Actual source code: mpiptap.c

  2: /*
  3:   Defines projective product routines where A is a MPIAIJ matrix
  4:           C = P^T * A * P
  5: */

  7: #include <../src/mat/impls/aij/seq/aij.h>   /*I "petscmat.h" I*/
  8: #include <../src/mat/utils/freespace.h>
  9: #include <../src/mat/impls/aij/mpi/mpiaij.h>
 10: #include <petscbt.h>

 15: PetscErrorCode  MatDestroy_MPIAIJ_MatPtAP(Mat A)
 16: {
 17:   PetscErrorCode       ierr;
 18:   PetscContainer       container;

 21:   PetscObjectQuery((PetscObject)A,"MatMergeSeqsToMPI",(PetscObject *)&container);
 22:   if (container) {
 23:     Mat_Merge_SeqsToMPI  *merge;
 24:     PetscContainerGetPointer(container,(void **)&merge);
 25:     PetscFree(merge->id_r);
 26:     PetscFree(merge->len_s);
 27:     PetscFree(merge->len_r);
 28:     PetscFree(merge->bi);
 29:     PetscFree(merge->bj);
 30:     PetscFree(merge->buf_ri[0]);
 31:     PetscFree(merge->buf_ri);
 32:     PetscFree(merge->buf_rj[0]);
 33:     PetscFree(merge->buf_rj);
 34:     PetscFree(merge->coi);
 35:     PetscFree(merge->coj);
 36:     PetscFree(merge->owners_co);
 37:     PetscLayoutDestroy(&merge->rowmap);
 38:     merge->destroy(A);
 39:     PetscFree(merge);
 40:     PetscObjectCompose((PetscObject)A,"MatMergeSeqsToMPI",0);
 41:   }
 42:   return(0);
 43: }

 47: PetscErrorCode MatDuplicate_MPIAIJ_MatPtAP(Mat A, MatDuplicateOption op, Mat *M)
 48: {
 49:   PetscErrorCode       ierr;
 50:   Mat_Merge_SeqsToMPI  *merge;
 51:   PetscContainer       container;

 54:   PetscObjectQuery((PetscObject)A,"MatMergeSeqsToMPI",(PetscObject *)&container);
 55:   if (container) {
 56:     PetscContainerGetPointer(container,(void **)&merge);
 57:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Container does not exit");
 58:   (*merge->duplicate)(A,op,M);
 59:   (*M)->ops->destroy   = merge->destroy;   /* =MatDestroy_MPIAIJ, *M doesn't duplicate A's container! */
 60:   (*M)->ops->duplicate = merge->duplicate; /* =MatDuplicate_ MPIAIJ */
 61:   return(0);
 62: }

 66: PetscErrorCode MatPtAPSymbolic_MPIAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
 67: {

 71:   if (!P->ops->ptapsymbolic_mpiaij) SETERRQ2(((PetscObject)A)->comm,PETSC_ERR_SUP,"Not implemented for A=%s and P=%s",((PetscObject)A)->type_name,((PetscObject)P)->type_name);
 72:   (*P->ops->ptapsymbolic_mpiaij)(A,P,fill,C);
 73:   return(0);
 74: }

 78: PetscErrorCode MatPtAPNumeric_MPIAIJ(Mat A,Mat P,Mat C)
 79: {

 83:   if (!P->ops->ptapnumeric_mpiaij) SETERRQ2(((PetscObject)A)->comm,PETSC_ERR_SUP,"Not implemented for A=%s and P=%s",((PetscObject)A)->type_name,((PetscObject)P)->type_name);
 84:   (*P->ops->ptapnumeric_mpiaij)(A,P,C);
 85:   return(0);
 86: }

