 
1272   PetscFunctionBegin;
1273   if (aij->getrowactive == PETSC_FALSE) {
1274     SETERRQ(PETSC_ERR_ARG_WRONGSTATE,"MatGetRow not called");
1275   }
1276   aij->getrowactive = PETSC_FALSE;
1277   PetscFunctionReturn(0);
1278 }
1279 
1280 #undef __FUNCT__
1281 #define __FUNCT__ "MatNorm_MPIAIJ"
1282 int MatNorm_MPIAIJ(Mat mat,NormType type,PetscReal *norm)
1283 {
1284   Mat_MPIAIJ   *aij = (Mat_MPIAIJ*)mat->data;
1285   Mat_SeqAIJ   *amat = (Mat_SeqAIJ*)aij->A->data,*bmat = (Mat_SeqAIJ*)aij->B->data;
1286   int          ierr,i,j,cstart = aij->cstart;
1287   PetscReal    sum = 0.0;
1288   PetscScalar  *v;
1289 
1290   PetscFunctionBegin;
1291   if (aij->size == 1) {
1292     ierr =  MatNorm(aij->A,type,norm);CHKERRQ(ierr);
1293   } else {
1294     if (type == NORM_FROBENIUS) {
1295       v = amat->a;
1296       for (i=0; i<amat->nz; i++) {
1297 #if defined(PETSC_USE_COMPLEX)
1298         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1299 #else
1300         sum += (*v)*(*v); v++;
1301 #endif
1302       }
1303       v = bmat->a;
1304       for (i=0; i<bmat->nz; i++) {
1305 #if defined(PETSC_USE_COMPLEX)
1306         sum += PetscRealPart(PetscConj(*v)*(*v)); v++;
1307 #else
1308         sum += (*v)*(*v); v++;
1309 #endif
1310       }
1311       ierr = MPI_Allreduce(&sum,norm,1,MPIU_REAL,MPI_SUM,mat->comm);CHKERRQ(ierr);
1312       *norm = sqrt(*norm);
1313     } else if (type == NORM_1) { /* max column norm */
1314       PetscReal *tmp,*tmp2;
1315       int    *jj,*garray = aij->garray;
1316       ierr = PetscMalloc((mat->N+1)*sizeof(PetscReal),&tmp);CHKERRQ(ierr);
1317       ierr = PetscMalloc((mat->N+1)*sizeof(PetscReal),&tmp2);CHKERRQ(ierr);
1318       ierr = PetscMemzero(tmp,mat->N*sizeof(PetscReal));CHKERRQ(ierr);
1319       *norm = 0.0;
1320       v = amat->a; jj = amat->j;
1321       for (j=0; j<amat->nz; j++) {
1322         tmp[cstart + *jj++ ] += PetscAbsScalar(*v);  v++;
1323       }
1324       v = bmat->a; jj = bmat->j;
1325       for (j=0; j<bmat->nz; j++) {
1326         tmp[garray[*jj++]] += PetscAbsScalar(*v); v++;
1327       }
1328       ierr = MPI_Allreduce(tmp,tmp2,mat->N,MPIU_REAL,MPI_SUM,mat->comm);CHKERRQ(ierr);
1329       for (j=0; j<mat->N; j++) {
1330         if (tmp2[j] > *norm) *norm = tmp2[j];
1331       }
1332       ierr = PetscFree(tmp);CHKERRQ(ierr);
1333       ierr = PetscFree(tmp2);CHKERRQ(ierr);
1334     } else if (type == NORM_INFINITY) { /* max row norm */
1335       PetscReal ntemp = 0.0;
1336       for (j=0; j<aij->A->m; j++) {
1337         v = amat->a + amat->i[j];
1338         sum = 0.0;
1339         for (i=0; i<amat->i[j+1]-amat->i[j]; i++) {
1340           sum += PetscAbsScalar(*v); v++;
1341         }
1342         v = bmat->a + bmat->i[j];
1343         for (i=0; i<bmat->i[j+1]-bmat->i[j]; i++) {
1344           sum += PetscAbsScalar(*v); v++;
1345         }
1346         if (sum > ntemp) ntemp = sum;
1347       }
1348       ierr = MPI_Allreduce(&ntemp,norm,1,MPIU_REAL,MPI_MAX,mat->comm);CHKERRQ(ierr);
1349     } else {
1350       SETERRQ(PETSC_ERR_SUP,"No support for two norm");
1351     }
1352   }
1353   PetscFunctionReturn(0);
1354 }
1355 
1356 #undef __FUNCT__
1357 #define __FUNCT__ "MatTranspose_MPIAIJ"
1358 int MatTranspose_MPIAIJ(Mat A,Mat *matout)
1359 {
1360   Mat_MPIAIJ   *a = (Mat_MPIAIJ*)A->data;
1361   Mat_SeqAIJ   *Aloc = (Mat_SeqAIJ*)a->A->data;
1362   int          ierr;
1363   int          M = A->M,N = A->N,m,*ai,*aj,row,*cols,i,*ct;
1364   Mat          B;
1365   PetscScalar  *array;
1366 
1367   PetscFunctionBegin;
1368   if (!matout && M != N) {
1369     SETERRQ(PETSC_ERR_ARG_SIZ,"Square matrix only for in-place");
1370   }
1371 
1372   ierr = MatCreate(A->comm,A->n,A->m,N,M,&B);CHKERRQ(ierr);
1373   ierr = MatSetType(B,A->type_name);CHKERRQ(ierr);
1374   ierr = MatMPIAIJSetPreallocation(B,0,PETSC_NULL,0,PETSC_NULL);CHKERRQ(ierr);
1375 
1376   /* copy over the A part */
1377   Aloc = (Mat_SeqAIJ*)a->A->data;
1378   m = a->A->m; ai = Aloc->i; aj = Aloc->j; array = Aloc->a;
1379   row = a->rstart;
1380   for (i=0; i<ai[m]; i++) {aj[i] += a->cstart ;}
1381   for (i=0; i<m; i++) {
1382     ierr = MatSetValues(B,ai[i+1]-ai[i],aj,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1383     row++; array += ai[i+1]-ai[i]; aj += ai[i+1]-ai[i];
1384   }
1385   aj = Aloc->j;
1386   for (i=0; i<ai[m]; i++) {aj[i] -= a->cstart ;}
1387 
1388   /* copy over the B part */
1389   Aloc = (Mat_SeqAIJ*)a->B->data;
1390   m = a->B->m;  ai = Aloc->i; aj = Aloc->j; array = Aloc->a;
1391   row  = a->rstart;
1392   ierr = PetscMalloc((1+ai[m])*sizeof(int),&cols);CHKERRQ(ierr);
1393   ct   = cols;
1394   for (i=0; i<ai[m]; i++) {cols[i] = a->garray[aj[i]];}
1395   for (i=0; i<m; i++) {
1396     ierr = MatSetValues(B,ai[i+1]-ai[i],cols,1,&row,array,INSERT_VALUES);CHKERRQ(ierr);
1397     row++; array += ai[i+1]-ai[i]; cols += ai[i+1]-ai[i];
1398   }
1399   ierr = PetscFree(ct);CHKERRQ(ierr);
1400   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1401   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
1402   if (matout) {
1403     *matout = B;
1404   } else {
1405     ierr = MatHeaderCopy(A,B);CHKERRQ(ierr);
1406   }
1407   PetscFunctionReturn(0);
1408 }
1409 
1410 #undef __FUNCT__
1411 #define __FUNCT__ "MatDiagonalScale_MPIAIJ"
1412 int MatDiagonalScale_MPIAIJ(Mat mat,Vec ll,Vec rr)
1413 {
1414   Mat_MPIAIJ *aij = (Mat_MPIAIJ*)mat->data;
1415   Mat        a = aij->A,b = aij->B;
1416   int        ierr,s1,s2,s3;
1417 
1418   PetscFunctionBegin;
1419   ierr = MatGetLocalSize(mat,&s2,&s3);CHKERRQ(ierr);
1420   if (rr) {
1421     ierr = VecGetLocalSize(rr,&s1);CHKERRQ(ierr);
1422     if (s1!=s3) SETERRQ(PETSC_ERR_ARG_SIZ,"right vector non-conforming local size");
1423     /* Overlap communication with computation. */
1424     ierr = VecScatterBegin(rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD,aij->Mvctx);CHKERRQ(ierr);
1425   }
1426   if (ll) {
1427     ierr = VecGetLocalSize(ll,&s1);CHKERRQ(ierr);
1428     if (s1!=s2) SETERRQ(PETSC_ERR_ARG_SIZ,"left vector non-conforming local size");
1429     ierr = (*b->ops->diagonalscale)(b,ll,0);CHKERRQ(ierr);
1430   }
1431   /* scale  the diagonal block */
1432   ierr = (*a->ops->diagonalscale)(a,ll,rr);CHKERRQ(ierr);
1433 
1434   if (rr) {
1435     /* Do a scatter end and then right scale the off-diagonal block */
1436     ierr = VecScatterEnd(rr,aij->lvec,INSERT_VALUES,SCATTER_FORWARD,aij->Mvctx);CHKERRQ(ierr);
1437     ierr = (*b->ops->diagonalscale)(b,0,aij->lvec);CHKERRQ(ierr);
1438   }
1439 
1440   PetscFunctionReturn(0);
1441 }
1442 
1443 
1444 #undef __FUNCT__
1445 #define __FUNCT__ "MatPrintHelp_MPIAIJ"
1446 int MatPrintHelp_MPIAIJ(Mat A)
1447 {
1448   Mat_MPIAIJ *a   = (Mat_MPIAIJ*)A->data;
1449   int        ierr;
1450 
1451   PetscFunctionBegin;
1452   if (!a->rank) {
1453     ierr = MatPrintHelp_SeqAIJ(a->A);CHKERRQ(ierr);
