Actual source code: mlocalref.c

      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;
     41:   PetscInt       buf[4096],*irowm=NULL,*icolm; /* suppress maybe-uninitialized warning */

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

     52: static PetscErrorCode MatSetValuesBlockedLocal_LocalRef_Scalar(Mat A,PetscInt nrow,const PetscInt irow[],PetscInt ncol,const PetscInt icol[],const PetscScalar y[],InsertMode addv)
     53: {
     54:   Mat_LocalRef   *lr = (Mat_LocalRef*)A->data;
     55:   PetscInt       rbs,cbs,buf[4096],*irowm,*icolm;

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

     68: static PetscErrorCode MatSetValuesLocal_LocalRef_Scalar(Mat A,PetscInt nrow,const PetscInt irow[],PetscInt ncol,const PetscInt icol[],const PetscScalar y[],InsertMode addv)
     69: {
     70:   Mat_LocalRef   *lr = (Mat_LocalRef*)A->data;
     71:   PetscInt       buf[4096],*irowm,*icolm;

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

     92: /* Compose an IS with an ISLocalToGlobalMapping to map from IS source indices to global indices */
     93: static PetscErrorCode ISL2GCompose(IS is,ISLocalToGlobalMapping ltog,ISLocalToGlobalMapping *cltog)
     94: {
     95:   const PetscInt *idx;
     96:   PetscInt       m,*idxm;
     97:   PetscInt       bs;
     98:   PetscBool      isblock;

    103:   PetscObjectTypeCompare((PetscObject)is,ISBLOCK,&isblock);
    104:   if (isblock) {
    105:     PetscInt lbs;

    107:     ISGetBlockSize(is,&bs);
    108:     ISLocalToGlobalMappingGetBlockSize(ltog,&lbs);
    109:     if (bs == lbs) {
    110:       ISGetLocalSize(is,&m);
    111:       m    = m/bs;
    112:       ISBlockGetIndices(is,&idx);
    113:       PetscMalloc1(m,&idxm);
    114:       ISLocalToGlobalMappingApplyBlock(ltog,m,idx,idxm);
    115:       ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)is),bs,m,idxm,PETSC_OWN_POINTER,cltog);
    116:       ISBlockRestoreIndices(is,&idx);
    117:       return 0;
    118:     }
    119:   }
    120:   ISGetLocalSize(is,&m);
    121:   ISGetIndices(is,&idx);
    122:   ISGetBlockSize(is,&bs);
    123:   PetscMalloc1(m,&idxm);
    124:   if (ltog) {
    125:     ISLocalToGlobalMappingApply(ltog,m,idx,idxm);
    126:   } else {
    127:     PetscArraycpy(idxm,idx,m);
    128:   }
    129:   ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)is),bs,m,idxm,PETSC_OWN_POINTER,cltog);
    130:   ISRestoreIndices(is,&idx);
    131:   return 0;
    132: }

    134: static PetscErrorCode ISL2GComposeBlock(IS is,ISLocalToGlobalMapping ltog,ISLocalToGlobalMapping *cltog)
    135: {
    136:   const PetscInt *idx;
    137:   PetscInt       m,*idxm,bs;

    142:   ISBlockGetLocalSize(is,&m);
    143:   ISBlockGetIndices(is,&idx);
    144:   ISLocalToGlobalMappingGetBlockSize(ltog,&bs);
    145:   PetscMalloc1(m,&idxm);
    146:   if (ltog) {
    147:     ISLocalToGlobalMappingApplyBlock(ltog,m,idx,idxm);
    148:   } else {
    149:     PetscArraycpy(idxm,idx,m);
    150:   }
    151:   ISLocalToGlobalMappingCreate(PetscObjectComm((PetscObject)is),bs,m,idxm,PETSC_OWN_POINTER,cltog);
    152:   ISBlockRestoreIndices(is,&idx);
    153:   return 0;
    154: }

    156: static PetscErrorCode MatDestroy_LocalRef(Mat B)
    157: {
    158:   PetscFree(B->data);
    159:   return 0;
    160: }

    162: /*@
    163:    MatCreateLocalRef - Gets a logical reference to a local submatrix, for use in assembly

    165:    Not Collective

    167:    Input Parameters:
    168: + A - Full matrix, generally parallel
    169: . isrow - Local index set for the rows
    170: - iscol - Local index set for the columns