 90: PetscErrorCode MatPtAPSymbolic_MPIAIJ_MPIAIJ(Mat A,Mat P,PetscReal fill,Mat *C)
 91: {
 92:   PetscErrorCode       ierr;
 93:   Mat                  B_mpi;
 94:   Mat_MatMatMultMPI    *ap;
 95:   PetscContainer       container;
 96:   PetscFreeSpaceList   free_space=PETSC_NULL,current_space=PETSC_NULL;
 97:   Mat_MPIAIJ           *a=(Mat_MPIAIJ*)A->data,*p=(Mat_MPIAIJ*)P->data;
 98:   Mat_SeqAIJ           *ad=(Mat_SeqAIJ*)(a->A)->data,*ao=(Mat_SeqAIJ*)(a->B)->data;
 99:   Mat_SeqAIJ           *p_loc,*p_oth;
100:   PetscInt             *pi_loc,*pj_loc,*pi_oth,*pj_oth,*pdti,*pdtj,*poti,*potj,*ptJ;
101:   PetscInt             *adi=ad->i,*adj=ad->j,*aoi=ao->i,*aoj=ao->j,nnz;
102:   PetscInt             nlnk,*lnk,*owners_co,*coi,*coj,i,k,pnz,row;
103:   PetscInt             am=A->rmap->n,pN=P->cmap->N,pn=P->cmap->n;
104:   PetscBT              lnkbt;
105:   MPI_Comm             comm=((PetscObject)A)->comm;
106:   PetscMPIInt          size,rank,tag,*len_si,*len_s,*len_ri;
107:   PetscInt             **buf_rj,**buf_ri,**buf_ri_k;
108:   PetscInt             len,proc,*dnz,*onz,*owners;
109:   PetscInt             nzi,*bi,*bj;
110:   PetscInt             nrows,*buf_s,*buf_si,*buf_si_i,**nextrow,**nextci;
111:   MPI_Request          *swaits,*rwaits;
112:   MPI_Status           *sstatus,rstatus;
113:   Mat_Merge_SeqsToMPI  *merge;
114:   PetscInt             *api,*apj,*Jptr,apnz,*prmap=p->garray,pon,nspacedouble=0;
115:   PetscMPIInt          j;

118:   MPI_Comm_size(comm,&size);
119:   MPI_Comm_rank(comm,&rank);

121:   /* destroy the container 'Mat_MatMatMultMPI' in case that P is attached to it */
122:   PetscObjectQuery((PetscObject)P,"Mat_MatMatMultMPI",(PetscObject *)&container);
123:   if (container) {
124:     /* reset functions */
125:     PetscContainerGetPointer(container,(void **)&ap);
126:     P->ops->destroy   = ap->destroy;
127:     P->ops->duplicate = ap->duplicate;
128:     /* destroy container and contents */
129:     PetscObjectCompose((PetscObject)P,"Mat_MatMatMultMPI",0);
130:   }

132:   /* create the container 'Mat_MatMatMultMPI' and attach it to P */
133:   PetscNew(Mat_MatMatMultMPI,&ap);
134:   ap->abi=PETSC_NULL; ap->abj=PETSC_NULL;
135:   ap->abnz_max = 0;

137:   PetscContainerCreate(PETSC_COMM_SELF,&container);
138:   PetscContainerSetPointer(container,ap);
139:   PetscContainerSetUserDestroy(container,PetscContainerDestroy_Mat_MatMatMultMPI);
140:   PetscObjectCompose((PetscObject)P,"Mat_MatMatMultMPI",(PetscObject)container);
141:   PetscContainerDestroy(&container);
142:   ap->destroy     = P->ops->destroy;
143:   P->ops->destroy = MatDestroy_MPIAIJ_MatMatMult;
144:   ap->reuse       = MAT_INITIAL_MATRIX;

146:   /* get P_oth by taking rows of P (= non-zero cols of local A) from other processors */
147:   MatGetBrowsOfAoCols(A,P,MAT_INITIAL_MATRIX,&ap->startsj,&ap->startsj_r,&ap->bufa,&ap->B_oth);
148:   /* get P_loc by taking all local rows of P */
149:   MatMPIAIJGetLocalMat(P,MAT_INITIAL_MATRIX,&ap->B_loc);

151:   p_loc = (Mat_SeqAIJ*)(ap->B_loc)->data;
152:   p_oth = (Mat_SeqAIJ*)(ap->B_oth)->data;
153:   pi_loc = p_loc->i; pj_loc = p_loc->j;
154:   pi_oth = p_oth->i; pj_oth = p_oth->j;

156:   /* first, compute symbolic AP = A_loc*P = A_diag*P_loc + A_off*P_oth */
157:   /*-------------------------------------------------------------------*/
158:   PetscMalloc((am+2)*sizeof(PetscInt),&api);
159:   ap->abi = api;
160:   api[0] = 0;

162:   /* create and initialize a linked list */
163:   nlnk = pN+1;
164:   PetscLLCreate(pN,pN,nlnk,lnk,lnkbt);

166:   /* Initial FreeSpace size is fill*nnz(A) */
167:   PetscFreeSpaceGet((PetscInt)(fill*(adi[am]+aoi[am])),&free_space);
168:   current_space = free_space;

