Actual source code: matstash.c

  1: /*$Id: matstash.c,v 1.50 2001/03/23 23:22:45 balay Exp $*/

 3:  #include src/mat/matimpl.h

  5: /*
  6:        The input to the stash is ALWAYS in MatScalar precision, and the 
  7:     internal storage and output is also in MatScalar.
  8: */
  9: #define DEFAULT_STASH_SIZE   10000

 11: /*
 12:   MatStashCreate_Private - Creates a stash,currently used for all the parallel 
 13:   matrix implementations. The stash is where elements of a matrix destined 
 14:   to be stored on other processors are kept until matrix assembly is done.

 16:   This is a simple minded stash. Simply adds entries to end of stash.

 18:   Input Parameters:
 19:   comm - communicator, required for scatters.
 20:   bs   - stash block size. used when stashing blocks of values

 22:   Output Parameters:
 23:   stash    - the newly created stash
 24: */
 27: int MatStashCreate_Private(MPI_Comm comm,int bs,MatStash *stash)
 28: {
 29:   int        ierr,max,*opt,nopt;
 30:   PetscTruth flg;

 33:   /* Require 2 tags,get the second using PetscCommGetNewTag() */
 34:   stash->comm = comm;
 35:   PetscCommGetNewTag(stash->comm,&stash->tag1);
 36:   PetscCommGetNewTag(stash->comm,&stash->tag2);
 37:   MPI_Comm_size(stash->comm,&stash->size);
 38:   MPI_Comm_rank(stash->comm,&stash->rank);

 40:   nopt = stash->size;
 41:   PetscMalloc(nopt*sizeof(int),&opt);
 42:   PetscOptionsGetIntArray(PETSC_NULL,"-matstash_initial_size",opt,&nopt,&flg);
 43:   if (flg) {
 44:     if (nopt == 1)                max = opt[0];
 45:     else if (nopt == stash->size) max = opt[stash->rank];
 46:     else if (stash->rank < nopt)  max = opt[stash->rank];
 47:     else                          max = 0; /* Use default */
 48:     stash->umax = max;
 49:   } else {
 50:     stash->umax = 0;
 51:   }
 52:   PetscFree(opt);
 53:   if (bs <= 0) bs = 1;

 55:   stash->bs       = bs;
 56:   stash->nmax     = 0;
 57:   stash->oldnmax  = 0;
 58:   stash->n        = 0;
 59:   stash->reallocs = -1;
 60:   stash->idx      = 0;
 61:   stash->idy      = 0;
 62:   stash->array    = 0;

 64:   stash->send_waits  = 0;
 65:   stash->recv_waits  = 0;
 66:   stash->send_status = 0;
 67:   stash->nsends      = 0;
 68:   stash->nrecvs      = 0;
 69:   stash->svalues     = 0;
 70:   stash->rvalues     = 0;
 71:   stash->rmax        = 0;
 72:   stash->nprocs      = 0;
 73:   stash->nprocessed  = 0;
 74:   return(0);
 75: }

 77: /* 
 78:    MatStashDestroy_Private - Destroy the stash
 79: */
 82: int MatStashDestroy_Private(MatStash *stash)
 83: {

 87:   if (stash->array) {
 88:     PetscFree(stash->array);
 89:     stash->array = 0;
 90:   }
 91:   return(0);
 92: }

 94: /* 
 95:    MatStashScatterEnd_Private - This is called as the fial stage of
 96:    scatter. The final stages of messagepassing is done here, and
 97:    all the memory used for messagepassing is cleanedu up. This
 98:    routine also resets the stash, and deallocates the memory used
 99:    for the stash. It also keeps track of the current memory usage
100:    so that the same value can be used the next time through.
101: */
104: int MatStashScatterEnd_Private(MatStash *stash)
105: {
106:   int         nsends=stash->nsends,ierr,bs2,oldnmax;
107:   MPI_Status  *send_status;

