Date: 2022-03-04T17:37:31+00:00

Actual source code: index.c

      1: /*
      2:    Defines the abstract operations on index sets, i.e. the public interface.
      3: */
      4: #include <petsc/private/isimpl.h>
      5: #include <petscviewer.h>
      6: #include <petscsf.h>

      8: /* Logging support */
      9: PetscClassId IS_CLASSID;
     10: /* TODO: Much more events are missing! */
     11: PetscLogEvent IS_View;
     12: PetscLogEvent IS_Load;

     14: /*@
     15:    ISRenumber - Renumbers an index set (with multiplicities) in a contiguous way.

     17:    Collective on IS

     19:    Input Parameters:
     20: +  subset - the index set
     21: -  subset_mult - the multiplcity of each entry in subset (optional, can be NULL)

     23:    Output Parameters:
     24: +  N - the maximum entry of the new IS
     25: -  subset_n - the new IS

     27:    Level: intermediate

     29: .seealso:
     30: @*/
     31: PetscErrorCode ISRenumber(IS subset, IS subset_mult, PetscInt *N, IS *subset_n)
     32: {
     33:   PetscSF        sf;
     34:   PetscLayout    map;
     35:   const PetscInt *idxs;
     36:   PetscInt       *leaf_data,*root_data,*gidxs;
     37:   PetscInt       N_n,n,i,lbounds[2],gbounds[2],Nl;
     38:   PetscInt       n_n,nlocals,start,first_index;
     39:   PetscMPIInt    commsize;
     40:   PetscBool      first_found;

     45:   if (subset_mult) {
     47:   }
     48:   if (!N && !subset_n) return(0);
     49:   ISGetLocalSize(subset,&n);
     50:   if (subset_mult) {
     51:     ISGetLocalSize(subset_mult,&i);
     52:     if (i != n) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Local subset and multiplicity sizes don't match! %d != %d",n,i);
     53:   }
     54:   /* create workspace layout for computing global indices of subset */
     55:   ISGetIndices(subset,&idxs);
     56:   lbounds[0] = lbounds[1] = 0;
     57:   for (i=0;i<n;i++) {
     58:     if (idxs[i] < lbounds[0]) lbounds[0] = idxs[i];
     59:     else if (idxs[i] > lbounds[1]) lbounds[1] = idxs[i];
     60:   }
     61:   lbounds[0] = -lbounds[0];
     62:   MPIU_Allreduce(lbounds,gbounds,2,MPIU_INT,MPI_MAX,PetscObjectComm((PetscObject)subset));
     63:   gbounds[0] = -gbounds[0];
     64:   N_n  = gbounds[1] - gbounds[0] + 1;

     66:   PetscLayoutCreate(PetscObjectComm((PetscObject)subset),&map);
     67:   PetscLayoutSetBlockSize(map,1);
     68:   PetscLayoutSetSize(map,N_n);
     69:   PetscLayoutSetUp(map);
     70:   PetscLayoutGetLocalSize(map,&Nl);

     72:   /* create sf : leaf_data == multiplicity of indexes, root data == global index in layout */
     73:   PetscMalloc2(n,&leaf_data,Nl,&root_data);
     74:   if (subset_mult) {
     75:     const PetscInt* idxs_mult;

     77:     ISGetIndices(subset_mult,&idxs_mult);
     78:     PetscArraycpy(leaf_data,idxs_mult,n);
     79:     ISRestoreIndices(subset_mult,&idxs_mult);
     80:   } else {
     81:     for (i=0;i<n;i++) leaf_data[i] = 1;
     82:   }
     83:   /* local size of new subset */
     84:   n_n = 0;
     85:   for (i=0;i<n;i++) n_n += leaf_data[i];

     87:   /* global indexes in layout */
     88:   PetscMalloc1(n_n,&gidxs); /* allocating possibly extra space in gidxs which will be used later */
     89:   for (i=0;i<n;i++) gidxs[i] = idxs[i] - gbounds[0];
     90:   ISRestoreIndices(subset,&idxs);
     91:   PetscSFCreate(PetscObjectComm((PetscObject)subset),&sf);
     92:   PetscSFSetGraphLayout(sf,map,n,NULL,PETSC_COPY_VALUES,gidxs);
     93:   PetscLayoutDestroy(&map);

     95:   /* reduce from leaves to roots */
     96:   PetscArrayzero(root_data,Nl);
     97:   PetscSFReduceBegin(sf,MPIU_INT,leaf_data,root_data,MPI_MAX);
     98:   PetscSFReduceEnd(sf,MPIU_INT,leaf_data,root_data,MPI_MAX);

    100:   /* count indexes in local part of layout */
    101:   nlocals = 0;
    102:   first_index = -1;
    103:   first_found = PETSC_FALSE;
    104:   for (i=0;i<Nl;i++) {
    105:     if (!first_found && root_data[i]) {
    106:       first_found = PETSC_TRUE;
    107:       first_index = i;
    108:     }
    109:     nlocals += root_data[i];
    110:   }

    112:   /* cumulative of number of indexes and size of subset without holes */
    113: #if defined(PETSC_HAVE_MPI_EXSCAN)
    114:   start = 0;
    115:   MPI_Exscan(&nlocals,&start,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)subset));
    116: #else
    117:   MPI_Scan(&nlocals,&start,1,MPIU_INT,MPI_SUM,PetscObjectComm((PetscObject)subset));
    118:   start = start-nlocals;
    119: #endif

    121:   if (N) { /* compute total size of new subset if requested */
    122:     *N   = start + nlocals;
    123:     MPI_Comm_size(PetscObjectComm((PetscObject)subset),&commsize);
    124:     MPI_Bcast(N,1,MPIU_INT,commsize-1,PetscObjectComm((PetscObject)subset));
    125:   }

    127:   if (!subset_n) {
    128:     PetscFree(gidxs);
    129:     PetscSFDestroy(&sf);
    130:     PetscFree2(leaf_data,root_data);
    131:     return(0);
    132:   }

    134:   /* adapt root data with cumulative */
    135:   if (first_found) {
    136:     PetscInt old_index;

    138:     root_data[first_index] += start;
    139:     old_index = first_index;
    140:     for (i=first_index+1;i<Nl;i++) {
    141:       if (root_data[i]) {
    142:         root_data[i] += root_data[old_index];
    143:         old_index = i;
    144:       }
    145:     }
    146:   }

    148:   /* from roots to leaves */
    149:   PetscSFBcastBegin(sf,MPIU_INT,root_data,leaf_data,MPI_REPLACE);
    150:   PetscSFBcastEnd(sf,MPIU_INT,root_data,leaf_data,MPI_REPLACE);
    151:   PetscSFDestroy(&sf);

    153:   /* create new IS with global indexes without holes */
    154:   if (subset_mult) {
    155:     const PetscInt* idxs_mult;
    156:     PetscInt        cum;

    158:     cum = 0;
    159:     ISGetIndices(subset_mult,&idxs_mult);
    160:     for (i=0;i<n;i++) {
    161:       PetscInt j;
    162:       for (j=0;j<idxs_mult[i];j++) gidxs[cum++] = leaf_data[i] - idxs_mult[i] + j;
    163:     }
    164:     ISRestoreIndices(subset_mult,&idxs_mult);
    165:   } else {
    166:     for (i=0;i<n;i++) {
    167:       gidxs[i] = leaf_data[i]-1;
    168:     }
    169:   }
    170:   ISCreateGeneral(PetscObjectComm((PetscObject)subset),n_n,gidxs,PETSC_OWN_POINTER,subset_n);
    171:   PetscFree2(leaf_data,root_data);
    172:   return(0);
    173: }

    175: /*@
    176:    ISCreateSubIS - Create a sub index set from a global index set selecting some components.

    178:    Collective on IS

    180:    Input Parameters:
    181: +  is - the index set
    182: -  comps - which components we will extract from is

    184:    Output Parameters:
    185: .  subis - the new sub index set

    187:    Level: intermediate

    189:    Example usage:
    190:    We have an index set (is) living on 3 processes with the following values:
    191:    | 4 9 0 | 2 6 7 | 10 11 1|
    192:    and another index set (comps) used to indicate which components of is  we want to take,
    193:    | 7 5  | 1 2 | 0 4|
    194:    The output index set (subis) should look like:
    195:    | 11 7 | 9 0 | 4 6|

    197: .seealso: VecGetSubVector(), MatCreateSubMatrix()
    198: @*/
    199: PetscErrorCode ISCreateSubIS(IS is,IS comps,IS *subis)
    200: {
    201:   PetscSF         sf;
    202:   const PetscInt  *is_indices,*comps_indices;
    203:   PetscInt        *subis_indices,nroots,nleaves,*mine,i,lidx;
    204:   PetscMPIInt     owner;
    205:   PetscSFNode     *remote;
    206:   PetscErrorCode  ierr;
    207:   MPI_Comm        comm;

    214:   PetscObjectGetComm((PetscObject)is, &comm);
    215:   ISGetLocalSize(comps,&nleaves);
    216:   ISGetLocalSize(is,&nroots);
    217:   PetscMalloc1(nleaves,&remote);
    218:   PetscMalloc1(nleaves,&mine);
    219:   ISGetIndices(comps,&comps_indices);
    220:   /*
    221:    * Construct a PetscSF in which "is" data serves as roots and "subis" is leaves.
    222:    * Root data are sent to leaves using PetscSFBcast().
    223:    * */
    224:   for (i=0; i<nleaves; i++) {
    225:     mine[i] = i;
    226:     /* Connect a remote root with the current leaf. The value on the remote root
    227:      * will be received by the current local leaf.
    228:      * */
    229:     owner = -1;
    230:     lidx =  -1;
    231:     PetscLayoutFindOwnerIndex(is->map,comps_indices[i],&owner,&lidx);
    232:     remote[i].rank = owner;
    233:     remote[i].index = lidx;
    234:   }
    235:   ISRestoreIndices(comps,&comps_indices);
    236:   PetscSFCreate(comm,&sf);
    237:   PetscSFSetFromOptions(sf);\
    238:   PetscSFSetGraph(sf,nroots,nleaves,mine,PETSC_OWN_POINTER,remote,PETSC_OWN_POINTER);