1454   }
1455   PetscFunctionReturn(0);
1456 }
1457 
1458 #undef __FUNCT__
1459 #define __FUNCT__ "MatGetBlockSize_MPIAIJ"
1460 int MatGetBlockSize_MPIAIJ(Mat A,int *bs)
1461 {
1462   PetscFunctionBegin;
1463   *bs = 1;
1464   PetscFunctionReturn(0);
1465 }
1466 #undef __FUNCT__
1467 #define __FUNCT__ "MatSetUnfactored_MPIAIJ"
1468 int MatSetUnfactored_MPIAIJ(Mat A)
1469 {
1470   Mat_MPIAIJ *a   = (Mat_MPIAIJ*)A->data;
1471   int        ierr;
1472 
1473   PetscFunctionBegin;
1474   ierr = MatSetUnfactored(a->A);CHKERRQ(ierr);
1475   PetscFunctionReturn(0);
1476 }
1477 
1478 #undef __FUNCT__
1479 #define __FUNCT__ "MatEqual_MPIAIJ"
1480 int MatEqual_MPIAIJ(Mat A,Mat B,PetscTruth *flag)
1481 {
1482   Mat_MPIAIJ *matB = (Mat_MPIAIJ*)B->data,*matA = (Mat_MPIAIJ*)A->data;
1483   Mat        a,b,c,d;
1484   PetscTruth flg;
1485   int        ierr;
1486 
1487   PetscFunctionBegin;
1488   a = matA->A; b = matA->B;
1489   c = matB->A; d = matB->B;
1490 
1491   ierr = MatEqual(a,c,&flg);CHKERRQ(ierr);
1492   if (flg == PETSC_TRUE) {
1493     ierr = MatEqual(b,d,&flg);CHKERRQ(ierr);
1494   }
1495   ierr = MPI_Allreduce(&flg,flag,1,MPI_INT,MPI_LAND,A->comm);CHKERRQ(ierr);
1496   PetscFunctionReturn(0);
1497 }
1498 
1499 #undef __FUNCT__
1500 #define __FUNCT__ "MatCopy_MPIAIJ"
1501 int MatCopy_MPIAIJ(Mat A,Mat B,MatStructure str)
1502 {
1503   int        ierr;
1504   Mat_MPIAIJ *a = (Mat_MPIAIJ *)A->data;
1505   Mat_MPIAIJ *b = (Mat_MPIAIJ *)B->data;
1506 
1507   PetscFunctionBegin;
1508   /* If the two matrices don't have the same copy implementation, they aren't compatible for fast copy. */
1509   if ((str != SAME_NONZERO_PATTERN) || (A->ops->copy != B->ops->copy)) {
1510     /* because of the column compression in the off-processor part of the matrix a->B,
1511        the number of columns in a->B and b->B may be different, hence we cannot call
1512        the MatCopy() directly on the two parts. If need be, we can provide a more
1513        efficient copy than the MatCopy_Basic() by first uncompressing the a->B matrices
1514        then copying the submatrices */
1515     ierr = MatCopy_Basic(A,B,str);CHKERRQ(ierr);
1516   } else {
1517     ierr = MatCopy(a->A,b->A,str);CHKERRQ(ierr);
1518     ierr = MatCopy(a->B,b->B,str);CHKERRQ(ierr);
1519   }
1520   PetscFunctionReturn(0);
1521 }
1522 
1523 #undef __FUNCT__
1524 #define __FUNCT__ "MatSetUpPreallocation_MPIAIJ"
1525 int MatSetUpPreallocation_MPIAIJ(Mat A)
1526 {
1527   int        ierr;
1528 
1529   PetscFunctionBegin;
1530   ierr =  MatMPIAIJSetPreallocation(A,PETSC_DEFAULT,0,PETSC_DEFAULT,0);CHKERRQ(ierr);
1531   PetscFunctionReturn(0);
1532 }
1533 
1534 #include "petscblaslapack.h"
1535 #undef __FUNCT__
1536 #define __FUNCT__ "MatAXPY_MPIAIJ"
1537 int MatAXPY_MPIAIJ(const PetscScalar a[],Mat X,Mat Y,MatStructure str)
1538 {
1539   int        ierr,one=1,i;
1540   Mat_MPIAIJ *xx = (Mat_MPIAIJ *)X->data,*yy = (Mat_MPIAIJ *)Y->data;
1541   Mat_SeqAIJ *x,*y;
1542 
1543   PetscFunctionBegin;
1544   if (str == SAME_NONZERO_PATTERN) {
1545     x = (Mat_SeqAIJ *)xx->A->data;
1546     y = (Mat_SeqAIJ *)yy->A->data;
1547     BLaxpy_(&x->nz,(PetscScalar*)a,x->a,&one,y->a,&one);
1548     x = (Mat_SeqAIJ *)xx->B->data;
1549     y = (Mat_SeqAIJ *)yy->B->data;
1550     BLaxpy_(&x->nz,(PetscScalar*)a,x->a,&one,y->a,&one);
1551   } else if (str == SUBSET_NONZERO_PATTERN) {
1552     ierr = MatAXPY_SeqAIJ(a,xx->A,yy->A,str);CHKERRQ(ierr);
1553 
1554     x = (Mat_SeqAIJ *)xx->B->data;
1555     y = (Mat_SeqAIJ *)yy->B->data;
1556     if (y->xtoy && y->XtoY != xx->B) {
1557       ierr = PetscFree(y->xtoy);CHKERRQ(ierr);
1558       ierr = MatDestroy(y->XtoY);CHKERRQ(ierr);
1559     }
1560     if (!y->xtoy) { /* get xtoy */
1561       ierr = MatAXPYGetxtoy_Private(xx->B->m,x->i,x->j,xx->garray,y->i,y->j,yy->garray,&y->xtoy);CHKERRQ(ierr);
1562       y->XtoY = xx->B;
1563     }
1564     for (i=0; i<x->nz; i++) y->a[y->xtoy[i]] += (*a)*(x->a[i]);
1565   } else {
1566     ierr = MatAXPY_Basic(a,X,Y,str);CHKERRQ(ierr);
1567   }
1568   PetscFunctionReturn(0);
1569 }
1570 
1571 /* -------------------------------------------------------------------*/
1572 static struct _MatOps MatOps_Values = {MatSetValues_MPIAIJ,
1573        MatGetRow_MPIAIJ,
1574        MatRestoreRow_MPIAIJ,
1575        MatMult_MPIAIJ,
1576 /* 4*/ MatMultAdd_MPIAIJ,
1577        MatMultTranspose_MPIAIJ,
1578        MatMultTransposeAdd_MPIAIJ,
1579        0,
1580        0,
1581        0,
1582 /*10*/ 0,
1583        0,
1584        0,
1585        MatRelax_MPIAIJ,
1586        MatTranspose_MPIAIJ,
1587 /*15*/ MatGetInfo_MPIAIJ,
1588        MatEqual_MPIAIJ,
1589        MatGetDiagonal_MPIAIJ,
1590        MatDiagonalScale_MPIAIJ,
1591        MatNorm_MPIAIJ,
1592 /*20*/ MatAssemblyBegin_MPIAIJ,
1593        MatAssemblyEnd_MPIAIJ,
1594        0,
1595        MatSetOption_MPIAIJ,
1596        MatZeroEntries_MPIAIJ,
1597 /*25*/ MatZeroRows_MPIAIJ,
1598 #if !defined(PETSC_USE_COMPLEX) && !defined(PETSC_USE_SINGLE)
1599        MatLUFactorSymbolic_MPIAIJ_TFS,
1600 #else
1601        0,
1602 #endif
1603        0,
1604        0,
1605        0,
1606 /*30*/ MatSetUpPreallocation_MPIAIJ,
1607        0,
1608        0,
1609        0,
1610        0,
1611 /*35*/ MatDuplicate_MPIAIJ,
1612        0,
1613        0,
1614        0,
1615        0,
1616 /*40*/ MatAXPY_MPIAIJ,
1617        MatGetSubMatrices_MPIAIJ,
1618        MatIncreaseOverlap_MPIAIJ,
1619        MatGetValues_MPIAIJ,
1620        MatCopy_MPIAIJ,
1621 /*45*/ MatPrintHelp_MPIAIJ,
1622        MatScale_MPIAIJ,
1623        0,
1624        0,
1625        0,
1626 /*50*/ MatGetBlockSize_MPIAIJ,
1627        0,
1628        0,
1629        0,
1630        0,
1631 /*55*/ MatFDColoringCreate_MPIAIJ,
1632        0,
1633        MatSetUnfactored_MPIAIJ,
1634        0,
1635        0,
1636 /*60*/ MatGetSubMatrix_MPIAIJ,
1637        MatDestroy_MPIAIJ,
1638        MatView_MPIAIJ,
1639        MatGetPetscMaps_Petsc,
1640        0,
1641 /*65*/ 0,
1642        0,
1643        0,
1644        0,
1645        0,
1646 /*70*/ 0,
1647        0,
1648        MatSetColoring_MPIAIJ,
1649        MatSetValuesAdic_MPIAIJ,
1650        MatSetValuesAdifor_MPIAIJ,
1651 /*75*/ 0,
1652        0,
1653        0,
1654        0,
1655        0,
1656 /*80*/ 0,
1657        0,
1658        0,
1659        0,
1660 /*85*/ MatLoad_MPIAIJ};
1661 
1662 /* ----------------------------------------------------------------------------------------*/
1663 
1664 EXTERN_C_BEGIN
1665 #undef __FUNCT__
1666 #define __FUNCT__ "MatStoreValues_MPIAIJ"
1667 int MatStoreValues_MPIAIJ(Mat mat)
1668 {
1669   Mat_MPIAIJ *aij = (Mat_MPIAIJ *)mat->data;
1670   int        ierr;
1671 
1672   PetscFunctionBegin;
1673   ierr = MatStoreValues(aij->A);CHKERRQ(ierr);
1674   ierr = MatStoreValues(aij->B);CHKERRQ(ierr);
1675   PetscFunctionReturn(0);
1676 }
1677 EXTERN_C_END
1678 
1679 EXTERN_C_BEGIN
