Actual source code: mmdense.c
petsc-3.15.0 2021-03-30
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      2: /*
      3:    Support for the parallel dense matrix vector multiply
      4: */
      5: #include <../src/mat/impls/dense/mpi/mpidense.h>
      6: #include <petscblaslapack.h>

      8: PetscErrorCode MatSetUpMultiply_MPIDense(Mat mat)
      9: {
     10:   Mat_MPIDense   *mdn = (Mat_MPIDense*)mat->data;

     14:   /* Create local vector that is used to scatter into */
     15:   VecDestroy(&mdn->lvec);
     16:   if (mdn->A) {
     17:     MatCreateVecs(mdn->A,&mdn->lvec,NULL);
     18:     PetscLogObjectParent((PetscObject)mat,(PetscObject)mdn->lvec);
     19:   }
     20:   if (!mdn->Mvctx) {
     21:     PetscLayoutSetUp(mat->cmap);
     22:     PetscSFCreate(PetscObjectComm((PetscObject)mat),&mdn->Mvctx);
     23:     PetscSFSetGraphWithPattern(mdn->Mvctx,mat->cmap,PETSCSF_PATTERN_ALLGATHER);
     24:     PetscLogObjectParent((PetscObject)mat,(PetscObject)mdn->Mvctx);
     25:   }
     26:   return(0);
     27: }

     29: static PetscErrorCode MatCreateSubMatrices_MPIDense_Local(Mat,PetscInt,const IS[],const IS[],MatReuse,Mat*);

     31: PetscErrorCode MatCreateSubMatrices_MPIDense(Mat C,PetscInt ismax,const IS isrow[],const IS iscol[],MatReuse scall,Mat *submat[])
     32: {
     34:   PetscInt       nmax,nstages_local,nstages,i,pos,max_no;

     37:   /* Allocate memory to hold all the submatrices */
     38:   if (scall != MAT_REUSE_MATRIX) {
     39:     PetscCalloc1(ismax+1,submat);
     40:   }
     41:   /* Determine the number of stages through which submatrices are done */
     42:   nmax = 20*1000000 / (C->cmap->N * sizeof(PetscInt));
     43:   if (!nmax) nmax = 1;
     44:   nstages_local = ismax/nmax + ((ismax % nmax) ? 1 : 0);

     46:   /* Make sure every processor loops through the nstages */
     47:   MPIU_Allreduce(&nstages_local,&nstages,1,MPIU_INT,MPI_MAX,PetscObjectComm((PetscObject)C));

     50:   for (i=0,pos=0; i<nstages; i++) {
     51:     if (pos+nmax <= ismax) max_no = nmax;
     52:     else if (pos == ismax) max_no = 0;
     53:     else                   max_no = ismax-pos;
     54:     MatCreateSubMatrices_MPIDense_Local(C,max_no,isrow+pos,iscol+pos,scall,*submat+pos);
     55:     pos += max_no;
     56:   }
     57:   return(0);
     58: }
     59: /* -------------------------------------------------------------------------*/
     60: PetscErrorCode MatCreateSubMatrices_MPIDense_Local(Mat C,PetscInt ismax,const IS isrow[],const IS iscol[],MatReuse scall,Mat *submats)
     61: {
     62:   Mat_MPIDense   *c = (Mat_MPIDense*)C->data;
     63:   Mat            A  = c->A;
     64:   Mat_SeqDense   *a = (Mat_SeqDense*)A->data,*mat;
     66:   PetscMPIInt    rank,size,tag0,tag1,idex,end,i;
     67:   PetscInt       N = C->cmap->N,rstart = C->rmap->rstart,count;
     68:   const PetscInt **irow,**icol,*irow_i;
     69:   PetscInt       *nrow,*ncol,*w1,*w3,*w4,*rtable,start;
     70:   PetscInt       **sbuf1,m,j,k,l,ct1,**rbuf1,row,proc;
     71:   PetscInt       nrqs,msz,**ptr,*ctr,*pa,*tmp,bsz,nrqr;
     72:   PetscInt       is_no,jmax,**rmap,*rmap_i;
     73:   PetscInt       ctr_j,*sbuf1_j,*rbuf1_i;
     74:   MPI_Request    *s_waits1,*r_waits1,*s_waits2,*r_waits2;
     75:   MPI_Status     *r_status1,*r_status2,*s_status1,*s_status2;
     76:   MPI_Comm       comm;
     77:   PetscScalar    **rbuf2,**sbuf2;
     78:   PetscBool      sorted;