    240:   PetscMalloc1(nleaves,&subis_indices);
    241:   ISGetIndices(is, &is_indices);
    242:   PetscSFBcastBegin(sf,MPIU_INT,is_indices,subis_indices,MPI_REPLACE);
    243:   PetscSFBcastEnd(sf,MPIU_INT,is_indices,subis_indices,MPI_REPLACE);
    244:   ISRestoreIndices(is,&is_indices);
    245:   PetscSFDestroy(&sf);
    246:   ISCreateGeneral(comm,nleaves,subis_indices,PETSC_OWN_POINTER,subis);
    247:   return(0);
    248: }

    250: /*@
    251:    ISClearInfoCache - clear the cache of computed index set properties

    253:    Not collective

    255:    Input Parameters:
    256: +  is - the index set
    257: -  clear_permanent_local - whether to remove the permanent status of local properties

    259:    NOTE: because all processes must agree on the global permanent status of a property,
    260:    the permanent status can only be changed with ISSetInfo(), because this routine is not collective

    262:    Level: developer

    264: .seealso:  ISInfo, ISInfoType, ISSetInfo(), ISClearInfoCache()

    266: @*/
    267: PetscErrorCode ISClearInfoCache(IS is, PetscBool clear_permanent_local)
    268: {
    269:   PetscInt i, j;

    274:   for (i = 0; i < IS_INFO_MAX; i++) {
    275:     if (clear_permanent_local) is->info_permanent[IS_LOCAL][i] = PETSC_FALSE;
    276:     for (j = 0; j < 2; j++) {
    277:       if (!is->info_permanent[j][i]) is->info[j][i] = IS_INFO_UNKNOWN;
    278:     }
    279:   }
    280:   return(0);
    281: }

    283: static PetscErrorCode ISSetInfo_Internal(IS is, ISInfo info, ISInfoType type, ISInfoBool ipermanent, PetscBool flg)
    284: {
    285:   ISInfoBool     iflg = flg ? IS_INFO_TRUE : IS_INFO_FALSE;
    286:   PetscInt       itype = (type == IS_LOCAL) ? 0 : 1;
    287:   PetscBool      permanent_set = (ipermanent == IS_INFO_UNKNOWN) ? PETSC_FALSE : PETSC_TRUE;
    288:   PetscBool      permanent = (ipermanent == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;

    291:   /* set this property */
    292:   is->info[itype][(int)info] = iflg;
    293:   if (permanent_set) is->info_permanent[itype][(int)info] = permanent;
    294:   /* set implications */
    295:   switch (info) {
    296:   case IS_SORTED:
    297:     if (flg && type == IS_GLOBAL) { /* an array that is globally sorted is also locally sorted */
    298:       is->info[IS_LOCAL][(int)info] = IS_INFO_TRUE;
    299:       /* global permanence implies local permanence */
    300:       if (permanent_set && permanent) is->info_permanent[IS_LOCAL][(int)info] = PETSC_TRUE;
    301:     }
    302:     if (!flg) { /* if an array is not sorted, it cannot be an interval or the identity */
    303:       is->info[itype][IS_INTERVAL] = IS_INFO_FALSE;
    304:       is->info[itype][IS_IDENTITY] = IS_INFO_FALSE;
    305:       if (permanent_set) {
    306:         is->info_permanent[itype][IS_INTERVAL] = permanent;
    307:         is->info_permanent[itype][IS_IDENTITY] = permanent;
    308:       }
    309:     }
    310:     break;
    311:   case IS_UNIQUE:
    312:     if (flg && type == IS_GLOBAL) { /* an array that is globally unique is also locally unique */
    313:       is->info[IS_LOCAL][(int)info] = IS_INFO_TRUE;
    314:       /* global permanence implies local permanence */
    315:       if (permanent_set && permanent) is->info_permanent[IS_LOCAL][(int)info] = PETSC_TRUE;
    316:     }
    317:     if (!flg) { /* if an array is not unique, it cannot be a permutation, and interval, or the identity */
    318:       is->info[itype][IS_PERMUTATION] = IS_INFO_FALSE;
    319:       is->info[itype][IS_INTERVAL]    = IS_INFO_FALSE;
    320:       is->info[itype][IS_IDENTITY]    = IS_INFO_FALSE;
    321:       if (permanent_set) {
    322:         is->info_permanent[itype][IS_PERMUTATION] = permanent;
    323:         is->info_permanent[itype][IS_INTERVAL]    = permanent;
    324:         is->info_permanent[itype][IS_IDENTITY]    = permanent;
    325:       }
    326:     }
    327:     break;
    328:   case IS_PERMUTATION:
    329:     if (flg) { /* an array that is a permutation is unique and is unique locally */
    330:       is->info[itype][IS_UNIQUE] = IS_INFO_TRUE;
    331:       is->info[IS_LOCAL][IS_UNIQUE] = IS_INFO_TRUE;
    332:       if (permanent_set && permanent) {
    333:         is->info_permanent[itype][IS_UNIQUE] = PETSC_TRUE;
    334:         is->info_permanent[IS_LOCAL][IS_UNIQUE] = PETSC_TRUE;
    335:       }
    336:     } else { /* an array that is not a permutation cannot be the identity */
    337:       is->info[itype][IS_IDENTITY] = IS_INFO_FALSE;
    338:       if (permanent_set) is->info_permanent[itype][IS_IDENTITY] = permanent;
    339:     }
    340:     break;
    341:   case IS_INTERVAL:
    342:     if (flg) { /* an array that is an interval is sorted and unique */
    343:       is->info[itype][IS_SORTED]         = IS_INFO_TRUE;
    344:       is->info[IS_LOCAL][IS_SORTED]      = IS_INFO_TRUE;
    345:       is->info[itype][IS_UNIQUE]         = IS_INFO_TRUE;
    346:       is->info[IS_LOCAL][IS_UNIQUE]      = IS_INFO_TRUE;
    347:       if (permanent_set && permanent) {
    348:         is->info_permanent[itype][IS_SORTED]    = PETSC_TRUE;
    349:         is->info_permanent[IS_LOCAL][IS_SORTED] = PETSC_TRUE;
    350:         is->info_permanent[itype][IS_UNIQUE]    = PETSC_TRUE;
    351:         is->info_permanent[IS_LOCAL][IS_UNIQUE] = PETSC_TRUE;
    352:       }
    353:     } else { /* an array that is not an interval cannot be the identity */
    354:       is->info[itype][IS_IDENTITY] = IS_INFO_FALSE;
    355:       if (permanent_set) is->info_permanent[itype][IS_IDENTITY] = permanent;
    356:     }
    357:     break;
    358:   case IS_IDENTITY:
    359:     if (flg) { /* an array that is the identity is sorted, unique, an interval, and a permutation */
    360:       is->info[itype][IS_SORTED]         = IS_INFO_TRUE;
    361:       is->info[IS_LOCAL][IS_SORTED]      = IS_INFO_TRUE;
    362:       is->info[itype][IS_UNIQUE]         = IS_INFO_TRUE;
    363:       is->info[IS_LOCAL][IS_UNIQUE]      = IS_INFO_TRUE;
    364:       is->info[itype][IS_PERMUTATION]    = IS_INFO_TRUE;
    365:       is->info[itype][IS_INTERVAL]       = IS_INFO_TRUE;
    366:       is->info[IS_LOCAL][IS_INTERVAL]    = IS_INFO_TRUE;
    367:       if (permanent_set && permanent) {
    368:         is->info_permanent[itype][IS_SORTED]         = PETSC_TRUE;
    369:         is->info_permanent[IS_LOCAL][IS_SORTED]      = PETSC_TRUE;
    370:         is->info_permanent[itype][IS_UNIQUE]         = PETSC_TRUE;
    371:         is->info_permanent[IS_LOCAL][IS_UNIQUE]      = PETSC_TRUE;
    372:         is->info_permanent[itype][IS_PERMUTATION]    = PETSC_TRUE;
    373:         is->info_permanent[itype][IS_INTERVAL]       = PETSC_TRUE;
    374:         is->info_permanent[IS_LOCAL][IS_INTERVAL]    = PETSC_TRUE;
    375:       }
    376:     }
    377:     break;
    378:   default:
    379:     if (type == IS_LOCAL) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_OUTOFRANGE, "Unknown IS property");
    380:     else SETERRQ(PetscObjectComm((PetscObject)is), PETSC_ERR_ARG_OUTOFRANGE, "Unknown IS property");
    381:   }
    382:   return(0);
    383: }

    385: /*@
    386:    ISSetInfo - Set known information about an index set.

