Actual source code: mmaij.c
petsc-3.15.0 2021-03-30
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      2: /*
      3:    Support for the parallel AIJ matrix vector multiply
      4: */
      5: #include <../src/mat/impls/aij/mpi/mpiaij.h>
      6: #include <petsc/private/vecimpl.h>
      7: #include <petsc/private/isimpl.h>

      9: PetscErrorCode MatSetUpMultiply_MPIAIJ(Mat mat)
     10: {
     11:   Mat_MPIAIJ     *aij = (Mat_MPIAIJ*)mat->data;
     12:   Mat_SeqAIJ     *B   = (Mat_SeqAIJ*)(aij->B->data);
     14:   PetscInt       i,j,*aj = B->j,ec = 0,*garray;
     15:   IS             from,to;
     16:   Vec            gvec;
     17: #if defined(PETSC_USE_CTABLE)
     18:   PetscTable         gid1_lid1;
     19:   PetscTablePosition tpos;
     20:   PetscInt           gid,lid;
     21: #else
     22:   PetscInt N = mat->cmap->N,*indices;
     23: #endif

     26:   if (!aij->garray) {
     27:     if (!aij->B) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Missing B mat");
     28: #if defined(PETSC_USE_CTABLE)
     29:     /* use a table */
     30:     PetscTableCreate(aij->B->rmap->n,mat->cmap->N+1,&gid1_lid1);
     31:     for (i=0; i<aij->B->rmap->n; i++) {
     32:       for (j=0; j<B->ilen[i]; j++) {
     33:         PetscInt data,gid1 = aj[B->i[i] + j] + 1;
     34:         PetscTableFind(gid1_lid1,gid1,&data);
     35:         if (!data) {
     36:           /* one based table */
     37:           PetscTableAdd(gid1_lid1,gid1,++ec,INSERT_VALUES);
     38:         }
     39:       }
     40:     }
     41:     /* form array of columns we need */
     42:     PetscMalloc1(ec+1,&garray);
     43:     PetscTableGetHeadPosition(gid1_lid1,&tpos);
     44:     while (tpos) {
     45:       PetscTableGetNext(gid1_lid1,&tpos,&gid,&lid);
     46:       gid--;
     47:       lid--;
     48:       garray[lid] = gid;
     49:     }
     50:     PetscSortInt(ec,garray); /* sort, and rebuild */
     51:     PetscTableRemoveAll(gid1_lid1);
     52:     for (i=0; i<ec; i++) {
     53:       PetscTableAdd(gid1_lid1,garray[i]+1,i+1,INSERT_VALUES);
     54:     }
     55:     /* compact out the extra columns in B */
     56:     for (i=0; i<aij->B->rmap->n; i++) {
     57:       for (j=0; j<B->ilen[i]; j++) {
     58:         PetscInt gid1 = aj[B->i[i] + j] + 1;
     59:         PetscTableFind(gid1_lid1,gid1,&lid);
     60:         lid--;
     61:         aj[B->i[i] + j] = lid;
     62:       }
     63:     }
     64:     PetscLayoutDestroy(&aij->B->cmap);
     65:     PetscLayoutCreateFromSizes(PetscObjectComm((PetscObject)aij->B),ec,ec,1,&aij->B->cmap);
     66:     PetscTableDestroy(&gid1_lid1);
     67: #else
     68:     /* Make an array as long as the number of columns */
     69:     /* mark those columns that are in aij->B */
     70:     PetscCalloc1(N+1,&indices);
     71:     for (i=0; i<aij->B->rmap->n; i++) {
     72:       for (j=0; j<B->ilen[i]; j++) {
     73:         if (!indices[aj[B->i[i] + j]]) ec++;
     74:         indices[aj[B->i[i] + j]] = 1;
     75:       }
     76:     }

     78:     /* form array of columns we need */
     79:     PetscMalloc1(ec+1,&garray);
     80:     ec   = 0;
     81:     for (i=0; i<N; i++) {
     82:       if (indices[i]) garray[ec++] = i;
     83:     }

     85:     /* make indices now point into garray */
     86:     for (i=0; i<ec; i++) {
     87:       indices[garray[i]] = i;
     88:     }

     90:     /* compact out the extra columns in B */
     91:     for (i=0; i<aij->B->rmap->n; i++) {
     92:       for (j=0; j<B->ilen[i]; j++) {
     93:         aj[B->i[i] + j] = indices[aj[B->i[i] + j]];
     94:       }
     95:     }
     96:     PetscLayoutDestroy(&aij->B->cmap);
     97:     PetscLayoutCreateFromSizes(PetscObjectComm((PetscObject)aij->B),ec,ec,1,&aij->B->cmap);
     98:     PetscFree(indices);
     99: #endif
    100:   } else {
    101:     garray = aij->garray;
    102:   }

    104:   if (!aij->lvec) {
    105:     if (!aij->B) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Missing B mat");
    106:     MatCreateVecs(aij->B,&aij->lvec,NULL);
    107:   }
    108:   VecGetSize(aij->lvec,&ec);

