Actual source code: aomemscalable.c

petsc-3.13.6 2020-09-29
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  2: /*
  3:     The memory scalable AO Section 1.5 Writing Application Codes with PETSc ordering routines. These store the
  4:   orderings on each processor for that processor's range of values
  5: */

  7:  #include <../src/vec/is/ao/aoimpl.h>

  9: typedef struct {
 10:   PetscInt    *app_loc;    /* app_loc[i] is the partner for the ith local PETSc slot */
 11:   PetscInt    *petsc_loc;  /* petsc_loc[j] is the partner for the jth local app slot */
 12:   PetscLayout map;         /* determines the local sizes of ao */
 13: } AO_MemoryScalable;

 15: /*
 16:        All processors ship the data to process 0 to be printed; note that this is not scalable because
 17:        process 0 allocates space for all the orderings entry across all the processes
 18: */
 19: PetscErrorCode AOView_MemoryScalable(AO ao,PetscViewer viewer)
 20: {
 21:   PetscErrorCode    ierr;
 22:   PetscMPIInt       rank,size;
 23:   AO_MemoryScalable *aomems = (AO_MemoryScalable*)ao->data;
 24:   PetscBool         iascii;
 25:   PetscMPIInt       tag_app,tag_petsc;
 26:   PetscLayout       map = aomems->map;
 27:   PetscInt          *app,*app_loc,*petsc,*petsc_loc,len,i,j;
 28:   MPI_Status        status;

 31:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
 32:   if (!iascii) SETERRQ1(PetscObjectComm((PetscObject)viewer),PETSC_ERR_SUP,"Viewer type %s not supported for AO MemoryScalable",((PetscObject)viewer)->type_name);

 34:   MPI_Comm_rank(PetscObjectComm((PetscObject)ao),&rank);
 35:   MPI_Comm_size(PetscObjectComm((PetscObject)ao),&size);

 37:   PetscObjectGetNewTag((PetscObject)ao,&tag_app);
 38:   PetscObjectGetNewTag((PetscObject)ao,&tag_petsc);

 40:   if (!rank) {
 41:     PetscViewerASCIIPrintf(viewer,"Number of elements in ordering %D\n",ao->N);
 42:     PetscViewerASCIIPrintf(viewer,  "PETSc->App  App->PETSc\n");

 44:     PetscMalloc2(map->N,&app,map->N,&petsc);
 45:     len  = map->n;
 46:     /* print local AO */
 47:     PetscViewerASCIIPrintf(viewer,"Process [%d]\n",rank);
 48:     for (i=0; i<len; i++) {
 49:       PetscViewerASCIIPrintf(viewer,"%3D  %3D    %3D  %3D\n",i,aomems->app_loc[i],i,aomems->petsc_loc[i]);
 50:     }

 52:     /* recv and print off-processor's AO */
 53:     for (i=1; i<size; i++) {
 54:       len       = map->range[i+1] - map->range[i];
 55:       app_loc   = app  + map->range[i];
 56:       petsc_loc = petsc+ map->range[i];
 57:       MPI_Recv(app_loc,(PetscMPIInt)len,MPIU_INT,i,tag_app,PetscObjectComm((PetscObject)ao),&status);
 58:       MPI_Recv(petsc_loc,(PetscMPIInt)len,MPIU_INT,i,tag_petsc,PetscObjectComm((PetscObject)ao),&status);
 59:       PetscViewerASCIIPrintf(viewer,"Process [%D]\n",i);
 60:       for (j=0; j<len; j++) {
 61:         PetscViewerASCIIPrintf(viewer,"%3D  %3D    %3D  %3D\n",map->range[i]+j,app_loc[j],map->range[i]+j,petsc_loc[j]);
 62:       }
 63:     }
 64:     PetscFree2(app,petsc);

 66:   } else {
 67:     /* send values */
 68:     MPI_Send((void*)aomems->app_loc,map->n,MPIU_INT,0,tag_app,PetscObjectComm((PetscObject)ao));
 69:     MPI_Send((void*)aomems->petsc_loc,map->n,MPIU_INT,0,tag_petsc,PetscObjectComm((PetscObject)ao));
 70:   }
 71:   PetscViewerFlush(viewer);
 72:   return(0);
 73: }