    388:    Logically Collective on IS if type is IS_GLOBAL

    390:    Input Parameters:
    391: +  is - the index set
    392: .  info - describing a property of the index set, one of those listed below,
    393: .  type - IS_LOCAL if the information describes the local portion of the index set,
    394:           IS_GLOBAL if it describes the whole index set
    395: .  permanent - PETSC_TRUE if it is known that the property will persist through changes to the index set, PETSC_FALSE otherwise
    396:                If the user sets a property as permanently known, it will bypass computation of that property
    397: -  flg - set the described property as true (PETSC_TRUE) or false (PETSC_FALSE)

    399:   Info Describing IS Structure:
    400: +    IS_SORTED - the [local part of the] index set is sorted in ascending order
    401: .    IS_UNIQUE - each entry in the [local part of the] index set is unique
    402: .    IS_PERMUTATION - the [local part of the] index set is a permutation of the integers {0, 1, ..., N-1}, where N is the size of the [local part of the] index set
    403: .    IS_INTERVAL - the [local part of the] index set is equal to a contiguous range of integers {f, f + 1, ..., f + N-1}
    404: -    IS_IDENTITY - the [local part of the] index set is equal to the integers {0, 1, ..., N-1}

    406:    Notes:
    407:    If type is IS_GLOBAL, all processes that share the index set must pass the same value in flg

    409:    It is possible to set a property with ISSetInfo() that contradicts what would be previously computed with ISGetInfo()

    411:    Level: advanced

    413: .seealso:  ISInfo, ISInfoType, IS

    415: @*/
    416: PetscErrorCode ISSetInfo(IS is, ISInfo info, ISInfoType type, PetscBool permanent, PetscBool flg)
    417: {
    418:   MPI_Comm       comm, errcomm;
    419:   PetscMPIInt    size;

    425:   comm = PetscObjectComm((PetscObject)is);
    426:   if (type == IS_GLOBAL) {
    430:     errcomm = comm;
    431:   } else {
    432:     errcomm = PETSC_COMM_SELF;
    433:   }

    435:   if (((int) info) <= IS_INFO_MIN || ((int) info) >= IS_INFO_MAX) SETERRQ1(errcomm,PETSC_ERR_ARG_OUTOFRANGE,"Options %d is out of range",(int)info);

    437:   MPI_Comm_size(comm, &size);
    438:   /* do not use global values if size == 1: it makes it easier to keep the implications straight */
    439:   if (size == 1) type = IS_LOCAL;
    440:   ISSetInfo_Internal(is, info, type, permanent ? IS_INFO_TRUE : IS_INFO_FALSE, flg);
    441:   return(0);
    442: }

    444: static PetscErrorCode ISGetInfo_Sorted(IS is, ISInfoType type, PetscBool *flg)
    445: {
    446:   MPI_Comm       comm;
    447:   PetscMPIInt    size, rank;

    451:   comm = PetscObjectComm((PetscObject)is);
    452:   MPI_Comm_size(comm, &size);
    453:   MPI_Comm_size(comm, &rank);
    454:   if (type == IS_GLOBAL && is->ops->sortedglobal) {
    455:     (*is->ops->sortedglobal)(is,flg);
    456:   } else {
    457:     PetscBool sortedLocal = PETSC_FALSE;

    459:     /* determine if the array is locally sorted */
    460:     if (type == IS_GLOBAL && size > 1) {
    461:       /* call ISGetInfo so that a cached value will be used if possible */
    462:       ISGetInfo(is, IS_SORTED, IS_LOCAL, PETSC_TRUE, &sortedLocal);
    463:     } else if (is->ops->sortedlocal) {
    464:       (*is->ops->sortedlocal)(is,&sortedLocal);
    465:     } else {
    466:       /* default: get the local indices and directly check */
    467:       const PetscInt *idx;
    468:       PetscInt n;

    470:       ISGetIndices(is, &idx);
    471:       ISGetLocalSize(is, &n);
    472:       PetscSortedInt(n, idx, &sortedLocal);
    473:       ISRestoreIndices(is, &idx);
    474:     }

    476:     if (type == IS_LOCAL || size == 1) {
    477:       *flg = sortedLocal;
    478:     } else {
    479:       MPI_Allreduce(&sortedLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    480:       if (*flg) {
    481:         PetscInt  n, min = PETSC_MAX_INT, max = PETSC_MIN_INT;
    482:         PetscInt  maxprev;

    484:         ISGetLocalSize(is, &n);
    485:         if (n) {ISGetMinMax(is, &min, &max);}
    486:         maxprev = PETSC_MIN_INT;
    487:         MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm);
    488:         if (rank && (maxprev > min)) sortedLocal = PETSC_FALSE;
    489:         MPI_Allreduce(&sortedLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    490:       }
    491:     }
    492:   }
    493:   return(0);
    494: }

    496: PetscErrorCode ISGetIndicesCopy(IS is, PetscInt idx[]);

    498: static PetscErrorCode ISGetInfo_Unique(IS is, ISInfoType type, PetscBool *flg)
    499: {
    500:   MPI_Comm       comm;
    501:   PetscMPIInt    size, rank;
    502:   PetscInt       i;

    506:   comm = PetscObjectComm((PetscObject)is);
    507:   MPI_Comm_size(comm, &size);
    508:   MPI_Comm_size(comm, &rank);
    509:   if (type == IS_GLOBAL && is->ops->uniqueglobal) {
    510:     (*is->ops->uniqueglobal)(is,flg);
    511:   } else {
    512:     PetscBool uniqueLocal;
    513:     PetscInt  n = -1;
    514:     PetscInt  *idx = NULL;

    516:     /* determine if the array is locally unique */
    517:     if (type == IS_GLOBAL && size > 1) {
    518:       /* call ISGetInfo so that a cached value will be used if possible */
    519:       ISGetInfo(is, IS_UNIQUE, IS_LOCAL, PETSC_TRUE, &uniqueLocal);
    520:     } else if (is->ops->uniquelocal) {
    521:       (*is->ops->uniquelocal)(is,&uniqueLocal);
    522:     } else {
    523:       /* default: get the local indices and directly check */
    524:       uniqueLocal = PETSC_TRUE;
    525:       ISGetLocalSize(is, &n);
    526:       PetscMalloc1(n, &idx);
    527:       ISGetIndicesCopy(is, idx);
    528:       PetscIntSortSemiOrdered(n, idx);
    529:       for (i = 1; i < n; i++) if (idx[i] == idx[i-1]) break;
    530:       if (i < n) uniqueLocal = PETSC_FALSE;
    531:     }

    533:     PetscFree(idx);
    534:     if (type == IS_LOCAL || size == 1) {
    535:       *flg = uniqueLocal;
    536:     } else {
    537:       MPI_Allreduce(&uniqueLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    538:       if (*flg) {
    539:         PetscInt  min = PETSC_MAX_INT, max = PETSC_MIN_INT, maxprev;

    541:         if (!idx) {
    542:           ISGetLocalSize(is, &n);
    543:           PetscMalloc1(n, &idx);
    544:           ISGetIndicesCopy(is, idx);
    545:         }
    546:         PetscParallelSortInt(is->map, is->map, idx, idx);
    547:         if (n) {
    548:           min = idx[0];
    549:           max = idx[n - 1];
    550:         }
    551:         for (i = 1; i < n; i++) if (idx[i] == idx[i-1]) break;
    552:         if (i < n) uniqueLocal = PETSC_FALSE;
    553:         maxprev = PETSC_MIN_INT;
    554:         MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm);
    555:         if (rank && (maxprev == min)) uniqueLocal = PETSC_FALSE;
    556:         MPI_Allreduce(&uniqueLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    557:       }
    558:     }
    559:     PetscFree(idx);
    560:   }
    561:   return(0);
    562: }

    564: static PetscErrorCode ISGetInfo_Permutation(IS is, ISInfoType type, PetscBool *flg)
    565: {
    566:   MPI_Comm       comm;
    567:   PetscMPIInt    size, rank;

    571:   comm = PetscObjectComm((PetscObject)is);
    572:   MPI_Comm_size(comm, &size);
    573:   MPI_Comm_size(comm, &rank);
    574:   if (type == IS_GLOBAL && is->ops->permglobal) {
    575:     (*is->ops->permglobal)(is,flg);
    576:   } else if (type == IS_LOCAL && is->ops->permlocal) {
    577:     (*is->ops->permlocal)(is,flg);
    578:   } else {
    579:     PetscBool permLocal;
    580:     PetscInt  n, i, rStart;
    581:     PetscInt  *idx;

    583:     ISGetLocalSize(is, &n);
    584:     PetscMalloc1(n, &idx);
    585:     ISGetIndicesCopy(is, idx);
    586:     if (type == IS_GLOBAL) {
    587:       PetscParallelSortInt(is->map, is->map, idx, idx);
    588:       PetscLayoutGetRange(is->map, &rStart, NULL);
    589:     } else {
    590:       PetscIntSortSemiOrdered(n, idx);
    591:       rStart = 0;
    592:     }
    593:     permLocal = PETSC_TRUE;
    594:     for (i = 0; i < n; i++) {
    595:       if (idx[i] != rStart + i) break;
    596:     }
    597:     if (i < n) permLocal = PETSC_FALSE;
    598:     if (type == IS_LOCAL || size == 1) {
    599:       *flg = permLocal;
    600:     } else {
    601:       MPI_Allreduce(&permLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    602:     }
    603:     PetscFree(idx);
    604:   }
    605:   return(0);
    606: }

    608: static PetscErrorCode ISGetInfo_Interval(IS is, ISInfoType type, PetscBool *flg)
    609: {
    610:   MPI_Comm       comm;
    611:   PetscMPIInt    size, rank;
    612:   PetscInt       i;

    616:   comm = PetscObjectComm((PetscObject)is);
    617:   MPI_Comm_size(comm, &size);
    618:   MPI_Comm_size(comm, &rank);
    619:   if (type == IS_GLOBAL && is->ops->intervalglobal) {
    620:     (*is->ops->intervalglobal)(is,flg);
    621:   } else {
    622:     PetscBool intervalLocal;