110:   /* wait on sends */
111:   if (nsends) {
112:     PetscMalloc(2*nsends*sizeof(MPI_Status),&send_status);
113:     MPI_Waitall(2*nsends,stash->send_waits,send_status);
114:     PetscFree(send_status);
115:   }

117:   /* Now update nmaxold to be app 10% more than max n used, this way the
118:      wastage of space is reduced the next time this stash is used.
119:      Also update the oldmax, only if it increases */
120:   if (stash->n) {
121:     bs2      = stash->bs*stash->bs;
122:     oldnmax  = ((int)(stash->n * 1.1) + 5)*bs2;
123:     if (oldnmax > stash->oldnmax) stash->oldnmax = oldnmax;
124:   }

126:   stash->nmax       = 0;
127:   stash->n          = 0;
128:   stash->reallocs   = -1;
129:   stash->rmax       = 0;
130:   stash->nprocessed = 0;

132:   if (stash->array) {
133:     PetscFree(stash->array);
134:     stash->array = 0;
135:     stash->idx   = 0;
136:     stash->idy   = 0;
137:   }
138:   if (stash->send_waits) {
139:     PetscFree(stash->send_waits);
140:     stash->send_waits = 0;
141:   }
142:   if (stash->recv_waits) {
143:     PetscFree(stash->recv_waits);
144:     stash->recv_waits = 0;
145:   }
146:   if (stash->svalues) {
147:     PetscFree(stash->svalues);
148:     stash->svalues = 0;
149:   }
150:   if (stash->rvalues) {
151:     PetscFree(stash->rvalues);
152:     stash->rvalues = 0;
153:   }
154:   if (stash->nprocs) {
155:     PetscFree(stash->nprocs);
156:     stash->nprocs = 0;
157:   }

159:   return(0);
160: }

162: /* 
163:    MatStashGetInfo_Private - Gets the relavant statistics of the stash

165:    Input Parameters:
166:    stash    - the stash
167:    nstash   - the size of the stash. Indicates the number of values stored.
168:    reallocs - the number of additional mallocs incurred.
169:    
170: */
173: int MatStashGetInfo_Private(MatStash *stash,int *nstash,int *reallocs)
174: {
175:   int bs2 = stash->bs*stash->bs;

178:   *nstash   = stash->n*bs2;
179:   if (stash->reallocs < 0) *reallocs = 0;
180:   else                     *reallocs = stash->reallocs;
181:   return(0);
182: }


185: /* 
186:    MatStashSetInitialSize_Private - Sets the initial size of the stash

188:    Input Parameters:
189:    stash  - the stash
190:    max    - the value that is used as the max size of the stash. 
191:             this value is used while allocating memory.
192: */
195: int MatStashSetInitialSize_Private(MatStash *stash,int max)
196: {
198:   stash->umax = max;
199:   return(0);
200: }

202: /* MatStashExpand_Private - Expand the stash. This function is called
203:    when the space in the stash is not sufficient to add the new values
204:    being inserted into the stash.
205:    
206:    Input Parameters:
207:    stash - the stash
208:    incr  - the minimum increase requested
209:    
210:    Notes: 
211:    This routine doubles the currently used memory. 
212:  */
215: static int MatStashExpand_Private(MatStash *stash,int incr)
216: {
217:   int       *n_idx,*n_idy,newnmax,bs2,ierr;
218:   MatScalar *n_array;

221:   /* allocate a larger stash */
222:   bs2     = stash->bs*stash->bs;
223:   if (!stash->oldnmax && !stash->nmax) { /* new stash */
224:     if (stash->umax)                  newnmax = stash->umax/bs2;
225:     else                              newnmax = DEFAULT_STASH_SIZE/bs2;
226:   } else if (!stash->nmax) { /* resuing stash */
227:     if (stash->umax > stash->oldnmax) newnmax = stash->umax/bs2;
228:     else                              newnmax = stash->oldnmax/bs2;
229:   } else                              newnmax = stash->nmax*2;
230:   if (newnmax  < (stash->nmax + incr)) newnmax += 2*incr;

