Date: 2022-03-31T04:47:21+00:00

Actual source code: matstash.c

      2: #include <petsc/private/matimpl.h>

      4: #define DEFAULT_STASH_SIZE   10000

      6: static PetscErrorCode MatStashScatterBegin_Ref(Mat,MatStash*,PetscInt*);
      7: PETSC_INTERN PetscErrorCode MatStashScatterGetMesg_Ref(MatStash*,PetscMPIInt*,PetscInt**,PetscInt**,PetscScalar**,PetscInt*);
      8: PETSC_INTERN PetscErrorCode MatStashScatterEnd_Ref(MatStash*);
      9: #if !defined(PETSC_HAVE_MPIUNI)
     10: static PetscErrorCode MatStashScatterBegin_BTS(Mat,MatStash*,PetscInt*);
     11: static PetscErrorCode MatStashScatterGetMesg_BTS(MatStash*,PetscMPIInt*,PetscInt**,PetscInt**,PetscScalar**,PetscInt*);
     12: static PetscErrorCode MatStashScatterEnd_BTS(MatStash*);
     13: #endif

     15: /*
     16:   MatStashCreate_Private - Creates a stash,currently used for all the parallel
     17:   matrix implementations. The stash is where elements of a matrix destined
     18:   to be stored on other processors are kept until matrix assembly is done.

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

     22:   Input Parameters:
     23:   comm - communicator, required for scatters.
     24:   bs   - stash block size. used when stashing blocks of values

     26:   Output Parameters:
     27:   stash    - the newly created stash
     28: */
     29: PetscErrorCode MatStashCreate_Private(MPI_Comm comm,PetscInt bs,MatStash *stash)
     30: {
     31:   PetscInt       max,*opt,nopt,i;
     32:   PetscBool      flg;

     34:   /* Require 2 tags,get the second using PetscCommGetNewTag() */
     35:   stash->comm = comm;

     37:   PetscCommGetNewTag(stash->comm,&stash->tag1);
     38:   PetscCommGetNewTag(stash->comm,&stash->tag2);
     39:   MPI_Comm_size(stash->comm,&stash->size);
     40:   MPI_Comm_rank(stash->comm,&stash->rank);
     41:   PetscMalloc1(2*stash->size,&stash->flg_v);
     42:   for (i=0; i<2*stash->size; i++) stash->flg_v[i] = -1;

     44:   nopt = stash->size;
     45:   PetscMalloc1(nopt,&opt);
     46:   PetscOptionsGetIntArray(NULL,NULL,"-matstash_initial_size",opt,&nopt,&flg);
     47:   if (flg) {
     48:     if (nopt == 1)                max = opt[0];
     49:     else if (nopt == stash->size) max = opt[stash->rank];
     50:     else if (stash->rank < nopt)  max = opt[stash->rank];
     51:     else                          max = 0; /* Use default */
     52:     stash->umax = max;
     53:   } else {
     54:     stash->umax = 0;
     55:   }
     56:   PetscFree(opt);
     57:   if (bs <= 0) bs = 1;

     59:   stash->bs         = bs;
     60:   stash->nmax       = 0;
     61:   stash->oldnmax    = 0;
     62:   stash->n          = 0;
     63:   stash->reallocs   = -1;
     64:   stash->space_head = NULL;
     65:   stash->space      = NULL;

     67:   stash->send_waits  = NULL;
     68:   stash->recv_waits  = NULL;
     69:   stash->send_status = NULL;
     70:   stash->nsends      = 0;
     71:   stash->nrecvs      = 0;
     72:   stash->svalues     = NULL;
     73:   stash->rvalues     = NULL;
     74:   stash->rindices    = NULL;
     75:   stash->nprocessed  = 0;
     76:   stash->reproduce   = PETSC_FALSE;
     77:   stash->blocktype   = MPI_DATATYPE_NULL;

     79:   PetscOptionsGetBool(NULL,NULL,"-matstash_reproduce",&stash->reproduce,NULL);
     80: #if !defined(PETSC_HAVE_MPIUNI)
     81:   flg  = PETSC_FALSE;
     82:   PetscOptionsGetBool(NULL,NULL,"-matstash_legacy",&flg,NULL);
     83:   if (!flg) {
     84:     stash->ScatterBegin   = MatStashScatterBegin_BTS;
     85:     stash->ScatterGetMesg = MatStashScatterGetMesg_BTS;
     86:     stash->ScatterEnd     = MatStashScatterEnd_BTS;
     87:     stash->ScatterDestroy = MatStashScatterDestroy_BTS;
     88:   } else {
     89: #endif
     90:     stash->ScatterBegin   = MatStashScatterBegin_Ref;
     91:     stash->ScatterGetMesg = MatStashScatterGetMesg_Ref;
     92:     stash->ScatterEnd     = MatStashScatterEnd_Ref;
     93:     stash->ScatterDestroy = NULL;
     94: #if !defined(PETSC_HAVE_MPIUNI)
     95:   }
     96: #endif
     97:   return 0;
     98: }

    100: /*
    101:    MatStashDestroy_Private - Destroy the stash
    102: */
    103: PetscErrorCode MatStashDestroy_Private(MatStash *stash)
    104: {
    105:   PetscMatStashSpaceDestroy(&stash->space_head);
    106:   if (stash->ScatterDestroy) (*stash->ScatterDestroy)(stash);

    108:   stash->space = NULL;

    110:   PetscFree(stash->flg_v);
    111:   return 0;
    112: }

    114: /*
    115:    MatStashScatterEnd_Private - This is called as the final stage of
    116:    scatter. The final stages of message passing is done here, and
    117:    all the memory used for message passing is cleaned up. This
    118:    routine also resets the stash, and deallocates the memory used
    119:    for the stash. It also keeps track of the current memory usage
    120:    so that the same value can be used the next time through.
    121: */
    122: PetscErrorCode MatStashScatterEnd_Private(MatStash *stash)
    123: {
    124:   (*stash->ScatterEnd)(stash);
    125:   return 0;
    126: }

