Date: 2013-07-02T14:40:27+00:00

Actual source code: stride.c
petsc-3.4.2 2013-07-02

      2: /*
      3:        Index sets of evenly space integers, defined by a
      4:     start, stride and length.
      5: */
      6: #include <petsc-private/isimpl.h>             /*I   "petscis.h"   I*/
      7: #include <petscvec.h>
      8: #include <petscviewer.h>

     10: typedef struct {
     11:   PetscInt N,n,first,step;
     12: } IS_Stride;

     16: PetscErrorCode ISIdentity_Stride(IS is,PetscBool  *ident)
     17: {
     18:   IS_Stride *is_stride = (IS_Stride*)is->data;

     21:   is->isidentity = PETSC_FALSE;
     22:   *ident         = PETSC_FALSE;
     23:   if (is_stride->first != 0) return(0);
     24:   if (is_stride->step  != 1) return(0);
     25:   *ident         = PETSC_TRUE;
     26:   is->isidentity = PETSC_TRUE;
     27:   return(0);
     28: }

     32: static PetscErrorCode ISCopy_Stride(IS is,IS isy)
     33: {
     34:   IS_Stride      *is_stride = (IS_Stride*)is->data,*isy_stride = (IS_Stride*)isy->data;

     38:   PetscMemcpy(isy_stride,is_stride,sizeof(IS_Stride));
     39:   return(0);
     40: }

     44: PetscErrorCode ISDuplicate_Stride(IS is,IS *newIS)
     45: {
     47:   IS_Stride      *sub = (IS_Stride*)is->data;

     50:   ISCreateStride(PetscObjectComm((PetscObject)is),sub->n,sub->first,sub->step,newIS);
     51:   return(0);
     52: }

     56: PetscErrorCode ISInvertPermutation_Stride(IS is,PetscInt nlocal,IS *perm)
     57: {
     58:   IS_Stride      *isstride = (IS_Stride*)is->data;

     62:   if (is->isidentity) {
     63:     ISCreateStride(PETSC_COMM_SELF,isstride->n,0,1,perm);
     64:   } else {
     65:     IS             tmp;
     66:     const PetscInt *indices,n = isstride->n;
     67:     ISGetIndices(is,&indices);
     68:     ISCreateGeneral(PetscObjectComm((PetscObject)is),n,indices,PETSC_COPY_VALUES,&tmp);
     69:     ISSetPermutation(tmp);
     70:     ISRestoreIndices(is,&indices);
     71:     ISInvertPermutation(tmp,nlocal,perm);
     72:     ISDestroy(&tmp);
     73:   }
     74:   return(0);
     75: }

     79: /*@
     80:    ISStrideGetInfo - Returns the first index in a stride index set and
     81:    the stride width.

     83:    Not Collective

     85:    Input Parameter:
     86: .  is - the index set

     88:    Output Parameters:
     89: .  first - the first index
     90: .  step - the stride width

     92:    Level: intermediate

     94:    Notes:
     95:    Returns info on stride index set. This is a pseudo-public function that
     96:    should not be needed by most users.

     98:    Concepts: index sets^getting information
     99:    Concepts: IS^getting information

    101: .seealso: ISCreateStride(), ISGetSize()
    102: @*/
    103: PetscErrorCode  ISStrideGetInfo(IS is,PetscInt *first,PetscInt *step)
    104: {
    105:   IS_Stride *sub;

    112:   sub = (IS_Stride*)is->data;
    113:   if (first) *first = sub->first;
    114:   if (step)  *step  = sub->step;
    115:   return(0);
    116: }

    120: PetscErrorCode ISDestroy_Stride(IS is)
    121: {

    125:   PetscObjectComposeFunction((PetscObject)is,"ISStrideSetStride_C",0);
    126:   PetscFree(is->data);
    127:   return(0);
    128: }

    132: PetscErrorCode  ISToGeneral_Stride(IS inis)
    133: {
    135:   const PetscInt *idx;
    136:   PetscInt       n;

    139:   ISGetLocalSize(inis,&n);
    140:   ISGetIndices(inis,&idx);
    141:   ISSetType(inis,ISGENERAL);
    142:   ISGeneralSetIndices(inis,n,idx,PETSC_OWN_POINTER);
    143:   return(0);
    144: }

    147: /*
    148:      Returns a legitimate index memory even if
    149:    the stride index set is empty.
    150: */
    153: PetscErrorCode ISGetIndices_Stride(IS in,const PetscInt *idx[])
    154: {
    155:   IS_Stride      *sub = (IS_Stride*)in->data;
    157:   PetscInt       i,**dx = (PetscInt**)idx;