232:   PetscMalloc((newnmax)*(2*sizeof(int)+bs2*sizeof(MatScalar)),&n_array);
233:   n_idx = (int*)(n_array + bs2*newnmax);
234:   n_idy = (int*)(n_idx + newnmax);
235:   PetscMemcpy(n_array,stash->array,bs2*stash->nmax*sizeof(MatScalar));
236:   PetscMemcpy(n_idx,stash->idx,stash->nmax*sizeof(int));
237:   PetscMemcpy(n_idy,stash->idy,stash->nmax*sizeof(int));
238:   if (stash->array) {PetscFree(stash->array);}
239:   stash->array   = n_array;
240:   stash->idx     = n_idx;
241:   stash->idy     = n_idy;
242:   stash->nmax    = newnmax;
243:   stash->reallocs++;
244:   return(0);
245: }
246: /*
247:   MatStashValuesRow_Private - inserts values into the stash. This function
248:   expects the values to be roworiented. Multiple columns belong to the same row
249:   can be inserted with a single call to this function.

251:   Input Parameters:
252:   stash  - the stash
253:   row    - the global row correspoiding to the values
254:   n      - the number of elements inserted. All elements belong to the above row.
255:   idxn   - the global column indices corresponding to each of the values.
256:   values - the values inserted
257: */
260: int MatStashValuesRow_Private(MatStash *stash,int row,int n,const int idxn[],const MatScalar values[])
261: {
262:   int    ierr,i;

265:   /* Check and see if we have sufficient memory */
266:   if ((stash->n + n) > stash->nmax) {
267:     MatStashExpand_Private(stash,n);
268:   }
269:   for (i=0; i<n; i++) {
270:     stash->idx[stash->n]   = row;
271:     stash->idy[stash->n]   = idxn[i];
272:     stash->array[stash->n] = values[i];
273:     stash->n++;
274:   }
275:   return(0);
276: }
277: /*
278:   MatStashValuesCol_Private - inserts values into the stash. This function
279:   expects the values to be columnoriented. Multiple columns belong to the same row
280:   can be inserted with a single call to this function.

282:   Input Parameters:
283:   stash   - the stash
284:   row     - the global row correspoiding to the values
285:   n       - the number of elements inserted. All elements belong to the above row.
286:   idxn    - the global column indices corresponding to each of the values.
287:   values  - the values inserted
288:   stepval - the consecutive values are sepated by a distance of stepval.
289:             this happens because the input is columnoriented.
290: */
293: int MatStashValuesCol_Private(MatStash *stash,int row,int n,const int idxn[],const MatScalar values[],int stepval)
294: {
295:   int    ierr,i;

298:   /* Check and see if we have sufficient memory */
299:   if ((stash->n + n) > stash->nmax) {
300:     MatStashExpand_Private(stash,n);
301:   }
302:   for (i=0; i<n; i++) {
303:     stash->idx[stash->n]   = row;
304:     stash->idy[stash->n]   = idxn[i];
305:     stash->array[stash->n] = values[i*stepval];
306:     stash->n++;
307:   }
308:   return(0);
309: }

311: /*
312:   MatStashValuesRowBlocked_Private - inserts blocks of values into the stash. 
313:   This function expects the values to be roworiented. Multiple columns belong 
314:   to the same block-row can be inserted with a single call to this function.
315:   This function extracts the sub-block of values based on the dimensions of
316:   the original input block, and the row,col values corresponding to the blocks.