170:   for (i=0;i<am;i++) {
171:     apnz = 0;
172:     /* diagonal portion of A */
173:     nzi = adi[i+1] - adi[i];
174:     for (j=0; j<nzi; j++){
175:       row = *adj++;
176:       pnz = pi_loc[row+1] - pi_loc[row];
177:       Jptr  = pj_loc + pi_loc[row];
178:       /* add non-zero cols of P into the sorted linked list lnk */
179:       PetscLLAdd(pnz,Jptr,pN,nlnk,lnk,lnkbt);
180:       apnz += nlnk;
181:     }
182:     /* off-diagonal portion of A */
183:     nzi = aoi[i+1] - aoi[i];
184:     for (j=0; j<nzi; j++){
185:       row = *aoj++;
186:       pnz = pi_oth[row+1] - pi_oth[row];
187:       Jptr  = pj_oth + pi_oth[row];
188:       PetscLLAdd(pnz,Jptr,pN,nlnk,lnk,lnkbt);
189:       apnz += nlnk;
190:     }

192:     api[i+1] = api[i] + apnz;
193:     if (ap->abnz_max < apnz) ap->abnz_max = apnz;

195:     /* if free space is not available, double the total space in the list */
196:     if (current_space->local_remaining<apnz) {
197:       PetscFreeSpaceGet(apnz+current_space->total_array_size,&current_space);
198:       nspacedouble++;
199:     }

201:     /* Copy data into free space, then initialize lnk */
202:     PetscLLClean(pN,pN,apnz,lnk,current_space->array,lnkbt);
203:     current_space->array           += apnz;
204:     current_space->local_used      += apnz;
205:     current_space->local_remaining -= apnz;
206:   }
207:   /* Allocate space for apj, initialize apj, and */
208:   /* destroy list of free space and other temporary array(s) */
209:   PetscMalloc((api[am]+1)*sizeof(PetscInt),&ap->abj);
210:   apj = ap->abj;
211:   PetscFreeSpaceContiguous(&free_space,ap->abj);

213:   /* determine symbolic Co=(p->B)^T*AP - send to others */
214:   /*----------------------------------------------------*/
215:   MatGetSymbolicTranspose_SeqAIJ(p->B,&poti,&potj);

217:   /* then, compute symbolic Co = (p->B)^T*AP */
218:   pon = (p->B)->cmap->n; /* total num of rows to be sent to other processors 
219:                          >= (num of nonzero rows of C_seq) - pn */
220:   PetscMalloc((pon+1)*sizeof(PetscInt),&coi);
221:   coi[0] = 0;

223:   /* set initial free space to be 3*pon*max( nnz(AP) per row) */
224:   nnz           = 3*pon*ap->abnz_max + 1;
225:   PetscFreeSpaceGet(nnz,&free_space);
226:   current_space = free_space;

228:   for (i=0; i<pon; i++) {
229:     nnz  = 0;
230:     pnz = poti[i+1] - poti[i];
231:     j     = pnz;
232:     ptJ   = potj + poti[i+1];
233:     while (j){/* assume cols are almost in increasing order, starting from its end saves computation */
234:       j--; ptJ--;
235:       row  = *ptJ; /* row of AP == col of Pot */
236:       apnz = api[row+1] - api[row];
237:       Jptr   = apj + api[row];
238:       /* add non-zero cols of AP into the sorted linked list lnk */
239:       PetscLLAdd(apnz,Jptr,pN,nlnk,lnk,lnkbt);
240:       nnz += nlnk;
241:     }

243:     /* If free space is not available, double the total space in the list */
244:     if (current_space->local_remaining<nnz) {
245:       PetscFreeSpaceGet(nnz+current_space->total_array_size,&current_space);
246:     }

248:     /* Copy data into free space, and zero out denserows */
249:     PetscLLClean(pN,pN,nnz,lnk,current_space->array,lnkbt);
250:     current_space->array           += nnz;
251:     current_space->local_used      += nnz;
252:     current_space->local_remaining -= nnz;
253:     coi[i+1] = coi[i] + nnz;
254:   }
255:   PetscMalloc((coi[pon]+1)*sizeof(PetscInt),&coj);
256:   PetscFreeSpaceContiguous(&free_space,coj);
257:   MatRestoreSymbolicTranspose_SeqAIJ(p->B,&poti,&potj);