    160:   PetscMalloc(sub->n*sizeof(PetscInt),idx);
    161:   if (sub->n) {
    162:     (*dx)[0] = sub->first;
    163:     for (i=1; i<sub->n; i++) (*dx)[i] = (*dx)[i-1] + sub->step;
    164:   }
    165:   return(0);
    166: }

    170: PetscErrorCode ISRestoreIndices_Stride(IS in,const PetscInt *idx[])
    171: {

    175:   PetscFree(*(void**)idx);
    176:   return(0);
    177: }

    181: PetscErrorCode ISGetSize_Stride(IS is,PetscInt *size)
    182: {
    183:   IS_Stride *sub = (IS_Stride*)is->data;

    186:   *size = sub->N;
    187:   return(0);
    188: }

    192: PetscErrorCode ISGetLocalSize_Stride(IS is,PetscInt *size)
    193: {
    194:   IS_Stride *sub = (IS_Stride*)is->data;

    197:   *size = sub->n;
    198:   return(0);
    199: }

    203: PetscErrorCode ISView_Stride(IS is,PetscViewer viewer)
    204: {
    205:   IS_Stride      *sub = (IS_Stride*)is->data;
    206:   PetscInt       i,n = sub->n;
    207:   PetscMPIInt    rank,size;
    208:   PetscBool      iascii;

    212:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
    213:   if (iascii) {
    214:     MPI_Comm_rank(PetscObjectComm((PetscObject)is),&rank);
    215:     MPI_Comm_size(PetscObjectComm((PetscObject)is),&size);
    216:     if (size == 1) {
    217:       if (is->isperm) {
    218:         PetscViewerASCIIPrintf(viewer,"Index set is permutation\n");
    219:       }
    220:       PetscViewerASCIIPrintf(viewer,"Number of indices in (stride) set %D\n",n);
    221:       for (i=0; i<n; i++) {
    222:         PetscViewerASCIIPrintf(viewer,"%D %D\n",i,sub->first + i*sub->step);
    223:       }
    224:       PetscViewerFlush(viewer);
    225:     } else {
    226:       PetscViewerASCIISynchronizedAllow(viewer,PETSC_TRUE);
    227:       if (is->isperm) {
    228:         PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Index set is permutation\n",rank);
    229:       }
    230:       PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Number of indices in (stride) set %D\n",rank,n);
    231:       for (i=0; i<n; i++) {
    232:         PetscViewerASCIISynchronizedPrintf(viewer,"[%d] %D %D\n",rank,i,sub->first + i*sub->step);
    233:       }
    234:       PetscViewerFlush(viewer);
    235:       PetscViewerASCIISynchronizedAllow(viewer,PETSC_FALSE);
    236:     }
    237:   }
    238:   return(0);
    239: }

    243: PetscErrorCode ISSort_Stride(IS is)
    244: {
    245:   IS_Stride *sub = (IS_Stride*)is->data;

    248:   if (sub->step >= 0) return(0);
    249:   sub->first += (sub->n - 1)*sub->step;
    250:   sub->step  *= -1;
    251:   return(0);
    252: }

    256: PetscErrorCode ISSorted_Stride(IS is,PetscBool * flg)
    257: {
    258:   IS_Stride *sub = (IS_Stride*)is->data;

    261:   if (sub->step >= 0) *flg = PETSC_TRUE;
    262:   else *flg = PETSC_FALSE;
    263:   return(0);
    264: }

    268: static PetscErrorCode ISOnComm_Stride(IS is,MPI_Comm comm,PetscCopyMode mode,IS *newis)
    269: {
    271:   IS_Stride      *sub = (IS_Stride*)is->data;

    274:   ISCreateStride(comm,sub->n,sub->first,sub->step,newis);
    275:   return(0);
    276: }

    280: static PetscErrorCode ISSetBlockSize_Stride(IS is,PetscInt bs)
    281: {
    282:   IS_Stride *sub = (IS_Stride*)is->data;

    285:   if (sub->step != 1 && bs != 1) SETERRQ2(PetscObjectComm((PetscObject)is),PETSC_ERR_ARG_SIZ,"ISSTRIDE has stride %D, cannot be blocked of size %D",sub->step,bs);
    286:   is->bs = bs;
    287:   return(0);
    288: }

    292: static PetscErrorCode ISContiguousLocal_Stride(IS is,PetscInt gstart,PetscInt gend,PetscInt *start,PetscBool *contig)
    293: {
    294:   IS_Stride *sub = (IS_Stride*)is->data;