    128: PETSC_INTERN PetscErrorCode MatStashScatterEnd_Ref(MatStash *stash)
    129: {
    130:   PetscInt       nsends=stash->nsends,bs2,oldnmax,i;
    131:   MPI_Status     *send_status;

    133:   for (i=0; i<2*stash->size; i++) stash->flg_v[i] = -1;
    134:   /* wait on sends */
    135:   if (nsends) {
    136:     PetscMalloc1(2*nsends,&send_status);
    137:     MPI_Waitall(2*nsends,stash->send_waits,send_status);
    138:     PetscFree(send_status);
    139:   }

    141:   /* Now update nmaxold to be app 10% more than max n used, this way the
    142:      wastage of space is reduced the next time this stash is used.
    143:      Also update the oldmax, only if it increases */
    144:   if (stash->n) {
    145:     bs2     = stash->bs*stash->bs;
    146:     oldnmax = ((int)(stash->n * 1.1) + 5)*bs2;
    147:     if (oldnmax > stash->oldnmax) stash->oldnmax = oldnmax;
    148:   }

    150:   stash->nmax       = 0;
    151:   stash->n          = 0;
    152:   stash->reallocs   = -1;
    153:   stash->nprocessed = 0;

    155:   PetscMatStashSpaceDestroy(&stash->space_head);

    157:   stash->space = NULL;

    159:   PetscFree(stash->send_waits);
    160:   PetscFree(stash->recv_waits);
    161:   PetscFree2(stash->svalues,stash->sindices);
    162:   PetscFree(stash->rvalues[0]);
    163:   PetscFree(stash->rvalues);
    164:   PetscFree(stash->rindices[0]);
    165:   PetscFree(stash->rindices);
    166:   return 0;
    167: }

    169: /*
    170:    MatStashGetInfo_Private - Gets the relavant statistics of the stash

    172:    Input Parameters:
    173:    stash    - the stash
    174:    nstash   - the size of the stash. Indicates the number of values stored.
    175:    reallocs - the number of additional mallocs incurred.

    177: */
    178: PetscErrorCode MatStashGetInfo_Private(MatStash *stash,PetscInt *nstash,PetscInt *reallocs)
    179: {
    180:   PetscInt bs2 = stash->bs*stash->bs;

    182:   if (nstash) *nstash = stash->n*bs2;
    183:   if (reallocs) {
    184:     if (stash->reallocs < 0) *reallocs = 0;
    185:     else                     *reallocs = stash->reallocs;
    186:   }
    187:   return 0;
    188: }

    190: /*
    191:    MatStashSetInitialSize_Private - Sets the initial size of the stash

    193:    Input Parameters:
    194:    stash  - the stash
    195:    max    - the value that is used as the max size of the stash.
    196:             this value is used while allocating memory.
    197: */
    198: PetscErrorCode MatStashSetInitialSize_Private(MatStash *stash,PetscInt max)
    199: {
    200:   stash->umax = max;
    201:   return 0;
    202: }

    204: /* MatStashExpand_Private - Expand the stash. This function is called
    205:    when the space in the stash is not sufficient to add the new values
    206:    being inserted into the stash.

    208:    Input Parameters:
    209:    stash - the stash
    210:    incr  - the minimum increase requested

    212:    Notes:
    213:    This routine doubles the currently used memory.
    214:  */
    215: static PetscErrorCode MatStashExpand_Private(MatStash *stash,PetscInt incr)
    216: {
    217:   PetscInt       newnmax,bs2= stash->bs*stash->bs;

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

    229:   /* Get a MatStashSpace and attach it to stash */
    230:   PetscMatStashSpaceGet(bs2,newnmax,&stash->space);
    231:   if (!stash->space_head) { /* new stash or resuing stash->oldnmax */
    232:     stash->space_head = stash->space;
    233:   }

    235:   stash->reallocs++;
    236:   stash->nmax = newnmax;
    237:   return 0;
    238: }
    239: /*
    240:   MatStashValuesRow_Private - inserts values into the stash. This function
    241:   expects the values to be roworiented. Multiple columns belong to the same row
    242:   can be inserted with a single call to this function.

    244:   Input Parameters:
    245:   stash  - the stash
    246:   row    - the global row correspoiding to the values
    247:   n      - the number of elements inserted. All elements belong to the above row.
    248:   idxn   - the global column indices corresponding to each of the values.
    249:   values - the values inserted
    250: */
    251: PetscErrorCode MatStashValuesRow_Private(MatStash *stash,PetscInt row,PetscInt n,const PetscInt idxn[],const PetscScalar values[],PetscBool ignorezeroentries)
    252: {
    253:   PetscInt           i,k,cnt = 0;
    254:   PetscMatStashSpace space=stash->space;

    256:   /* Check and see if we have sufficient memory */
    257:   if (!space || space->local_remaining < n) {
    258:     MatStashExpand_Private(stash,n);
    259:   }
    260:   space = stash->space;
    261:   k     = space->local_used;
    262:   for (i=0; i<n; i++) {
    263:     if (ignorezeroentries && values && values[i] == 0.0) continue;
    264:     space->idx[k] = row;
    265:     space->idy[k] = idxn[i];
    266:     space->val[k] = values ? values[i] : 0.0;
    267:     k++;
    268:     cnt++;
    269:   }
    270:   stash->n               += cnt;
    271:   space->local_used      += cnt;
    272:   space->local_remaining -= cnt;
    273:   return 0;
    274: }

    276: /*
    277:   MatStashValuesCol_Private - inserts values into the stash. This function
    278:   expects the values to be columnoriented. Multiple columns belong to the same row
    279:   can be inserted with a single call to this function.