    624:     /* determine if the array is locally an interval */
    625:     if (type == IS_GLOBAL && size > 1) {
    626:       /* call ISGetInfo so that a cached value will be used if possible */
    627:       ISGetInfo(is, IS_INTERVAL, IS_LOCAL, PETSC_TRUE, &intervalLocal);
    628:     } else if (is->ops->intervallocal) {
    629:       (*is->ops->intervallocal)(is,&intervalLocal);
    630:     } else {
    631:       PetscInt        n;
    632:       const PetscInt  *idx;
    633:       /* default: get the local indices and directly check */
    634:       intervalLocal = PETSC_TRUE;
    635:       ISGetLocalSize(is, &n);
    636:       PetscMalloc1(n, &idx);
    637:       ISGetIndices(is, &idx);
    638:       for (i = 1; i < n; i++) if (idx[i] != idx[i-1] + 1) break;
    639:       if (i < n) intervalLocal = PETSC_FALSE;
    640:       ISRestoreIndices(is, &idx);
    641:     }

    643:     if (type == IS_LOCAL || size == 1) {
    644:       *flg = intervalLocal;
    645:     } else {
    646:       MPI_Allreduce(&intervalLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    647:       if (*flg) {
    648:         PetscInt  n, min = PETSC_MAX_INT, max = PETSC_MIN_INT;
    649:         PetscInt  maxprev;

    651:         ISGetLocalSize(is, &n);
    652:         if (n) {ISGetMinMax(is, &min, &max);}
    653:         maxprev = PETSC_MIN_INT;
    654:         MPI_Exscan(&max, &maxprev, 1, MPIU_INT, MPI_MAX, comm);
    655:         if (rank && n && (maxprev != min - 1)) intervalLocal = PETSC_FALSE;
    656:         MPI_Allreduce(&intervalLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    657:       }
    658:     }
    659:   }
    660:   return(0);
    661: }

    663: static PetscErrorCode ISGetInfo_Identity(IS is, ISInfoType type, PetscBool *flg)
    664: {
    665:   MPI_Comm       comm;
    666:   PetscMPIInt    size, rank;

    670:   comm = PetscObjectComm((PetscObject)is);
    671:   MPI_Comm_size(comm, &size);
    672:   MPI_Comm_size(comm, &rank);
    673:   if (type == IS_GLOBAL && is->ops->intervalglobal) {
    674:     PetscBool isinterval;

    676:     (*is->ops->intervalglobal)(is,&isinterval);
    677:     *flg = PETSC_FALSE;
    678:     if (isinterval) {
    679:       PetscInt  min;

    681:       ISGetMinMax(is, &min, NULL);
    682:       MPI_Bcast(&min, 1, MPIU_INT, 0, comm);
    683:       if (min == 0) *flg = PETSC_TRUE;
    684:     }
    685:   } else if (type == IS_LOCAL && is->ops->intervallocal) {
    686:     PetscBool isinterval;

    688:     (*is->ops->intervallocal)(is,&isinterval);
    689:     *flg = PETSC_FALSE;
    690:     if (isinterval) {
    691:       PetscInt  min;

    693:       ISGetMinMax(is, &min, NULL);
    694:       if (min == 0) *flg = PETSC_TRUE;
    695:     }
    696:   } else {
    697:     PetscBool identLocal;
    698:     PetscInt  n, i, rStart;
    699:     const PetscInt *idx;

    701:     ISGetLocalSize(is, &n);
    702:     ISGetIndices(is, &idx);
    703:     PetscLayoutGetRange(is->map, &rStart, NULL);
    704:     identLocal = PETSC_TRUE;
    705:     for (i = 0; i < n; i++) {
    706:       if (idx[i] != rStart + i) break;
    707:     }
    708:     if (i < n) identLocal = PETSC_FALSE;
    709:     if (type == IS_LOCAL || size == 1) {
    710:       *flg = identLocal;
    711:     } else {
    712:       MPI_Allreduce(&identLocal, flg, 1, MPIU_BOOL, MPI_LAND, comm);
    713:     }
    714:     ISRestoreIndices(is, &idx);
    715:   }
    716:   return(0);
    717: }

    719: /*@
    720:    ISGetInfo - Determine whether an index set satisfies a given property

    722:    Collective or logically collective on IS if the type is IS_GLOBAL (logically collective if the value of the property has been permanently set with ISSetInfo())

    724:    Input Parameters:
    725: +  is - the index set
    726: .  info - describing a property of the index set, one of those listed in the documentation of ISSetInfo()
    727: .  compute - if PETSC_FALSE, the property will not be computed if it is not already known and the property will be assumed to be false
    728: -  type - whether the property is local (IS_LOCAL) or global (IS_GLOBAL)

    730:    Output Parameter:
    731: .  flg - wheter the property is true (PETSC_TRUE) or false (PETSC_FALSE)

    733:    Note: ISGetInfo uses cached values when possible, which will be incorrect if ISSetInfo() has been called with incorrect information.  To clear cached values, use ISClearInfoCache().

    735:    Level: advanced

    737: .seealso:  ISInfo, ISInfoType, ISSetInfo(), ISClearInfoCache()

    739: @*/
    740: PetscErrorCode ISGetInfo(IS is, ISInfo info, ISInfoType type, PetscBool compute, PetscBool *flg)
    741: {
    742:   MPI_Comm       comm, errcomm;
    743:   PetscMPIInt    rank, size;
    744:   PetscInt       itype;
    745:   PetscBool      hasprop;
    746:   PetscBool      infer;

    752:   comm = PetscObjectComm((PetscObject)is);
    753:   if (type == IS_GLOBAL) {
    755:     errcomm = comm;
    756:   } else {
    757:     errcomm = PETSC_COMM_SELF;
    758:   }

    760:   MPI_Comm_size(comm, &size);
    761:   MPI_Comm_rank(comm, &rank);

    763:   if (((int) info) <= IS_INFO_MIN || ((int) info) >= IS_INFO_MAX) SETERRQ1(errcomm,PETSC_ERR_ARG_OUTOFRANGE,"Options %d is out of range",(int)info);
    764:   if (size == 1) type = IS_LOCAL;
    765:   itype = (type == IS_LOCAL) ? 0 : 1;
    766:   hasprop = PETSC_FALSE;
    767:   infer = PETSC_FALSE;
    768:   if (is->info_permanent[itype][(int)info]) {
    769:     hasprop = (is->info[itype][(int)info] == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;
    770:     infer = PETSC_TRUE;
    771:   } else if ((itype == IS_LOCAL) && (is->info[IS_LOCAL][info] != IS_INFO_UNKNOWN)) {
    772:     /* we can cache local properties as long as we clear them when the IS changes */
    773:     /* NOTE: we only cache local values because there is no ISAssemblyBegin()/ISAssemblyEnd(),
    774:      so we have no way of knowing when a cached value has been invalidated by changes on a different process */
    775:     hasprop = (is->info[itype][(int)info] == IS_INFO_TRUE) ? PETSC_TRUE : PETSC_FALSE;
    776:     infer = PETSC_TRUE;
    777:   } else if (compute) {
    778:     switch (info) {
    779:     case IS_SORTED:
    780:       ISGetInfo_Sorted(is, type, &hasprop);
    781:       break;
    782:     case IS_UNIQUE:
    783:       ISGetInfo_Unique(is, type, &hasprop);
    784:       break;
    785:     case IS_PERMUTATION:
    786:       ISGetInfo_Permutation(is, type, &hasprop);
    787:       break;
    788:     case IS_INTERVAL:
    789:       ISGetInfo_Interval(is, type, &hasprop);
    790:       break;
    791:     case IS_IDENTITY:
    792:       ISGetInfo_Identity(is, type, &hasprop);
    793:       break;
    794:     default:
    795:       SETERRQ(errcomm, PETSC_ERR_ARG_OUTOFRANGE, "Unknown IS property");
    796:     }
    797:     infer = PETSC_TRUE;
    798:   }
    799:   /* call ISSetInfo_Internal to keep all of the implications straight */
    800:   if (infer) {ISSetInfo_Internal(is, info, type, IS_INFO_UNKNOWN, hasprop);}
    801:   *flg = hasprop;
    802:   return(0);
    803: }

    805: static PetscErrorCode ISCopyInfo(IS source, IS dest)
    806: {

    810:   PetscArraycpy(&dest->info[0], &source->info[0], 2);
    811:   PetscArraycpy(&dest->info_permanent[0], &source->info_permanent[0], 2);
    812:   return(0);
    813: }

    815: /*@
    816:    ISIdentity - Determines whether index set is the identity mapping.

    818:    Collective on IS

    820:    Input Parameters:
    821: .  is - the index set

    823:    Output Parameters:
    824: .  ident - PETSC_TRUE if an identity, else PETSC_FALSE

    826:    Level: intermediate

    828:    Note: If ISSetIdentity() (or ISSetInfo() for a permanent property) has been called,
    829:    ISIdentity() will return its answer without communication between processes, but
    830:    otherwise the output ident will be computed from ISGetInfo(),
    831:    which may require synchronization on the communicator of IS.  To avoid this computation,
    832:    call ISGetInfo() directly with the compute flag set to PETSC_FALSE, and ident will be assumed false.

    834: .seealso: ISSetIdentity(), ISGetInfo()
    835: @*/
    836: PetscErrorCode  ISIdentity(IS is,PetscBool  *ident)
    837: {

    843:   ISGetInfo(is,IS_IDENTITY,IS_GLOBAL,PETSC_TRUE,ident);
    844:   return(0);
    845: }

    847: /*@
    848:    ISSetIdentity - Informs the index set that it is an identity.

    850:    Logically Collective on IS

    852:    Input Parameter:
    853: .  is - the index set

    855:    Level: intermediate

    857:    Note: The IS will be considered the identity permanently, even if indices have been changes (for example, with
    858:    ISGeneralSetIndices()).  It's a good idea to only set this property if the IS will not change in the future.
    859:    To clear this property, use ISClearInfoCache().