     81:   PetscObjectGetComm((PetscObject)C,&comm);
     82:   tag0 = ((PetscObject)C)->tag;
     83:   MPI_Comm_rank(comm,&rank);
     84:   MPI_Comm_size(comm,&size);
     85:   m    = C->rmap->N;

     87:   /* Get some new tags to keep the communication clean */
     88:   PetscObjectGetNewTag((PetscObject)C,&tag1);

     90:   /* Check if the col indices are sorted */
     91:   for (i=0; i<ismax; i++) {
     92:     ISSorted(isrow[i],&sorted);
     93:     if (!sorted) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"ISrow is not sorted");
     94:     ISSorted(iscol[i],&sorted);
     95:     if (!sorted) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONGSTATE,"IScol is not sorted");
     96:   }

     98:   PetscMalloc5(ismax,(PetscInt***)&irow,ismax,(PetscInt***)&icol,ismax,&nrow,ismax,&ncol,m,&rtable);
     99:   for (i=0; i<ismax; i++) {
    100:     ISGetIndices(isrow[i],&irow[i]);
    101:     ISGetIndices(iscol[i],&icol[i]);
    102:     ISGetLocalSize(isrow[i],&nrow[i]);
    103:     ISGetLocalSize(iscol[i],&ncol[i]);
    104:   }

    106:   /* Create hash table for the mapping :row -> proc*/
    107:   for (i=0,j=0; i<size; i++) {
    108:     jmax = C->rmap->range[i+1];
    109:     for (; j<jmax; j++) rtable[j] = i;
    110:   }

    112:   /* evaluate communication - mesg to who,length of mesg, and buffer space
    113:      required. Based on this, buffers are allocated, and data copied into them*/
    114:   PetscMalloc3(2*size,&w1,size,&w3,size,&w4);
    115:   PetscArrayzero(w1,size*2); /* initialize work vector*/
    116:   PetscArrayzero(w3,size); /* initialize work vector*/
    117:   for (i=0; i<ismax; i++) {
    118:     PetscArrayzero(w4,size); /* initialize work vector*/
    119:     jmax   = nrow[i];
    120:     irow_i = irow[i];
    121:     for (j=0; j<jmax; j++) {
    122:       row  = irow_i[j];
    123:       proc = rtable[row];
    124:       w4[proc]++;
    125:     }
    126:     for (j=0; j<size; j++) {
    127:       if (w4[j]) { w1[2*j] += w4[j];  w3[j]++;}
    128:     }
    129:   }

    131:   nrqs       = 0;              /* no of outgoing messages */
    132:   msz        = 0;              /* total mesg length (for all procs) */
    133:   w1[2*rank] = 0;              /* no mesg sent to self */
    134:   w3[rank]   = 0;
    135:   for (i=0; i<size; i++) {
    136:     if (w1[2*i])  { w1[2*i+1] = 1; nrqs++;} /* there exists a message to proc i */
    137:   }
    138:   PetscMalloc1(nrqs+1,&pa); /*(proc -array)*/
    139:   for (i=0,j=0; i<size; i++) {
    140:     if (w1[2*i]) { pa[j] = i; j++; }
    141:   }

    143:   /* Each message would have a header = 1 + 2*(no of IS) + data */
    144:   for (i=0; i<nrqs; i++) {
    145:     j        = pa[i];
    146:     w1[2*j] += w1[2*j+1] + 2* w3[j];
    147:     msz     += w1[2*j];
    148:   }
    149:   /* Do a global reduction to determine how many messages to expect*/
    150:   PetscMaxSum(comm,w1,&bsz,&nrqr);