 75: PetscErrorCode AODestroy_MemoryScalable(AO ao)
 76: {
 77:   AO_MemoryScalable *aomems = (AO_MemoryScalable*)ao->data;
 78:   PetscErrorCode    ierr;

 81:   PetscFree2(aomems->app_loc,aomems->petsc_loc);
 82:   PetscLayoutDestroy(&aomems->map);
 83:   PetscFree(aomems);
 84:   return(0);
 85: }

 87: /*
 88:    Input Parameters:
 89: +   ao - the Section 1.5 Writing Application Codes with PETSc ordering context
 90: .   n  - the number of integers in ia[]
 91: .   ia - the integers; these are replaced with their mapped value
 92: -   maploc - app_loc or petsc_loc in struct "AO_MemoryScalable"

 94:    Output Parameter:
 95: .   ia - the mapped interges
 96:  */
 97: PetscErrorCode AOMap_MemoryScalable_private(AO ao,PetscInt n,PetscInt *ia,const PetscInt *maploc)
 98: {
 99:   PetscErrorCode    ierr;
100:   AO_MemoryScalable *aomems = (AO_MemoryScalable*)ao->data;
101:   MPI_Comm          comm;
102:   PetscMPIInt       rank,size,tag1,tag2;
103:   PetscInt          *owner,*start,*sizes,nsends,nreceives;
104:   PetscInt          nmax,count,*sindices,*rindices,i,j,idx,lastidx,*sindices2,*rindices2;
105:   const PetscInt    *owners = aomems->map->range;
106:   MPI_Request       *send_waits,*recv_waits,*send_waits2,*recv_waits2;
107:   MPI_Status        recv_status;
108:   PetscMPIInt       nindices,source,widx;
109:   PetscInt          *rbuf,*sbuf;
110:   MPI_Status        *send_status,*send_status2;

113:   PetscObjectGetComm((PetscObject)ao,&comm);
114:   MPI_Comm_rank(comm,&rank);
115:   MPI_Comm_size(comm,&size);

117:   /*  first count number of contributors to each processor */
118:   PetscMalloc1(size,&start);
119:   PetscCalloc2(2*size,&sizes,n,&owner);

121:   j       = 0;
122:   lastidx = -1;
123:   for (i=0; i<n; i++) {
124:     if (ia[i] < 0) owner[i] = -1; /* mark negative entries (which are not to be mapped) with a special negative value */
125:     if (ia[i] >= ao->N) owner[i] = -2; /* mark out of range entries with special negative value */
126:     else {
127:       /* if indices are NOT locally sorted, need to start search at the beginning */
128:       if (lastidx > (idx = ia[i])) j = 0;
129:       lastidx = idx;
130:       for (; j<size; j++) {
131:         if (idx >= owners[j] && idx < owners[j+1]) {
132:           sizes[2*j]++;     /* num of indices to be sent */
133:           sizes[2*j+1] = 1; /* send to proc[j] */
134:           owner[i]     = j;
135:           break;
136:         }
137:       }
138:     }
139:   }
140:   sizes[2*rank]=sizes[2*rank+1]=0; /* do not receive from self! */
141:   nsends        = 0;
142:   for (i=0; i<size; i++) nsends += sizes[2*i+1];

144:   /* inform other processors of number of messages and max length*/
145:   PetscMaxSum(comm,sizes,&nmax,&nreceives);

147:   /* allocate arrays */
148:   PetscObjectGetNewTag((PetscObject)ao,&tag1);
149:   PetscObjectGetNewTag((PetscObject)ao,&tag2);

151:   PetscMalloc2(nreceives*nmax,&rindices,nreceives,&recv_waits);
152:   PetscMalloc2(nsends*nmax,&rindices2,nsends,&recv_waits2);

154:   PetscMalloc3(n,&sindices,nsends,&send_waits,nsends,&send_status);
155:   PetscMalloc3(n,&sindices2,nreceives,&send_waits2,nreceives,&send_status2);

157:   /* post 1st receives: receive others requests
158:      since we don't know how long each individual message is we
159:      allocate the largest needed buffer for each receive. Potentially
160:      this is a lot of wasted space.
161:   */
162:   for (i=0,count=0; i<nreceives; i++) {
163:     MPI_Irecv(rindices+nmax*i,nmax,MPIU_INT,MPI_ANY_SOURCE,tag1,comm,recv_waits+count++);
164:   }