1680 #undef __FUNCT__
1681 #define __FUNCT__ "MatRetrieveValues_MPIAIJ"
1682 int MatRetrieveValues_MPIAIJ(Mat mat)
1683 {
1684   Mat_MPIAIJ *aij = (Mat_MPIAIJ *)mat->data;
1685   int        ierr;
1686 
1687   PetscFunctionBegin;
1688   ierr = MatRetrieveValues(aij->A);CHKERRQ(ierr);
1689   ierr = MatRetrieveValues(aij->B);CHKERRQ(ierr);
1690   PetscFunctionReturn(0);
1691 }
1692 EXTERN_C_END
1693 
1694 #include "petscpc.h"
1695 EXTERN_C_BEGIN
1696 #undef __FUNCT__
1697 #define __FUNCT__ "MatMPIAIJSetPreallocation_MPIAIJ"
1698 int MatMPIAIJSetPreallocation_MPIAIJ(Mat B,int d_nz,const int d_nnz[],int o_nz,const int o_nnz[])
1699 {
1700   Mat_MPIAIJ   *b;
1701   int          ierr,i;
1702 
1703   PetscFunctionBegin;
1704   B->preallocated = PETSC_TRUE;
1705   if (d_nz == PETSC_DEFAULT || d_nz == PETSC_DECIDE) d_nz = 5;
1706   if (o_nz == PETSC_DEFAULT || o_nz == PETSC_DECIDE) o_nz = 2;
1707   if (d_nz < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"d_nz cannot be less than 0: value %d",d_nz);
1708   if (o_nz < 0) SETERRQ1(PETSC_ERR_ARG_OUTOFRANGE,"o_nz cannot be less than 0: value %d",o_nz);
1709   if (d_nnz) {
1710     for (i=0; i<B->m; i++) {
1711       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]);
1712     }
1713   }
1714   if (o_nnz) {
1715     for (i=0; i<B->m; i++) {
1716       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]);
1717     }
1718   }
1719   b = (Mat_MPIAIJ*)B->data;
1720   ierr = MatSeqAIJSetPreallocation(b->A,d_nz,d_nnz);CHKERRQ(ierr);
1721   ierr = MatSeqAIJSetPreallocation(b->B,o_nz,o_nnz);CHKERRQ(ierr);
1722 
1723   PetscFunctionReturn(0);
1724 }
1725 EXTERN_C_END
1726 
1727 /*MC
1728    MATMPIAIJ - MATMPIAIJ = "mpiaij" - A matrix type to be used for parallel sparse matrices.
1729 
1730    Options Database Keys:
1731 . -mat_type mpiaij - sets the matrix type to "mpiaij" during a call to MatSetFromOptions()
1732 
1733   Level: beginner
1734 
1735 .seealso: MatCreateMPIAIJ
1736 M*/
1737 
1738 EXTERN_C_BEGIN
1739 #undef __FUNCT__
1740 #define __FUNCT__ "MatCreate_MPIAIJ"
1741 int MatCreate_MPIAIJ(Mat B)
1742 {
1743   Mat_MPIAIJ *b;
1744   int        ierr,i,size;
1745 
1746   PetscFunctionBegin;
1747   ierr = MPI_Comm_size(B->comm,&size);CHKERRQ(ierr);
1748 
1749   ierr            = PetscNew(Mat_MPIAIJ,&b);CHKERRQ(ierr);
1750   B->data         = (void*)b;
1751   ierr            = PetscMemzero(b,sizeof(Mat_MPIAIJ));CHKERRQ(ierr);
1752   ierr            = PetscMemcpy(B->ops,&MatOps_Values,sizeof(struct _MatOps));CHKERRQ(ierr);
1753   B->factor       = 0;
1754   B->assembled    = PETSC_FALSE;
1755   B->mapping      = 0;
1756 
1757   B->insertmode      = NOT_SET_VALUES;
1758   b->size            = size;
1759   ierr = MPI_Comm_rank(B->comm,&b->rank);CHKERRQ(ierr);
1760 
1761   ierr = PetscSplitOwnership(B->comm,&B->m,&B->M);CHKERRQ(ierr);
1762   ierr = PetscSplitOwnership(B->comm,&B->n,&B->N);CHKERRQ(ierr);
1763 
1764   /* the information in the maps duplicates the information computed below, eventually
1765      we should remove the duplicate information that is not contained in the maps */
1766   ierr = PetscMapCreateMPI(B->comm,B->m,B->M,&B->rmap);CHKERRQ(ierr);
1767   ierr = PetscMapCreateMPI(B->comm,B->n,B->N,&B->cmap);CHKERRQ(ierr);
1768 
1769   /* build local table of row and column ownerships */
1770   ierr = PetscMalloc(2*(b->size+2)*sizeof(int),&b->rowners);CHKERRQ(ierr);
1771   PetscLogObjectMemory(B,2*(b->size+2)*sizeof(int)+sizeof(struct _p_Mat)+sizeof(Mat_MPIAIJ));
1772   b->cowners = b->rowners + b->size + 2;
1773   ierr = MPI_Allgather(&B->m,1,MPI_INT,b->rowners+1,1,MPI_INT,B->comm);CHKERRQ(ierr);
1774   b->rowners[0] = 0;
1775   for (i=2; i<=b->size; i++) {
1776     b->rowners[i] += b->rowners[i-1];
1777   }
1778   b->rstart = b->rowners[b->rank];
1779   b->rend   = b->rowners[b->rank+1];
1780   ierr = MPI_Allgather(&B->n,1,MPI_INT,b->cowners+1,1,MPI_INT,B->comm);CHKERRQ(ierr);
1781   b->cowners[0] = 0;
1782   for (i=2; i<=b->size; i++) {
1783     b->cowners[i] += b->cowners[i-1];
1784   }
1785   b->cstart = b->cowners[b->rank];
1786   b->cend   = b->cowners[b->rank+1];
1787 
1788   /* build cache for off array entries formed */
1789   ierr = MatStashCreate_Private(B->comm,1,&B->stash);CHKERRQ(ierr);
1790   b->donotstash  = PETSC_FALSE;
1791   b->colmap      = 0;
1792   b->garray      = 0;
1793   b->roworiented = PETSC_TRUE;
1794 
1795   /* stuff used for matrix vector multiply */
1796   b->lvec      = PETSC_NULL;
1797   b->Mvctx     = PETSC_NULL;
1798 
1799   /* stuff for MatGetRow() */
1800   b->rowindices   = 0;
1801   b->rowvalues    = 0;
1802   b->getrowactive = PETSC_FALSE;
1803 
1804   /* Explicitly create 2 MATSEQAIJ matrices. */
1805   ierr = MatCreate(PETSC_COMM_SELF,B->m,B->n,B->m,B->n,&b->A);CHKERRQ(ierr);
1806   ierr = MatSetType(b->A,MATSEQAIJ);CHKERRQ(ierr);
1807   PetscLogObjectParent(B,b->A);
1808   ierr = MatCreate(PETSC_COMM_SELF,B->m,B->N,B->m,B->N,&b->B);CHKERRQ(ierr);
1809   ierr = MatSetType(b->B,MATSEQAIJ);CHKERRQ(ierr);
1810   PetscLogObjectParent(B,b->B);
1811 
1812   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatStoreValues_C",
1813                                      "MatStoreValues_MPIAIJ",
1814                                      MatStoreValues_MPIAIJ);CHKERRQ(ierr);
1815   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatRetrieveValues_C",
1816                                      "MatRetrieveValues_MPIAIJ",
1817                                      MatRetrieveValues_MPIAIJ);CHKERRQ(ierr);
1818   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatGetDiagonalBlock_C",
1819 				     "MatGetDiagonalBlock_MPIAIJ",
1820                                      MatGetDiagonalBlock_MPIAIJ);CHKERRQ(ierr);
1821   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatIsTranspose_C",
1822 				     "MatIsTranspose_MPIAIJ",
1823 				     MatIsTranspose_MPIAIJ);CHKERRQ(ierr);
1824   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatMPIAIJSetPreallocation_C",
1825 				     "MatMPIAIJSetPreallocation_MPIAIJ",
1826 				     MatMPIAIJSetPreallocation_MPIAIJ);CHKERRQ(ierr);
1827   ierr = PetscObjectComposeFunctionDynamic((PetscObject)B,"MatDiagonalScaleLocal_C",
1828 				     "MatDiagonalScaleLocal_MPIAIJ",
1829 				     MatDiagonalScaleLocal_MPIAIJ);CHKERRQ(ierr);
1830   PetscFunctionReturn(0);
1831 }
1832 EXTERN_C_END
1833 
1834 /*MC
1835    MATAIJ - MATAIJ = "aij" - A matrix type to be used for sparse matrices.
1836 
1837    This matrix type is identical to MATSEQAIJ when constructed with a single process communicator,
1838    and MATMPIAIJ otherwise.  As a result, for single process communicators,
1839   MatSeqAIJSetPreallocation is supported, and similarly MatMPIAIJSetPreallocation is supported
1840   for communicators controlling multiple processes.  It is recommended that you call both of
1841   the above preallocation routines for simplicity.