259:   /* send j-array (coj) of Co to other processors */
260:   /*----------------------------------------------*/
261:   /* determine row ownership */
262:   PetscNew(Mat_Merge_SeqsToMPI,&merge);
263:   PetscLayoutCreate(comm,&merge->rowmap);
264:   merge->rowmap->n = pn;
265:   merge->rowmap->bs = 1;
266:   PetscLayoutSetUp(merge->rowmap);
267:   owners = merge->rowmap->range;

269:   /* determine the number of messages to send, their lengths */
270:   PetscMalloc(size*sizeof(PetscMPIInt),&len_si);
271:   PetscMemzero(len_si,size*sizeof(PetscMPIInt));
272:   PetscMalloc(size*sizeof(PetscMPIInt),&merge->len_s);
273:   len_s = merge->len_s;
274:   merge->nsend = 0;
275: 
276:   PetscMalloc((size+2)*sizeof(PetscInt),&owners_co);
277:   PetscMemzero(len_s,size*sizeof(PetscMPIInt));

279:   proc = 0;
280:   for (i=0; i<pon; i++){
281:     while (prmap[i] >= owners[proc+1]) proc++;
282:     len_si[proc]++;  /* num of rows in Co to be sent to [proc] */
283:     len_s[proc] += coi[i+1] - coi[i];
284:   }

286:   len   = 0;  /* max length of buf_si[] */
287:   owners_co[0] = 0;
288:   for (proc=0; proc<size; proc++){
289:     owners_co[proc+1] = owners_co[proc] + len_si[proc];
290:     if (len_si[proc]){
291:       merge->nsend++;
292:       len_si[proc] = 2*(len_si[proc] + 1);
293:       len += len_si[proc];
294:     }
295:   }

297:   /* determine the number and length of messages to receive for coi and coj  */
298:   PetscGatherNumberOfMessages(comm,PETSC_NULL,len_s,&merge->nrecv);
299:   PetscGatherMessageLengths2(comm,merge->nsend,merge->nrecv,len_s,len_si,&merge->id_r,&merge->len_r,&len_ri);

301:   /* post the Irecv and Isend of coj */
302:   PetscCommGetNewTag(comm,&tag);
303:   PetscPostIrecvInt(comm,tag,merge->nrecv,merge->id_r,merge->len_r,&buf_rj,&rwaits);

305:   PetscMalloc((merge->nsend+1)*sizeof(MPI_Request),&swaits);

307:   for (proc=0, k=0; proc<size; proc++){
308:     if (!len_s[proc]) continue;
309:     i = owners_co[proc];
310:     MPI_Isend(coj+coi[i],len_s[proc],MPIU_INT,proc,tag,comm,swaits+k);
311:     k++;
312:   }

314:   /* receives and sends of coj are complete */
315:   PetscMalloc(size*sizeof(MPI_Status),&sstatus);
316:   i = merge->nrecv;
317:   while (i--) {
318:     MPI_Waitany(merge->nrecv,rwaits,&j,&rstatus);
319:   }
320:   PetscFree(rwaits);
321:   if (merge->nsend) {MPI_Waitall(merge->nsend,swaits,sstatus);}
322: 
323:   /* send and recv coi */
324:   /*-------------------*/
325:   PetscPostIrecvInt(comm,tag,merge->nrecv,merge->id_r,len_ri,&buf_ri,&rwaits);
326: 
327:   PetscMalloc((len+1)*sizeof(PetscInt),&buf_s);
328:   buf_si = buf_s;  /* points to the beginning of k-th msg to be sent */
329:   for (proc=0,k=0; proc<size; proc++){
330:     if (!len_s[proc]) continue;
331:     /* form outgoing message for i-structure: 
332:          buf_si[0]:                 nrows to be sent
333:                [1:nrows]:           row index (global)
334:                [nrows+1:2*nrows+1]: i-structure index
335:     */
336:     /*-------------------------------------------*/
337:     nrows = len_si[proc]/2 - 1;
338:     buf_si_i    = buf_si + nrows+1;
339:     buf_si[0]   = nrows;
340:     buf_si_i[0] = 0;
341:     nrows = 0;
342:     for (i=owners_co[proc]; i<owners_co[proc+1]; i++){
343:       nzi = coi[i+1] - coi[i];
344:       buf_si_i[nrows+1] = buf_si_i[nrows] + nzi; /* i-structure */
345:       buf_si[nrows+1] =prmap[i] -owners[proc]; /* local row index */
346:       nrows++;
347:     }
348:     MPI_Isend(buf_si,len_si[proc],MPIU_INT,proc,tag,comm,swaits+k);
349:     k++;
350:     buf_si += len_si[proc];
351:   }
352:   i = merge->nrecv;
353:   while (i--) {
354:     MPI_Waitany(merge->nrecv,rwaits,&j,&rstatus);
355:   }
356:   PetscFree(rwaits);
357:   if (merge->nsend) {MPI_Waitall(merge->nsend,swaits,sstatus);}
358:   /*
359:   PetscInfo2(A,"nsend: %d, nrecv: %d\n",merge->nsend,merge->nrecv);
360:   for (i=0; i<merge->nrecv; i++){
361:     PetscInfo3(A,"recv len_ri=%d, len_rj=%d from [%d]\n",len_ri[i],merge->len_r[i],merge->id_r[i]);
362:   }
363:   */
364:   PetscFree(len_si);
365:   PetscFree(len_ri);
366:   PetscFree(swaits);
367:   PetscFree(sstatus);
368:   PetscFree(buf_s);