    152:   /* Allocate memory for recv buffers . Make sure rbuf1[0] exists by adding 1 to the buffer length */
    153:   PetscMalloc1(nrqr+1,&rbuf1);
    154:   PetscMalloc1(nrqr*bsz,&rbuf1[0]);
    155:   for (i=1; i<nrqr; ++i) rbuf1[i] = rbuf1[i-1] + bsz;

    157:   /* Post the receives */
    158:   PetscMalloc1(nrqr+1,&r_waits1);
    159:   for (i=0; i<nrqr; ++i) {
    160:     MPI_Irecv(rbuf1[i],bsz,MPIU_INT,MPI_ANY_SOURCE,tag0,comm,r_waits1+i);
    161:   }

    163:   /* Allocate Memory for outgoing messages */
    164:   PetscMalloc4(size,&sbuf1,size,&ptr,2*msz,&tmp,size,&ctr);
    165:   PetscArrayzero(sbuf1,size);
    166:   PetscArrayzero(ptr,size);
    167:   {
    168:     PetscInt *iptr = tmp,ict = 0;
    169:     for (i=0; i<nrqs; i++) {
    170:       j        = pa[i];
    171:       iptr    += ict;
    172:       sbuf1[j] = iptr;
    173:       ict      = w1[2*j];
    174:     }
    175:   }

    177:   /* Form the outgoing messages */
    178:   /* Initialize the header space */
    179:   for (i=0; i<nrqs; i++) {
    180:     j           = pa[i];
    181:     sbuf1[j][0] = 0;
    182:     PetscArrayzero(sbuf1[j]+1,2*w3[j]);
    183:     ptr[j]      = sbuf1[j] + 2*w3[j] + 1;
    184:   }

    186:   /* Parse the isrow and copy data into outbuf */
    187:   for (i=0; i<ismax; i++) {
    188:     PetscArrayzero(ctr,size);
    189:     irow_i = irow[i];
    190:     jmax   = nrow[i];
    191:     for (j=0; j<jmax; j++) {  /* parse the indices of each IS */
    192:       row  = irow_i[j];
    193:       proc = rtable[row];
    194:       if (proc != rank) { /* copy to the outgoing buf*/
    195:         ctr[proc]++;
    196:         *ptr[proc] = row;
    197:         ptr[proc]++;
    198:       }
    199:     }
    200:     /* Update the headers for the current IS */
    201:     for (j=0; j<size; j++) { /* Can Optimise this loop too */
    202:       if ((ctr_j = ctr[j])) {
    203:         sbuf1_j        = sbuf1[j];
    204:         k              = ++sbuf1_j[0];
    205:         sbuf1_j[2*k]   = ctr_j;
    206:         sbuf1_j[2*k-1] = i;
    207:       }
    208:     }
    209:   }

    211:   /*  Now  post the sends */
    212:   PetscMalloc1(nrqs+1,&s_waits1);
    213:   for (i=0; i<nrqs; ++i) {
    214:     j    = pa[i];
    215:     MPI_Isend(sbuf1[j],w1[2*j],MPIU_INT,j,tag0,comm,s_waits1+i);
    216:   }

    218:   /* Post receives to capture the row_data from other procs */
    219:   PetscMalloc1(nrqs+1,&r_waits2);
    220:   PetscMalloc1(nrqs+1,&rbuf2);
    221:   for (i=0; i<nrqs; i++) {
    222:     j     = pa[i];
    223:     count = (w1[2*j] - (2*sbuf1[j][0] + 1))*N;
    224:     PetscMalloc1(count+1,&rbuf2[i]);
    225:     MPI_Irecv(rbuf2[i],count,MPIU_SCALAR,j,tag1,comm,r_waits2+i);
    226:   }

    228:   /* Receive messages(row_nos) and then, pack and send off the rowvalues
    229:      to the correct processors */

    231:   PetscMalloc1(nrqr+1,&s_waits2);
    232:   PetscMalloc1(nrqr+1,&r_status1);
    233:   PetscMalloc1(nrqr+1,&sbuf2);