    861: .seealso: ISIdentity(), ISSetInfo(), ISClearInfoCache()
    862: @*/
    863: PetscErrorCode  ISSetIdentity(IS is)
    864: {

    869:   ISSetInfo(is,IS_IDENTITY,IS_GLOBAL,PETSC_TRUE,PETSC_TRUE);
    870:   return(0);
    871: }

    873: /*@
    874:    ISContiguousLocal - Locates an index set with contiguous range within a global range, if possible

    876:    Not Collective

    878:    Input Parameters:
    879: +  is - the index set
    880: .  gstart - global start
    881: -  gend - global end

    883:    Output Parameters:
    884: +  start - start of contiguous block, as an offset from gstart
    885: -  contig - PETSC_TRUE if the index set refers to contiguous entries on this process, else PETSC_FALSE

    887:    Level: developer

    889: .seealso: ISGetLocalSize(), VecGetOwnershipRange()
    890: @*/
    891: PetscErrorCode  ISContiguousLocal(IS is,PetscInt gstart,PetscInt gend,PetscInt *start,PetscBool *contig)
    892: {

    899:   *start  = -1;
    900:   *contig = PETSC_FALSE;
    901:   if (is->ops->contiguous) {
    902:     (*is->ops->contiguous)(is,gstart,gend,start,contig);
    903:   }
    904:   return(0);
    905: }

    907: /*@
    908:    ISPermutation - PETSC_TRUE or PETSC_FALSE depending on whether the
    909:    index set has been declared to be a permutation.

    911:    Logically Collective on IS

    913:    Input Parameter:
    914: .  is - the index set

    916:    Output Parameter:
    917: .  perm - PETSC_TRUE if a permutation, else PETSC_FALSE

    919:    Level: intermediate

    921:    Note: If it is not alread known that the IS is a permutation (if ISSetPermutation()
    922:    or ISSetInfo() has not been called), this routine will not attempt to compute
    923:    whether the index set is a permutation and will assume perm is PETSC_FALSE.
    924:    To compute the value when it is not already known, use ISGetInfo() with
    925:    the compute flag set to PETSC_TRUE.

    927: .seealso: ISSetPermutation(), ISGetInfo()
    928: @*/
    929: PetscErrorCode  ISPermutation(IS is,PetscBool  *perm)
    930: {

    936:   ISGetInfo(is,IS_PERMUTATION,IS_GLOBAL,PETSC_FALSE,perm);
    937:   return(0);
    938: }

    940: /*@
    941:    ISSetPermutation - Informs the index set that it is a permutation.

    943:    Logically Collective on IS

    945:    Input Parameter:
    946: .  is - the index set

    948:    Level: intermediate

    950:    The debug version of the libraries (./configure --with-debugging=1) checks if the
    951:   index set is actually a permutation. The optimized version just believes you.

    953:    Note: The IS will be considered a permutation permanently, even if indices have been changes (for example, with
    954:    ISGeneralSetIndices()).  It's a good idea to only set this property if the IS will not change in the future.
    955:    To clear this property, use ISClearInfoCache().

    957: .seealso: ISPermutation(), ISSetInfo(), ISClearInfoCache().
    958: @*/
    959: PetscErrorCode  ISSetPermutation(IS is)
    960: {

    965:   if (PetscDefined(USE_DEBUG)) {
    966:     PetscMPIInt    size;

    968:     MPI_Comm_size(PetscObjectComm((PetscObject)is),&size);
    969:     if (size == 1) {
    970:       PetscInt       i,n,*idx;
    971:       const PetscInt *iidx;

    973:       ISGetSize(is,&n);
    974:       PetscMalloc1(n,&idx);
    975:       ISGetIndices(is,&iidx);
    976:       PetscArraycpy(idx,iidx,n);
    977:       PetscIntSortSemiOrdered(n,idx);
    978:       for (i=0; i<n; i++) {
    979:         if (idx[i] != i) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Index set is not a permutation");
    980:       }
    981:       PetscFree(idx);
    982:       ISRestoreIndices(is,&iidx);
    983:     }
    984:   }
    985:   ISSetInfo(is,IS_PERMUTATION,IS_GLOBAL,PETSC_TRUE,PETSC_TRUE);
    986:   return(0);
    987: }

    989: /*@C
    990:    ISDestroy - Destroys an index set.

    992:    Collective on IS

    994:    Input Parameters:
    995: .  is - the index set

    997:    Level: beginner

    999: .seealso: ISCreateGeneral(), ISCreateStride(), ISCreateBlocked()
    1000: @*/
    1001: PetscErrorCode  ISDestroy(IS *is)
    1002: {

    1006:   if (!*is) return(0);
    1008:   if (--((PetscObject)(*is))->refct > 0) {*is = NULL; return(0);}
    1009:   if ((*is)->complement) {
    1010:     PetscInt refcnt;
    1011:     PetscObjectGetReference((PetscObject)((*is)->complement), &refcnt);
    1012:     if (refcnt > 1) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Nonlocal IS has not been restored");
    1013:     ISDestroy(&(*is)->complement);
    1014:   }
    1015:   if ((*is)->ops->destroy) {
    1016:     (*(*is)->ops->destroy)(*is);
    1017:   }
    1018:   PetscLayoutDestroy(&(*is)->map);
    1019:   /* Destroy local representations of offproc data. */
    1020:   PetscFree((*is)->total);
    1021:   PetscFree((*is)->nonlocal);
    1022:   PetscHeaderDestroy(is);
    1023:   return(0);
    1024: }

    1026: /*@
    1027:    ISInvertPermutation - Creates a new permutation that is the inverse of
    1028:                          a given permutation.

    1030:    Collective on IS

    1032:    Input Parameters:
    1033: +  is - the index set
    1034: -  nlocal - number of indices on this processor in result (ignored for 1 proccessor) or
    1035:             use PETSC_DECIDE

    1037:    Output Parameter:
    1038: .  isout - the inverse permutation

    1040:    Level: intermediate

    1042:    Notes:
    1043:     For parallel index sets this does the complete parallel permutation, but the
    1044:     code is not efficient for huge index sets (10,000,000 indices).

    1046: @*/
    1047: PetscErrorCode  ISInvertPermutation(IS is,PetscInt nlocal,IS *isout)
    1048: {
    1049:   PetscBool      isperm, isidentity, issame;

    1055:   ISGetInfo(is,IS_PERMUTATION,IS_GLOBAL,PETSC_TRUE,&isperm);
    1056:   if (!isperm) SETERRQ(PetscObjectComm((PetscObject)is),PETSC_ERR_ARG_WRONG,"Not a permutation");
    1057:   ISGetInfo(is,IS_IDENTITY,IS_GLOBAL,PETSC_TRUE,&isidentity);
    1058:   issame = PETSC_FALSE;
    1059:   if (isidentity) {
    1060:     PetscInt n;
    1061:     PetscBool isallsame;

    1063:     ISGetLocalSize(is, &n);
    1064:     issame = (PetscBool) (n == nlocal);
    1065:     MPI_Allreduce(&issame, &isallsame, 1, MPIU_BOOL, MPI_LAND, PetscObjectComm((PetscObject)is));
    1066:     issame = isallsame;
    1067:   }
    1068:   if (issame) {
    1069:     ISDuplicate(is,isout);
    1070:   } else {
    1071:     (*is->ops->invertpermutation)(is,nlocal,isout);
    1072:     ISSetPermutation(*isout);
    1073:   }
    1074:   return(0);
    1075: }

    1077: /*@
    1078:    ISGetSize - Returns the global length of an index set.

    1080:    Not Collective

    1082:    Input Parameter:
    1083: .  is - the index set

    1085:    Output Parameter:
    1086: .  size - the global size

    1088:    Level: beginner

    1090: @*/
    1091: PetscErrorCode  ISGetSize(IS is,PetscInt *size)
    1092: {
    1096:   *size = is->map->N;
    1097:   return(0);
    1098: }

    1100: /*@
    1101:    ISGetLocalSize - Returns the local (processor) length of an index set.

    1103:    Not Collective

    1105:    Input Parameter:
    1106: .  is - the index set

    1108:    Output Parameter:
    1109: .  size - the local size

    1111:    Level: beginner

    1113: @*/
    1114: PetscErrorCode  ISGetLocalSize(IS is,PetscInt *size)
    1115: {
    1119:   *size = is->map->n;
    1120:   return(0);
    1121: }

    1123: /*@
    1124:    ISGetLayout - get PetscLayout describing index set layout

    1126:    Not Collective

    1128:    Input Parameter:
    1129: .  is - the index set

    1131:    Output Parameter:
    1132: .  map - the layout

    1134:    Level: developer

    1136: .seealso: ISGetSize(), ISGetLocalSize()
    1137: @*/
    1138: PetscErrorCode ISGetLayout(IS is,PetscLayout *map)
    1139: {

    1144:   *map = is->map;
    1145:   return(0);
    1146: }

    1148: /*@C
    1149:    ISGetIndices - Returns a pointer to the indices.  The user should call
    1150:    ISRestoreIndices() after having looked at the indices.  The user should
    1151:    NOT change the indices.

    1153:    Not Collective

    1155:    Input Parameter:
    1156: .  is - the index set

    1158:    Output Parameter:
    1159: .  ptr - the location to put the pointer to the indices

    1161:    Fortran Note:
    1162:    This routine has two different interfaces from Fortran; the first is not recommend, it does not require Fortran 90
    1163: $    IS          is
    1164: $    integer     is_array(1)
    1165: $    PetscOffset i_is
    1166: $    int         ierr
    1167: $       call ISGetIndices(is,is_array,i_is,ierr)
    1168: $
    1169: $   Access first local entry in list
    1170: $      value = is_array(i_is + 1)
    1171: $
    1172: $      ...... other code
    1173: $       call ISRestoreIndices(is,is_array,i_is,ierr)
    1174:    The second Fortran interface is recommended.
    1175: $          use petscisdef
    1176: $          PetscInt, pointer :: array(:)
    1177: $          PetscErrorCode  ierr
    1178: $          IS       i
    1179: $          call ISGetIndicesF90(i,array,ierr)

    1181:    See the Fortran chapter of the users manual and
    1182:    petsc/src/is/[tutorials,tests] for details.