    110:   /* create two temporary Index sets for build scatter gather */
    111:   ISCreateGeneral(PETSC_COMM_SELF,ec,garray,PETSC_COPY_VALUES,&from);
    112:   ISCreateStride(PETSC_COMM_SELF,ec,0,1,&to);

    114:   /* create temporary global vector to generate scatter context */
    115:   /* This does not allocate the array's memory so is efficient */
    116:   VecCreateMPIWithArray(PetscObjectComm((PetscObject)mat),1,mat->cmap->n,mat->cmap->N,NULL,&gvec);

    118:   /* generate the scatter context */
    119:   VecScatterDestroy(&aij->Mvctx);
    120:   VecScatterCreate(gvec,from,aij->lvec,to,&aij->Mvctx);
    121:   PetscLogObjectParent((PetscObject)mat,(PetscObject)aij->Mvctx);
    122:   PetscLogObjectParent((PetscObject)mat,(PetscObject)aij->lvec);
    123:   PetscLogObjectMemory((PetscObject)mat,(ec+1)*sizeof(PetscInt));
    124:   aij->garray = garray;

    126:   PetscLogObjectParent((PetscObject)mat,(PetscObject)from);
    127:   PetscLogObjectParent((PetscObject)mat,(PetscObject)to);

    129:   ISDestroy(&from);
    130:   ISDestroy(&to);
    131:   VecDestroy(&gvec);
    132:   return(0);
    133: }

    135: /*
    136:      Takes the local part of an already assembled MPIAIJ matrix
    137:    and disassembles it. This is to allow new nonzeros into the matrix
    138:    that require more communication in the matrix vector multiply.
    139:    Thus certain data-structures must be rebuilt.

    141:    Kind of slow! But that's what application programmers get when
    142:    they are sloppy.
    143: */
    144: PetscErrorCode MatDisAssemble_MPIAIJ(Mat A)
    145: {
    146:   Mat_MPIAIJ     *aij  = (Mat_MPIAIJ*)A->data;
    147:   Mat            B     = aij->B,Bnew;
    148:   Mat_SeqAIJ     *Baij = (Mat_SeqAIJ*)B->data;
    150:   PetscInt       i,j,m = B->rmap->n,n = A->cmap->N,col,ct = 0,*garray = aij->garray,*nz,ec;
    151:   PetscScalar    v;

    154:   /* free stuff related to matrix-vec multiply */
    155:   VecGetSize(aij->lvec,&ec); /* needed for PetscLogObjectMemory below */
    156:   VecDestroy(&aij->lvec);
    157:   if (aij->colmap) {
    158: #if defined(PETSC_USE_CTABLE)
    159:     PetscTableDestroy(&aij->colmap);
    160: #else
    161:     PetscFree(aij->colmap);
    162:     PetscLogObjectMemory((PetscObject)A,-aij->B->cmap->n*sizeof(PetscInt));
    163: #endif
    164:   }

    166:   /* make sure that B is assembled so we can access its values */
    167:   MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
    168:   MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);

    170:   /* invent new B and copy stuff over */
    171:   PetscMalloc1(m+1,&nz);
    172:   for (i=0; i<m; i++) {
    173:     nz[i] = Baij->i[i+1] - Baij->i[i];
    174:   }
    175:   MatCreate(PETSC_COMM_SELF,&Bnew);
    176:   MatSetSizes(Bnew,m,n,m,n);
    177:   MatSetBlockSizesFromMats(Bnew,A,A);
    178:   MatSetType(Bnew,((PetscObject)B)->type_name);
    179:   MatSeqAIJSetPreallocation(Bnew,0,nz);

    181:   if (Baij->nonew >= 0) { /* Inherit insertion error options (if positive). */
    182:     ((Mat_SeqAIJ*)Bnew->data)->nonew = Baij->nonew;
    183:   }

    185:   /*
    186:    Ensure that B's nonzerostate is monotonically increasing.
    187:    Or should this follow the MatSetValues() loop to preserve B's nonzerstate across a MatDisAssemble() call?
    188:    */
    189:   Bnew->nonzerostate = B->nonzerostate;

    191:   PetscFree(nz);
    192:   for (i=0; i<m; i++) {
    193:     for (j=Baij->i[i]; j<Baij->i[i+1]; j++) {
    194:       col  = garray[Baij->j[ct]];
    195:       v    = Baij->a[ct++];
    196:       MatSetValues(Bnew,1,&i,1,&col,&v,B->insertmode);
    197:     }
    198:   }
    199:   PetscFree(aij->garray);
    200:   PetscLogObjectMemory((PetscObject)A,-ec*sizeof(PetscInt));
    201:   MatDestroy(&B);
    202:   PetscLogObjectParent((PetscObject)A,(PetscObject)Bnew);

    204:   aij->B           = Bnew;
    205:   A->was_assembled = PETSC_FALSE;
    206:   return(0);
    207: }