    281:   Input Parameters:
    282:   stash   - the stash
    283:   row     - the global row correspoiding to the values
    284:   n       - the number of elements inserted. All elements belong to the above row.
    285:   idxn    - the global column indices corresponding to each of the values.
    286:   values  - the values inserted
    287:   stepval - the consecutive values are sepated by a distance of stepval.
    288:             this happens because the input is columnoriented.
    289: */
    290: PetscErrorCode MatStashValuesCol_Private(MatStash *stash,PetscInt row,PetscInt n,const PetscInt idxn[],const PetscScalar values[],PetscInt stepval,PetscBool ignorezeroentries)
    291: {
    292:   PetscInt           i,k,cnt = 0;
    293:   PetscMatStashSpace space=stash->space;

    295:   /* Check and see if we have sufficient memory */
    296:   if (!space || space->local_remaining < n) {
    297:     MatStashExpand_Private(stash,n);
    298:   }
    299:   space = stash->space;
    300:   k     = space->local_used;
    301:   for (i=0; i<n; i++) {
    302:     if (ignorezeroentries && values && values[i*stepval] == 0.0) continue;
    303:     space->idx[k] = row;
    304:     space->idy[k] = idxn[i];
    305:     space->val[k] = values ? values[i*stepval] : 0.0;
    306:     k++;
    307:     cnt++;
    308:   }
    309:   stash->n               += cnt;
    310:   space->local_used      += cnt;
    311:   space->local_remaining -= cnt;
    312:   return 0;
    313: }

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

    322:   Input Parameters:
    323:   stash  - the stash
    324:   row    - the global block-row correspoiding to the values
    325:   n      - the number of elements inserted. All elements belong to the above row.
    326:   idxn   - the global block-column indices corresponding to each of the blocks of
    327:            values. Each block is of size bs*bs.
    328:   values - the values inserted
    329:   rmax   - the number of block-rows in the original block.
    330:   cmax   - the number of block-columns on the original block.
    331:   idx    - the index of the current block-row in the original block.
    332: */
    333: PetscErrorCode MatStashValuesRowBlocked_Private(MatStash *stash,PetscInt row,PetscInt n,const PetscInt idxn[],const PetscScalar values[],PetscInt rmax,PetscInt cmax,PetscInt idx)
    334: {
    335:   PetscInt           i,j,k,bs2,bs=stash->bs,l;
    336:   const PetscScalar  *vals;
    337:   PetscScalar        *array;
    338:   PetscMatStashSpace space=stash->space;

    340:   if (!space || space->local_remaining < n) {
    341:     MatStashExpand_Private(stash,n);
    342:   }
    343:   space = stash->space;
    344:   l     = space->local_used;
    345:   bs2   = bs*bs;
    346:   for (i=0; i<n; i++) {
    347:     space->idx[l] = row;
    348:     space->idy[l] = idxn[i];
    349:     /* Now copy over the block of values. Store the values column oriented.
    350:        This enables inserting multiple blocks belonging to a row with a single
    351:        funtion call */
    352:     array = space->val + bs2*l;
    353:     vals  = values + idx*bs2*n + bs*i;
    354:     for (j=0; j<bs; j++) {
    355:       for (k=0; k<bs; k++) array[k*bs] = values ? vals[k] : 0.0;
    356:       array++;
    357:       vals += cmax*bs;
    358:     }
    359:     l++;
    360:   }
    361:   stash->n               += n;
    362:   space->local_used      += n;
    363:   space->local_remaining -= n;
    364:   return 0;
    365: }

    367: /*
    368:   MatStashValuesColBlocked_Private - inserts blocks of values into the stash.
    369:   This function expects the values to be roworiented. Multiple columns belong
    370:   to the same block-row can be inserted with a single call to this function.
    371:   This function extracts the sub-block of values based on the dimensions of
    372:   the original input block, and the row,col values corresponding to the blocks.

    374:   Input Parameters:
    375:   stash  - the stash
    376:   row    - the global block-row correspoiding to the values
    377:   n      - the number of elements inserted. All elements belong to the above row.
    378:   idxn   - the global block-column indices corresponding to each of the blocks of
    379:            values. Each block is of size bs*bs.
    380:   values - the values inserted
    381:   rmax   - the number of block-rows in the original block.
    382:   cmax   - the number of block-columns on the original block.
    383:   idx    - the index of the current block-row in the original block.
    384: */
    385: PetscErrorCode MatStashValuesColBlocked_Private(MatStash *stash,PetscInt row,PetscInt n,const PetscInt idxn[],const PetscScalar values[],PetscInt rmax,PetscInt cmax,PetscInt idx)
    386: {
    387:   PetscInt           i,j,k,bs2,bs=stash->bs,l;
    388:   const PetscScalar  *vals;
    389:   PetscScalar        *array;
    390:   PetscMatStashSpace space=stash->space;

    392:   if (!space || space->local_remaining < n) {
    393:     MatStashExpand_Private(stash,n);
    394:   }
    395:   space = stash->space;
    396:   l     = space->local_used;
    397:   bs2   = bs*bs;
    398:   for (i=0; i<n; i++) {
    399:     space->idx[l] = row;
    400:     space->idy[l] = idxn[i];
    401:     /* Now copy over the block of values. Store the values column oriented.
    402:      This enables inserting multiple blocks belonging to a row with a single
    403:      funtion call */
    404:     array = space->val + bs2*l;
    405:     vals  = values + idx*bs2*n + bs*i;
    406:     for (j=0; j<bs; j++) {
    407:       for (k=0; k<bs; k++) array[k] = values ? vals[k] : 0.0;
    408:       array += bs;
    409:       vals  += rmax*bs;
    410:     }
    411:     l++;
    412:   }
    413:   stash->n               += n;
    414:   space->local_used      += n;
    415:   space->local_remaining -= n;
    416:   return 0;
    417: }
    418: /*
    419:   MatStashScatterBegin_Private - Initiates the transfer of values to the
    420:   correct owners. This function goes through the stash, and check the
    421:   owners of each stashed value, and sends the values off to the owner
    422:   processors.

    424:   Input Parameters:
    425:   stash  - the stash
    426:   owners - an array of size 'no-of-procs' which gives the ownership range
    427:            for each node.