    1184:    Level: intermediate

    1186: .seealso: ISRestoreIndices(), ISGetIndicesF90()
    1187: @*/
    1188: PetscErrorCode  ISGetIndices(IS is,const PetscInt *ptr[])
    1189: {

    1195:   (*is->ops->getindices)(is,ptr);
    1196:   return(0);
    1197: }

    1199: /*@C
    1200:    ISGetMinMax - Gets the minimum and maximum values in an IS

    1202:    Not Collective

    1204:    Input Parameter:
    1205: .  is - the index set

    1207:    Output Parameters:
    1208: +   min - the minimum value
    1209: -   max - the maximum value

    1211:    Level: intermediate

    1213:    Notes:
    1214:     Empty index sets return min=PETSC_MAX_INT and max=PETSC_MIN_INT.
    1215:     In parallel, it returns the min and max of the local portion of the IS

    1217: .seealso: ISGetIndices(), ISRestoreIndices(), ISGetIndicesF90()
    1218: @*/
    1219: PetscErrorCode  ISGetMinMax(IS is,PetscInt *min,PetscInt *max)
    1220: {
    1223:   if (min) *min = is->min;
    1224:   if (max) *max = is->max;
    1225:   return(0);
    1226: }

    1228: /*@
    1229:   ISLocate - determine the location of an index within the local component of an index set

    1231:   Not Collective

    1233:   Input Parameters:
    1234: + is - the index set
    1235: - key - the search key

    1237:   Output Parameter:
    1238: . location - if >= 0, a location within the index set that is equal to the key, otherwise the key is not in the index set

    1240:   Level: intermediate
    1241: @*/
    1242: PetscErrorCode ISLocate(IS is, PetscInt key, PetscInt *location)
    1243: {

    1247:   if (is->ops->locate) {
    1248:     (*is->ops->locate)(is,key,location);
    1249:   } else {
    1250:     PetscInt       numIdx;
    1251:     PetscBool      sorted;
    1252:     const PetscInt *idx;

    1254:     ISGetLocalSize(is,&numIdx);
    1255:     ISGetIndices(is,&idx);
    1256:     ISSorted(is,&sorted);
    1257:     if (sorted) {
    1258:       PetscFindInt(key,numIdx,idx,location);
    1259:     } else {
    1260:       PetscInt i;

    1262:       *location = -1;
    1263:       for (i = 0; i < numIdx; i++) {
    1264:         if (idx[i] == key) {
    1265:           *location = i;
    1266:           break;
    1267:         }
    1268:       }
    1269:     }
    1270:     ISRestoreIndices(is,&idx);
    1271:   }
    1272:   return(0);
    1273: }

    1275: /*@C
    1276:    ISRestoreIndices - Restores an index set to a usable state after a call
    1277:                       to ISGetIndices().

    1279:    Not Collective

    1281:    Input Parameters:
    1282: +  is - the index set
    1283: -  ptr - the pointer obtained by ISGetIndices()

    1285:    Fortran Note:
    1286:    This routine is used differently from Fortran
    1287: $    IS          is
    1288: $    integer     is_array(1)
    1289: $    PetscOffset i_is
    1290: $    int         ierr
    1291: $       call ISGetIndices(is,is_array,i_is,ierr)
    1292: $
    1293: $   Access first local entry in list
    1294: $      value = is_array(i_is + 1)
    1295: $
    1296: $      ...... other code
    1297: $       call ISRestoreIndices(is,is_array,i_is,ierr)

    1299:    See the Fortran chapter of the users manual and
    1300:    petsc/src/vec/is/tests for details.

    1302:    Level: intermediate

    1304:    Note:
    1305:    This routine zeros out ptr. This is to prevent accidental us of the array after it has been restored.

    1307: .seealso: ISGetIndices(), ISRestoreIndicesF90()
    1308: @*/
    1309: PetscErrorCode  ISRestoreIndices(IS is,const PetscInt *ptr[])
    1310: {

    1316:   if (is->ops->restoreindices) {
    1317:     (*is->ops->restoreindices)(is,ptr);
    1318:   }
    1319:   return(0);
    1320: }

    1322: static PetscErrorCode ISGatherTotal_Private(IS is)
    1323: {
    1325:   PetscInt       i,n,N;
    1326:   const PetscInt *lindices;
    1327:   MPI_Comm       comm;
    1328:   PetscMPIInt    rank,size,*sizes = NULL,*offsets = NULL,nn;

    1333:   PetscObjectGetComm((PetscObject)is,&comm);
    1334:   MPI_Comm_size(comm,&size);
    1335:   MPI_Comm_rank(comm,&rank);
    1336:   ISGetLocalSize(is,&n);
    1337:   PetscMalloc2(size,&sizes,size,&offsets);

    1339:   PetscMPIIntCast(n,&nn);
    1340:   MPI_Allgather(&nn,1,MPI_INT,sizes,1,MPI_INT,comm);
    1341:   offsets[0] = 0;
    1342:   for (i=1; i<size; ++i) offsets[i] = offsets[i-1] + sizes[i-1];
    1343:   N = offsets[size-1] + sizes[size-1];

    1345:   PetscMalloc1(N,&(is->total));
    1346:   ISGetIndices(is,&lindices);
    1347:   MPI_Allgatherv((void*)lindices,nn,MPIU_INT,is->total,sizes,offsets,MPIU_INT,comm);
    1348:   ISRestoreIndices(is,&lindices);
    1349:   is->local_offset = offsets[rank];
    1350:   PetscFree2(sizes,offsets);
    1351:   return(0);
    1352: }

    1354: /*@C
    1355:    ISGetTotalIndices - Retrieve an array containing all indices across the communicator.

    1357:    Collective on IS

    1359:    Input Parameter:
    1360: .  is - the index set

    1362:    Output Parameter:
    1363: .  indices - total indices with rank 0 indices first, and so on; total array size is
    1364:              the same as returned with ISGetSize().

    1366:    Level: intermediate

    1368:    Notes:
    1369:     this is potentially nonscalable, but depends on the size of the total index set
    1370:      and the size of the communicator. This may be feasible for index sets defined on
    1371:      subcommunicators, such that the set size does not grow with PETSC_WORLD_COMM.
    1372:      Note also that there is no way to tell where the local part of the indices starts
    1373:      (use ISGetIndices() and ISGetNonlocalIndices() to retrieve just the local and just
    1374:       the nonlocal part (complement), respectively).

    1376: .seealso: ISRestoreTotalIndices(), ISGetNonlocalIndices(), ISGetSize()
    1377: @*/
    1378: PetscErrorCode ISGetTotalIndices(IS is, const PetscInt *indices[])
    1379: {
    1381:   PetscMPIInt    size;

    1386:   MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);
    1387:   if (size == 1) {
    1388:     (*is->ops->getindices)(is,indices);
    1389:   } else {
    1390:     if (!is->total) {
    1391:       ISGatherTotal_Private(is);
    1392:     }
    1393:     *indices = is->total;
    1394:   }
    1395:   return(0);
    1396: }

    1398: /*@C
    1399:    ISRestoreTotalIndices - Restore the index array obtained with ISGetTotalIndices().

    1401:    Not Collective.

    1403:    Input Parameters:
    1404: +  is - the index set
    1405: -  indices - index array; must be the array obtained with ISGetTotalIndices()

    1407:    Level: intermediate

    1409: .seealso: ISRestoreTotalIndices(), ISGetNonlocalIndices()
    1410: @*/
    1411: PetscErrorCode  ISRestoreTotalIndices(IS is, const PetscInt *indices[])
    1412: {
    1414:   PetscMPIInt    size;

    1419:   MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);
    1420:   if (size == 1) {
    1421:     (*is->ops->restoreindices)(is,indices);
    1422:   } else {
    1423:     if (is->total != *indices) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index array pointer being restored does not point to the array obtained from the IS.");
    1424:   }
    1425:   return(0);
    1426: }
    1427: /*@C
    1428:    ISGetNonlocalIndices - Retrieve an array of indices from remote processors
    1429:                        in this communicator.

    1431:    Collective on IS

    1433:    Input Parameter:
    1434: .  is - the index set

    1436:    Output Parameter:
    1437: .  indices - indices with rank 0 indices first, and so on,  omitting
    1438:              the current rank.  Total number of indices is the difference
    1439:              total and local, obtained with ISGetSize() and ISGetLocalSize(),
    1440:              respectively.

    1442:    Level: intermediate

    1444:    Notes:
    1445:     restore the indices using ISRestoreNonlocalIndices().
    1446:           The same scalability considerations as those for ISGetTotalIndices
    1447:           apply here.

    1449: .seealso: ISGetTotalIndices(), ISRestoreNonlocalIndices(), ISGetSize(), ISGetLocalSize().
    1450: @*/
    1451: PetscErrorCode  ISGetNonlocalIndices(IS is, const PetscInt *indices[])
    1452: {
    1454:   PetscMPIInt    size;
    1455:   PetscInt       n, N;

    1460:   MPI_Comm_size(PetscObjectComm((PetscObject)is), &size);
    1461:   if (size == 1) *indices = NULL;
    1462:   else {
    1463:     if (!is->total) {
    1464:       ISGatherTotal_Private(is);
    1465:     }
    1466:     ISGetLocalSize(is,&n);
    1467:     ISGetSize(is,&N);
    1468:     PetscMalloc1(N-n, &(is->nonlocal));
    1469:     PetscArraycpy(is->nonlocal, is->total, is->local_offset);
    1470:     PetscArraycpy(is->nonlocal+is->local_offset, is->total+is->local_offset+n,N - is->local_offset - n);
    1471:     *indices = is->nonlocal;
    1472:   }
    1473:   return(0);
    1474: }

    1476: /*@C
    1477:    ISRestoreNonlocalIndices - Restore the index array obtained with ISGetNonlocalIndices().