318:   Input Parameters:
319:   stash  - the stash
320:   row    - the global block-row correspoiding to the values
321:   n      - the number of elements inserted. All elements belong to the above row.
322:   idxn   - the global block-column indices corresponding to each of the blocks of 
323:            values. Each block is of size bs*bs.
324:   values - the values inserted
325:   rmax   - the number of block-rows in the original block.
326:   cmax   - the number of block-columsn on the original block.
327:   idx    - the index of the current block-row in the original block.
328: */
331: int MatStashValuesRowBlocked_Private(MatStash *stash,int row,int n,const int idxn[],const MatScalar values[],int rmax,int cmax,int idx)
332: {
333:   int             ierr,i,j,k,bs2,bs=stash->bs;
334:   const MatScalar *vals;
335:   MatScalar       *array;

338:   bs2 = bs*bs;
339:   if ((stash->n+n) > stash->nmax) {
340:     MatStashExpand_Private(stash,n);
341:   }
342:   for (i=0; i<n; i++) {
343:     stash->idx[stash->n]   = row;
344:     stash->idy[stash->n] = idxn[i];
345:     /* Now copy over the block of values. Store the values column oriented.
346:        This enables inserting multiple blocks belonging to a row with a single
347:        funtion call */
348:     array = stash->array + bs2*stash->n;
349:     vals  = values + idx*bs2*n + bs*i;
350:     for (j=0; j<bs; j++) {
351:       for (k=0; k<bs; k++) {array[k*bs] = vals[k];}
352:       array += 1;
353:       vals  += cmax*bs;
354:     }
355:     stash->n++;
356:   }
357:   return(0);
358: }

360: /*
361:   MatStashValuesColBlocked_Private - inserts blocks of values into the stash. 
362:   This function expects the values to be roworiented. Multiple columns belong 
363:   to the same block-row can be inserted with a single call to this function.
364:   This function extracts the sub-block of values based on the dimensions of
365:   the original input block, and the row,col values corresponding to the blocks.

367:   Input Parameters:
368:   stash  - the stash
369:   row    - the global block-row correspoiding to the values
370:   n      - the number of elements inserted. All elements belong to the above row.
371:   idxn   - the global block-column indices corresponding to each of the blocks of 
372:            values. Each block is of size bs*bs.
373:   values - the values inserted
374:   rmax   - the number of block-rows in the original block.
375:   cmax   - the number of block-columsn on the original block.
376:   idx    - the index of the current block-row in the original block.
377: */
380: int MatStashValuesColBlocked_Private(MatStash *stash,int row,int n,const int idxn[],const MatScalar values[],int rmax,int cmax,int idx)
381: {
382:   int             ierr,i,j,k,bs2,bs=stash->bs;
383:   const MatScalar *vals;
384:   MatScalar       *array;

387:   bs2 = bs*bs;
388:   if ((stash->n+n) > stash->nmax) {
389:     MatStashExpand_Private(stash,n);
390:   }
391:   for (i=0; i<n; i++) {
392:     stash->idx[stash->n]   = row;
393:     stash->idy[stash->n] = idxn[i];
394:     /* Now copy over the block of values. Store the values column oriented.
395:      This enables inserting multiple blocks belonging to a row with a single
396:      funtion call */
397:     array = stash->array + bs2*stash->n;
398:     vals  = values + idx*bs + bs2*rmax*i;
399:     for (j=0; j<bs; j++) {
400:       for (k=0; k<bs; k++) {array[k] = vals[k];}
401:       array += bs;
402:       vals  += rmax*bs;
403:     }
404:     stash->n++;
405:   }
406:   return(0);
407: }
408: /*
409:   MatStashScatterBegin_Private - Initiates the transfer of values to the
410:   correct owners. This function goes through the stash, and check the
411:   owners of each stashed value, and sends the values off to the owner
412:   processors.

414:   Input Parameters:
415:   stash  - the stash
416:   owners - an array of size 'no-of-procs' which gives the ownership range
417:            for each node.