    235:   {
    236:     PetscScalar *sbuf2_i,*v_start;
    237:     PetscInt    s_proc;
    238:     for (i=0; i<nrqr; ++i) {
    239:       MPI_Waitany(nrqr,r_waits1,&idex,r_status1+i);
    240:       s_proc  = r_status1[i].MPI_SOURCE;         /* send processor */
    241:       rbuf1_i = rbuf1[idex];         /* Actual message from s_proc */
    242:       /* no of rows = end - start; since start is array idex[], 0idex, whel end
    243:          is length of the buffer - which is 1idex */
    244:       start = 2*rbuf1_i[0] + 1;
    245:       MPI_Get_count(r_status1+i,MPIU_INT,&end);
    246:       /* allocate memory sufficinet to hold all the row values */
    247:       PetscMalloc1((end-start)*N,&sbuf2[idex]);
    248:       sbuf2_i = sbuf2[idex];
    249:       /* Now pack the data */
    250:       for (j=start; j<end; j++) {
    251:         row     = rbuf1_i[j] - rstart;
    252:         v_start = a->v + row;
    253:         for (k=0; k<N; k++) {
    254:           sbuf2_i[0] = v_start[0];
    255:           sbuf2_i++;
    256:           v_start += a->lda;
    257:         }
    258:       }
    259:       /* Now send off the data */
    260:       MPI_Isend(sbuf2[idex],(end-start)*N,MPIU_SCALAR,s_proc,tag1,comm,s_waits2+i);
    261:     }
    262:   }
    263:   /* End Send-Recv of IS + row_numbers */
    264:   PetscFree(r_status1);
    265:   PetscFree(r_waits1);
    266:   PetscMalloc1(nrqs+1,&s_status1);
    267:   if (nrqs) {MPI_Waitall(nrqs,s_waits1,s_status1);}
    268:   PetscFree(s_status1);
    269:   PetscFree(s_waits1);

    271:   /* Create the submatrices */
    272:   if (scall == MAT_REUSE_MATRIX) {
    273:     for (i=0; i<ismax; i++) {
    274:       mat = (Mat_SeqDense*)(submats[i]->data);
    275:       if ((submats[i]->rmap->n != nrow[i]) || (submats[i]->cmap->n != ncol[i])) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Cannot reuse matrix. wrong size");
    276:       PetscArrayzero(mat->v,submats[i]->rmap->n*submats[i]->cmap->n);

    278:       submats[i]->factortype = C->factortype;
    279:     }
    280:   } else {
    281:     for (i=0; i<ismax; i++) {
    282:       MatCreate(PETSC_COMM_SELF,submats+i);
    283:       MatSetSizes(submats[i],nrow[i],ncol[i],nrow[i],ncol[i]);
    284:       MatSetType(submats[i],((PetscObject)A)->type_name);
    285:       MatSeqDenseSetPreallocation(submats[i],NULL);
    286:     }
    287:   }

    289:   /* Assemble the matrices */
    290:   {
    291:     PetscInt    col;
    292:     PetscScalar *imat_v,*mat_v,*imat_vi,*mat_vi;

    294:     for (i=0; i<ismax; i++) {
    295:       mat    = (Mat_SeqDense*)submats[i]->data;
    296:       mat_v  = a->v;
    297:       imat_v = mat->v;
    298:       irow_i = irow[i];
    299:       m      = nrow[i];
    300:       for (j=0; j<m; j++) {
    301:         row  = irow_i[j];
    302:         proc = rtable[row];
    303:         if (proc == rank) {
    304:           row     = row - rstart;
    305:           mat_vi  = mat_v + row;
    306:           imat_vi = imat_v + j;
    307:           for (k=0; k<ncol[i]; k++) {
    308:             col          = icol[i][k];
    309:             imat_vi[k*m] = mat_vi[col*a->lda];
    310:           }
    311:         }
    312:       }
    313:     }
    314:   }

    316:   /* Create row map-> This maps c->row to submat->row for each submat*/
    317:   /* this is a very expensive operation wrt memory usage */
    318:   PetscMalloc1(ismax,&rmap);
    319:   PetscCalloc1(ismax*C->rmap->N,&rmap[0]);
    320:   for (i=1; i<ismax; i++) rmap[i] = rmap[i-1] + C->rmap->N;
    321:   for (i=0; i<ismax; i++) {
    322:     rmap_i = rmap[i];
    323:     irow_i = irow[i];
    324:     jmax   = nrow[i];
    325:     for (j=0; j<jmax; j++) {
    326:       rmap_i[irow_i[j]] = j;
    327:     }
    328:   }

