Actual source code: mlocalref.c
petsc-3.10.5 2019-03-28
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      2:  #include <petsc/private/matimpl.h>

      4: typedef struct {
      5:   Mat Top;
      6:   PetscBool rowisblock;
      7:   PetscBool colisblock;
      8:   PetscErrorCode (*SetValues)(Mat,PetscInt,const PetscInt[],PetscInt,const PetscInt[],const PetscScalar[],InsertMode);
      9:   PetscErrorCode (*SetValuesBlocked)(Mat,PetscInt,const PetscInt[],PetscInt,const PetscInt[],const PetscScalar[],InsertMode);
     10: } Mat_LocalRef;

     12: /* These need to be macros because they use sizeof */
     13: #define IndexSpaceGet(buf,nrow,ncol,irowm,icolm) do {                   \
     14:     if (nrow + ncol > (PetscInt)(sizeof(buf)/sizeof(buf[0]))) {         \
     15:       PetscMalloc2(nrow,&irowm,ncol,&icolm); \
     16:     } else {                                                            \
     17:       irowm = &buf[0];                                                  \
     18:       icolm = &buf[nrow];                                               \
     19:     }                                                                   \
     20: } while (0)

     22: #define IndexSpaceRestore(buf,nrow,ncol,irowm,icolm) do {       \
     23:     if (nrow + ncol > (PetscInt)(sizeof(buf)/sizeof(buf[0]))) { \
     24:       PetscFree2(irowm,icolm);             \
     25:     }                                                           \
     26: } while (0)

     28: static void BlockIndicesExpand(PetscInt n,const PetscInt idx[],PetscInt bs,PetscInt idxm[])
     29: {
     30:   PetscInt i,j;
     31:   for (i=0; i<n; i++) {
     32:     for (j=0; j<bs; j++) {
     33:       idxm[i*bs+j] = idx[i]*bs + j;
     34:     }
     35:   }
     36: }

     38: static PetscErrorCode MatSetValuesBlockedLocal_LocalRef_Block(Mat A,PetscInt nrow,const PetscInt irow[],PetscInt ncol,const PetscInt icol[],const PetscScalar y[],InsertMode addv)
     39: {
     40:   Mat_LocalRef   *lr = (Mat_LocalRef*)A->data;
     42:   PetscInt       buf[4096],*irowm=NULL,*icolm; /* suppress maybe-uninitialized warning */

     45:   if (!nrow || !ncol) return(0);
     46:   IndexSpaceGet(buf,nrow,ncol,irowm,icolm);
     47:   ISLocalToGlobalMappingApplyBlock(A->rmap->mapping,nrow,irow,irowm);
     48:   ISLocalToGlobalMappingApplyBlock(A->cmap->mapping,ncol,icol,icolm);
     49:   (*lr->SetValuesBlocked)(lr->Top,nrow,irowm,ncol,icolm,y,addv);
     50:   IndexSpaceRestore(buf,nrow,ncol,irowm,icolm);
     51:   return(0);
     52: }

     54: static PetscErrorCode MatSetValuesBlockedLocal_LocalRef_Scalar(Mat A,PetscInt nrow,const PetscInt irow[],PetscInt ncol,const PetscInt icol[],const PetscScalar y[],InsertMode addv)
     55: {
     56:   Mat_LocalRef   *lr = (Mat_LocalRef*)A->data;
     58:   PetscInt       rbs,cbs,buf[4096],*irowm,*icolm;

     61:   MatGetBlockSizes(A,&rbs,&cbs);
     62:   IndexSpaceGet(buf,nrow*rbs,ncol*cbs,irowm,icolm);
     63:   BlockIndicesExpand(nrow,irow,rbs,irowm);
     64:   BlockIndicesExpand(ncol,icol,cbs,icolm);
     65:   ISLocalToGlobalMappingApplyBlock(A->rmap->mapping,nrow*rbs,irowm,irowm);
     66:   ISLocalToGlobalMappingApplyBlock(A->cmap->mapping,ncol*cbs,icolm,icolm);
     67:   (*lr->SetValues)(lr->Top,nrow*rbs,irowm,ncol*cbs,icolm,y,addv);
     68:   IndexSpaceRestore(buf,nrow*rbs,ncol*cbs,irowm,icolm);
     69:   return(0);
     70: }

     72: static PetscErrorCode MatSetValuesLocal_LocalRef_Scalar(Mat A,PetscInt nrow,const PetscInt irow[],PetscInt ncol,const PetscInt icol[],const PetscScalar y[],InsertMode addv)
     73: {
     74:   Mat_LocalRef   *lr = (Mat_LocalRef*)A->data;
     76:   PetscInt       buf[4096],*irowm,*icolm;