419:   Notes: The 'owners' array in the cased of the blocked-stash has the 
420:   ranges specified blocked global indices, and for the regular stash in
421:   the proper global indices.
422: */
425: int MatStashScatterBegin_Private(MatStash *stash,int *owners)
426: {
427:   int         *owner,*startv,*starti,tag1=stash->tag1,tag2=stash->tag2,bs2;
428:   int         size=stash->size,*nprocs,nsends,nreceives;
429:   int         nmax,count,ierr,*sindices,*rindices,i,j,idx;
430:   MatScalar   *rvalues,*svalues;
431:   MPI_Comm    comm = stash->comm;
432:   MPI_Request *send_waits,*recv_waits;


436:   bs2   = stash->bs*stash->bs;
437:   /*  first count number of contributors to each processor */
438:   PetscMalloc(2*size*sizeof(int),&nprocs);
439:   PetscMemzero(nprocs,2*size*sizeof(int));
440:   PetscMalloc((stash->n+1)*sizeof(int),&owner);

442:   for (i=0; i<stash->n; i++) {
443:     idx = stash->idx[i];
444:     for (j=0; j<size; j++) {
445:       if (idx >= owners[j] && idx < owners[j+1]) {
446:         nprocs[2*j]++; nprocs[2*j+1] = 1; owner[i] = j; break;
447:       }
448:     }
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:   PetscMaxSum(comm,nprocs,&nmax,&nreceives);

455:   /* post receives: 
456:      since we don't know how long each individual message is we 
457:      allocate the largest needed buffer for each receive. Potentially 
458:      this is a lot of wasted space.
459:   */
460:   PetscMalloc((nreceives+1)*(nmax+1)*(bs2*sizeof(MatScalar)+2*sizeof(int)),&rvalues);
461:   rindices = (int*)(rvalues + bs2*nreceives*nmax);
462:   PetscMalloc((nreceives+1)*2*sizeof(MPI_Request),&recv_waits);
463:   for (i=0,count=0; i<nreceives; i++) {
464:     MPI_Irecv(rvalues+bs2*nmax*i,bs2*nmax,MPIU_MATSCALAR,MPI_ANY_SOURCE,tag1,comm,
465:                      recv_waits+count++);
466:     MPI_Irecv(rindices+2*nmax*i,2*nmax,MPI_INT,MPI_ANY_SOURCE,tag2,comm,recv_waits+count++);
467:   }

469:   /* do sends:
470:       1) starts[i] gives the starting index in svalues for stuff going to 
471:          the ith processor
472:   */
473:   PetscMalloc((stash->n+1)*(bs2*sizeof(MatScalar)+2*sizeof(int)),&svalues);
474:   sindices = (int*)(svalues + bs2*stash->n);
475:   PetscMalloc(2*(nsends+1)*sizeof(MPI_Request),&send_waits);
476:   PetscMalloc(2*size*sizeof(int),&startv);
477:   starti   = startv + size;
478:   /* use 2 sends the first with all_a, the next with all_i and all_j */
479:   startv[0]  = 0; starti[0] = 0;
480:   for (i=1; i<size; i++) {
481:     startv[i] = startv[i-1] + nprocs[2*i-2];
482:     starti[i] = starti[i-1] + nprocs[2*i-2]*2;
483:   }
484:   for (i=0; i<stash->n; i++) {
485:     j = owner[i];
486:     if (bs2 == 1) {
487:       svalues[startv[j]]              = stash->array[i];
488:     } else {
489:       int       k;
490:       MatScalar *buf1,*buf2;
491:       buf1 = svalues+bs2*startv[j];
492:       buf2 = stash->array+bs2*i;
493:       for (k=0; k<bs2; k++){ buf1[k] = buf2[k]; }
494:     }
495:     sindices[starti[j]]               = stash->idx[i];
496:     sindices[starti[j]+nprocs[2*j]]   = stash->idy[i];
497:     startv[j]++;
498:     starti[j]++;
499:   }
500:   startv[0] = 0;
501:   for (i=1; i<size; i++) { startv[i] = startv[i-1] + nprocs[2*i-2];}
502:   for (i=0,count=0; i<size; i++) {
503:     if (nprocs[2*i+1]) {
504:       MPI_Isend(svalues+bs2*startv[i],bs2*nprocs[2*i],MPIU_MATSCALAR,i,tag1,comm,
505:                        send_waits+count++);
506:       MPI_Isend(sindices+2*startv[i],2*nprocs[2*i],MPI_INT,i,tag2,comm,
507:                        send_waits+count++);
508:     }
509:   }
510:   PetscFree(owner);
511:   PetscFree(startv);
512:   /* This memory is reused in scatter end  for a different purpose*/
513:   for (i=0; i<2*size; i++) nprocs[i] = -1;
514:   stash->nprocs      = nprocs;