    1479:    Not Collective.

    1481:    Input Parameters:
    1482: +  is - the index set
    1483: -  indices - index array; must be the array obtained with ISGetNonlocalIndices()

    1485:    Level: intermediate

    1487: .seealso: ISGetTotalIndices(), ISGetNonlocalIndices(), ISRestoreTotalIndices()
    1488: @*/
    1489: PetscErrorCode  ISRestoreNonlocalIndices(IS is, const PetscInt *indices[])
    1490: {
    1494:   if (is->nonlocal != *indices) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Index array pointer being restored does not point to the array obtained from the IS.");
    1495:   return(0);
    1496: }

    1498: /*@
    1499:    ISGetNonlocalIS - Gather all nonlocal indices for this IS and present
    1500:                      them as another sequential index set.

    1502:    Collective on IS

    1504:    Input Parameter:
    1505: .  is - the index set

    1507:    Output Parameter:
    1508: .  complement - sequential IS with indices identical to the result of
    1509:                 ISGetNonlocalIndices()

    1511:    Level: intermediate

    1513:    Notes:
    1514:     complement represents the result of ISGetNonlocalIndices as an IS.
    1515:           Therefore scalability issues similar to ISGetNonlocalIndices apply.
    1516:           The resulting IS must be restored using ISRestoreNonlocalIS().

    1518: .seealso: ISGetNonlocalIndices(), ISRestoreNonlocalIndices(),  ISAllGather(), ISGetSize()
    1519: @*/
    1520: PetscErrorCode  ISGetNonlocalIS(IS is, IS *complement)
    1521: {

    1527:   /* Check if the complement exists already. */
    1528:   if (is->complement) {
    1529:     *complement = is->complement;
    1530:     PetscObjectReference((PetscObject)(is->complement));
    1531:   } else {
    1532:     PetscInt       N, n;
    1533:     const PetscInt *idx;
    1534:     ISGetSize(is, &N);
    1535:     ISGetLocalSize(is,&n);
    1536:     ISGetNonlocalIndices(is, &idx);
    1537:     ISCreateGeneral(PETSC_COMM_SELF, N-n,idx, PETSC_USE_POINTER, &(is->complement));
    1538:     PetscObjectReference((PetscObject)is->complement);
    1539:     *complement = is->complement;
    1540:   }
    1541:   return(0);
    1542: }

    1544: /*@
    1545:    ISRestoreNonlocalIS - Restore the IS obtained with ISGetNonlocalIS().

    1547:    Not collective.

    1549:    Input Parameters:
    1550: +  is         - the index set
    1551: -  complement - index set of is's nonlocal indices

    1553:    Level: intermediate

    1555: .seealso: ISGetNonlocalIS(), ISGetNonlocalIndices(), ISRestoreNonlocalIndices()
    1556: @*/
    1557: PetscErrorCode  ISRestoreNonlocalIS(IS is, IS *complement)
    1558: {
    1560:   PetscInt       refcnt;

    1565:   if (*complement != is->complement) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Complement IS being restored was not obtained with ISGetNonlocalIS()");
    1566:   PetscObjectGetReference((PetscObject)(is->complement), &refcnt);
    1567:   if (refcnt <= 1) SETERRQ(PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Duplicate call to ISRestoreNonlocalIS() detected");
    1568:   PetscObjectDereference((PetscObject)(is->complement));
    1569:   return(0);
    1570: }

    1572: /*@C
    1573:    ISViewFromOptions - View from Options

    1575:    Collective on IS

    1577:    Input Parameters:
    1578: +  A - the index set
    1579: .  obj - Optional object
    1580: -  name - command line option

    1582:    Level: intermediate
    1583: .seealso:  IS, ISView, PetscObjectViewFromOptions(), ISCreate()
    1584: @*/
    1585: PetscErrorCode  ISViewFromOptions(IS A,PetscObject obj,const char name[])
    1586: {

    1591:   PetscObjectViewFromOptions((PetscObject)A,obj,name);
    1592:   return(0);
    1593: }

    1595: /*@C
    1596:    ISView - Displays an index set.

    1598:    Collective on IS

    1600:    Input Parameters:
    1601: +  is - the index set
    1602: -  viewer - viewer used to display the set, for example PETSC_VIEWER_STDOUT_SELF.

    1604:    Level: intermediate

    1606: .seealso: PetscViewerASCIIOpen()
    1607: @*/
    1608: PetscErrorCode  ISView(IS is,PetscViewer viewer)
    1609: {

    1614:   if (!viewer) {PetscViewerASCIIGetStdout(PetscObjectComm((PetscObject)is),&viewer);}

    1618:   PetscObjectPrintClassNamePrefixType((PetscObject)is,viewer);
    1619:   PetscLogEventBegin(IS_View,is,viewer,0,0);
    1620:   (*is->ops->view)(is,viewer);
    1621:   PetscLogEventEnd(IS_View,is,viewer,0,0);
    1622:   return(0);
    1623: }

    1625: /*@
    1626:   ISLoad - Loads a vector that has been stored in binary or HDF5 format with ISView().

    1628:   Collective on PetscViewer

    1630:   Input Parameters:
    1631: + is - the newly loaded vector, this needs to have been created with ISCreate() or some related function before a call to ISLoad().
    1632: - viewer - binary file viewer, obtained from PetscViewerBinaryOpen() or HDF5 file viewer, obtained from PetscViewerHDF5Open()

    1634:   Level: intermediate

    1636:   Notes:
    1637:   IF using HDF5, you must assign the IS the same name as was used in the IS
    1638:   that was stored in the file using PetscObjectSetName(). Otherwise you will
    1639:   get the error message: "Cannot H5DOpen2() with Vec name NAMEOFOBJECT"

    1641: .seealso: PetscViewerBinaryOpen(), ISView(), MatLoad(), VecLoad()
    1642: @*/
    1643: PetscErrorCode ISLoad(IS is, PetscViewer viewer)
    1644: {
    1645:   PetscBool      isbinary, ishdf5;

    1652:   PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERBINARY, &isbinary);
    1653:   PetscObjectTypeCompare((PetscObject) viewer, PETSCVIEWERHDF5, &ishdf5);
    1654:   if (!isbinary && !ishdf5) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_ARG_WRONG,"Invalid viewer; open viewer with PetscViewerBinaryOpen()");
    1655:   if (!((PetscObject)is)->type_name) {ISSetType(is, ISGENERAL);}
    1656:   PetscLogEventBegin(IS_Load,is,viewer,0,0);
    1657:   (*is->ops->load)(is, viewer);
    1658:   PetscLogEventEnd(IS_Load,is,viewer,0,0);
    1659:   return(0);
    1660: }

    1662: /*@
    1663:    ISSort - Sorts the indices of an index set.

    1665:    Collective on IS

    1667:    Input Parameters:
    1668: .  is - the index set

    1670:    Level: intermediate

    1672: .seealso: ISSortRemoveDups(), ISSorted()
    1673: @*/
    1674: PetscErrorCode  ISSort(IS is)
    1675: {

    1680:   (*is->ops->sort)(is);
    1681:   ISSetInfo(is,IS_SORTED,IS_LOCAL,is->info_permanent[IS_LOCAL][IS_SORTED],PETSC_TRUE);
    1682:   return(0);
    1683: }

    1685: /*@
    1686:   ISSortRemoveDups - Sorts the indices of an index set, removing duplicates.

    1688:   Collective on IS

    1690:   Input Parameters:
    1691: . is - the index set

    1693:   Level: intermediate

    1695: .seealso: ISSort(), ISSorted()
    1696: @*/
    1697: PetscErrorCode ISSortRemoveDups(IS is)
    1698: {

    1703:   ISClearInfoCache(is,PETSC_FALSE);
    1704:   (*is->ops->sortremovedups)(is);
    1705:   ISSetInfo(is,IS_SORTED,IS_LOCAL,is->info_permanent[IS_LOCAL][IS_SORTED],PETSC_TRUE);
    1706:   ISSetInfo(is,IS_UNIQUE,IS_LOCAL,is->info_permanent[IS_LOCAL][IS_UNIQUE],PETSC_TRUE);
    1707:   return(0);
    1708: }

    1710: /*@
    1711:    ISToGeneral - Converts an IS object of any type to ISGENERAL type

    1713:    Collective on IS

    1715:    Input Parameters:
    1716: .  is - the index set

    1718:    Level: intermediate

    1720: .seealso: ISSorted()
    1721: @*/
    1722: PetscErrorCode  ISToGeneral(IS is)
    1723: {

    1728:   if (is->ops->togeneral) {
    1729:     (*is->ops->togeneral)(is);
    1730:   } else SETERRQ1(PetscObjectComm((PetscObject)is),PETSC_ERR_SUP,"Not written for this type %s",((PetscObject)is)->type_name);
    1731:   return(0);
    1732: }

    1734: /*@
    1735:    ISSorted - Checks the indices to determine whether they have been sorted.

    1737:    Collective on IS

    1739:    Input Parameter:
    1740: .  is - the index set

    1742:    Output Parameter:
    1743: .  flg - output flag, either PETSC_TRUE if the index set is sorted,
    1744:          or PETSC_FALSE otherwise.

    1746:    Notes:
    1747:     For parallel IS objects this only indicates if the local part of the IS
    1748:           is sorted. So some processors may return PETSC_TRUE while others may
    1749:           return PETSC_FALSE.