1842 
1843    Options Database Keys:
1844 . -mat_type aij - sets the matrix type to "aij" during a call to MatSetFromOptions()
1845 
1846   Level: beginner
1847 
1848 .seealso: MatCreateMPIAIJ,MATSEQAIJ,MATMPIAIJ
1849 M*/
1850 
1851 EXTERN_C_BEGIN
1852 #undef __FUNCT__
1853 #define __FUNCT__ "MatCreate_AIJ"
1854 int MatCreate_AIJ(Mat A) {
1855   int ierr,size;
1856 
1857   PetscFunctionBegin;
1858   ierr = PetscObjectChangeTypeName((PetscObject)A,MATAIJ);CHKERRQ(ierr);
1859   ierr = MPI_Comm_size(A->comm,&size);CHKERRQ(ierr);
1860   if (size == 1) {
1861     ierr = MatSetType(A,MATSEQAIJ);CHKERRQ(ierr);
1862   } else {
1863     ierr = MatSetType(A,MATMPIAIJ);CHKERRQ(ierr);
1864   }
1865   PetscFunctionReturn(0);
1866 }
1867 EXTERN_C_END
1868 
1869 #undef __FUNCT__
1870 #define __FUNCT__ "MatDuplicate_MPIAIJ"
1871 int MatDuplicate_MPIAIJ(Mat matin,MatDuplicateOption cpvalues,Mat *newmat)
1872 {
1873   Mat        mat;
1874   Mat_MPIAIJ *a,*oldmat = (Mat_MPIAIJ*)matin->data;
1875   int        ierr;
1876 
1877   PetscFunctionBegin;
1878   *newmat       = 0;
1879   ierr = MatCreate(matin->comm,matin->m,matin->n,matin->M,matin->N,&mat);CHKERRQ(ierr);
1880   ierr = MatSetType(mat,matin->type_name);CHKERRQ(ierr);
1881   a    = (Mat_MPIAIJ*)mat->data;
1882 
1883   mat->factor       = matin->factor;
1884   mat->assembled    = PETSC_TRUE;
1885   mat->insertmode   = NOT_SET_VALUES;
1886   mat->preallocated = PETSC_TRUE;
1887 
1888   a->rstart       = oldmat->rstart;
1889   a->rend         = oldmat->rend;
1890   a->cstart       = oldmat->cstart;
1891   a->cend         = oldmat->cend;
1892   a->size         = oldmat->size;
1893   a->rank         = oldmat->rank;
1894   a->donotstash   = oldmat->donotstash;
1895   a->roworiented  = oldmat->roworiented;
1896   a->rowindices   = 0;
1897   a->rowvalues    = 0;
1898   a->getrowactive = PETSC_FALSE;
1899 
1900   ierr       = PetscMemcpy(a->rowners,oldmat->rowners,2*(a->size+2)*sizeof(int));CHKERRQ(ierr);
1901   ierr       = MatStashCreate_Private(matin->comm,1,&mat->stash);CHKERRQ(ierr);
1902   if (oldmat->colmap) {
1903 #if defined (PETSC_USE_CTABLE)
1904     ierr = PetscTableCreateCopy(oldmat->colmap,&a->colmap);CHKERRQ(ierr);
1905 #else
1906     ierr = PetscMalloc((mat->N)*sizeof(int),&a->colmap);CHKERRQ(ierr);
1907     PetscLogObjectMemory(mat,(mat->N)*sizeof(int));
1908     ierr      = PetscMemcpy(a->colmap,oldmat->colmap,(mat->N)*sizeof(int));CHKERRQ(ierr);
1909 #endif
1910   } else a->colmap = 0;
1911   if (oldmat->garray) {
1912     int len;
1913     len  = oldmat->B->n;
1914     ierr = PetscMalloc((len+1)*sizeof(int),&a->garray);CHKERRQ(ierr);
1915     PetscLogObjectMemory(mat,len*sizeof(int));
1916     if (len) { ierr = PetscMemcpy(a->garray,oldmat->garray,len*sizeof(int));CHKERRQ(ierr); }
1917   } else a->garray = 0;
1918 
1919   ierr =  VecDuplicate(oldmat->lvec,&a->lvec);CHKERRQ(ierr);
1920   PetscLogObjectParent(mat,a->lvec);
1921   ierr =  VecScatterCopy(oldmat->Mvctx,&a->Mvctx);CHKERRQ(ierr);
1922   PetscLogObjectParent(mat,a->Mvctx);
1923   ierr =  MatDestroy(a->A);CHKERRQ(ierr);
1924   ierr =  MatDuplicate(oldmat->A,cpvalues,&a->A);CHKERRQ(ierr);
1925   PetscLogObjectParent(mat,a->A);
1926   ierr =  MatDestroy(a->B);CHKERRQ(ierr);
1927   ierr =  MatDuplicate(oldmat->B,cpvalues,&a->B);CHKERRQ(ierr);
1928   PetscLogObjectParent(mat,a->B);
1929   ierr = PetscFListDuplicate(matin->qlist,&mat->qlist);CHKERRQ(ierr);
1930   *newmat = mat;
1931   PetscFunctionReturn(0);
1932 }
1933 
1934 #include "petscsys.h"
1935 
1936 #undef __FUNCT__
1937 #define __FUNCT__ "MatLoad_MPIAIJ"
1938 int MatLoad_MPIAIJ(PetscViewer viewer,const MatType type,Mat *newmat)
1939 {
1940   Mat          A;
1941   PetscScalar  *vals,*svals;
1942   MPI_Comm     comm = ((PetscObject)viewer)->comm;
1943   MPI_Status   status;
1944   int          i,nz,ierr,j,rstart,rend,fd;
1945   int          header[4],rank,size,*rowlengths = 0,M,N,m,*rowners,maxnz,*cols;
1946   int          *ourlens,*sndcounts = 0,*procsnz = 0,*offlens,jj,*mycols,*smycols;
1947   int          tag = ((PetscObject)viewer)->tag,cend,cstart,n;
1948 
1949   PetscFunctionBegin;
1950   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
1951   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
1952   if (!rank) {
1953     ierr = PetscViewerBinaryGetDescriptor(viewer,&fd);CHKERRQ(ierr);
1954     ierr = PetscBinaryRead(fd,(char *)header,4,PETSC_INT);CHKERRQ(ierr);
1955     if (header[0] != MAT_FILE_COOKIE) SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"not matrix object");
1956     if (header[3] < 0) {
1957       SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"Matrix in special format on disk, cannot load as MPIAIJ");
1958     }
1959   }
1960 
1961   ierr = MPI_Bcast(header+1,3,MPI_INT,0,comm);CHKERRQ(ierr);
1962   M = header[1]; N = header[2];
1963   /* determine ownership of all rows */
1964   m = M/size + ((M % size) > rank);
1965   ierr = PetscMalloc((size+2)*sizeof(int),&rowners);CHKERRQ(ierr);
1966   ierr = MPI_Allgather(&m,1,MPI_INT,rowners+1,1,MPI_INT,comm);CHKERRQ(ierr);
1967   rowners[0] = 0;
1968   for (i=2; i<=size; i++) {
1969     rowners[i] += rowners[i-1];
1970   }
1971   rstart = rowners[rank];
1972   rend   = rowners[rank+1];
1973 
1974   /* distribute row lengths to all processors */
1975   ierr    = PetscMalloc(2*(rend-rstart+1)*sizeof(int),&ourlens);CHKERRQ(ierr);
1976   offlens = ourlens + (rend-rstart);
1977   if (!rank) {
1978     ierr = PetscMalloc(M*sizeof(int),&rowlengths);CHKERRQ(ierr);
1979     ierr = PetscBinaryRead(fd,rowlengths,M,PETSC_INT);CHKERRQ(ierr);
1980     ierr = PetscMalloc(size*sizeof(int),&sndcounts);CHKERRQ(ierr);
1981     for (i=0; i<size; i++) sndcounts[i] = rowners[i+1] - rowners[i];
1982     ierr = MPI_Scatterv(rowlengths,sndcounts,rowners,MPI_INT,ourlens,rend-rstart,MPI_INT,0,comm);CHKERRQ(ierr);
1983     ierr = PetscFree(sndcounts);CHKERRQ(ierr);
1984   } else {
1985     ierr = MPI_Scatterv(0,0,0,MPI_INT,ourlens,rend-rstart,MPI_INT,0,comm);CHKERRQ(ierr);
1986   }
1987 
1988   if (!rank) {
1989     /* calculate the number of nonzeros on each processor */
1990     ierr = PetscMalloc(size*sizeof(int),&procsnz);CHKERRQ(ierr);
1991     ierr = PetscMemzero(procsnz,size*sizeof(int));CHKERRQ(ierr);
1992     for (i=0; i<size; i++) {
1993       for (j=rowners[i]; j< rowners[i+1]; j++) {
1994         procsnz[i] += rowlengths[j];
1995       }
1996     }
1997     ierr = PetscFree(rowlengths);CHKERRQ(ierr);
1998 
1999     /* determine max buffer needed and allocate it */
2000     maxnz = 0;
2001     for (i=0; i<size; i++) {
2002       maxnz = PetscMax(maxnz,procsnz[i]);
2003     }
2004     ierr = PetscMalloc(maxnz*sizeof(int),&cols);CHKERRQ(ierr);
2005 
2006     /* read in my part of the matrix column indices  */
2007     nz   = procsnz[0];
2008     ierr = PetscMalloc(nz*sizeof(int),&mycols);CHKERRQ(ierr);
2009     ierr = PetscBinaryRead(fd,mycols,nz,PETSC_INT);CHKERRQ(ierr);
2010 
2011     /* read in every one elses and ship off */
2012     for (i=1; i<size; i++) {
2013       nz   = procsnz[i];
2014       ierr = PetscBinaryRead(fd,cols,nz,PETSC_INT);CHKERRQ(ierr);
2015       ierr = MPI_Send(cols,nz,MPI_INT,i,tag,comm);CHKERRQ(ierr);
2016     }
2017     ierr = PetscFree(cols);CHKERRQ(ierr);
2018   } else {
2019     /* determine buffer space needed for message */
2020     nz = 0;
2021     for (i=0; i<m; i++) {
2022       nz += ourlens[i];