    429:   Notes:
    430:     The 'owners' array in the cased of the blocked-stash has the
    431:   ranges specified blocked global indices, and for the regular stash in
    432:   the proper global indices.
    433: */
    434: PetscErrorCode MatStashScatterBegin_Private(Mat mat,MatStash *stash,PetscInt *owners)
    435: {
    436:   (*stash->ScatterBegin)(mat,stash,owners);
    437:   return 0;
    438: }

    440: static PetscErrorCode MatStashScatterBegin_Ref(Mat mat,MatStash *stash,PetscInt *owners)
    441: {
    442:   PetscInt           *owner,*startv,*starti,tag1=stash->tag1,tag2=stash->tag2,bs2;
    443:   PetscInt           size=stash->size,nsends;
    444:   PetscInt           count,*sindices,**rindices,i,j,idx,lastidx,l;
    445:   PetscScalar        **rvalues,*svalues;
    446:   MPI_Comm           comm = stash->comm;
    447:   MPI_Request        *send_waits,*recv_waits,*recv_waits1,*recv_waits2;
    448:   PetscMPIInt        *sizes,*nlengths,nreceives;
    449:   PetscInt           *sp_idx,*sp_idy;
    450:   PetscScalar        *sp_val;
    451:   PetscMatStashSpace space,space_next;

    453:   {                             /* make sure all processors are either in INSERTMODE or ADDMODE */
    454:     InsertMode addv;
    455:     MPIU_Allreduce((PetscEnum*)&mat->insertmode,(PetscEnum*)&addv,1,MPIU_ENUM,MPI_BOR,PetscObjectComm((PetscObject)mat));
    457:     mat->insertmode = addv; /* in case this processor had no cache */
    458:   }

    460:   bs2 = stash->bs*stash->bs;

    462:   /*  first count number of contributors to each processor */
    463:   PetscCalloc1(size,&nlengths);
    464:   PetscMalloc1(stash->n+1,&owner);

    466:   i       = j    = 0;
    467:   lastidx = -1;
    468:   space   = stash->space_head;
    469:   while (space) {
    470:     space_next = space->next;
    471:     sp_idx     = space->idx;
    472:     for (l=0; l<space->local_used; l++) {
    473:       /* if indices are NOT locally sorted, need to start search at the beginning */
    474:       if (lastidx > (idx = sp_idx[l])) j = 0;
    475:       lastidx = idx;
    476:       for (; j<size; j++) {
    477:         if (idx >= owners[j] && idx < owners[j+1]) {
    478:           nlengths[j]++; owner[i] = j; break;
    479:         }
    480:       }
    481:       i++;
    482:     }
    483:     space = space_next;
    484:   }

    486:   /* Now check what procs get messages - and compute nsends. */
    487:   PetscCalloc1(size,&sizes);
    488:   for (i=0, nsends=0; i<size; i++) {
    489:     if (nlengths[i]) {
    490:       sizes[i] = 1; nsends++;
    491:     }
    492:   }

    494:   {PetscMPIInt *onodes,*olengths;
    495:    /* Determine the number of messages to expect, their lengths, from from-ids */
    496:    PetscGatherNumberOfMessages(comm,sizes,nlengths,&nreceives);
    497:    PetscGatherMessageLengths(comm,nsends,nreceives,nlengths,&onodes,&olengths);
    498:    /* since clubbing row,col - lengths are multiplied by 2 */
    499:    for (i=0; i<nreceives; i++) olengths[i] *=2;
    500:    PetscPostIrecvInt(comm,tag1,nreceives,onodes,olengths,&rindices,&recv_waits1);
    501:    /* values are size 'bs2' lengths (and remove earlier factor 2 */
    502:    for (i=0; i<nreceives; i++) olengths[i] = olengths[i]*bs2/2;
    503:    PetscPostIrecvScalar(comm,tag2,nreceives,onodes,olengths,&rvalues,&recv_waits2);
    504:    PetscFree(onodes);
    505:    PetscFree(olengths);}

    507:   /* do sends:
    508:       1) starts[i] gives the starting index in svalues for stuff going to
    509:          the ith processor
    510:   */
    511:   PetscMalloc2(bs2*stash->n,&svalues,2*(stash->n+1),&sindices);
    512:   PetscMalloc1(2*nsends,&send_waits);
    513:   PetscMalloc2(size,&startv,size,&starti);
    514:   /* use 2 sends the first with all_a, the next with all_i and all_j */
    515:   startv[0] = 0; starti[0] = 0;
    516:   for (i=1; i<size; i++) {
    517:     startv[i] = startv[i-1] + nlengths[i-1];
    518:     starti[i] = starti[i-1] + 2*nlengths[i-1];
    519:   }

    521:   i     = 0;
    522:   space = stash->space_head;
    523:   while (space) {
    524:     space_next = space->next;
    525:     sp_idx     = space->idx;
    526:     sp_idy     = space->idy;
    527:     sp_val     = space->val;
    528:     for (l=0; l<space->local_used; l++) {
    529:       j = owner[i];
    530:       if (bs2 == 1) {
    531:         svalues[startv[j]] = sp_val[l];
    532:       } else {
    533:         PetscInt    k;
    534:         PetscScalar *buf1,*buf2;
    535:         buf1 = svalues+bs2*startv[j];
    536:         buf2 = space->val + bs2*l;
    537:         for (k=0; k<bs2; k++) buf1[k] = buf2[k];
    538:       }
    539:       sindices[starti[j]]             = sp_idx[l];
    540:       sindices[starti[j]+nlengths[j]] = sp_idy[l];
    541:       startv[j]++;
    542:       starti[j]++;
    543:       i++;
    544:     }
    545:     space = space_next;
    546:   }
    547:   startv[0] = 0;
    548:   for (i=1; i<size; i++) startv[i] = startv[i-1] + nlengths[i-1];