     79:   IndexSpaceGet(buf,nrow,ncol,irowm,icolm);
     80:   /* If the row IS defining this submatrix was an ISBLOCK, then the unblocked LGMapApply is the right one to use.  If
     81:    * instead it was (say) an ISSTRIDE with a block size > 1, then we need to use LGMapApplyBlock */
     82:   if (lr->rowisblock) {
     83:     ISLocalToGlobalMappingApply(A->rmap->mapping,nrow,irow,irowm);
     84:   } else {
     85:     ISLocalToGlobalMappingApplyBlock(A->rmap->mapping,nrow,irow,irowm);
     86:   }
     87:   /* As above, but for the column IS. */
     88:   if (lr->colisblock) {
     89:     ISLocalToGlobalMappingApply(A->cmap->mapping,ncol,icol,icolm);
     90:   } else {
     91:     ISLocalToGlobalMappingApplyBlock(A->cmap->mapping,ncol,icol,icolm);
     92:   }
     93:   (*lr->SetValues)(lr->Top,nrow,irowm,ncol,icolm,y,addv);
     94:   IndexSpaceRestore(buf,nrow,ncol,irowm,icolm);
     95:   return(0);
     96: }

     98: /* Compose an IS with an ISLocalToGlobalMapping to map from IS source indices to global indices */
     99: static PetscErrorCode ISL2GCompose(IS is,ISLocalToGlobalMapping ltog,ISLocalToGlobalMapping *cltog)
    100: {
    102:   const PetscInt *idx;
    103:   PetscInt       m,*idxm;
    104:   PetscInt       bs;
    105:   PetscBool      isblock;

    111:   PetscObjectTypeCompare((PetscObject)is,ISBLOCK,&isblock);
    112:   if (isblock) {
    113:     PetscInt lbs;

    115:     ISGetBlockSize(is,&bs);
    116:     ISLocalToGlobalMappingGetBlockSize(ltog,&lbs);
    117:     if (bs == lbs) {
    118:       ISGetLocalSize(is,&m);
    119:       m    = m/bs;
    120:       ISBlockGetIndices(is,&idx);
    121:       PetscMalloc1(m,&idxm);
    122:       ISLocalToGlobalMappingApplyBlock(ltog,m,idx,idxm);
    123:       ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)is),bs,m,idxm,PETSC_OWN_POINTER,cltog);
    124:       ISBlockRestoreIndices(is,&idx);
    125:       return(0);
    126:     }
    127:   }
    128:   ISGetLocalSize(is,&m);
    129:   ISGetIndices(is,&idx);
    130:   ISGetBlockSize(is,&bs);
    131:   PetscMalloc1(m,&idxm);
    132:   if (ltog) {
    133:     ISLocalToGlobalMappingApply(ltog,m,idx,idxm);
    134:   } else {
    135:     PetscMemcpy(idxm,idx,m*sizeof(PetscInt));
    136:   }
    137:   ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)is),bs,m,idxm,PETSC_OWN_POINTER,cltog);
    138:   ISRestoreIndices(is,&idx);
    139:   return(0);
    140: }

    142: static PetscErrorCode ISL2GComposeBlock(IS is,ISLocalToGlobalMapping ltog,ISLocalToGlobalMapping *cltog)
    143: {
    145:   const PetscInt *idx;
    146:   PetscInt       m,*idxm,bs;

    152:   ISBlockGetLocalSize(is,&m);
    153:   ISBlockGetIndices(is,&idx);
    154:   ISLocalToGlobalMappingGetBlockSize(ltog,&bs);
    155:   PetscMalloc1(m,&idxm);
    156:   if (ltog) {
    157:     ISLocalToGlobalMappingApplyBlock(ltog,m,idx,idxm);
    158:   } else {
    159:     PetscMemcpy(idxm,idx,m*sizeof(PetscInt));
    160:   }
    161:   ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)is),bs,m,idxm,PETSC_OWN_POINTER,cltog);
    162:   ISBlockRestoreIndices(is,&idx);
    163:   return(0);
    164: }

    166: static PetscErrorCode MatDestroy_LocalRef(Mat B)
    167: {

    171:   PetscFree(B->data);
    172:   return(0);
    173: }

    176: /*@
    177:    MatCreateLocalRef - Gets a logical reference to a local submatrix, for use in assembly

    179:    Not Collective

    181:    Input Arguments:
    182: + A - Full matrix, generally parallel
    183: . isrow - Local index set for the rows
    184: - iscol - Local index set for the columns

    186:    Output Arguments:
    187: . newmat - New serial Mat

    189:    Level: developer

    191:    Notes:
    192:    Most will use MatGetLocalSubMatrix() which returns a real matrix corresponding to the local
    193:    block if it available, such as with matrix formats that store these blocks separately.

    195:    The new matrix forwards MatSetValuesLocal() and MatSetValuesBlockedLocal() to the global system.
    196:    In general, it does not define MatMult() or any other functions.  Local submatrices can be nested.