2023     }
2024     ierr = PetscMalloc((nz+1)*sizeof(int),&mycols);CHKERRQ(ierr);
2025 
2026     /* receive message of column indices*/
2027     ierr = MPI_Recv(mycols,nz,MPI_INT,0,tag,comm,&status);CHKERRQ(ierr);
2028     ierr = MPI_Get_count(&status,MPI_INT,&maxnz);CHKERRQ(ierr);
2029     if (maxnz != nz) SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"something is wrong with file");
2030   }
2031 
2032   /* determine column ownership if matrix is not square */
2033   if (N != M) {
2034     n      = N/size + ((N % size) > rank);
2035     ierr   = MPI_Scan(&n,&cend,1,MPI_INT,MPI_SUM,comm);CHKERRQ(ierr);
2036     cstart = cend - n;
2037   } else {
2038     cstart = rstart;
2039     cend   = rend;
2040     n      = cend - cstart;
2041   }
2042 
2043   /* loop over local rows, determining number of off diagonal entries */
2044   ierr = PetscMemzero(offlens,m*sizeof(int));CHKERRQ(ierr);
2045   jj = 0;
2046   for (i=0; i<m; i++) {
2047     for (j=0; j<ourlens[i]; j++) {
2048       if (mycols[jj] < cstart || mycols[jj] >= cend) offlens[i]++;
2049       jj++;
2050     }
2051   }
2052 
2053   /* create our matrix */
2054   for (i=0; i<m; i++) {
2055     ourlens[i] -= offlens[i];
2056   }
2057   ierr = MatCreate(comm,m,n,M,N,&A);CHKERRQ(ierr);
2058   ierr = MatSetType(A,type);CHKERRQ(ierr);
2059   ierr = MatMPIAIJSetPreallocation(A,0,ourlens,0,offlens);CHKERRQ(ierr);
2060 
2061   ierr = MatSetOption(A,MAT_COLUMNS_SORTED);CHKERRQ(ierr);
2062   for (i=0; i<m; i++) {
2063     ourlens[i] += offlens[i];
2064   }
2065 
2066   if (!rank) {
2067     ierr = PetscMalloc(maxnz*sizeof(PetscScalar),&vals);CHKERRQ(ierr);
2068 
2069     /* read in my part of the matrix numerical values  */
2070     nz   = procsnz[0];
2071     ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2072 
2073     /* insert into matrix */
2074     jj      = rstart;
2075     smycols = mycols;
2076     svals   = vals;
2077     for (i=0; i<m; i++) {
2078       ierr = MatSetValues(A,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2079       smycols += ourlens[i];
2080       svals   += ourlens[i];
2081       jj++;
2082     }
2083 
2084     /* read in other processors and ship out */
2085     for (i=1; i<size; i++) {
2086       nz   = procsnz[i];
2087       ierr = PetscBinaryRead(fd,vals,nz,PETSC_SCALAR);CHKERRQ(ierr);
2088       ierr = MPI_Send(vals,nz,MPIU_SCALAR,i,A->tag,comm);CHKERRQ(ierr);
2089     }
2090     ierr = PetscFree(procsnz);CHKERRQ(ierr);
2091   } else {
2092     /* receive numeric values */
2093     ierr = PetscMalloc((nz+1)*sizeof(PetscScalar),&vals);CHKERRQ(ierr);
2094 
2095     /* receive message of values*/
2096     ierr = MPI_Recv(vals,nz,MPIU_SCALAR,0,A->tag,comm,&status);CHKERRQ(ierr);
2097     ierr = MPI_Get_count(&status,MPIU_SCALAR,&maxnz);CHKERRQ(ierr);
2098     if (maxnz != nz) SETERRQ(PETSC_ERR_FILE_UNEXPECTED,"something is wrong with file");
2099 
2100     /* insert into matrix */
2101     jj      = rstart;
2102     smycols = mycols;
2103     svals   = vals;
2104     for (i=0; i<m; i++) {
2105       ierr     = MatSetValues(A,1,&jj,ourlens[i],smycols,svals,INSERT_VALUES);CHKERRQ(ierr);
2106       smycols += ourlens[i];
2107       svals   += ourlens[i];
2108       jj++;
2109     }
2110   }
2111   ierr = PetscFree(ourlens);CHKERRQ(ierr);
2112   ierr = PetscFree(vals);CHKERRQ(ierr);
2113   ierr = PetscFree(mycols);CHKERRQ(ierr);
2114   ierr = PetscFree(rowners);CHKERRQ(ierr);
2115 
2116   ierr = MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2117   ierr = MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2118   *newmat = A;
2119   PetscFunctionReturn(0);
2120 }
2121 
2122 #undef __FUNCT__
2123 #define __FUNCT__ "MatGetSubMatrix_MPIAIJ"
2124 /*
2125     Not great since it makes two copies of the submatrix, first an SeqAIJ
2126   in local and then by concatenating the local matrices the end result.
2127   Writing it directly would be much like MatGetSubMatrices_MPIAIJ()
2128 */
2129 int MatGetSubMatrix_MPIAIJ(Mat mat,IS isrow,IS iscol,int csize,MatReuse call,Mat *newmat)
2130 {
2131   int          ierr,i,m,n,rstart,row,rend,nz,*cwork,size,rank,j;
2132   int          *ii,*jj,nlocal,*dlens,*olens,dlen,olen,jend,mglobal;
2133   Mat          *local,M,Mreuse;
2134   PetscScalar  *vwork,*aa;
2135   MPI_Comm     comm = mat->comm;
2136   Mat_SeqAIJ   *aij;
2137 
2138 
2139   PetscFunctionBegin;
2140   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
2141   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2142 
2143   if (call ==  MAT_REUSE_MATRIX) {
2144     ierr = PetscObjectQuery((PetscObject)*newmat,"SubMatrix",(PetscObject *)&Mreuse);CHKERRQ(ierr);
2145     if (!Mreuse) SETERRQ(1,"Submatrix passed in was not used before, cannot reuse");
2146     local = &Mreuse;
2147     ierr  = MatGetSubMatrices(mat,1,&isrow,&iscol,MAT_REUSE_MATRIX,&local);CHKERRQ(ierr);
2148   } else {
2149     ierr   = MatGetSubMatrices(mat,1,&isrow,&iscol,MAT_INITIAL_MATRIX,&local);CHKERRQ(ierr);
2150     Mreuse = *local;
2151     ierr   = PetscFree(local);CHKERRQ(ierr);
2152   }
2153 
2154   /*
2155       m - number of local rows
2156       n - number of columns (same on all processors)
2157       rstart - first row in new global matrix generated
2158   */
2159   ierr = MatGetSize(Mreuse,&m,&n);CHKERRQ(ierr);
2160   if (call == MAT_INITIAL_MATRIX) {
2161     aij = (Mat_SeqAIJ*)(Mreuse)->data;
2162     ii  = aij->i;
2163     jj  = aij->j;
2164 
2165     /*
2166         Determine the number of non-zeros in the diagonal and off-diagonal
2167         portions of the matrix in order to do correct preallocation
2168     */
2169 
2170     /* first get start and end of "diagonal" columns */
2171     if (csize == PETSC_DECIDE) {
2172       ierr = ISGetSize(isrow,&mglobal);CHKERRQ(ierr);
2173       if (mglobal == n) { /* square matrix */
2174 	nlocal = m;
2175       } else {
2176         nlocal = n/size + ((n % size) > rank);
2177       }
2178     } else {
2179       nlocal = csize;
2180     }
2181     ierr   = MPI_Scan(&nlocal,&rend,1,MPI_INT,MPI_SUM,comm);CHKERRQ(ierr);
2182     rstart = rend - nlocal;
2183     if (rank == size - 1 && rend != n) {
2184       SETERRQ2(1,"Local column sizes %d do not add up to total number of columns %d",rend,n);
2185     }
2186 
2187     /* next, compute all the lengths */
2188     ierr  = PetscMalloc((2*m+1)*sizeof(int),&dlens);CHKERRQ(ierr);
2189     olens = dlens + m;
2190     for (i=0; i<m; i++) {
2191       jend = ii[i+1] - ii[i];
2192       olen = 0;
2193       dlen = 0;
2194       for (j=0; j<jend; j++) {
2195         if (*jj < rstart || *jj >= rend) olen++;
2196         else dlen++;
2197         jj++;
2198       }
2199       olens[i] = olen;
2200       dlens[i] = dlen;
2201     }
2202     ierr = MatCreate(comm,m,nlocal,PETSC_DECIDE,n,&M);CHKERRQ(ierr);
2203     ierr = MatSetType(M,mat->type_name);CHKERRQ(ierr);
2204     ierr = MatMPIAIJSetPreallocation(M,0,dlens,0,olens);CHKERRQ(ierr);
2205     ierr = PetscFree(dlens);CHKERRQ(ierr);
2206   } else {
2207     int ml,nl;
2208 
2209     M = *newmat;
2210     ierr = MatGetLocalSize(M,&ml,&nl);CHKERRQ(ierr);
2211     if (ml != m) SETERRQ(PETSC_ERR_ARG_SIZ,"Previous matrix must be same size/layout as request");
2212     ierr = MatZeroEntries(M);CHKERRQ(ierr);
2213     /*
2214          The next two lines are needed so we may call MatSetValues_MPIAIJ() below directly,
2215        rather than the slower MatSetValues().