    1751:    Level: intermediate

    1753: .seealso: ISSort(), ISSortRemoveDups()
    1754: @*/
    1755: PetscErrorCode  ISSorted(IS is,PetscBool  *flg)
    1756: {

    1762:   ISGetInfo(is,IS_SORTED,IS_LOCAL,PETSC_TRUE,flg);
    1763:   return(0);
    1764: }

    1766: /*@
    1767:    ISDuplicate - Creates a duplicate copy of an index set.

    1769:    Collective on IS

    1771:    Input Parameter:
    1772: .  is - the index set

    1774:    Output Parameter:
    1775: .  isnew - the copy of the index set

    1777:    Level: beginner

    1779: .seealso: ISCreateGeneral(), ISCopy()
    1780: @*/
    1781: PetscErrorCode  ISDuplicate(IS is,IS *newIS)
    1782: {

    1788:   (*is->ops->duplicate)(is,newIS);
    1789:   ISCopyInfo(is,*newIS);
    1790:   return(0);
    1791: }

    1793: /*@
    1794:    ISCopy - Copies an index set.

    1796:    Collective on IS

    1798:    Input Parameter:
    1799: .  is - the index set

    1801:    Output Parameter:
    1802: .  isy - the copy of the index set

    1804:    Level: beginner

    1806: .seealso: ISDuplicate()
    1807: @*/
    1808: PetscErrorCode  ISCopy(IS is,IS isy)
    1809: {

    1816:   if (is == isy) return(0);
    1817:   ISCopyInfo(is,isy);
    1818:   isy->max        = is->max;
    1819:   isy->min        = is->min;
    1820:   (*is->ops->copy)(is,isy);
    1821:   return(0);
    1822: }

    1824: /*@
    1825:    ISOnComm - Split a parallel IS on subcomms (usually self) or concatenate index sets on subcomms into a parallel index set

    1827:    Collective on IS

    1829:    Input Parameters:
    1830: + is - index set
    1831: . comm - communicator for new index set
    1832: - mode - copy semantics, PETSC_USE_POINTER for no-copy if possible, otherwise PETSC_COPY_VALUES

    1834:    Output Parameter:
    1835: . newis - new IS on comm

    1837:    Level: advanced

    1839:    Notes:
    1840:    It is usually desirable to create a parallel IS and look at the local part when necessary.

    1842:    This function is useful if serial ISs must be created independently, or to view many
    1843:    logically independent serial ISs.

    1845:    The input IS must have the same type on every process.
    1846: @*/
    1847: PetscErrorCode  ISOnComm(IS is,MPI_Comm comm,PetscCopyMode mode,IS *newis)
    1848: {
    1850:   PetscMPIInt    match;

    1855:   MPI_Comm_compare(PetscObjectComm((PetscObject)is),comm,&match);
    1856:   if (mode != PETSC_COPY_VALUES && (match == MPI_IDENT || match == MPI_CONGRUENT)) {
    1857:     PetscObjectReference((PetscObject)is);
    1858:     *newis = is;
    1859:   } else {
    1860:     (*is->ops->oncomm)(is,comm,mode,newis);
    1861:   }
    1862:   return(0);
    1863: }

    1865: /*@
    1866:    ISSetBlockSize - informs an index set that it has a given block size

    1868:    Logicall Collective on IS

    1870:    Input Parameters:
    1871: + is - index set
    1872: - bs - block size

    1874:    Level: intermediate

    1876:    Notes:
    1877:    This is much like the block size for Vecs. It indicates that one can think of the indices as
    1878:    being in a collection of equal size blocks. For ISBlock() these collections of blocks are all contiquous
    1879:    within a block but this is not the case for other IS.
    1880:    ISBlockGetIndices() only works for ISBlock IS, not others.

    1882: .seealso: ISGetBlockSize(), ISCreateBlock(), ISBlockGetIndices(),
    1883: @*/
    1884: PetscErrorCode  ISSetBlockSize(IS is,PetscInt bs)
    1885: {

    1891:   if (bs < 1) SETERRQ1(PetscObjectComm((PetscObject)is),PETSC_ERR_ARG_OUTOFRANGE,"Block size %D, must be positive",bs);
    1892:   (*is->ops->setblocksize)(is,bs);
    1893:   return(0);
    1894: }

    1896: /*@
    1897:    ISGetBlockSize - Returns the number of elements in a block.

    1899:    Not Collective

    1901:    Input Parameter:
    1902: .  is - the index set

    1904:    Output Parameter:
    1905: .  size - the number of elements in a block

    1907:    Level: intermediate

    1909: Notes:
    1910:    This is much like the block size for Vecs. It indicates that one can think of the indices as
    1911:    being in a collection of equal size blocks. For ISBlock() these collections of blocks are all contiquous
    1912:    within a block but this is not the case for other IS.
    1913:    ISBlockGetIndices() only works for ISBlock IS, not others.

    1915: .seealso: ISBlockGetSize(), ISGetSize(), ISCreateBlock(), ISSetBlockSize()
    1916: @*/
    1917: PetscErrorCode  ISGetBlockSize(IS is,PetscInt *size)
    1918: {

    1922:   PetscLayoutGetBlockSize(is->map, size);
    1923:   return(0);
    1924: }

    1926: PetscErrorCode ISGetIndicesCopy(IS is, PetscInt idx[])
    1927: {
    1929:   PetscInt       len,i;
    1930:   const PetscInt *ptr;

    1933:   ISGetLocalSize(is,&len);
    1934:   ISGetIndices(is,&ptr);
    1935:   for (i=0; i<len; i++) idx[i] = ptr[i];
    1936:   ISRestoreIndices(is,&ptr);
    1937:   return(0);
    1938: }

    1940: /*MC
    1941:     ISGetIndicesF90 - Accesses the elements of an index set from Fortran90.
    1942:     The users should call ISRestoreIndicesF90() after having looked at the
    1943:     indices.  The user should NOT change the indices.

    1945:     Synopsis:
    1946:     ISGetIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

    1948:     Not collective

    1950:     Input Parameter:
    1951: .   x - index set

    1953:     Output Parameters:
    1954: +   xx_v - the Fortran90 pointer to the array
    1955: -   ierr - error code

    1957:     Example of Usage:
    1958: .vb
    1959:     PetscInt, pointer xx_v(:)
    1960:     ....
    1961:     call ISGetIndicesF90(x,xx_v,ierr)
    1962:     a = xx_v(3)
    1963:     call ISRestoreIndicesF90(x,xx_v,ierr)
    1964: .ve

    1966:     Level: intermediate

    1968: .seealso:  ISRestoreIndicesF90(), ISGetIndices(), ISRestoreIndices()

    1970: M*/

    1972: /*MC
    1973:     ISRestoreIndicesF90 - Restores an index set to a usable state after
    1974:     a call to ISGetIndicesF90().

    1976:     Synopsis:
    1977:     ISRestoreIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

    1979:     Not collective

    1981:     Input Parameters:
    1982: +   x - index set
    1983: -   xx_v - the Fortran90 pointer to the array

    1985:     Output Parameter:
    1986: .   ierr - error code

    1988:     Example of Usage:
    1989: .vb
    1990:     PetscInt, pointer xx_v(:)
    1991:     ....
    1992:     call ISGetIndicesF90(x,xx_v,ierr)
    1993:     a = xx_v(3)
    1994:     call ISRestoreIndicesF90(x,xx_v,ierr)
    1995: .ve

    1997:     Level: intermediate

    1999: .seealso:  ISGetIndicesF90(), ISGetIndices(), ISRestoreIndices()

    2001: M*/

    2003: /*MC
    2004:     ISBlockGetIndicesF90 - Accesses the elements of an index set from Fortran90.
    2005:     The users should call ISBlockRestoreIndicesF90() after having looked at the
    2006:     indices.  The user should NOT change the indices.

    2008:     Synopsis:
    2009:     ISBlockGetIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

    2011:     Not collective

    2013:     Input Parameter:
    2014: .   x - index set

    2016:     Output Parameters:
    2017: +   xx_v - the Fortran90 pointer to the array
    2018: -   ierr - error code
    2019:     Example of Usage:
    2020: .vb
    2021:     PetscInt, pointer xx_v(:)
    2022:     ....
    2023:     call ISBlockGetIndicesF90(x,xx_v,ierr)
    2024:     a = xx_v(3)
    2025:     call ISBlockRestoreIndicesF90(x,xx_v,ierr)
    2026: .ve

    2028:     Level: intermediate

    2030: .seealso:  ISBlockRestoreIndicesF90(), ISGetIndices(), ISRestoreIndices(),
    2031:            ISRestoreIndices()

    2033: M*/

    2035: /*MC
    2036:     ISBlockRestoreIndicesF90 - Restores an index set to a usable state after
    2037:     a call to ISBlockGetIndicesF90().

    2039:     Synopsis:
    2040:     ISBlockRestoreIndicesF90(IS x,{integer, pointer :: xx_v(:)},integer ierr)

    2042:     Not Collective

    2044:     Input Parameters:
    2045: +   x - index set
    2046: -   xx_v - the Fortran90 pointer to the array

    2048:     Output Parameter:
    2049: .   ierr - error code

    2051:     Example of Usage:
    2052: .vb
    2053:     PetscInt, pointer xx_v(:)
    2054:     ....
    2055:     call ISBlockGetIndicesF90(x,xx_v,ierr)
    2056:     a = xx_v(3)
    2057:     call ISBlockRestoreIndicesF90(x,xx_v,ierr)
    2058: .ve

    2060:     Notes:
    2061:     Not yet supported for all F90 compilers

    2063:     Level: intermediate

    2065: .seealso:  ISBlockGetIndicesF90(), ISGetIndices(), ISRestoreIndices(), ISRestoreIndicesF90()

    2067: M*/