Date: 2022-03-04T17:37:32+00:00

Actual source code: stride.c

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

      9: typedef struct {
     10:   PetscInt first,step;
     11: } IS_Stride;

     13: static PetscErrorCode ISCopy_Stride(IS is,IS isy)
     14: {
     15:   IS_Stride      *is_stride = (IS_Stride*)is->data,*isy_stride = (IS_Stride*)isy->data;

     19:   PetscMemcpy(isy_stride,is_stride,sizeof(IS_Stride));
     20:   return(0);
     21: }

     23: PetscErrorCode ISDuplicate_Stride(IS is,IS *newIS)
     24: {
     26:   IS_Stride      *sub = (IS_Stride*)is->data;

     29:   ISCreateStride(PetscObjectComm((PetscObject)is),is->map->n,sub->first,sub->step,newIS);
     30:   return(0);
     31: }

     33: PetscErrorCode ISInvertPermutation_Stride(IS is,PetscInt nlocal,IS *perm)
     34: {
     35:   PetscBool      isident;

     39:   ISGetInfo(is,IS_IDENTITY,IS_GLOBAL,PETSC_TRUE,&isident);
     40:   if (isident) {
     41:     PetscInt rStart, rEnd;

     43:     PetscLayoutGetRange(is->map, &rStart, &rEnd);
     44:     ISCreateStride(PETSC_COMM_SELF,PetscMax(rEnd - rStart, 0),rStart,1,perm);
     45:   } else {
     46:     IS             tmp;
     47:     const PetscInt *indices,n = is->map->n;

     49:     ISGetIndices(is,&indices);
     50:     ISCreateGeneral(PetscObjectComm((PetscObject)is),n,indices,PETSC_COPY_VALUES,&tmp);
     51:     ISSetPermutation(tmp);
     52:     ISRestoreIndices(is,&indices);
     53:     ISInvertPermutation(tmp,nlocal,perm);
     54:     ISDestroy(&tmp);
     55:   }
     56:   return(0);
     57: }

     59: /*@
     60:    ISStrideGetInfo - Returns the first index in a stride index set and the stride width.

     62:    Not Collective

     64:    Input Parameter:
     65: .  is - the index set

     67:    Output Parameters:
     68: +  first - the first index
     69: -  step - the stride width

     71:    Level: intermediate

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

     77: .seealso: ISCreateStride(), ISGetSize(), ISSTRIDE
     78: @*/
     79: PetscErrorCode  ISStrideGetInfo(IS is,PetscInt *first,PetscInt *step)
     80: {
     81:   IS_Stride      *sub;
     82:   PetscBool      flg;

     89:   PetscObjectTypeCompare((PetscObject)is,ISSTRIDE,&flg);
     90:   if (!flg) SETERRQ(PetscObjectComm((PetscObject)is),PETSC_ERR_ARG_WRONG,"IS must be of type ISSTRIDE");

     92:   sub = (IS_Stride*)is->data;
     93:   if (first) *first = sub->first;
     94:   if (step)  *step  = sub->step;
     95:   return(0);
     96: }

     98: PetscErrorCode ISDestroy_Stride(IS is)
     99: {

    103:   PetscObjectComposeFunction((PetscObject)is,"ISStrideSetStride_C",NULL);
    104:   PetscFree(is->data);
    105:   return(0);
    106: }

    108: PetscErrorCode  ISToGeneral_Stride(IS inis)
    109: {
    111:   const PetscInt *idx;
    112:   PetscInt       n;

    115:   ISGetLocalSize(inis,&n);
    116:   ISGetIndices(inis,&idx);
    117:   ISSetType(inis,ISGENERAL);
    118:   ISGeneralSetIndices(inis,n,idx,PETSC_OWN_POINTER);
    119:   return(0);
    120: }

    122: PetscErrorCode ISLocate_Stride(IS is,PetscInt key,PetscInt *location)
    123: {
    124:   IS_Stride      *sub = (IS_Stride*)is->data;
    125:   PetscInt       rem, step;

    128:   *location = -1;
    129:   step      = sub->step;
    130:   key      -= sub->first;
    131:   rem       = key / step;
    132:   if ((rem < is->map->n) && !(key % step)) {
    133:     *location = rem;
    134:   }
    135:   return(0);
    136: }

    138: /*
    139:      Returns a legitimate index memory even if
    140:    the stride index set is empty.
    141: */
    142: PetscErrorCode ISGetIndices_Stride(IS is,const PetscInt *idx[])
    143: {
    144:   IS_Stride      *sub = (IS_Stride*)is->data;
    146:   PetscInt       i,**dx = (PetscInt**)idx;

    149:   PetscMalloc1(is->map->n,(PetscInt**)idx);
    150:   if (is->map->n) {
    151:     (*dx)[0] = sub->first;
    152:     for (i=1; i<is->map->n; i++) (*dx)[i] = (*dx)[i-1] + sub->step;
    153:   }
    154:   return(0);
    155: }

    157: PetscErrorCode ISRestoreIndices_Stride(IS in,const PetscInt *idx[])
    158: {