2216     */
2217     M->was_assembled = PETSC_TRUE;
2218     M->assembled     = PETSC_FALSE;
2219   }
2220   ierr = MatGetOwnershipRange(M,&rstart,&rend);CHKERRQ(ierr);
2221   aij = (Mat_SeqAIJ*)(Mreuse)->data;
2222   ii  = aij->i;
2223   jj  = aij->j;
2224   aa  = aij->a;
2225   for (i=0; i<m; i++) {
2226     row   = rstart + i;
2227     nz    = ii[i+1] - ii[i];
2228     cwork = jj;     jj += nz;
2229     vwork = aa;     aa += nz;
2230     ierr = MatSetValues_MPIAIJ(M,1,&row,nz,cwork,vwork,INSERT_VALUES);CHKERRQ(ierr);
2231   }
2232 
2233   ierr = MatAssemblyBegin(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2234   ierr = MatAssemblyEnd(M,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2235   *newmat = M;
2236 
2237   /* save submatrix used in processor for next request */
2238   if (call ==  MAT_INITIAL_MATRIX) {
2239     ierr = PetscObjectCompose((PetscObject)M,"SubMatrix",(PetscObject)Mreuse);CHKERRQ(ierr);
2240     ierr = PetscObjectDereference((PetscObject)Mreuse);CHKERRQ(ierr);
2241   }
2242 
2243   PetscFunctionReturn(0);
2244 }
2245 
2246 #undef __FUNCT__
2247 #define __FUNCT__ "MatMPIAIJSetPreallocation"
2248 /*@C
2249    MatMPIAIJSetPreallocation - Creates a sparse parallel matrix in AIJ format
2250    (the default parallel PETSc format).  For good matrix assembly performance
2251    the user should preallocate the matrix storage by setting the parameters
2252    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
2253    performance can be increased by more than a factor of 50.
2254 
2255    Collective on MPI_Comm
2256 
2257    Input Parameters:
2258 +  A - the matrix
2259 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
2260            (same value is used for all local rows)
2261 .  d_nnz - array containing the number of nonzeros in the various rows of the
2262            DIAGONAL portion of the local submatrix (possibly different for each row)
2263            or PETSC_NULL, if d_nz is used to specify the nonzero structure.
2264            The size of this array is equal to the number of local rows, i.e 'm'.
2265            You must leave room for the diagonal entry even if it is zero.
2266 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
2267            submatrix (same value is used for all local rows).
2268 -  o_nnz - array containing the number of nonzeros in the various rows of the
2269            OFF-DIAGONAL portion of the local submatrix (possibly different for
2270            each row) or PETSC_NULL, if o_nz is used to specify the nonzero
2271            structure. The size of this array is equal to the number
2272            of local rows, i.e 'm'.
2273 
2274    The AIJ format (also called the Yale sparse matrix format or
2275    compressed row storage), is fully compatible with standard Fortran 77
2276    storage.  That is, the stored row and column indices can begin at
2277    either one (as in Fortran) or zero.  See the users manual for details.
2278 
2279    The user MUST specify either the local or global matrix dimensions
2280    (possibly both).
2281 
2282    The parallel matrix is partitioned such that the first m0 rows belong to
2283    process 0, the next m1 rows belong to process 1, the next m2 rows belong
2284    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.
2285 
2286    The DIAGONAL portion of the local submatrix of a processor can be defined
2287    as the submatrix which is obtained by extraction the part corresponding
2288    to the rows r1-r2 and columns r1-r2 of the global matrix, where r1 is the
2289    first row that belongs to the processor, and r2 is the last row belonging
2290    to the this processor. This is a square mxm matrix. The remaining portion
2291    of the local submatrix (mxN) constitute the OFF-DIAGONAL portion.
2292 
2293    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
2294 
2295    By default, this format uses inodes (identical nodes) when possible.
2296    We search for consecutive rows with the same nonzero structure, thereby
2297    reusing matrix information to achieve increased efficiency.
2298 
2299    Options Database Keys:
2300 +  -mat_aij_no_inode  - Do not use inodes
2301 .  -mat_aij_inode_limit <limit> - Sets inode limit (max limit=5)
2302 -  -mat_aij_oneindex - Internally use indexing starting at 1
2303         rather than 0.  Note that when calling MatSetValues(),
2304         the user still MUST index entries starting at 0!
2305 
2306    Example usage:
2307 
2308    Consider the following 8x8 matrix with 34 non-zero values, that is
2309    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
2310    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
2311    as follows:
2312 
2313 .vb
2314             1  2  0  |  0  3  0  |  0  4
2315     Proc0   0  5  6  |  7  0  0  |  8  0
2316             9  0 10  | 11  0  0  | 12  0
2317     -------------------------------------
2318            13  0 14  | 15 16 17  |  0  0
2319     Proc1   0 18  0  | 19 20 21  |  0  0
2320             0  0  0  | 22 23  0  | 24  0
2321     -------------------------------------
2322     Proc2  25 26 27  |  0  0 28  | 29  0
2323            30  0  0  | 31 32 33  |  0 34
2324 .ve
2325 
2326    This can be represented as a collection of submatrices as:
2327 
2328 .vb
2329       A B C
2330       D E F
2331       G H I
2332 .ve
2333 
2334    Where the submatrices A,B,C are owned by proc0, D,E,F are
2335    owned by proc1, G,H,I are owned by proc2.
2336 
2337    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2338    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2339    The 'M','N' parameters are 8,8, and have the same values on all procs.
2340 
2341    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
2342    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
2343    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
2344    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
2345    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
2346    matrix, ans [DF] as another SeqAIJ matrix.
2347 
2348    When d_nz, o_nz parameters are specified, d_nz storage elements are
2349    allocated for every row of the local diagonal submatrix, and o_nz
2350    storage locations are allocated for every row of the OFF-DIAGONAL submat.
2351    One way to choose d_nz and o_nz is to use the max nonzerors per local
2352    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
2353    In this case, the values of d_nz,o_nz are:
2354 .vb
2355      proc0 : dnz = 2, o_nz = 2
2356      proc1 : dnz = 3, o_nz = 2
2357      proc2 : dnz = 1, o_nz = 4
2358 .ve
2359    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
2360    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
2361    for proc3. i.e we are using 12+15+10=37 storage locations to store
2362    34 values.
2363 
2364    When d_nnz, o_nnz parameters are specified, the storage is specified
2365    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
2366    In the above case the values for d_nnz,o_nnz are:
2367 .vb
2368      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
2369      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
2370      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
2371 .ve
2372    Here the space allocated is sum of all the above values i.e 34, and
2373    hence pre-allocation is perfect.
2374 
2375    Level: intermediate
2376 
2377 .keywords: matrix, aij, compressed row, sparse, parallel
2378 
2379 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues()
2380 @*/
2381 int MatMPIAIJSetPreallocation(Mat B,int d_nz,const int d_nnz[],int o_nz,const int o_nnz[])
2382 {
2383   int ierr,(*f)(Mat,int,const int[],int,const int[]);
2384 
2385   PetscFunctionBegin;
2386   ierr = PetscObjectQueryFunction((PetscObject)B,"MatMPIAIJSetPreallocation_C",(void (**)(void))&f);CHKERRQ(ierr);
2387   if (f) {
2388     ierr = (*f)(B,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
2389   }
2390   PetscFunctionReturn(0);
2391 }
2392 
2393 #undef __FUNCT__
2394 #define __FUNCT__ "MatCreateMPIAIJ"
2395 /*@C
2396    MatCreateMPIAIJ - Creates a sparse parallel matrix in AIJ format
2397    (the default parallel PETSc format).  For good matrix assembly performance
2398    the user should preallocate the matrix storage by setting the parameters
2399    d_nz (or d_nnz) and o_nz (or o_nnz).  By setting these parameters accurately,
2400    performance can be increased by more than a factor of 50.
2401 
2402    Collective on MPI_Comm
2403 
2404    Input Parameters:
2405 +  comm - MPI communicator
2406 .  m - number of local rows (or PETSC_DECIDE to have calculated if M is given)
2407            This value should be the same as the local size used in creating the
2408            y vector for the matrix-vector product y = Ax.
2409 .  n - This value should be the same as the local size used in creating the
2410        x vector for the matrix-vector product y = Ax. (or PETSC_DECIDE to have
2411        calculated if N is given) For square matrices n is almost always m.
2412 .  M - number of global rows (or PETSC_DETERMINE to have calculated if m is given)
2413 .  N - number of global columns (or PETSC_DETERMINE to have calculated if n is given)
2414 .  d_nz  - number of nonzeros per row in DIAGONAL portion of local submatrix
2415            (same value is used for all local rows)
2416 .  d_nnz - array containing the number of nonzeros in the various rows of the
2417            DIAGONAL portion of the local submatrix (possibly different for each row)
2418            or PETSC_NULL, if d_nz is used to specify the nonzero structure.