    550:   for (i=0,count=0; i<size; i++) {
    551:     if (sizes[i]) {
    552:       MPI_Isend(sindices+2*startv[i],2*nlengths[i],MPIU_INT,i,tag1,comm,send_waits+count++);
    553:       MPI_Isend(svalues+bs2*startv[i],bs2*nlengths[i],MPIU_SCALAR,i,tag2,comm,send_waits+count++);
    554:     }
    555:   }
    556: #if defined(PETSC_USE_INFO)
    557:   PetscInfo(NULL,"No of messages: %" PetscInt_FMT " \n",nsends);
    558:   for (i=0; i<size; i++) {
    559:     if (sizes[i]) {
    560:       PetscInfo(NULL,"Mesg_to: %" PetscInt_FMT ": size: %zu bytes\n",i,(size_t)(nlengths[i]*(bs2*sizeof(PetscScalar)+2*sizeof(PetscInt))));
    561:     }
    562:   }
    563: #endif
    564:   PetscFree(nlengths);
    565:   PetscFree(owner);
    566:   PetscFree2(startv,starti);
    567:   PetscFree(sizes);

    569:   /* recv_waits need to be contiguous for MatStashScatterGetMesg_Private() */
    570:   PetscMalloc1(2*nreceives,&recv_waits);

    572:   for (i=0; i<nreceives; i++) {
    573:     recv_waits[2*i]   = recv_waits1[i];
    574:     recv_waits[2*i+1] = recv_waits2[i];
    575:   }
    576:   stash->recv_waits = recv_waits;

    578:   PetscFree(recv_waits1);
    579:   PetscFree(recv_waits2);

    581:   stash->svalues         = svalues;
    582:   stash->sindices        = sindices;
    583:   stash->rvalues         = rvalues;
    584:   stash->rindices        = rindices;
    585:   stash->send_waits      = send_waits;
    586:   stash->nsends          = nsends;
    587:   stash->nrecvs          = nreceives;
    588:   stash->reproduce_count = 0;
    589:   return 0;
    590: }

    592: /*
    593:    MatStashScatterGetMesg_Private - This function waits on the receives posted
    594:    in the function MatStashScatterBegin_Private() and returns one message at
    595:    a time to the calling function. If no messages are left, it indicates this
    596:    by setting flg = 0, else it sets flg = 1.

    598:    Input Parameters:
    599:    stash - the stash

    601:    Output Parameters:
    602:    nvals - the number of entries in the current message.
    603:    rows  - an array of row indices (or blocked indices) corresponding to the values
    604:    cols  - an array of columnindices (or blocked indices) corresponding to the values
    605:    vals  - the values
    606:    flg   - 0 indicates no more message left, and the current call has no values associated.
    607:            1 indicates that the current call successfully received a message, and the
    608:              other output parameters nvals,rows,cols,vals are set appropriately.
    609: */
    610: PetscErrorCode MatStashScatterGetMesg_Private(MatStash *stash,PetscMPIInt *nvals,PetscInt **rows,PetscInt **cols,PetscScalar **vals,PetscInt *flg)
    611: {
    612:   (*stash->ScatterGetMesg)(stash,nvals,rows,cols,vals,flg);
    613:   return 0;
    614: }

    616: PETSC_INTERN PetscErrorCode MatStashScatterGetMesg_Ref(MatStash *stash,PetscMPIInt *nvals,PetscInt **rows,PetscInt **cols,PetscScalar **vals,PetscInt *flg)
    617: {
    618:   PetscMPIInt    i,*flg_v = stash->flg_v,i1,i2;
    619:   PetscInt       bs2;
    620:   MPI_Status     recv_status;
    621:   PetscBool      match_found = PETSC_FALSE;

    623:   *flg = 0; /* When a message is discovered this is reset to 1 */
    624:   /* Return if no more messages to process */
    625:   if (stash->nprocessed == stash->nrecvs) return 0;

    627:   bs2 = stash->bs*stash->bs;
    628:   /* If a matching pair of receives are found, process them, and return the data to
    629:      the calling function. Until then keep receiving messages */
    630:   while (!match_found) {
    631:     if (stash->reproduce) {
    632:       i    = stash->reproduce_count++;
    633:       MPI_Wait(stash->recv_waits+i,&recv_status);
    634:     } else {
    635:       MPI_Waitany(2*stash->nrecvs,stash->recv_waits,&i,&recv_status);
    636:     }

    639:     /* Now pack the received message into a structure which is usable by others */
    640:     if (i % 2) {
    641:       MPI_Get_count(&recv_status,MPIU_SCALAR,nvals);

    643:       flg_v[2*recv_status.MPI_SOURCE] = i/2;

    645:       *nvals = *nvals/bs2;
    646:     } else {
    647:       MPI_Get_count(&recv_status,MPIU_INT,nvals);

    649:       flg_v[2*recv_status.MPI_SOURCE+1] = i/2;

    651:       *nvals = *nvals/2; /* This message has both row indices and col indices */
    652:     }

    654:     /* Check if we have both messages from this proc */
    655:     i1 = flg_v[2*recv_status.MPI_SOURCE];
    656:     i2 = flg_v[2*recv_status.MPI_SOURCE+1];
    657:     if (i1 != -1 && i2 != -1) {
    658:       *rows = stash->rindices[i2];
    659:       *cols = *rows + *nvals;
    660:       *vals = stash->rvalues[i1];
    661:       *flg  = 1;
    662:       stash->nprocessed++;
    663:       match_found = PETSC_TRUE;
    664:     }
    665:   }
    666:   return 0;
    667: }

    669: #if !defined(PETSC_HAVE_MPIUNI)
    670: typedef struct {
    671:   PetscInt row;
    672:   PetscInt col;
    673:   PetscScalar vals[1];          /* Actually an array of length bs2 */
    674: } MatStashBlock;

    676: static PetscErrorCode MatStashSortCompress_Private(MatStash *stash,InsertMode insertmode)
    677: {
    678:   PetscMatStashSpace space;
    679:   PetscInt n = stash->n,bs = stash->bs,bs2 = bs*bs,cnt,*row,*col,*perm,rowstart,i;
    680:   PetscScalar **valptr;