370:   /* compute the local portion of C (mpi mat) */
371:   /*------------------------------------------*/
372:   MatGetSymbolicTranspose_SeqAIJ(p->A,&pdti,&pdtj);

374:   /* allocate bi array and free space for accumulating nonzero column info */
375:   PetscMalloc((pn+1)*sizeof(PetscInt),&bi);
376:   bi[0] = 0;
377: 
378:   /* set initial free space to be 3*pn*max( nnz(AP) per row) */
379:   nnz           = 3*pn*ap->abnz_max + 1;
380:   PetscFreeSpaceGet(nnz,&free_space);
381:   current_space = free_space;

383:   PetscMalloc3(merge->nrecv,PetscInt**,&buf_ri_k,merge->nrecv,PetscInt*,&nextrow,merge->nrecv,PetscInt*,&nextci);
384:   for (k=0; k<merge->nrecv; k++){
385:     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
386:     nrows       = *buf_ri_k[k];
387:     nextrow[k]  = buf_ri_k[k] + 1;  /* next row number of k-th recved i-structure */
388:     nextci[k]   = buf_ri_k[k] + (nrows + 1);/* poins to the next i-structure of k-th recved i-structure  */
389:   }
390:   MatPreallocateInitialize(comm,pn,pn,dnz,onz);
391:   for (i=0; i<pn; i++) {
392:     /* add pdt[i,:]*AP into lnk */
393:     nnz = 0;
394:     pnz  = pdti[i+1] - pdti[i];
395:     j    = pnz;
396:     ptJ  = pdtj + pdti[i+1];
397:     while (j){/* assume cols are almost in increasing order, starting from its end saves computation */
398:       j--; ptJ--;
399:       row  = *ptJ; /* row of AP == col of Pt */
400:       apnz = api[row+1] - api[row];
401:       Jptr   = apj + api[row];
402:       /* add non-zero cols of AP into the sorted linked list lnk */
403:       PetscLLAdd(apnz,Jptr,pN,nlnk,lnk,lnkbt);
404:       nnz += nlnk;
405:     }
406:     /* add received col data into lnk */
407:     for (k=0; k<merge->nrecv; k++){ /* k-th received message */
408:       if (i == *nextrow[k]) { /* i-th row */
409:         nzi = *(nextci[k]+1) - *nextci[k];
410:         Jptr  = buf_rj[k] + *nextci[k];
411:         PetscLLAdd(nzi,Jptr,pN,nlnk,lnk,lnkbt);
412:         nnz += nlnk;
413:         nextrow[k]++; nextci[k]++;
414:       }
415:     }

417:     /* if free space is not available, make more free space */
418:     if (current_space->local_remaining<nnz) {
419:       PetscFreeSpaceGet(nnz+current_space->total_array_size,&current_space);
420:     }
421:     /* copy data into free space, then initialize lnk */
422:     PetscLLClean(pN,pN,nnz,lnk,current_space->array,lnkbt);
423:     MatPreallocateSet(i+owners[rank],nnz,current_space->array,dnz,onz);
424:     current_space->array           += nnz;
425:     current_space->local_used      += nnz;
426:     current_space->local_remaining -= nnz;
427:     bi[i+1] = bi[i] + nnz;
428:   }
429:   MatRestoreSymbolicTranspose_SeqAIJ(p->A,&pdti,&pdtj);
430:   PetscFree3(buf_ri_k,nextrow,nextci);

432:   PetscMalloc((bi[pn]+1)*sizeof(PetscInt),&bj);
433:   PetscFreeSpaceContiguous(&free_space,bj);
434:   PetscLLDestroy(lnk,lnkbt);