2419            The size of this array is equal to the number of local rows, i.e 'm'.
2420            You must leave room for the diagonal entry even if it is zero.
2421 .  o_nz  - number of nonzeros per row in the OFF-DIAGONAL portion of local
2422            submatrix (same value is used for all local rows).
2423 -  o_nnz - array containing the number of nonzeros in the various rows of the
2424            OFF-DIAGONAL portion of the local submatrix (possibly different for
2425            each row) or PETSC_NULL, if o_nz is used to specify the nonzero
2426            structure. The size of this array is equal to the number
2427            of local rows, i.e 'm'.
2428 
2429    Output Parameter:
2430 .  A - the matrix
2431 
2432    Notes:
2433    m,n,M,N parameters specify the size of the matrix, and its partitioning across
2434    processors, while d_nz,d_nnz,o_nz,o_nnz parameters specify the approximate
2435    storage requirements for this matrix.
2436 
2437    If PETSC_DECIDE or  PETSC_DETERMINE is used for a particular argument on one
2438    processor than it must be used on all processors that share the object for
2439    that argument.
2440 
2441    The AIJ format (also called the Yale sparse matrix format or
2442    compressed row storage), is fully compatible with standard Fortran 77
2443    storage.  That is, the stored row and column indices can begin at
2444    either one (as in Fortran) or zero.  See the users manual for details.
2445 
2446    The user MUST specify either the local or global matrix dimensions
2447    (possibly both).
2448 
2449    The parallel matrix is partitioned such that the first m0 rows belong to
2450    process 0, the next m1 rows belong to process 1, the next m2 rows belong
2451    to process 2 etc.. where m0,m1,m2... are the input parameter 'm'.
2452 
2453    The DIAGONAL portion of the local submatrix of a processor can be defined
2454    as the submatrix which is obtained by extraction the part corresponding
2455    to the rows r1-r2 and columns r1-r2 of the global matrix, where r1 is the
2456    first row that belongs to the processor, and r2 is the last row belonging
2457    to the this processor. This is a square mxm matrix. The remaining portion
2458    of the local submatrix (mxN) constitute the OFF-DIAGONAL portion.
2459 
2460    If o_nnz, d_nnz are specified, then o_nz, and d_nz are ignored.
2461 
2462    When calling this routine with a single process communicator, a matrix of
2463    type SEQAIJ is returned.  If a matrix of type MPIAIJ is desired for this
2464    type of communicator, use the construction mechanism:
2465      MatCreate(...,&A); MatSetType(A,MPIAIJ); MatMPIAIJSetPreallocation(A,...);
2466 
2467    By default, this format uses inodes (identical nodes) when possible.
2468    We search for consecutive rows with the same nonzero structure, thereby
2469    reusing matrix information to achieve increased efficiency.
2470 
2471    Options Database Keys:
2472 +  -mat_aij_no_inode  - Do not use inodes
2473 .  -mat_aij_inode_limit <limit> - Sets inode limit (max limit=5)
2474 -  -mat_aij_oneindex - Internally use indexing starting at 1
2475         rather than 0.  Note that when calling MatSetValues(),
2476         the user still MUST index entries starting at 0!
2477 
2478 
2479    Example usage:
2480 
2481    Consider the following 8x8 matrix with 34 non-zero values, that is
2482    assembled across 3 processors. Lets assume that proc0 owns 3 rows,
2483    proc1 owns 3 rows, proc2 owns 2 rows. This division can be shown
2484    as follows:
2485 
2486 .vb
2487             1  2  0  |  0  3  0  |  0  4
2488     Proc0   0  5  6  |  7  0  0  |  8  0
2489             9  0 10  | 11  0  0  | 12  0
2490     -------------------------------------
2491            13  0 14  | 15 16 17  |  0  0
2492     Proc1   0 18  0  | 19 20 21  |  0  0
2493             0  0  0  | 22 23  0  | 24  0
2494     -------------------------------------
2495     Proc2  25 26 27  |  0  0 28  | 29  0
2496            30  0  0  | 31 32 33  |  0 34
2497 .ve
2498 
2499    This can be represented as a collection of submatrices as:
2500 
2501 .vb
2502       A B C
2503       D E F
2504       G H I
2505 .ve
2506 
2507    Where the submatrices A,B,C are owned by proc0, D,E,F are
2508    owned by proc1, G,H,I are owned by proc2.
2509 
2510    The 'm' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2511    The 'n' parameters for proc0,proc1,proc2 are 3,3,2 respectively.
2512    The 'M','N' parameters are 8,8, and have the same values on all procs.
2513 
2514    The DIAGONAL submatrices corresponding to proc0,proc1,proc2 are
2515    submatrices [A], [E], [I] respectively. The OFF-DIAGONAL submatrices
2516    corresponding to proc0,proc1,proc2 are [BC], [DF], [GH] respectively.
2517    Internally, each processor stores the DIAGONAL part, and the OFF-DIAGONAL
2518    part as SeqAIJ matrices. for eg: proc1 will store [E] as a SeqAIJ
2519    matrix, ans [DF] as another SeqAIJ matrix.
2520 
2521    When d_nz, o_nz parameters are specified, d_nz storage elements are
2522    allocated for every row of the local diagonal submatrix, and o_nz
2523    storage locations are allocated for every row of the OFF-DIAGONAL submat.
2524    One way to choose d_nz and o_nz is to use the max nonzerors per local
2525    rows for each of the local DIAGONAL, and the OFF-DIAGONAL submatrices.
2526    In this case, the values of d_nz,o_nz are:
2527 .vb
2528      proc0 : dnz = 2, o_nz = 2
2529      proc1 : dnz = 3, o_nz = 2
2530      proc2 : dnz = 1, o_nz = 4
2531 .ve
2532    We are allocating m*(d_nz+o_nz) storage locations for every proc. This
2533    translates to 3*(2+2)=12 for proc0, 3*(3+2)=15 for proc1, 2*(1+4)=10
2534    for proc3. i.e we are using 12+15+10=37 storage locations to store
2535    34 values.
2536 
2537    When d_nnz, o_nnz parameters are specified, the storage is specified
2538    for every row, coresponding to both DIAGONAL and OFF-DIAGONAL submatrices.
2539    In the above case the values for d_nnz,o_nnz are:
2540 .vb
2541      proc0: d_nnz = [2,2,2] and o_nnz = [2,2,2]
2542      proc1: d_nnz = [3,3,2] and o_nnz = [2,1,1]
2543      proc2: d_nnz = [1,1]   and o_nnz = [4,4]
2544 .ve
2545    Here the space allocated is sum of all the above values i.e 34, and
2546    hence pre-allocation is perfect.
2547 
2548    Level: intermediate
2549 
2550 .keywords: matrix, aij, compressed row, sparse, parallel
2551 
2552 .seealso: MatCreate(), MatCreateSeqAIJ(), MatSetValues()
2553 @*/
2554 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)
2555 {
2556   int ierr,size;
2557 
2558   PetscFunctionBegin;
2559   ierr = MatCreate(comm,m,n,M,N,A);CHKERRQ(ierr);
2560   ierr = MPI_Comm_size(comm,&size);CHKERRQ(ierr);
2561   if (size > 1) {
2562     ierr = MatSetType(*A,MATMPIAIJ);CHKERRQ(ierr);
2563     ierr = MatMPIAIJSetPreallocation(*A,d_nz,d_nnz,o_nz,o_nnz);CHKERRQ(ierr);
2564   } else {
2565     ierr = MatSetType(*A,MATSEQAIJ);CHKERRQ(ierr);
2566     ierr = MatSeqAIJSetPreallocation(*A,d_nz,d_nnz);CHKERRQ(ierr);
2567   }
2568   PetscFunctionReturn(0);
2569 }
2570 
2571 #undef __FUNCT__
2572 #define __FUNCT__ "MatMPIAIJGetSeqAIJ"
2573 int MatMPIAIJGetSeqAIJ(Mat A,Mat *Ad,Mat *Ao,int *colmap[])
2574 {
2575   Mat_MPIAIJ *a = (Mat_MPIAIJ *)A->data;
2576   PetscFunctionBegin;
2577   *Ad     = a->A;
2578   *Ao     = a->B;
2579   *colmap = a->garray;
2580   PetscFunctionReturn(0);
2581 }
2582 
2583 #undef __FUNCT__
2584 #define __FUNCT__ "MatSetColoring_MPIAIJ"
2585 int MatSetColoring_MPIAIJ(Mat A,ISColoring coloring)
2586 {
2587   int        ierr,i;
2588   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
2589 
2590   PetscFunctionBegin;
2591   if (coloring->ctype == IS_COLORING_LOCAL) {
2592     ISColoringValue *allcolors,*colors;
2593     ISColoring      ocoloring;
2594 
2595     /* set coloring for diagonal portion */
2596     ierr = MatSetColoring_SeqAIJ(a->A,coloring);CHKERRQ(ierr);