    162:   PetscFree(*(void**)idx);
    163:   return(0);
    164: }

    166: PetscErrorCode ISView_Stride(IS is,PetscViewer viewer)
    167: {
    168:   IS_Stride         *sub = (IS_Stride*)is->data;
    169:   PetscInt          i,n = is->map->n;
    170:   PetscMPIInt       rank,size;
    171:   PetscBool         iascii,ibinary;
    172:   PetscViewerFormat fmt;
    173:   PetscErrorCode    ierr;

    176:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
    177:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERBINARY,&ibinary);
    178:   if (iascii) {
    179:     PetscBool matl, isperm;

    181:     MPI_Comm_rank(PetscObjectComm((PetscObject)is),&rank);
    182:     MPI_Comm_size(PetscObjectComm((PetscObject)is),&size);
    183:     PetscViewerGetFormat(viewer,&fmt);
    184:     matl = (PetscBool)(fmt == PETSC_VIEWER_ASCII_MATLAB);
    185:     ISGetInfo(is,IS_PERMUTATION,IS_GLOBAL,PETSC_FALSE,&isperm);
    186:     if (isperm && !matl) {PetscViewerASCIIPrintf(viewer,"Index set is permutation\n");}
    187:     if (size == 1) {
    188:       if (matl) {
    189:         const char* name;

    191:         PetscObjectGetName((PetscObject)is,&name);
    192:         PetscViewerASCIIPrintf(viewer,"%s = [%D : %D : %D];\n",name,sub->first+1,sub->step,sub->first + sub->step*(n-1)+1);
    193:       } else {
    194:         PetscViewerASCIIPrintf(viewer,"Number of indices in (stride) set %D\n",n);
    195:         for (i=0; i<n; i++) {
    196:           PetscViewerASCIIPrintf(viewer,"%D %D\n",i,sub->first + i*sub->step);
    197:         }
    198:       }
    199:       PetscViewerFlush(viewer);
    200:     } else {
    201:       PetscViewerASCIIPushSynchronized(viewer);
    202:       if (matl) {
    203:         const char* name;

    205:         PetscObjectGetName((PetscObject)is,&name);
    206:         PetscViewerASCIISynchronizedPrintf(viewer,"%s_%d = [%D : %D : %D];\n",name,rank,sub->first+1,sub->step,sub->first + sub->step*(n-1)+1);
    207:       } else {
    208:         PetscViewerASCIISynchronizedPrintf(viewer,"[%d] Number of indices in (stride) set %D\n",rank,n);
    209:         for (i=0; i<n; i++) {
    210:           PetscViewerASCIISynchronizedPrintf(viewer,"[%d] %D %D\n",rank,i,sub->first + i*sub->step);
    211:         }
    212:       }
    213:       PetscViewerFlush(viewer);
    214:       PetscViewerASCIIPopSynchronized(viewer);
    215:     }
    216:   } else if (ibinary) {
    217:     ISView_Binary(is,viewer);
    218:   }
    219:   return(0);
    220: }

    222: PetscErrorCode ISSort_Stride(IS is)
    223: {
    224:   IS_Stride *sub = (IS_Stride*)is->data;

    227:   if (sub->step >= 0) return(0);
    228:   sub->first += (is->map->n - 1)*sub->step;
    229:   sub->step  *= -1;
    230:   return(0);
    231: }

    233: PetscErrorCode ISSorted_Stride(IS is,PetscBool * flg)
    234: {
    235:   IS_Stride *sub = (IS_Stride*)is->data;

    238:   if (sub->step >= 0) *flg = PETSC_TRUE;
    239:   else *flg = PETSC_FALSE;
    240:   return(0);
    241: }

    243: static PetscErrorCode ISUniqueLocal_Stride(IS is, PetscBool *flg)
    244: {
    245:   IS_Stride *sub = (IS_Stride*)is->data;

    248:   if (!(is->map->n) || sub->step != 0) *flg = PETSC_TRUE;
    249:   else *flg = PETSC_FALSE;
    250:   return(0);
    251: }

    253: static PetscErrorCode ISPermutationLocal_Stride(IS is, PetscBool *flg)
    254: {
    255:   IS_Stride *sub = (IS_Stride*)is->data;

    258:   if (!(is->map->n) || (PetscAbsInt(sub->step) == 1 && is->min == 0)) *flg = PETSC_TRUE;
    259:   else *flg = PETSC_FALSE;
    260:   return(0);
    261: }

    263: static PetscErrorCode ISIntervalLocal_Stride(IS is, PetscBool *flg)
    264: {
    265:   IS_Stride *sub = (IS_Stride*)is->data;

    268:   if (!(is->map->n) || sub->step == 1) *flg = PETSC_TRUE;
    269:   else *flg = PETSC_FALSE;
    270:   return(0);
    271: }

    273: static PetscErrorCode ISOnComm_Stride(IS is,MPI_Comm comm,PetscCopyMode mode,IS *newis)
    274: {
    276:   IS_Stride      *sub = (IS_Stride*)is->data;

    279:   ISCreateStride(comm,is->map->n,sub->first,sub->step,newis);
    280:   return(0);
    281: }