436:   /* create symbolic parallel matrix B_mpi */
437:   /*---------------------------------------*/
438:   MatCreate(comm,&B_mpi);
439:   MatSetSizes(B_mpi,pn,pn,PETSC_DETERMINE,PETSC_DETERMINE);
440:   MatSetType(B_mpi,MATMPIAIJ);
441:   MatMPIAIJSetPreallocation(B_mpi,0,dnz,0,onz);
442:   MatPreallocateFinalize(dnz,onz);

444:   merge->bi            = bi;
445:   merge->bj            = bj;
446:   merge->coi           = coi;
447:   merge->coj           = coj;
448:   merge->buf_ri        = buf_ri;
449:   merge->buf_rj        = buf_rj;
450:   merge->owners_co     = owners_co;
451:   merge->destroy       = B_mpi->ops->destroy;
452:   merge->duplicate     = B_mpi->ops->duplicate;

454:   /* B_mpi is not ready for use - assembly will be done by MatPtAPNumeric() */
455:   B_mpi->assembled     = PETSC_FALSE;
456:   B_mpi->ops->destroy  = MatDestroy_MPIAIJ_MatPtAP;
457:   B_mpi->ops->duplicate = MatDuplicate_MPIAIJ_MatPtAP;

459:   /* attach the supporting struct to B_mpi for reuse */
460:   PetscContainerCreate(PETSC_COMM_SELF,&container);
461:   PetscContainerSetPointer(container,merge);
462:   PetscObjectCompose((PetscObject)B_mpi,"MatMergeSeqsToMPI",(PetscObject)container);
463:   PetscContainerDestroy(&container);
464:   *C = B_mpi;
465: #if defined(PETSC_USE_INFO)
466:   if (bi[pn] != 0) {
467:     PetscReal afill = ((PetscReal)bi[pn])/(adi[am]+aoi[am]);
468:     if (afill < 1.0) afill = 1.0;
469:     PetscInfo3(B_mpi,"Reallocs %D; Fill ratio: given %G needed %G when computing A*P.\n",nspacedouble,fill,afill);
470:     PetscInfo1(B_mpi,"Use MatPtAP(A,P,MatReuse,%G,&C) for best performance.\n",afill);
471:   } else {
472:     PetscInfo(B_mpi,"Empty matrix product\n");
473:   }
474: #endif
475:   return(0);
476: }

480: PetscErrorCode MatPtAPNumeric_MPIAIJ_MPIAIJ(Mat A,Mat P,Mat C)
481: {
482:   PetscErrorCode       ierr;
483:   Mat_Merge_SeqsToMPI  *merge;
484:   Mat_MatMatMultMPI    *ap;
485:   PetscContainer       cont_merge,cont_ptap;
486:   Mat_MPIAIJ           *a=(Mat_MPIAIJ*)A->data,*p=(Mat_MPIAIJ*)P->data;
487:   Mat_SeqAIJ           *ad=(Mat_SeqAIJ*)(a->A)->data,*ao=(Mat_SeqAIJ*)(a->B)->data;
488:   Mat_SeqAIJ           *pd=(Mat_SeqAIJ*)(p->A)->data,*po=(Mat_SeqAIJ*)(p->B)->data;
489:   Mat_SeqAIJ           *p_loc,*p_oth;
490:   PetscInt             *adi=ad->i,*aoi=ao->i,*adj=ad->j,*aoj=ao->j,*apJ,nextp;
491:   PetscInt             *pi_loc,*pj_loc,*pi_oth,*pj_oth,*pJ,*pj;
492:   PetscInt             i,j,k,anz,pnz,apnz,nextap,row,*cj;
493:   MatScalar            *ada=ad->a,*aoa=ao->a,*apa,*pa,*ca,*pa_loc,*pa_oth;
494:   PetscInt             am=A->rmap->n,cm=C->rmap->n,pon=(p->B)->cmap->n;
495:   MPI_Comm             comm=((PetscObject)C)->comm;
496:   PetscMPIInt          size,rank,taga,*len_s;
497:   PetscInt             *owners,proc,nrows,**buf_ri_k,**nextrow,**nextci;
498:   PetscInt             **buf_ri,**buf_rj;
499:   PetscInt             cnz=0,*bj_i,*bi,*bj,bnz,nextcj; /* bi,bj,ba: local array of C(mpi mat) */
500:   MPI_Request          *s_waits,*r_waits;
501:   MPI_Status           *status;
502:   MatScalar            **abuf_r,*ba_i,*pA,*coa,*ba;
503:   PetscInt             *api,*apj,*coi,*coj;
504:   PetscInt             *poJ=po->j,*pdJ=pd->j,pcstart=P->cmap->rstart,pcend=P->cmap->rend;