    209: /*      ugly stuff added for Glenn someday we should fix this up */

    211: static PetscInt *auglyrmapd = NULL,*auglyrmapo = NULL; /* mapping from the local ordering to the "diagonal" and "off-diagonal" parts of the local matrix */
    212: static Vec auglydd          = NULL,auglyoo     = NULL; /* work vectors used to scale the two parts of the local matrix */

    215: PetscErrorCode MatMPIAIJDiagonalScaleLocalSetUp(Mat inA,Vec scale)
    216: {
    217:   Mat_MPIAIJ     *ina = (Mat_MPIAIJ*) inA->data; /*access private part of matrix */
    219:   PetscInt       i,n,nt,cstart,cend,no,*garray = ina->garray,*lindices;
    220:   PetscInt       *r_rmapd,*r_rmapo;

    223:   MatGetOwnershipRange(inA,&cstart,&cend);
    224:   MatGetSize(ina->A,NULL,&n);
    225:   PetscCalloc1(inA->rmap->mapping->n+1,&r_rmapd);
    226:   nt   = 0;
    227:   for (i=0; i<inA->rmap->mapping->n; i++) {
    228:     if (inA->rmap->mapping->indices[i] >= cstart && inA->rmap->mapping->indices[i] < cend) {
    229:       nt++;
    230:       r_rmapd[i] = inA->rmap->mapping->indices[i] + 1;
    231:     }
    232:   }
    233:   if (nt != n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Hmm nt %D n %D",nt,n);
    234:   PetscMalloc1(n+1,&auglyrmapd);
    235:   for (i=0; i<inA->rmap->mapping->n; i++) {
    236:     if (r_rmapd[i]) {
    237:       auglyrmapd[(r_rmapd[i]-1)-cstart] = i;
    238:     }
    239:   }
    240:   PetscFree(r_rmapd);
    241:   VecCreateSeq(PETSC_COMM_SELF,n,&auglydd);

    243:   PetscCalloc1(inA->cmap->N+1,&lindices);
    244:   for (i=0; i<ina->B->cmap->n; i++) {
    245:     lindices[garray[i]] = i+1;
    246:   }
    247:   no   = inA->rmap->mapping->n - nt;
    248:   PetscCalloc1(inA->rmap->mapping->n+1,&r_rmapo);
    249:   nt   = 0;
    250:   for (i=0; i<inA->rmap->mapping->n; i++) {
    251:     if (lindices[inA->rmap->mapping->indices[i]]) {
    252:       nt++;
    253:       r_rmapo[i] = lindices[inA->rmap->mapping->indices[i]];
    254:     }
    255:   }
    256:   if (nt > no) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Hmm nt %D no %D",nt,n);
    257:   PetscFree(lindices);
    258:   PetscMalloc1(nt+1,&auglyrmapo);
    259:   for (i=0; i<inA->rmap->mapping->n; i++) {
    260:     if (r_rmapo[i]) {
    261:       auglyrmapo[(r_rmapo[i]-1)] = i;
    262:     }
    263:   }
    264:   PetscFree(r_rmapo);
    265:   VecCreateSeq(PETSC_COMM_SELF,nt,&auglyoo);
    266:   return(0);
    267: }

    269: PetscErrorCode MatMPIAIJDiagonalScaleLocal(Mat A,Vec scale)
    270: {
    271:   /* This routine should really be abandoned as it duplicates MatDiagonalScaleLocal */

    275:   PetscTryMethod(A,"MatDiagonalScaleLocal_C",(Mat,Vec),(A,scale));
    276:   return(0);
    277: }

    279: PetscErrorCode  MatDiagonalScaleLocal_MPIAIJ(Mat A,Vec scale)
    280: {
    281:   Mat_MPIAIJ        *a = (Mat_MPIAIJ*) A->data; /*access private part of matrix */
    282:   PetscErrorCode    ierr;
    283:   PetscInt          n,i;
    284:   PetscScalar       *d,*o;
    285:   const PetscScalar *s;

    288:   if (!auglyrmapd) {
    289:     MatMPIAIJDiagonalScaleLocalSetUp(A,scale);
    290:   }

    292:   VecGetArrayRead(scale,&s);

    294:   VecGetLocalSize(auglydd,&n);
    295:   VecGetArray(auglydd,&d);
    296:   for (i=0; i<n; i++) {
    297:     d[i] = s[auglyrmapd[i]]; /* copy "diagonal" (true local) portion of scale into dd vector */
    298:   }
    299:   VecRestoreArray(auglydd,&d);
    300:   /* column scale "diagonal" portion of local matrix */
    301:   MatDiagonalScale(a->A,NULL,auglydd);

    303:   VecGetLocalSize(auglyoo,&n);
    304:   VecGetArray(auglyoo,&o);
    305:   for (i=0; i<n; i++) {
    306:     o[i] = s[auglyrmapo[i]]; /* copy "off-diagonal" portion of scale into oo vector */
    307:   }
    308:   VecRestoreArrayRead(scale,&s);
    309:   VecRestoreArray(auglyoo,&o);
    310:   /* column scale "off-diagonal" portion of local matrix */
    311:   MatDiagonalScale(a->B,NULL,auglyoo);
    312:   return(0);
    313: }