166:   /* do 1st sends:
167:       1) starts[i] gives the starting index in svalues for stuff going to
168:          the ith processor
169:   */
170:   start[0] = 0;
171:   for (i=1; i<size; i++) start[i] = start[i-1] + sizes[2*i-2];
172:   for (i=0; i<n; i++) {
173:     j = owner[i];
174:     if (j == -1) continue; /* do not remap negative entries in ia[] */
175:     else if (j == -2) { /* out of range entries get mapped to -1 */
176:       ia[i] = -1;
177:       continue; 
178:     } else if (j != rank) {
179:       sindices[start[j]++]  = ia[i];
180:     } else { /* compute my own map */
181:       ia[i] = maploc[ia[i]-owners[rank]];
182:     }
183:   }

185:   start[0] = 0;
186:   for (i=1; i<size; i++) start[i] = start[i-1] + sizes[2*i-2];
187:   for (i=0,count=0; i<size; i++) {
188:     if (sizes[2*i+1]) {
189:       /* send my request to others */
190:       MPI_Isend(sindices+start[i],sizes[2*i],MPIU_INT,i,tag1,comm,send_waits+count);
191:       /* post receive for the answer of my request */
192:       MPI_Irecv(sindices2+start[i],sizes[2*i],MPIU_INT,i,tag2,comm,recv_waits2+count);
193:       count++;
194:     }
195:   }
196:   if (nsends != count) SETERRQ2(comm,PETSC_ERR_SUP,"nsends %d != count %d",nsends,count);

198:   /* wait on 1st sends */
199:   if (nsends) {
200:     MPI_Waitall(nsends,send_waits,send_status);
201:   }

203:   /* 1st recvs: other's requests */
204:   for (j=0; j< nreceives; j++) {
205:     MPI_Waitany(nreceives,recv_waits,&widx,&recv_status); /* idx: index of handle for operation that completed */
206:     MPI_Get_count(&recv_status,MPIU_INT,&nindices);
207:     rbuf   = rindices+nmax*widx; /* global index */
208:     source = recv_status.MPI_SOURCE;

210:     /* compute mapping */
211:     sbuf = rbuf;
212:     for (i=0; i<nindices; i++) sbuf[i] = maploc[rbuf[i]-owners[rank]];

214:     /* send mapping back to the sender */
215:     MPI_Isend(sbuf,nindices,MPIU_INT,source,tag2,comm,send_waits2+widx);
216:   }

218:   /* wait on 2nd sends */
219:   if (nreceives) {
220:     MPI_Waitall(nreceives,send_waits2,send_status2);
221:   }

223:   /* 2nd recvs: for the answer of my request */
224:   for (j=0; j< nsends; j++) {
225:     MPI_Waitany(nsends,recv_waits2,&widx,&recv_status);
226:     MPI_Get_count(&recv_status,MPIU_INT,&nindices);
227:     source = recv_status.MPI_SOURCE;
228:     /* pack output ia[] */
229:     rbuf  = sindices2+start[source];
230:     count = 0;
231:     for (i=0; i<n; i++) {
232:       if (source == owner[i]) ia[i] = rbuf[count++];
233:     }
234:   }

236:   /* free arrays */
237:   PetscFree(start);
238:   PetscFree2(sizes,owner);
239:   PetscFree2(rindices,recv_waits);
240:   PetscFree2(rindices2,recv_waits2);
241:   PetscFree3(sindices,send_waits,send_status);
242:   PetscFree3(sindices2,send_waits2,send_status2);
243:   return(0);
244: }

246: PetscErrorCode AOPetscToApplication_MemoryScalable(AO ao,PetscInt n,PetscInt *ia)
247: {
248:   PetscErrorCode    ierr;
249:   AO_MemoryScalable *aomems  = (AO_MemoryScalable*)ao->data;
250:   PetscInt          *app_loc = aomems->app_loc;

253:   AOMap_MemoryScalable_private(ao,n,ia,app_loc);
254:   return(0);
255: }

257: PetscErrorCode AOApplicationToPetsc_MemoryScalable(AO ao,PetscInt n,PetscInt *ia)
258: {
259:   PetscErrorCode    ierr;
260:   AO_MemoryScalable *aomems    = (AO_MemoryScalable*)ao->data;
261:   PetscInt          *petsc_loc = aomems->petsc_loc;