516:   stash->svalues    = svalues;    stash->rvalues    = rvalues;
517:   stash->nsends     = nsends;     stash->nrecvs     = nreceives;
518:   stash->send_waits = send_waits; stash->recv_waits = recv_waits;
519:   stash->rmax       = nmax;
520:   return(0);
521: }

523: /* 
524:    MatStashScatterGetMesg_Private - This function waits on the receives posted 
525:    in the function MatStashScatterBegin_Private() and returns one message at 
526:    a time to the calling function. If no messages are left, it indicates this
527:    by setting flg = 0, else it sets flg = 1.

529:    Input Parameters:
530:    stash - the stash

532:    Output Parameters:
533:    nvals - the number of entries in the current message.
534:    rows  - an array of row indices (or blocked indices) corresponding to the values
535:    cols  - an array of columnindices (or blocked indices) corresponding to the values
536:    vals  - the values
537:    flg   - 0 indicates no more message left, and the current call has no values associated.
538:            1 indicates that the current call successfully received a message, and the
539:              other output parameters nvals,rows,cols,vals are set appropriately.
540: */
543: int MatStashScatterGetMesg_Private(MatStash *stash,int *nvals,int **rows,int** cols,MatScalar **vals,int *flg)
544: {
545:   int         i,ierr,*flg_v,i1,i2,*rindices,bs2;
546:   MPI_Status  recv_status;
547:   PetscTruth  match_found = PETSC_FALSE;


551:   *flg = 0; /* When a message is discovered this is reset to 1 */
552:   /* Return if no more messages to process */
553:   if (stash->nprocessed == stash->nrecvs) { return(0); }

555:   flg_v = stash->nprocs;
556:   bs2   = stash->bs*stash->bs;
557:   /* If a matching pair of receieves are found, process them, and return the data to
558:      the calling function. Until then keep receiving messages */
559:   while (!match_found) {
560:     MPI_Waitany(2*stash->nrecvs,stash->recv_waits,&i,&recv_status);
561:     /* Now pack the received message into a structure which is useable by others */
562:     if (i % 2) {
563:       MPI_Get_count(&recv_status,MPI_INT,nvals);
564:       flg_v[2*recv_status.MPI_SOURCE+1] = i/2;
565:       *nvals = *nvals/2; /* This message has both row indices and col indices */
566:     } else {
567:       MPI_Get_count(&recv_status,MPIU_MATSCALAR,nvals);
568:       flg_v[2*recv_status.MPI_SOURCE] = i/2;
569:       *nvals = *nvals/bs2;
570:     }
571: 
572:     /* Check if we have both the messages from this proc */
573:     i1 = flg_v[2*recv_status.MPI_SOURCE];
574:     i2 = flg_v[2*recv_status.MPI_SOURCE+1];
575:     if (i1 != -1 && i2 != -1) {
576:       rindices    = (int*)(stash->rvalues + bs2*stash->rmax*stash->nrecvs);
577:       *rows       = rindices + 2*i2*stash->rmax;
578:       *cols       = *rows + *nvals;
579:       *vals       = stash->rvalues + i1*bs2*stash->rmax;
580:       *flg        = 1;
581:       stash->nprocessed ++;
582:       match_found = PETSC_TRUE;
583:     }
584:   }
585:   return(0);
586: }