    297:   if (sub->step == 1 && sub->first >= gstart && sub->first+sub->n <= gend) {
    298:     *start  = sub->first - gstart;
    299:     *contig = PETSC_TRUE;
    300:   } else {
    301:     *start  = -1;
    302:     *contig = PETSC_FALSE;
    303:   }
    304:   return(0);
    305: }

    308: static struct _ISOps myops = { ISGetSize_Stride,
    309:                                ISGetLocalSize_Stride,
    310:                                ISGetIndices_Stride,
    311:                                ISRestoreIndices_Stride,
    312:                                ISInvertPermutation_Stride,
    313:                                ISSort_Stride,
    314:                                ISSorted_Stride,
    315:                                ISDuplicate_Stride,
    316:                                ISDestroy_Stride,
    317:                                ISView_Stride,
    318:                                ISIdentity_Stride,
    319:                                ISCopy_Stride,
    320:                                ISToGeneral_Stride,
    321:                                ISOnComm_Stride,
    322:                                ISSetBlockSize_Stride,
    323:                                ISContiguousLocal_Stride};

    328: /*@
    329:    ISStrideSetStride - Sets the stride information for a stride index set.

    331:    Collective on IS

    333:    Input Parameters:
    334: +  is - the index set
    335: .  n - the length of the locally owned portion of the index set
    336: .  first - the first element of the locally owned portion of the index set
    337: -  step - the change to the next index

    339:    Level: beginner

    341:   Concepts: IS^stride
    342:   Concepts: index sets^stride
    343:   Concepts: stride^index set

    345: .seealso: ISCreateGeneral(), ISCreateBlock(), ISAllGather()
    346: @*/
    347: PetscErrorCode  ISStrideSetStride(IS is,PetscInt n,PetscInt first,PetscInt step)
    348: {

    352:   if (n < 0) SETERRQ1(PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_OUTOFRANGE, "Negative length %d not valid", n);
    353:   PetscUseMethod(is,"ISStrideSetStride_C",(IS,PetscInt,PetscInt,PetscInt),(is,n,first,step));
    354:   return(0);
    355: }

    359: PetscErrorCode  ISStrideSetStride_Stride(IS is,PetscInt n,PetscInt first,PetscInt step)
    360: {
    362:   PetscInt       min,max;
    363:   IS_Stride      *sub = (IS_Stride*)is->data;

    366:   sub->n     = n;
    367:   MPI_Allreduce(&n,&sub->N,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)is));
    368:   sub->first = first;
    369:   sub->step  = step;
    370:   if (step > 0) {min = first; max = first + step*(n-1);}
    371:   else          {max = first; min = first + step*(n-1);}

    373:   is->min  = n > 0 ? min : -1;
    374:   is->max  = n > 0 ? max : -1;
    375:   is->data = (void*)sub;

    377:   if ((!first && step == 1) || (first == max && step == -1 && !min)) is->isperm = PETSC_TRUE;
    378:   else is->isperm = PETSC_FALSE;
    379:   return(0);
    380: }

    384: /*@
    385:    ISCreateStride - Creates a data structure for an index set
    386:    containing a list of evenly spaced integers.

    388:    Collective on MPI_Comm

    390:    Input Parameters:
    391: +  comm - the MPI communicator
    392: .  n - the length of the locally owned portion of the index set
    393: .  first - the first element of the locally owned portion of the index set
    394: -  step - the change to the next index

    396:    Output Parameter:
    397: .  is - the new index set

    399:    Notes:
    400:    When the communicator is not MPI_COMM_SELF, the operations on IS are NOT
    401:    conceptually the same as MPI_Group operations. The IS are the
    402:    distributed sets of indices and thus certain operations on them are collective.

    404:    Level: beginner

    406:   Concepts: IS^stride
    407:   Concepts: index sets^stride
    408:   Concepts: stride^index set

    410: .seealso: ISCreateGeneral(), ISCreateBlock(), ISAllGather()
    411: @*/
    412: PetscErrorCode  ISCreateStride(MPI_Comm comm,PetscInt n,PetscInt first,PetscInt step,IS *is)
    413: {

    417:   ISCreate(comm,is);
    418:   ISSetType(*is,ISSTRIDE);
    419:   ISStrideSetStride(*is,n,first,step);
    420:   return(0);
    421: }

    425: PETSC_EXTERN PetscErrorCode ISCreate_Stride(IS is)
    426: {
    428:   IS_Stride      *sub;

    431:   PetscMemcpy(is->ops,&myops,sizeof(myops));
    432:   PetscNewLog(is,IS_Stride,&sub);
    433:   is->bs   = 1;
    434:   is->data = sub;
    435:   PetscObjectComposeFunction((PetscObject)is,"ISStrideSetStride_C",ISStrideSetStride_Stride);
    436:   return(0);
    437: }