    682:   PetscMalloc4(n,&row,n,&col,n,&valptr,n,&perm);
    683:   for (space=stash->space_head,cnt=0; space; space=space->next) {
    684:     for (i=0; i<space->local_used; i++) {
    685:       row[cnt] = space->idx[i];
    686:       col[cnt] = space->idy[i];
    687:       valptr[cnt] = &space->val[i*bs2];
    688:       perm[cnt] = cnt;          /* Will tell us where to find valptr after sorting row[] and col[] */
    689:       cnt++;
    690:     }
    691:   }
    693:   PetscSortIntWithArrayPair(n,row,col,perm);
    694:   /* Scan through the rows, sorting each one, combining duplicates, and packing send buffers */
    695:   for (rowstart=0,cnt=0,i=1; i<=n; i++) {
    696:     if (i == n || row[i] != row[rowstart]) {         /* Sort the last row. */
    697:       PetscInt colstart;
    698:       PetscSortIntWithArray(i-rowstart,&col[rowstart],&perm[rowstart]);
    699:       for (colstart=rowstart; colstart<i;) { /* Compress multiple insertions to the same location */
    700:         PetscInt j,l;
    701:         MatStashBlock *block;
    702:         PetscSegBufferGet(stash->segsendblocks,1,&block);
    703:         block->row = row[rowstart];
    704:         block->col = col[colstart];
    705:         PetscArraycpy(block->vals,valptr[perm[colstart]],bs2);
    706:         for (j=colstart+1; j<i && col[j] == col[colstart]; j++) { /* Add any extra stashed blocks at the same (row,col) */
    707:           if (insertmode == ADD_VALUES) {
    708:             for (l=0; l<bs2; l++) block->vals[l] += valptr[perm[j]][l];
    709:           } else {
    710:             PetscArraycpy(block->vals,valptr[perm[j]],bs2);
    711:           }
    712:         }
    713:         colstart = j;
    714:       }
    715:       rowstart = i;
    716:     }
    717:   }
    718:   PetscFree4(row,col,valptr,perm);
    719:   return 0;
    720: }

    722: static PetscErrorCode MatStashBlockTypeSetUp(MatStash *stash)
    723: {
    724:   if (stash->blocktype == MPI_DATATYPE_NULL) {
    725:     PetscInt     bs2 = PetscSqr(stash->bs);
    726:     PetscMPIInt  blocklens[2];
    727:     MPI_Aint     displs[2];
    728:     MPI_Datatype types[2],stype;
    729:     /* Note that DummyBlock is a type having standard layout, even when PetscScalar is C++ std::complex.
    730:        std::complex itself has standard layout, so does DummyBlock, recursively.
    731:        To be compatible with C++ std::complex, complex implementations on GPUs must also have standard layout,
    732:        though they can have different alignment, e.g, 16 bytes for double complex, instead of 8 bytes as in GCC stdlibc++.
    733:        offsetof(type, member) only requires type to have standard layout. Ref. https://en.cppreference.com/w/cpp/types/offsetof.

    735:        We can test if std::complex has standard layout with the following code:
    736:        #include <iostream>
    737:        #include <type_traits>
    738:        #include <complex>
    739:        int main() {
    740:          std::cout << std::boolalpha;
    741:          std::cout << std::is_standard_layout<std::complex<double> >::value << '\n';
    742:        }
    743:        Output: true
    744:      */
    745:     struct DummyBlock {PetscInt row,col; PetscScalar vals;};

    747:     stash->blocktype_size = offsetof(struct DummyBlock,vals) + bs2*sizeof(PetscScalar);
    748:     if (stash->blocktype_size % sizeof(PetscInt)) { /* Implies that PetscInt is larger and does not satisfy alignment without padding */
    749:       stash->blocktype_size += sizeof(PetscInt) - stash->blocktype_size % sizeof(PetscInt);
    750:     }
    751:     PetscSegBufferCreate(stash->blocktype_size,1,&stash->segsendblocks);
    752:     PetscSegBufferCreate(stash->blocktype_size,1,&stash->segrecvblocks);
    753:     PetscSegBufferCreate(sizeof(MatStashFrame),1,&stash->segrecvframe);
    754:     blocklens[0] = 2;
    755:     blocklens[1] = bs2;
    756:     displs[0] = offsetof(struct DummyBlock,row);
    757:     displs[1] = offsetof(struct DummyBlock,vals);
    758:     types[0] = MPIU_INT;
    759:     types[1] = MPIU_SCALAR;
    760:     MPI_Type_create_struct(2,blocklens,displs,types,&stype);
    761:     MPI_Type_commit(&stype);
    762:     MPI_Type_create_resized(stype,0,stash->blocktype_size,&stash->blocktype);
    763:     MPI_Type_commit(&stash->blocktype);
    764:     MPI_Type_free(&stype);
    765:   }
    766:   return 0;
    767: }

    769: /* Callback invoked after target rank has initiatied receive of rendezvous message.
    770:  * Here we post the main sends.
    771:  */
    772: static PetscErrorCode MatStashBTSSend_Private(MPI_Comm comm,const PetscMPIInt tag[],PetscMPIInt rankid,PetscMPIInt rank,void *sdata,MPI_Request req[],void *ctx)
    773: {
    774:   MatStash *stash = (MatStash*)ctx;
    775:   MatStashHeader *hdr = (MatStashHeader*)sdata;

    778:   MPI_Isend(stash->sendframes[rankid].buffer,hdr->count,stash->blocktype,rank,tag[0],comm,&req[0]);
    779:   stash->sendframes[rankid].count = hdr->count;
    780:   stash->sendframes[rankid].pending = 1;
    781:   return 0;
    782: }

    784: /* Callback invoked by target after receiving rendezvous message.
    785:  * Here we post the main recvs.
    786:  */
    787: static PetscErrorCode MatStashBTSRecv_Private(MPI_Comm comm,const PetscMPIInt tag[],PetscMPIInt rank,void *rdata,MPI_Request req[],void *ctx)
    788: {
    789:   MatStash *stash = (MatStash*)ctx;
    790:   MatStashHeader *hdr = (MatStashHeader*)rdata;
    791:   MatStashFrame *frame;