264:   AOMap_MemoryScalable_private(ao,n,ia,petsc_loc);
265:   return(0);
266: }

268: static struct _AOOps AOOps_MemoryScalable = {
269:   AOView_MemoryScalable,
270:   AODestroy_MemoryScalable,
271:   AOPetscToApplication_MemoryScalable,
272:   AOApplicationToPetsc_MemoryScalable,
273:   0,
274:   0,
275:   0,
276:   0
277: };

279: PetscErrorCode  AOCreateMemoryScalable_private(MPI_Comm comm,PetscInt napp,const PetscInt from_array[],const PetscInt to_array[],AO ao, PetscInt *aomap_loc)
280: {
281:   PetscErrorCode    ierr;
282:   AO_MemoryScalable *aomems = (AO_MemoryScalable*)ao->data;
283:   PetscLayout       map     = aomems->map;
284:   PetscInt          n_local = map->n,i,j;
285:   PetscMPIInt       rank,size,tag;
286:   PetscInt          *owner,*start,*sizes,nsends,nreceives;
287:   PetscInt          nmax,count,*sindices,*rindices,idx,lastidx;
288:   PetscInt          *owners = aomems->map->range;
289:   MPI_Request       *send_waits,*recv_waits;
290:   MPI_Status        recv_status;
291:   PetscMPIInt       nindices,widx;
292:   PetscInt          *rbuf;
293:   PetscInt          n=napp,ip,ia;
294:   MPI_Status        *send_status;

297:   PetscArrayzero(aomap_loc,n_local);

299:   MPI_Comm_rank(comm,&rank);
300:   MPI_Comm_size(comm,&size);

302:   /*  first count number of contributors (of from_array[]) to each processor */
303:   PetscCalloc1(2*size,&sizes);
304:   PetscMalloc1(n,&owner);

306:   j       = 0;
307:   lastidx = -1;
308:   for (i=0; i<n; i++) {
309:     /* if indices are NOT locally sorted, need to start search at the beginning */
310:     if (lastidx > (idx = from_array[i])) j = 0;
311:     lastidx = idx;
312:     for (; j<size; j++) {
313:       if (idx >= owners[j] && idx < owners[j+1]) {
314:         sizes[2*j]  += 2; /* num of indices to be sent - in pairs (ip,ia) */
315:         sizes[2*j+1] = 1; /* send to proc[j] */
316:         owner[i]     = j;
317:         break;
318:       }
319:     }
320:   }
321:   sizes[2*rank]=sizes[2*rank+1]=0; /* do not receive from self! */
322:   nsends        = 0;
323:   for (i=0; i<size; i++) nsends += sizes[2*i+1];

325:   /* inform other processors of number of messages and max length*/
326:   PetscMaxSum(comm,sizes,&nmax,&nreceives);

328:   /* allocate arrays */
329:   PetscObjectGetNewTag((PetscObject)ao,&tag);
330:   PetscMalloc2(nreceives*nmax,&rindices,nreceives,&recv_waits);
331:   PetscMalloc3(2*n,&sindices,nsends,&send_waits,nsends,&send_status);
332:   PetscMalloc1(size,&start);

334:   /* post receives: */
335:   for (i=0; i<nreceives; i++) {
336:     MPI_Irecv(rindices+nmax*i,nmax,MPIU_INT,MPI_ANY_SOURCE,tag,comm,recv_waits+i);
337:   }

339:   /* do sends:
340:       1) starts[i] gives the starting index in svalues for stuff going to
341:          the ith processor
342:   */
343:   start[0] = 0;
344:   for (i=1; i<size; i++) start[i] = start[i-1] + sizes[2*i-2];
345:   for (i=0; i<n; i++) {
346:     j = owner[i];
347:     if (j != rank) {
348:       ip                   = from_array[i];
349:       ia                   = to_array[i];
350:       sindices[start[j]++] = ip;
351:       sindices[start[j]++] = ia;
352:     } else { /* compute my own map */
353:       ip            = from_array[i] - owners[rank];
354:       ia            = to_array[i];
355:       aomap_loc[ip] = ia;
356:     }
357:   }