507:   MPI_Comm_size(comm,&size);
508:   MPI_Comm_rank(comm,&rank);

510:   PetscObjectQuery((PetscObject)C,"MatMergeSeqsToMPI",(PetscObject *)&cont_merge);
511:   if (cont_merge) {
512:     PetscContainerGetPointer(cont_merge,(void **)&merge);
513:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Matrix C does not posses an object container");

515:   PetscObjectQuery((PetscObject)P,"Mat_MatMatMultMPI",(PetscObject *)&cont_ptap);
516:   if (cont_ptap) {
517:     PetscContainerGetPointer(cont_ptap,(void **)&ap);
518:     if (ap->reuse == MAT_INITIAL_MATRIX){
519:       ap->reuse = MAT_REUSE_MATRIX;
520:     } else { /* update numerical values of P_oth and P_loc */
521:       MatGetBrowsOfAoCols(A,P,MAT_REUSE_MATRIX,&ap->startsj,&ap->startsj_r,&ap->bufa,&ap->B_oth);
522:       MatMPIAIJGetLocalMat(P,MAT_REUSE_MATRIX,&ap->B_loc);
523:     }
524:   } else SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE, "Matrix P does not posses an object container");

526:   /* get data from symbolic products */
527:   p_loc = (Mat_SeqAIJ*)(ap->B_loc)->data;
528:   p_oth = (Mat_SeqAIJ*)(ap->B_oth)->data;
529:   pi_loc=p_loc->i; pj_loc=p_loc->j; pJ=pj_loc; pa_loc=p_loc->a,pA=pa_loc;
530:   pi_oth=p_oth->i; pj_oth=p_oth->j; pa_oth=p_oth->a;
531: 
532:   coi = merge->coi; coj = merge->coj;
533:   PetscMalloc((coi[pon]+1)*sizeof(MatScalar),&coa);
534:   PetscMemzero(coa,coi[pon]*sizeof(MatScalar));

536:   bi     = merge->bi; bj = merge->bj;
537:   owners = merge->rowmap->range;
538:   PetscMalloc((bi[cm]+1)*sizeof(MatScalar),&ba);
539:   PetscMemzero(ba,bi[cm]*sizeof(MatScalar));

541:   /* get data from symbolic A*P */
542:   PetscMalloc((ap->abnz_max+1)*sizeof(MatScalar),&apa);
543:   PetscMemzero(apa,ap->abnz_max*sizeof(MatScalar));

545:   /* compute numeric C_seq=P_loc^T*A_loc*P */
546:   api = ap->abi; apj = ap->abj;
547:   for (i=0;i<am;i++) {
548:     /* form i-th sparse row of A*P */
549:     apnz = api[i+1] - api[i];
550:     apJ  = apj + api[i];
551:     /* diagonal portion of A */
552:     anz  = adi[i+1] - adi[i];
553:     for (j=0;j<anz;j++) {
554:       row = *adj++;
555:       pnz = pi_loc[row+1] - pi_loc[row];
556:       pj  = pj_loc + pi_loc[row];
557:       pa  = pa_loc + pi_loc[row];
558:       nextp = 0;
559:       for (k=0; nextp<pnz; k++) {
560:         if (apJ[k] == pj[nextp]) { /* col of AP == col of P */
561:           apa[k] += (*ada)*pa[nextp++];
562:         }
563:       }
564:       PetscLogFlops(2.0*pnz);
565:       ada++;
566:     }
567:     /* off-diagonal portion of A */
568:     anz  = aoi[i+1] - aoi[i];
569:     for (j=0; j<anz; j++) {
570:       row = *aoj++;
571:       pnz = pi_oth[row+1] - pi_oth[row];
572:       pj  = pj_oth + pi_oth[row];
573:       pa  = pa_oth + pi_oth[row];
574:       nextp = 0;
575:       for (k=0; nextp<pnz; k++) {
576:         if (apJ[k] == pj[nextp]) { /* col of AP == col of P */
577:           apa[k] += (*aoa)*pa[nextp++];
578:         }
579:       }
580:       PetscLogFlops(2.0*pnz);
581:       aoa++;
582:     }