    283: static PetscErrorCode ISSetBlockSize_Stride(IS is,PetscInt bs)
    284: {
    285:   IS_Stride     *sub = (IS_Stride*)is->data;

    289:   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);
    290:   PetscLayoutSetBlockSize(is->map, bs);
    291:   return(0);
    292: }

    294: static PetscErrorCode ISContiguousLocal_Stride(IS is,PetscInt gstart,PetscInt gend,PetscInt *start,PetscBool *contig)
    295: {
    296:   IS_Stride *sub = (IS_Stride*)is->data;

    299:   if (sub->step == 1 && sub->first >= gstart && sub->first+is->map->n <= gend) {
    300:     *start  = sub->first - gstart;
    301:     *contig = PETSC_TRUE;
    302:   } else {
    303:     *start  = -1;
    304:     *contig = PETSC_FALSE;
    305:   }
    306:   return(0);
    307: }

    309: static struct _ISOps myops = { ISGetIndices_Stride,
    310:                                ISRestoreIndices_Stride,
    311:                                ISInvertPermutation_Stride,
    312:                                ISSort_Stride,
    313:                                ISSort_Stride,
    314:                                ISSorted_Stride,
    315:                                ISDuplicate_Stride,
    316:                                ISDestroy_Stride,
    317:                                ISView_Stride,
    318:                                ISLoad_Default,
    319:                                ISCopy_Stride,
    320:                                ISToGeneral_Stride,
    321:                                ISOnComm_Stride,
    322:                                ISSetBlockSize_Stride,
    323:                                ISContiguousLocal_Stride,
    324:                                ISLocate_Stride,
    325:                                ISSorted_Stride,
    326:                                NULL,
    327:                                ISUniqueLocal_Stride,
    328:                                NULL,
    329:                                ISPermutationLocal_Stride,
    330:                                NULL,
    331:                                ISIntervalLocal_Stride,
    332:                                NULL};

    334: /*@
    335:    ISStrideSetStride - Sets the stride information for a stride index set.

    337:    Collective on IS

    339:    Input Parameters:
    340: +  is - the index set
    341: .  n - the length of the locally owned portion of the index set
    342: .  first - the first element of the locally owned portion of the index set
    343: -  step - the change to the next index

    345:    Level: beginner

    347: .seealso: ISCreateGeneral(), ISCreateBlock(), ISAllGather(), ISSTRIDE, ISCreateStride(), ISStrideGetInfo()
    348: @*/
    349: PetscErrorCode  ISStrideSetStride(IS is,PetscInt n,PetscInt first,PetscInt step)
    350: {

    354:   if (n < 0) SETERRQ1(PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_OUTOFRANGE, "Negative length %D not valid", n);
    355:   ISClearInfoCache(is,PETSC_FALSE);
    356:   PetscUseMethod(is,"ISStrideSetStride_C",(IS,PetscInt,PetscInt,PetscInt),(is,n,first,step));
    357:   return(0);
    358: }

    360: PetscErrorCode  ISStrideSetStride_Stride(IS is,PetscInt n,PetscInt first,PetscInt step)
    361: {
    363:   PetscInt       min,max;
    364:   IS_Stride      *sub = (IS_Stride*)is->data;
    365:   PetscLayout    map;

    368:   PetscLayoutCreateFromSizes(PetscObjectComm((PetscObject)is),n,is->map->N,is->map->bs,&map);
    369:   PetscLayoutDestroy(&is->map);
    370:   is->map = map;

    372:   sub->first = first;
    373:   sub->step  = step;
    374:   if (step > 0) {min = first; max = first + step*(n-1);}
    375:   else          {max = first; min = first + step*(n-1);}

    377:   is->min  = n > 0 ? min : PETSC_MAX_INT;
    378:   is->max  = n > 0 ? max : PETSC_MIN_INT;
    379:   is->data = (void*)sub;
    380:   return(0);
    381: }

    383: /*@
    384:    ISCreateStride - Creates a data structure for an index set
    385:    containing a list of evenly spaced integers.

    387:    Collective

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

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

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

    403:    Level: beginner

    405: .seealso: ISCreateGeneral(), ISCreateBlock(), ISAllGather(), ISSTRIDE
    406: @*/
    407: PetscErrorCode  ISCreateStride(MPI_Comm comm,PetscInt n,PetscInt first,PetscInt step,IS *is)
    408: {

    412:   ISCreate(comm,is);
    413:   ISSetType(*is,ISSTRIDE);
    414:   ISStrideSetStride(*is,n,first,step);
    415:   return(0);
    416: }

    418: PETSC_EXTERN PetscErrorCode ISCreate_Stride(IS is)
    419: {
    421:   IS_Stride      *sub;

    424:   PetscNewLog(is,&sub);
    425:   is->data = (void *) sub;
    426:   PetscMemcpy(is->ops,&myops,sizeof(myops));
    427:   PetscObjectComposeFunction((PetscObject)is,"ISStrideSetStride_C",ISStrideSetStride_Stride);
    428:   return(0);
    429: }