359:   start[0] = 0;
360:   for (i=1; i<size; i++) start[i] = start[i-1] + sizes[2*i-2];
361:   for (i=0,count=0; i<size; i++) {
362:     if (sizes[2*i+1]) {
363:       MPI_Isend(sindices+start[i],sizes[2*i],MPIU_INT,i,tag,comm,send_waits+count);
364:       count++;
365:     }
366:   }
367:   if (nsends != count) SETERRQ2(comm,PETSC_ERR_SUP,"nsends %d != count %d",nsends,count);

369:   /* wait on sends */
370:   if (nsends) {
371:     MPI_Waitall(nsends,send_waits,send_status);
372:   }

374:   /* recvs */
375:   count=0;
376:   for (j= nreceives; j>0; j--) {
377:     MPI_Waitany(nreceives,recv_waits,&widx,&recv_status);
378:     MPI_Get_count(&recv_status,MPIU_INT,&nindices);
379:     rbuf = rindices+nmax*widx; /* global index */

381:     /* compute local mapping */
382:     for (i=0; i<nindices; i+=2) { /* pack aomap_loc */
383:       ip            = rbuf[i] - owners[rank]; /* local index */
384:       ia            = rbuf[i+1];
385:       aomap_loc[ip] = ia;
386:     }
387:     count++;
388:   }

390:   PetscFree(start);
391:   PetscFree3(sindices,send_waits,send_status);
392:   PetscFree2(rindices,recv_waits);
393:   PetscFree(owner);
394:   PetscFree(sizes);
395:   return(0);
396: }

398: PETSC_EXTERN PetscErrorCode AOCreate_MemoryScalable(AO ao)
399: {
400:   PetscErrorCode    ierr;
401:   IS                isapp=ao->isapp,ispetsc=ao->ispetsc;
402:   const PetscInt    *mypetsc,*myapp;
403:   PetscInt          napp,n_local,N,i,start,*petsc,*lens,*disp;
404:   MPI_Comm          comm;
405:   AO_MemoryScalable *aomems;
406:   PetscLayout       map;
407:   PetscMPIInt       size,rank;

410:   if (!isapp) SETERRQ(PetscObjectComm((PetscObject)ao),PETSC_ERR_ARG_WRONGSTATE,"AOSetIS() must be called before AOSetType()");
411:   /* create special struct aomems */
412:   PetscNewLog(ao,&aomems);
413:   ao->data = (void*) aomems;
414:   PetscMemcpy(ao->ops,&AOOps_MemoryScalable,sizeof(struct _AOOps));
415:   PetscObjectChangeTypeName((PetscObject)ao,AOMEMORYSCALABLE);

417:   /* transmit all local lengths of isapp to all processors */
418:   PetscObjectGetComm((PetscObject)isapp,&comm);
419:   MPI_Comm_size(comm, &size);
420:   MPI_Comm_rank(comm, &rank);
421:   PetscMalloc2(size,&lens,size,&disp);
422:   ISGetLocalSize(isapp,&napp);
423:   MPI_Allgather(&napp, 1, MPIU_INT, lens, 1, MPIU_INT, comm);

425:   N = 0;
426:   for (i = 0; i < size; i++) {
427:     disp[i] = N;
428:     N      += lens[i];
429:   }

431:   /* If ispetsc is 0 then use "natural" numbering */
432:   if (napp) {
433:     if (!ispetsc) {
434:       start = disp[rank];
435:       PetscMalloc1(napp+1, &petsc);
436:       for (i=0; i<napp; i++) petsc[i] = start + i;
437:     } else {
438:       ISGetIndices(ispetsc,&mypetsc);
439:       petsc = (PetscInt*)mypetsc;
440:     }
441:   } else {
442:     petsc = NULL;
443:   }

445:   /* create a map with global size N - used to determine the local sizes of ao - shall we use local napp instead of N? */
446:   PetscLayoutCreate(comm,&map);
447:   map->bs = 1;
448:   map->N  = N;
449:   PetscLayoutSetUp(map);

451:   ao->N       = N;
452:   ao->n       = map->n;
453:   aomems->map = map;