    172:    Output Parameter:
    173: . newmat - New serial Mat

    175:    Level: developer

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

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

    184: .seealso: MatSetValuesLocal(), MatSetValuesBlockedLocal(), MatGetLocalSubMatrix(), MatCreateSubMatrix()
    185: @*/
    186: PetscErrorCode  MatCreateLocalRef(Mat A,IS isrow,IS iscol,Mat *newmat)
    187: {
    188:   Mat_LocalRef   *lr;
    189:   Mat            B;
    190:   PetscInt       m,n;
    191:   PetscBool      islr;

    198:   *newmat = NULL;

    200:   MatCreate(PETSC_COMM_SELF,&B);
    201:   ISGetLocalSize(isrow,&m);
    202:   ISGetLocalSize(iscol,&n);
    203:   MatSetSizes(B,m,n,m,n);
    204:   PetscObjectChangeTypeName((PetscObject)B,MATLOCALREF);
    205:   MatSetUp(B);

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

    209:   PetscNewLog(B,&lr);
    210:   B->data = (void*)lr;

    212:   PetscObjectTypeCompare((PetscObject)A,MATLOCALREF,&islr);
    213:   if (islr) {
    214:     Mat_LocalRef *alr = (Mat_LocalRef*)A->data;
    215:     lr->Top = alr->Top;
    216:   } else {
    217:     /* This does not increase the reference count because MatLocalRef is not allowed to live longer than its parent */
    218:     lr->Top = A;
    219:   }
    220:   {
    221:     ISLocalToGlobalMapping rltog,cltog;
    222:     PetscInt               arbs,acbs,rbs,cbs;

    224:     /* We will translate directly to global indices for the top level */
    225:     lr->SetValues        = MatSetValues;
    226:     lr->SetValuesBlocked = MatSetValuesBlocked;

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

    230:     ISL2GCompose(isrow,A->rmap->mapping,&rltog);
    231:     if (isrow == iscol && A->rmap->mapping == A->cmap->mapping) {
    232:       PetscObjectReference((PetscObject)rltog);
    233:       cltog = rltog;
    234:     } else {
    235:       ISL2GCompose(iscol,A->cmap->mapping,&cltog);
    236:     }
    237:     /* Remember if the ISes we used to pull out the submatrix are of type ISBLOCK.  Will be used later in
    238:      * MatSetValuesLocal_LocalRef_Scalar. */
    239:     PetscObjectTypeCompare((PetscObject)isrow,ISBLOCK,&lr->rowisblock);
    240:     PetscObjectTypeCompare((PetscObject)iscol,ISBLOCK,&lr->colisblock);
    241:     MatSetLocalToGlobalMapping(B,rltog,cltog);
    242:     ISLocalToGlobalMappingDestroy(&rltog);
    243:     ISLocalToGlobalMappingDestroy(&cltog);

    245:     MatGetBlockSizes(A,&arbs,&acbs);
    246:     ISGetBlockSize(isrow,&rbs);
    247:     ISGetBlockSize(iscol,&cbs);
    248:     /* Always support block interface insertion on submatrix */
    249:     PetscLayoutSetBlockSize(B->rmap,rbs);
    250:     PetscLayoutSetBlockSize(B->cmap,cbs);
    251:     if (arbs != rbs || acbs != cbs || (arbs == 1 && acbs == 1)) {
    252:       /* Top-level matrix has different block size, so we have to call its scalar insertion interface */
    253:       B->ops->setvaluesblockedlocal = MatSetValuesBlockedLocal_LocalRef_Scalar;
    254:     } else {
    255:       /* Block sizes match so we can forward values to the top level using the block interface */
    256:       B->ops->setvaluesblockedlocal = MatSetValuesBlockedLocal_LocalRef_Block;

    258:       ISL2GComposeBlock(isrow,A->rmap->mapping,&rltog);
    259:       if (isrow == iscol && A->rmap->mapping == A->cmap->mapping) {
    260:         PetscObjectReference((PetscObject)rltog);
    261:         cltog = rltog;
    262:       } else {
    263:         ISL2GComposeBlock(iscol,A->cmap->mapping,&cltog);
    264:       }
    265:       MatSetLocalToGlobalMapping(B,rltog,cltog);
    266:       ISLocalToGlobalMappingDestroy(&rltog);
    267:       ISLocalToGlobalMappingDestroy(&cltog);
    268:     }
    269:   }
    270:   *newmat = B;
    271:   return 0;
    272: }