2597 
2598     /* set coloring for off-diagonal portion */
2599     ierr = ISAllGatherColors(A->comm,coloring->n,coloring->colors,PETSC_NULL,&allcolors);CHKERRQ(ierr);
2600     ierr = PetscMalloc((a->B->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
2601     for (i=0; i<a->B->n; i++) {
2602       colors[i] = allcolors[a->garray[i]];
2603     }
2604     ierr = PetscFree(allcolors);CHKERRQ(ierr);
2605     ierr = ISColoringCreate(MPI_COMM_SELF,a->B->n,colors,&ocoloring);CHKERRQ(ierr);
2606     ierr = MatSetColoring_SeqAIJ(a->B,ocoloring);CHKERRQ(ierr);
2607     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
2608   } else if (coloring->ctype == IS_COLORING_GHOSTED) {
2609     ISColoringValue *colors;
2610     int             *larray;
2611     ISColoring      ocoloring;
2612 
2613     /* set coloring for diagonal portion */
2614     ierr = PetscMalloc((a->A->n+1)*sizeof(int),&larray);CHKERRQ(ierr);
2615     for (i=0; i<a->A->n; i++) {
2616       larray[i] = i + a->cstart;
2617     }
2618     ierr = ISGlobalToLocalMappingApply(A->mapping,IS_GTOLM_MASK,a->A->n,larray,PETSC_NULL,larray);CHKERRQ(ierr);
2619     ierr = PetscMalloc((a->A->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
2620     for (i=0; i<a->A->n; i++) {
2621       colors[i] = coloring->colors[larray[i]];
2622     }
2623     ierr = PetscFree(larray);CHKERRQ(ierr);
2624     ierr = ISColoringCreate(PETSC_COMM_SELF,a->A->n,colors,&ocoloring);CHKERRQ(ierr);
2625     ierr = MatSetColoring_SeqAIJ(a->A,ocoloring);CHKERRQ(ierr);
2626     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
2627 
2628     /* set coloring for off-diagonal portion */
2629     ierr = PetscMalloc((a->B->n+1)*sizeof(int),&larray);CHKERRQ(ierr);
2630     ierr = ISGlobalToLocalMappingApply(A->mapping,IS_GTOLM_MASK,a->B->n,a->garray,PETSC_NULL,larray);CHKERRQ(ierr);
2631     ierr = PetscMalloc((a->B->n+1)*sizeof(ISColoringValue),&colors);CHKERRQ(ierr);
2632     for (i=0; i<a->B->n; i++) {
2633       colors[i] = coloring->colors[larray[i]];
2634     }
2635     ierr = PetscFree(larray);CHKERRQ(ierr);
2636     ierr = ISColoringCreate(MPI_COMM_SELF,a->B->n,colors,&ocoloring);CHKERRQ(ierr);
2637     ierr = MatSetColoring_SeqAIJ(a->B,ocoloring);CHKERRQ(ierr);
2638     ierr = ISColoringDestroy(ocoloring);CHKERRQ(ierr);
2639   } else {
2640     SETERRQ1(1,"No support ISColoringType %d",coloring->ctype);
2641   }
2642 
2643   PetscFunctionReturn(0);
2644 }
2645 
2646 #undef __FUNCT__
2647 #define __FUNCT__ "MatSetValuesAdic_MPIAIJ"
2648 int MatSetValuesAdic_MPIAIJ(Mat A,void *advalues)
2649 {
2650   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
2651   int        ierr;
2652 
2653   PetscFunctionBegin;
2654   ierr = MatSetValuesAdic_SeqAIJ(a->A,advalues);CHKERRQ(ierr);
2655   ierr = MatSetValuesAdic_SeqAIJ(a->B,advalues);CHKERRQ(ierr);
2656   PetscFunctionReturn(0);
2657 }
2658 
2659 #undef __FUNCT__
2660 #define __FUNCT__ "MatSetValuesAdifor_MPIAIJ"
2661 int MatSetValuesAdifor_MPIAIJ(Mat A,int nl,void *advalues)
2662 {
2663   Mat_MPIAIJ *a = (Mat_MPIAIJ*)A->data;
2664   int        ierr;
2665 
2666   PetscFunctionBegin;
2667   ierr = MatSetValuesAdifor_SeqAIJ(a->A,nl,advalues);CHKERRQ(ierr);
2668   ierr = MatSetValuesAdifor_SeqAIJ(a->B,nl,advalues);CHKERRQ(ierr);
2669   PetscFunctionReturn(0);
2670 }
2671 
2672 #undef __FUNCT__
2673 #define __FUNCT__ "MatMerge"
2674 /*@C
2675       MatMerge - Creates a single large PETSc matrix by concatinating sequential
2676                  matrices from each processor
2677 
2678     Collective on MPI_Comm
2679 
2680    Input Parameters:
2681 +    comm - the communicators the parallel matrix will live on
2682 -    inmat - the input sequential matrices
2683 
2684    Output Parameter:
2685 .    outmat - the parallel matrix generated
2686 
2687     Level: advanced
2688 
2689    Notes: The number of columns of the matrix in EACH of the seperate files
2690       MUST be the same.
2691 
2692 @*/
2693 int MatMerge(MPI_Comm comm,Mat inmat, Mat *outmat)
2694 {
2695   int         ierr,m,n,i,rstart,*indx,nnz,I,*dnz,*onz;
2696   PetscScalar *values;
2697   PetscMap    columnmap,rowmap;
2698 
2699   PetscFunctionBegin;
2700 
2701   ierr = MatGetSize(inmat,&m,&n);CHKERRQ(ierr);
2702 
2703   /* count nonzeros in each row, for diagonal and off diagonal portion of matrix */
2704   ierr = PetscMapCreate(comm,&columnmap);CHKERRQ(ierr);
2705   ierr = PetscMapSetSize(columnmap,n);CHKERRQ(ierr);
2706   ierr = PetscMapSetType(columnmap,MAP_MPI);CHKERRQ(ierr);
2707   ierr = PetscMapGetLocalSize(columnmap,&n);CHKERRQ(ierr);
2708   ierr = PetscMapDestroy(columnmap);CHKERRQ(ierr);
2709 
2710   ierr = PetscMapCreate(comm,&rowmap);CHKERRQ(ierr);
2711   ierr = PetscMapSetLocalSize(rowmap,m);CHKERRQ(ierr);
2712   ierr = PetscMapSetType(rowmap,MAP_MPI);CHKERRQ(ierr);
2713   ierr = PetscMapGetLocalRange(rowmap,&rstart,0);CHKERRQ(ierr);
2714   ierr = PetscMapDestroy(rowmap);CHKERRQ(ierr);
2715 
2716   ierr = MatPreallocateInitialize(comm,m,n,dnz,onz);CHKERRQ(ierr);
2717   for (i=0;i<m;i++) {
2718     ierr = MatGetRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2719     ierr = MatPreallocateSet(i+rstart,nnz,indx,dnz,onz);CHKERRQ(ierr);
2720     ierr = MatRestoreRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2721   }
2722   /* This routine will ONLY return MPIAIJ type matrix */
2723   ierr = MatCreate(comm,m,n,PETSC_DETERMINE,PETSC_DETERMINE,outmat);CHKERRQ(ierr);
2724   ierr = MatSetType(*outmat,MATMPIAIJ);CHKERRQ(ierr);
2725   ierr = MatMPIAIJSetPreallocation(*outmat,0,dnz,0,onz);CHKERRQ(ierr);
2726   ierr = MatPreallocateFinalize(dnz,onz);CHKERRQ(ierr);
2727 
2728   for (i=0;i<m;i++) {
2729     ierr = MatGetRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2730     I    = i + rstart;
2731     ierr = MatSetValues(*outmat,1,&I,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
2732     ierr = MatRestoreRow(inmat,i,&nnz,&indx,&values);CHKERRQ(ierr);
2733   }
2734   ierr = MatDestroy(inmat);CHKERRQ(ierr);
2735   ierr = MatAssemblyBegin(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2736   ierr = MatAssemblyEnd(*outmat,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2737 
2738   PetscFunctionReturn(0);
2739 }
2740 
2741 #undef __FUNCT__
2742 #define __FUNCT__ "MatFileSplit"
2743 int MatFileSplit(Mat A,char *outfile)
2744 {
2745   int         ierr,rank,len,m,N,i,rstart,*indx,nnz;
2746   PetscViewer out;
2747   char        *name;
2748   Mat         B;
2749   PetscScalar *values;
2750 
2751   PetscFunctionBegin;
2752 
2753   ierr = MatGetLocalSize(A,&m,0);CHKERRQ(ierr);
2754   ierr = MatGetSize(A,0,&N);CHKERRQ(ierr);
2755   /* Should this be the type of the diagonal block of A? */
2756   ierr = MatCreate(PETSC_COMM_SELF,m,N,m,N,&B);CHKERRQ(ierr);
2757   ierr = MatSetType(B,MATSEQAIJ);CHKERRQ(ierr);
2758   ierr = MatSeqAIJSetPreallocation(B,0,PETSC_NULL);CHKERRQ(ierr);
2759   ierr = MatGetOwnershipRange(A,&rstart,0);CHKERRQ(ierr);
2760   for (i=0;i<m;i++) {
2761     ierr = MatGetRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
2762     ierr = MatSetValues(B,1,&i,nnz,indx,values,INSERT_VALUES);CHKERRQ(ierr);
2763     ierr = MatRestoreRow(A,i+rstart,&nnz,&indx,&values);CHKERRQ(ierr);
2764   }
2765   ierr = MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2766   ierr = MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);CHKERRQ(ierr);
2767 
2768   ierr = MPI_Comm_rank(A->comm,&rank);CHKERRQ(ierr);
2769   ierr = PetscStrlen(outfile,&len);CHKERRQ(ierr);
2770   ierr = PetscMalloc((len+5)*sizeof(char),&name);CHKERRQ(ierr);
2771   sprintf(name,"%s.%d",outfile,rank);
2772   ierr = PetscViewerBinaryOpen(PETSC_COMM_SELF,name,PETSC_FILE_CREATE,&out);CHKERRQ(ierr);
2773   ierr = PetscFree(name);
2774   ierr = MatView(B,out);CHKERRQ(ierr);
2775   ierr = PetscViewerDestroy(out);CHKERRQ(ierr);
2776   ierr = MatDestroy(B);CHKERRQ(ierr);
2777   PetscFunctionReturn(0);
2778 }
2779