455:   /* create distributed indices app_loc: petsc->app and petsc_loc: app->petsc */
456:   n_local = map->n;
457:   PetscCalloc2(n_local, &aomems->app_loc,n_local,&aomems->petsc_loc);
458:   PetscLogObjectMemory((PetscObject)ao,2*n_local*sizeof(PetscInt));
459:   ISGetIndices(isapp,&myapp);

461:   AOCreateMemoryScalable_private(comm,napp,petsc,myapp,ao,aomems->app_loc);
462:   AOCreateMemoryScalable_private(comm,napp,myapp,petsc,ao,aomems->petsc_loc);

464:   ISRestoreIndices(isapp,&myapp);
465:   if (napp) {
466:     if (ispetsc) {
467:       ISRestoreIndices(ispetsc,&mypetsc);
468:     } else {
469:       PetscFree(petsc);
470:     }
471:   }
472:   PetscFree2(lens,disp);
473:   return(0);
474: }

476: /*@C
477:    AOCreateMemoryScalable - Creates a memory scalable Section 1.5 Writing Application Codes with PETSc ordering using two integer arrays.

479:    Collective

481:    Input Parameters:
482: +  comm - MPI communicator that is to share AO
483: .  napp - size of integer arrays
484: .  myapp - integer array that defines an ordering
485: -  mypetsc - integer array that defines another ordering (may be NULL to
486:              indicate the natural ordering, that is 0,1,2,3,...)

488:    Output Parameter:
489: .  aoout - the new Section 1.5 Writing Application Codes with PETSc ordering

491:    Level: beginner

493:     Notes:
494:     The arrays myapp and mypetsc must contain the all the integers 0 to napp-1 with no duplicates; that is there cannot be any "holes"
495:            in the indices. Use AOCreateMapping() or AOCreateMappingIS() if you wish to have "holes" in the indices.
496:            Comparing with AOCreateBasic(), this routine trades memory with message communication.

498: .seealso: AOCreateMemoryScalableIS(), AODestroy(), AOPetscToApplication(), AOApplicationToPetsc()
499: @*/
500: PetscErrorCode AOCreateMemoryScalable(MPI_Comm comm,PetscInt napp,const PetscInt myapp[],const PetscInt mypetsc[],AO *aoout)
501: {
503:   IS             isapp,ispetsc;
504:   const PetscInt *app=myapp,*petsc=mypetsc;

507:   ISCreateGeneral(comm,napp,app,PETSC_USE_POINTER,&isapp);
508:   if (mypetsc) {
509:     ISCreateGeneral(comm,napp,petsc,PETSC_USE_POINTER,&ispetsc);
510:   } else {
511:     ispetsc = NULL;
512:   }
513:   AOCreateMemoryScalableIS(isapp,ispetsc,aoout);
514:   ISDestroy(&isapp);
515:   if (mypetsc) {
516:     ISDestroy(&ispetsc);
517:   }
518:   return(0);
519: }

521: /*@C
522:    AOCreateMemoryScalableIS - Creates a memory scalable Section 1.5 Writing Application Codes with PETSc ordering using two index sets.

524:    Collective on IS

526:    Input Parameters:
527: +  isapp - index set that defines an ordering
528: -  ispetsc - index set that defines another ordering (may be NULL to use the
529:              natural ordering)

531:    Output Parameter:
532: .  aoout - the new Section 1.5 Writing Application Codes with PETSc ordering

534:    Level: beginner

536:     Notes:
537:     The index sets isapp and ispetsc must contain the all the integers 0 to napp-1 (where napp is the length of the index sets) with no duplicates;
538:            that is there cannot be any "holes".
539:            Comparing with AOCreateBasicIS(), this routine trades memory with message communication.
540: .seealso: AOCreateMemoryScalable(),  AODestroy()
541: @*/
542: PetscErrorCode  AOCreateMemoryScalableIS(IS isapp,IS ispetsc,AO *aoout)
543: {
545:   MPI_Comm       comm;
546:   AO             ao;

549:   PetscObjectGetComm((PetscObject)isapp,&comm);
550:   AOCreate(comm,&ao);
551:   AOSetIS(ao,isapp,ispetsc);
552:   AOSetType(ao,AOMEMORYSCALABLE);
553:   AOViewFromOptions(ao,NULL,"-ao_view");
554:   *aoout = ao;
555:   return(0);
556: }