584:     /* Compute P_loc[i,:]^T*AP[i,:] using outer product */
585:     pnz = pi_loc[i+1] - pi_loc[i];
586:     for (j=0; j<pnz; j++) {
587:       nextap = 0;
588:       row    = *pJ++; /* global index */
589:       if (row < pcstart || row >=pcend) { /* put the value into Co */
590:         cj  = coj + coi[*poJ];
591:         ca  = coa + coi[*poJ++];
592:       } else {                            /* put the value into Cd */
593:         cj   = bj + bi[*pdJ];
594:         ca   = ba + bi[*pdJ++];
595:       }
596:       for (k=0; nextap<apnz; k++) {
597:         if (cj[k]==apJ[nextap]) ca[k] += (*pA)*apa[nextap++];
598:       }
599:       PetscLogFlops(2.0*apnz);
600:       pA++;
601:     }

603:     /* zero the current row info for A*P */
604:     PetscMemzero(apa,apnz*sizeof(MatScalar));
605:   }
606:   PetscFree(apa);
607: 
608:   /* send and recv matrix values */
609:   /*-----------------------------*/
610:   buf_ri = merge->buf_ri;
611:   buf_rj = merge->buf_rj;
612:   len_s  = merge->len_s;
613:   PetscCommGetNewTag(comm,&taga);
614:   PetscPostIrecvScalar(comm,taga,merge->nrecv,merge->id_r,merge->len_r,&abuf_r,&r_waits);

616:   PetscMalloc((merge->nsend+1)*sizeof(MPI_Request),&s_waits);
617:   for (proc=0,k=0; proc<size; proc++){
618:     if (!len_s[proc]) continue;
619:     i = merge->owners_co[proc];
620:     MPI_Isend(coa+coi[i],len_s[proc],MPIU_MATSCALAR,proc,taga,comm,s_waits+k);
621:     k++;
622:   }
623:   PetscMalloc(size*sizeof(MPI_Status),&status);
624:   if (merge->nrecv) {MPI_Waitall(merge->nrecv,r_waits,status);}
625:   if (merge->nsend) {MPI_Waitall(merge->nsend,s_waits,status);}
626:   PetscFree(status);

628:   PetscFree(s_waits);
629:   PetscFree(r_waits);
630:   PetscFree(coa);

632:   /* insert local and received values into C */
633:   /*-----------------------------------------*/
634:   PetscMalloc3(merge->nrecv,PetscInt**,&buf_ri_k,merge->nrecv,PetscInt*,&nextrow,merge->nrecv,PetscInt*,&nextci);

636:   for (k=0; k<merge->nrecv; k++){
637:     buf_ri_k[k] = buf_ri[k]; /* beginning of k-th recved i-structure */
638:     nrows       = *(buf_ri_k[k]);
639:     nextrow[k]  = buf_ri_k[k]+1;  /* next row number of k-th recved i-structure */
640:     nextci[k]   = buf_ri_k[k] + (nrows + 1);/* poins to the next i-structure of k-th recved i-structure  */
641:   }

643:   for (i=0; i<cm; i++) {
644:     row = owners[rank] + i; /* global row index of C_seq */
645:     bj_i = bj + bi[i];  /* col indices of the i-th row of C */
646:     ba_i = ba + bi[i];
647:     bnz  = bi[i+1] - bi[i];
648:     /* add received vals into ba */
649:     for (k=0; k<merge->nrecv; k++){ /* k-th received message */
650:       /* i-th row */
651:       if (i == *nextrow[k]) {
652:         cnz = *(nextci[k]+1) - *nextci[k];
653:         cj  = buf_rj[k] + *(nextci[k]);
654:         ca  = abuf_r[k] + *(nextci[k]);
655:         nextcj = 0;
656:         for (j=0; nextcj<cnz; j++){
657:           if (bj_i[j] == cj[nextcj]){ /* bcol == ccol */
658:             ba_i[j] += ca[nextcj++];
659:           }
660:         }
661:         nextrow[k]++; nextci[k]++;
662:       }
663:     }
664:     MatSetValues(C,1,&row,bnz,bj_i,ba_i,INSERT_VALUES);
665:     PetscLogFlops(2.0*cnz);
666:   }
667:   MatSetBlockSize(C,1);
668:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
669:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

671:   PetscFree(ba);
672:   PetscFree(abuf_r[0]);
673:   PetscFree(abuf_r);
674:   PetscFree3(buf_ri_k,nextrow,nextci);
675:   return(0);
676: }