    793:   PetscSegBufferGet(stash->segrecvframe,1,&frame);
    794:   PetscSegBufferGet(stash->segrecvblocks,hdr->count,&frame->buffer);
    795:   MPI_Irecv(frame->buffer,hdr->count,stash->blocktype,rank,tag[0],comm,&req[0]);
    796:   frame->count = hdr->count;
    797:   frame->pending = 1;
    798:   return 0;
    799: }

    801: /*
    802:  * owners[] contains the ownership ranges; may be indexed by either blocks or scalars
    803:  */
    804: static PetscErrorCode MatStashScatterBegin_BTS(Mat mat,MatStash *stash,PetscInt owners[])
    805: {
    807:   size_t nblocks;
    808:   char *sendblocks;

    810:   if (PetscDefined(USE_DEBUG)) { /* make sure all processors are either in INSERTMODE or ADDMODE */
    811:     InsertMode addv;
    812:     MPIU_Allreduce((PetscEnum*)&mat->insertmode,(PetscEnum*)&addv,1,MPIU_ENUM,MPI_BOR,PetscObjectComm((PetscObject)mat));
    814:   }

    816:   MatStashBlockTypeSetUp(stash);
    817:   MatStashSortCompress_Private(stash,mat->insertmode);
    818:   PetscSegBufferGetSize(stash->segsendblocks,&nblocks);
    819:   PetscSegBufferExtractInPlace(stash->segsendblocks,&sendblocks);
    820:   if (stash->first_assembly_done) { /* Set up sendhdrs and sendframes for each rank that we sent before */
    821:     PetscInt i;
    822:     size_t b;
    823:     for (i=0,b=0; i<stash->nsendranks; i++) {
    824:       stash->sendframes[i].buffer = &sendblocks[b*stash->blocktype_size];
    825:       /* sendhdr is never actually sent, but the count is used by MatStashBTSSend_Private */
    826:       stash->sendhdr[i].count = 0; /* Might remain empty (in which case we send a zero-sized message) if no values are communicated to that process */
    827:       for (; b<nblocks; b++) {
    828:         MatStashBlock *sendblock_b = (MatStashBlock*)&sendblocks[b*stash->blocktype_size];
    830:         if (sendblock_b->row >= owners[stash->sendranks[i]+1]) break;
    831:         stash->sendhdr[i].count++;
    832:       }
    833:     }
    834:   } else {                      /* Dynamically count and pack (first time) */
    835:     PetscInt sendno;
    836:     size_t i,rowstart;

    838:     /* Count number of send ranks and allocate for sends */
    839:     stash->nsendranks = 0;
    840:     for (rowstart=0; rowstart<nblocks;) {
    841:       PetscInt owner;
    842:       MatStashBlock *sendblock_rowstart = (MatStashBlock*)&sendblocks[rowstart*stash->blocktype_size];
    843:       PetscFindInt(sendblock_rowstart->row,stash->size+1,owners,&owner);
    844:       if (owner < 0) owner = -(owner+2);
    845:       for (i=rowstart+1; i<nblocks; i++) { /* Move forward through a run of blocks with the same owner */
    846:         MatStashBlock *sendblock_i = (MatStashBlock*)&sendblocks[i*stash->blocktype_size];
    847:         if (sendblock_i->row >= owners[owner+1]) break;
    848:       }
    849:       stash->nsendranks++;
    850:       rowstart = i;
    851:     }
    852:     PetscMalloc3(stash->nsendranks,&stash->sendranks,stash->nsendranks,&stash->sendhdr,stash->nsendranks,&stash->sendframes);

    854:     /* Set up sendhdrs and sendframes */
    855:     sendno = 0;
    856:     for (rowstart=0; rowstart<nblocks;) {
    857:       PetscInt owner;
    858:       MatStashBlock *sendblock_rowstart = (MatStashBlock*)&sendblocks[rowstart*stash->blocktype_size];
    859:       PetscFindInt(sendblock_rowstart->row,stash->size+1,owners,&owner);
    860:       if (owner < 0) owner = -(owner+2);
    861:       stash->sendranks[sendno] = owner;
    862:       for (i=rowstart+1; i<nblocks; i++) { /* Move forward through a run of blocks with the same owner */
    863:         MatStashBlock *sendblock_i = (MatStashBlock*)&sendblocks[i*stash->blocktype_size];
    864:         if (sendblock_i->row >= owners[owner+1]) break;
    865:       }
    866:       stash->sendframes[sendno].buffer = sendblock_rowstart;
    867:       stash->sendframes[sendno].pending = 0;
    868:       stash->sendhdr[sendno].count = i - rowstart;
    869:       sendno++;
    870:       rowstart = i;
    871:     }
    873:   }

    875:   /* Encode insertmode on the outgoing messages. If we want to support more than two options, we would need a new
    876:    * message or a dummy entry of some sort. */
    877:   if (mat->insertmode == INSERT_VALUES) {
    878:     size_t i;
    879:     for (i=0; i<nblocks; i++) {
    880:       MatStashBlock *sendblock_i = (MatStashBlock*)&sendblocks[i*stash->blocktype_size];
    881:       sendblock_i->row = -(sendblock_i->row+1);
    882:     }
    883:   }