    198: .seealso: MatSetValuesLocal(), MatSetValuesBlockedLocal(), MatGetLocalSubMatrix(), MatCreateSubMatrix()
    199: @*/
    200: PetscErrorCode  MatCreateLocalRef(Mat A,IS isrow,IS iscol,Mat *newmat)
    201: {
    203:   Mat_LocalRef   *lr;
    204:   Mat            B;
    205:   PetscInt       m,n;
    206:   PetscBool      islr;

    213:   if (!A->rmap->mapping) SETERRQ(PetscObjectComm((PetscObject)A),PETSC_ERR_ARG_WRONGSTATE,"Matrix must have local to global mapping provided before this call");
    214:   *newmat = 0;

    216:   MatCreate(PETSC_COMM_SELF,&B);
    217:   ISGetLocalSize(isrow,&m);
    218:   ISGetLocalSize(iscol,&n);
    219:   MatSetSizes(B,m,n,m,n);
    220:   PetscObjectChangeTypeName((PetscObject)B,MATLOCALREF);
    221:   MatSetUp(B);

    223:   B->ops->destroy = MatDestroy_LocalRef;

    225:   PetscNewLog(B,&lr);
    226:   B->data = (void*)lr;

    228:   PetscObjectTypeCompare((PetscObject)A,MATLOCALREF,&islr);
    229:   if (islr) {
    230:     Mat_LocalRef *alr = (Mat_LocalRef*)A->data;
    231:     lr->Top = alr->Top;
    232:   } else {
    233:     /* This does not increase the reference count because MatLocalRef is not allowed to live longer than its parent */
    234:     lr->Top = A;
    235:   }
    236:   {
    237:     ISLocalToGlobalMapping rltog,cltog;
    238:     PetscInt               arbs,acbs,rbs,cbs;

    240:     /* We will translate directly to global indices for the top level */
    241:     lr->SetValues        = MatSetValues;
    242:     lr->SetValuesBlocked = MatSetValuesBlocked;

    244:     B->ops->setvalueslocal = MatSetValuesLocal_LocalRef_Scalar;

    246:     ISL2GCompose(isrow,A->rmap->mapping,&rltog);
    247:     if (isrow == iscol && A->rmap->mapping == A->cmap->mapping) {
    248:       PetscObjectReference((PetscObject)rltog);
    249:       cltog = rltog;
    250:     } else {
    251:       ISL2GCompose(iscol,A->cmap->mapping,&cltog);
    252:     }
    253:     /* Remember if the ISes we used to pull out the submatrix are of type ISBLOCK.  Will be used later in
    254:      * MatSetValuesLocal_LocalRef_Scalar. */
    255:     PetscObjectTypeCompare((PetscObject)isrow,ISBLOCK,&lr->rowisblock);
    256:     PetscObjectTypeCompare((PetscObject)iscol,ISBLOCK,&lr->colisblock);
    257:     MatSetLocalToGlobalMapping(B,rltog,cltog);
    258:     ISLocalToGlobalMappingDestroy(&rltog);
    259:     ISLocalToGlobalMappingDestroy(&cltog);

    261:     MatGetBlockSizes(A,&arbs,&acbs);
    262:     ISGetBlockSize(isrow,&rbs);
    263:     ISGetBlockSize(iscol,&cbs);
    264:     /* Always support block interface insertion on submatrix */
    265:     PetscLayoutSetBlockSize(B->rmap,rbs);
    266:     PetscLayoutSetBlockSize(B->cmap,cbs);
    267:     if (arbs != rbs || acbs != cbs || (arbs == 1 && acbs == 1)) {
    268:       /* Top-level matrix has different block size, so we have to call its scalar insertion interface */
    269:       B->ops->setvaluesblockedlocal = MatSetValuesBlockedLocal_LocalRef_Scalar;
    270:     } else {
    271:       /* Block sizes match so we can forward values to the top level using the block interface */
    272:       B->ops->setvaluesblockedlocal = MatSetValuesBlockedLocal_LocalRef_Block;

    274:       ISL2GComposeBlock(isrow,A->rmap->mapping,&rltog);
    275:       if (isrow == iscol && A->rmap->mapping == A->cmap->mapping) {
    276:          PetscObjectReference((PetscObject)rltog);
    277:         cltog = rltog;
    278:       } else {
    279:         ISL2GComposeBlock(iscol,A->cmap->mapping,&cltog);
    280:       }
    281:       MatSetLocalToGlobalMapping(B,rltog,cltog);
    282:       ISLocalToGlobalMappingDestroy(&rltog);
    283:       ISLocalToGlobalMappingDestroy(&cltog);
    284:     }
    285:   }
    286:   *newmat = B;
    287:   return(0);
    288: }