    330:   /* Now Receive the row_values and assemble the rest of the matrix */
    331:   PetscMalloc1(nrqs+1,&r_status2);
    332:   {
    333:     PetscInt    is_max,tmp1,col,*sbuf1_i,is_sz;
    334:     PetscScalar *rbuf2_i,*imat_v,*imat_vi;

    336:     for (tmp1=0; tmp1<nrqs; tmp1++) { /* For each message */
    337:       MPI_Waitany(nrqs,r_waits2,&i,r_status2+tmp1);
    338:       /* Now dig out the corresponding sbuf1, which contains the IS data_structure */
    339:       sbuf1_i = sbuf1[pa[i]];
    340:       is_max  = sbuf1_i[0];
    341:       ct1     = 2*is_max+1;
    342:       rbuf2_i = rbuf2[i];
    343:       for (j=1; j<=is_max; j++) { /* For each IS belonging to the message */
    344:         is_no  = sbuf1_i[2*j-1];
    345:         is_sz  = sbuf1_i[2*j];
    346:         mat    = (Mat_SeqDense*)submats[is_no]->data;
    347:         imat_v = mat->v;
    348:         rmap_i = rmap[is_no];
    349:         m      = nrow[is_no];
    350:         for (k=0; k<is_sz; k++,rbuf2_i+=N) {  /* For each row */
    351:           row     = sbuf1_i[ct1]; ct1++;
    352:           row     = rmap_i[row];
    353:           imat_vi = imat_v + row;
    354:           for (l=0; l<ncol[is_no]; l++) { /* For each col */
    355:             col          = icol[is_no][l];
    356:             imat_vi[l*m] = rbuf2_i[col];
    357:           }
    358:         }
    359:       }
    360:     }
    361:   }
    362:   /* End Send-Recv of row_values */
    363:   PetscFree(r_status2);
    364:   PetscFree(r_waits2);
    365:   PetscMalloc1(nrqr+1,&s_status2);
    366:   if (nrqr) {MPI_Waitall(nrqr,s_waits2,s_status2);}
    367:   PetscFree(s_status2);
    368:   PetscFree(s_waits2);

    370:   /* Restore the indices */
    371:   for (i=0; i<ismax; i++) {
    372:     ISRestoreIndices(isrow[i],irow+i);
    373:     ISRestoreIndices(iscol[i],icol+i);
    374:   }

    376:   PetscFree5(*(PetscInt***)&irow,*(PetscInt***)&icol,nrow,ncol,rtable);
    377:   PetscFree3(w1,w3,w4);
    378:   PetscFree(pa);

    380:   for (i=0; i<nrqs; ++i) {
    381:     PetscFree(rbuf2[i]);
    382:   }
    383:   PetscFree(rbuf2);
    384:   PetscFree4(sbuf1,ptr,tmp,ctr);
    385:   PetscFree(rbuf1[0]);
    386:   PetscFree(rbuf1);

    388:   for (i=0; i<nrqr; ++i) {
    389:     PetscFree(sbuf2[i]);
    390:   }

    392:   PetscFree(sbuf2);
    393:   PetscFree(rmap[0]);
    394:   PetscFree(rmap);

    396:   for (i=0; i<ismax; i++) {
    397:     MatAssemblyBegin(submats[i],MAT_FINAL_ASSEMBLY);
    398:     MatAssemblyEnd(submats[i],MAT_FINAL_ASSEMBLY);
    399:   }
    400:   return(0);
    401: }

    403: PETSC_INTERN PetscErrorCode MatScale_MPIDense(Mat inA,PetscScalar alpha)
    404: {
    405:   Mat_MPIDense   *A = (Mat_MPIDense*)inA->data;

    409:   MatScale(A->A,alpha);
    410:   return(0);
    411: }