    885:   if (stash->first_assembly_done) {
    886:     PetscMPIInt i,tag;
    887:     PetscCommGetNewTag(stash->comm,&tag);
    888:     for (i=0; i<stash->nrecvranks; i++) {
    889:       MatStashBTSRecv_Private(stash->comm,&tag,stash->recvranks[i],&stash->recvhdr[i],&stash->recvreqs[i],stash);
    890:     }
    891:     for (i=0; i<stash->nsendranks; i++) {
    892:       MatStashBTSSend_Private(stash->comm,&tag,i,stash->sendranks[i],&stash->sendhdr[i],&stash->sendreqs[i],stash);
    893:     }
    894:     stash->use_status = PETSC_TRUE; /* Use count from message status. */
    895:   } else {
    896:     PetscCommBuildTwoSidedFReq(stash->comm,1,MPIU_INT,stash->nsendranks,stash->sendranks,(PetscInt*)stash->sendhdr,
    897:                                       &stash->nrecvranks,&stash->recvranks,(PetscInt*)&stash->recvhdr,1,&stash->sendreqs,&stash->recvreqs,
    898:                                       MatStashBTSSend_Private,MatStashBTSRecv_Private,stash);
    899:     PetscMalloc2(stash->nrecvranks,&stash->some_indices,stash->nrecvranks,&stash->some_statuses);
    900:     stash->use_status = PETSC_FALSE; /* Use count from header instead of from message. */
    901:   }

    903:   PetscSegBufferExtractInPlace(stash->segrecvframe,&stash->recvframes);
    904:   stash->recvframe_active     = NULL;
    905:   stash->recvframe_i          = 0;
    906:   stash->some_i               = 0;
    907:   stash->some_count           = 0;
    908:   stash->recvcount            = 0;
    909:   stash->first_assembly_done  = mat->assembly_subset; /* See the same logic in VecAssemblyBegin_MPI_BTS */
    910:   stash->insertmode           = &mat->insertmode;
    911:   return 0;
    912: }

    914: static PetscErrorCode MatStashScatterGetMesg_BTS(MatStash *stash,PetscMPIInt *n,PetscInt **row,PetscInt **col,PetscScalar **val,PetscInt *flg)
    915: {
    916:   MatStashBlock *block;

    918:   *flg = 0;
    919:   while (!stash->recvframe_active || stash->recvframe_i == stash->recvframe_count) {
    920:     if (stash->some_i == stash->some_count) {
    921:       if (stash->recvcount == stash->nrecvranks) return 0; /* Done */
    922:       MPI_Waitsome(stash->nrecvranks,stash->recvreqs,&stash->some_count,stash->some_indices,stash->use_status?stash->some_statuses:MPI_STATUSES_IGNORE);
    923:       stash->some_i = 0;
    924:     }
    925:     stash->recvframe_active = &stash->recvframes[stash->some_indices[stash->some_i]];
    926:     stash->recvframe_count = stash->recvframe_active->count; /* From header; maximum count */
    927:     if (stash->use_status) { /* Count what was actually sent */
    928:       MPI_Get_count(&stash->some_statuses[stash->some_i],stash->blocktype,&stash->recvframe_count);
    929:     }
    930:     if (stash->recvframe_count > 0) { /* Check for InsertMode consistency */
    931:       block = (MatStashBlock*)&((char*)stash->recvframe_active->buffer)[0];
    932:       if (PetscUnlikely(*stash->insertmode == NOT_SET_VALUES)) *stash->insertmode = block->row < 0 ? INSERT_VALUES : ADD_VALUES;
    935:     }
    936:     stash->some_i++;
    937:     stash->recvcount++;
    938:     stash->recvframe_i = 0;
    939:   }
    940:   *n = 1;
    941:   block = (MatStashBlock*)&((char*)stash->recvframe_active->buffer)[stash->recvframe_i*stash->blocktype_size];
    942:   if (block->row < 0) block->row = -(block->row + 1);
    943:   *row = &block->row;
    944:   *col = &block->col;
    945:   *val = block->vals;
    946:   stash->recvframe_i++;
    947:   *flg = 1;
    948:   return 0;
    949: }

    951: static PetscErrorCode MatStashScatterEnd_BTS(MatStash *stash)
    952: {
    953:   MPI_Waitall(stash->nsendranks,stash->sendreqs,MPI_STATUSES_IGNORE);
    954:   if (stash->first_assembly_done) { /* Reuse the communication contexts, so consolidate and reset segrecvblocks  */
    955:     void *dummy;
    956:     PetscSegBufferExtractInPlace(stash->segrecvblocks,&dummy);
    957:   } else {                      /* No reuse, so collect everything. */
    958:     MatStashScatterDestroy_BTS(stash);
    959:   }

    961:   /* Now update nmaxold to be app 10% more than max n used, this way the
    962:      wastage of space is reduced the next time this stash is used.
    963:      Also update the oldmax, only if it increases */
    964:   if (stash->n) {
    965:     PetscInt bs2     = stash->bs*stash->bs;
    966:     PetscInt oldnmax = ((int)(stash->n * 1.1) + 5)*bs2;
    967:     if (oldnmax > stash->oldnmax) stash->oldnmax = oldnmax;
    968:   }

    970:   stash->nmax       = 0;
    971:   stash->n          = 0;
    972:   stash->reallocs   = -1;
    973:   stash->nprocessed = 0;

    975:   PetscMatStashSpaceDestroy(&stash->space_head);

    977:   stash->space = NULL;

    979:   return 0;
    980: }

    982: PetscErrorCode MatStashScatterDestroy_BTS(MatStash *stash)
    983: {
    984:   PetscSegBufferDestroy(&stash->segsendblocks);
    985:   PetscSegBufferDestroy(&stash->segrecvframe);
    986:   stash->recvframes = NULL;
    987:   PetscSegBufferDestroy(&stash->segrecvblocks);
    988:   if (stash->blocktype != MPI_DATATYPE_NULL) {
    989:     MPI_Type_free(&stash->blocktype);
    990:   }
    991:   stash->nsendranks = 0;
    992:   stash->nrecvranks = 0;
    993:   PetscFree3(stash->sendranks,stash->sendhdr,stash->sendframes);
    994:   PetscFree(stash->sendreqs);
    995:   PetscFree(stash->recvreqs);
    996:   PetscFree(stash->recvranks);
    997:   PetscFree(stash->recvhdr);
    998:   PetscFree2(stash->some_indices,stash->some_statuses);
    999:   return 0;
    1000: }
    1001: #endif