Date: 2021-03-03T22:26:03+00:00

Actual source code: sfbasic.c
petsc-3.14.5 2021-03-03
Report Typos and Errors

      2: #include "petscsf.h"
      3: #include <../src/vec/is/sf/impls/basic/sfbasic.h>
      4: #include <../src/vec/is/sf/impls/basic/sfpack.h>

      6: /*===================================================================================*/
      7: /*              SF public interface implementations                                  */
      8: /*===================================================================================*/
      9: PETSC_INTERN PetscErrorCode PetscSFSetUp_Basic(PetscSF sf)
     10: {
     12:   PetscSF_Basic  *bas = (PetscSF_Basic*)sf->data;
     13:   PetscInt       *rlengths,*ilengths,i;
     14:   PetscMPIInt    rank,niranks,*iranks,tag;
     15:   MPI_Comm       comm;
     16:   MPI_Group      group;
     17:   MPI_Request    *rootreqs,*leafreqs;

     20:   MPI_Comm_group(PETSC_COMM_SELF,&group);
     21:   PetscSFSetUpRanks(sf,group);
     22:   MPI_Group_free(&group);
     23:   PetscObjectGetComm((PetscObject)sf,&comm);
     24:   PetscObjectGetNewTag((PetscObject)sf,&tag);
     25:   MPI_Comm_rank(comm,&rank);
     26:   /*
     27:    * Inform roots about how many leaves and from which ranks
     28:    */
     29:   PetscMalloc1(sf->nranks,&rlengths);
     30:   /* Determine number, sending ranks and length of incoming */
     31:   for (i=0; i<sf->nranks; i++) {
     32:     rlengths[i] = sf->roffset[i+1] - sf->roffset[i]; /* Number of roots referenced by my leaves; for rank sf->ranks[i] */
     33:   }
     34:   PetscCommBuildTwoSided(comm,1,MPIU_INT,sf->nranks-sf->ndranks,sf->ranks+sf->ndranks,rlengths+sf->ndranks,&niranks,&iranks,(void**)&ilengths);

     36:   /* Sort iranks. See use of VecScatterGetRemoteOrdered_Private() in MatGetBrowsOfAoCols_MPIAIJ() on why.
     37:      We could sort ranks there at the price of allocating extra working arrays. Presumably, niranks is
     38:      small and the sorting is cheap.
     39:    */
     40:   PetscSortMPIIntWithIntArray(niranks,iranks,ilengths);

     42:   /* Partition into distinguished and non-distinguished incoming ranks */
     43:   bas->ndiranks = sf->ndranks;
     44:   bas->niranks = bas->ndiranks + niranks;
     45:   PetscMalloc2(bas->niranks,&bas->iranks,bas->niranks+1,&bas->ioffset);
     46:   bas->ioffset[0] = 0;
     47:   for (i=0; i<bas->ndiranks; i++) {
     48:     bas->iranks[i] = sf->ranks[i];
     49:     bas->ioffset[i+1] = bas->ioffset[i] + rlengths[i];
     50:   }
     51:   if (bas->ndiranks > 1 || (bas->ndiranks == 1 && bas->iranks[0] != rank)) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Broken setup for shared ranks");
     52:   for (; i<bas->niranks; i++) {
     53:     bas->iranks[i] = iranks[i-bas->ndiranks];
     54:     bas->ioffset[i+1] = bas->ioffset[i] + ilengths[i-bas->ndiranks];
     55:   }
     56:   bas->itotal = bas->ioffset[i];
     57:   PetscFree(rlengths);
     58:   PetscFree(iranks);
     59:   PetscFree(ilengths);

     61:   /* Send leaf identities to roots */
     62:   PetscMalloc1(bas->itotal,&bas->irootloc);
     63:   PetscMalloc2(bas->niranks-bas->ndiranks,&rootreqs,sf->nranks-sf->ndranks,&leafreqs);
     64:   for (i=bas->ndiranks; i<bas->niranks; i++) {
     65:     MPI_Irecv(bas->irootloc+bas->ioffset[i],bas->ioffset[i+1]-bas->ioffset[i],MPIU_INT,bas->iranks[i],tag,comm,&rootreqs[i-bas->ndiranks]);
     66:   }
     67:   for (i=0; i<sf->nranks; i++) {
     68:     PetscMPIInt npoints;
     69:     PetscMPIIntCast(sf->roffset[i+1] - sf->roffset[i],&npoints);
     70:     if (i < sf->ndranks) {
     71:       if (sf->ranks[i] != rank) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot interpret distinguished leaf rank");
     72:       if (bas->iranks[0] != rank) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Cannot interpret distinguished root rank");
     73:       if (npoints != bas->ioffset[1]-bas->ioffset[0]) SETERRQ(PETSC_COMM_SELF,PETSC_ERR_PLIB,"Distinguished rank exchange has mismatched lengths");
     74:       PetscArraycpy(bas->irootloc+bas->ioffset[0],sf->rremote+sf->roffset[i],npoints);
     75:       continue;
     76:     }
     77:     MPI_Isend(sf->rremote+sf->roffset[i],npoints,MPIU_INT,sf->ranks[i],tag,comm,&leafreqs[i-sf->ndranks]);
     78:   }
     79:   MPI_Waitall(bas->niranks-bas->ndiranks,rootreqs,MPI_STATUSES_IGNORE);
     80:   MPI_Waitall(sf->nranks-sf->ndranks,leafreqs,MPI_STATUSES_IGNORE);
     81:   PetscFree2(rootreqs,leafreqs);

     83:   sf->nleafreqs  = sf->nranks - sf->ndranks;
     84:   bas->nrootreqs = bas->niranks - bas->ndiranks;
     85:   sf->persistent = PETSC_TRUE;

     87:   /* Setup fields related to packing */
     88:   PetscSFSetUpPackFields(sf);
     89:   return(0);
     90: }

     92: PETSC_INTERN PetscErrorCode PetscSFReset_Basic(PetscSF sf)
     93: {
     94:   PetscErrorCode    ierr;
     95:   PetscSF_Basic     *bas = (PetscSF_Basic*)sf->data;

     98:   if (bas->inuse) SETERRQ(PetscObjectComm((PetscObject)sf),PETSC_ERR_ARG_WRONGSTATE,"Outstanding operation has not been completed");
     99:   PetscFree2(bas->iranks,bas->ioffset);
    100:   PetscFree(bas->irootloc);
    101: #if defined(PETSC_HAVE_DEVICE)
    102:   for (PetscInt i=0; i<2; i++) {PetscSFFree(sf,PETSC_MEMTYPE_DEVICE,bas->irootloc_d[i]);}
    103: #endif
    104:   PetscSFLinkDestroy(sf,&bas->avail);
    105:   PetscSFResetPackFields(sf);
    106:   return(0);
    107: }

    109: PETSC_INTERN PetscErrorCode PetscSFDestroy_Basic(PetscSF sf)
    110: {

    114:   PetscSFReset_Basic(sf);
    115:   PetscFree(sf->data);
    116:   return(0);
    117: }

    119: PETSC_INTERN PetscErrorCode PetscSFView_Basic(PetscSF sf,PetscViewer viewer)
    120: {
    122:   PetscBool      iascii;

    125:   PetscObjectTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);
    126:   if (iascii) {PetscViewerASCIIPrintf(viewer,"  sort=%s\n",sf->rankorder ? "rank-order" : "unordered");}
    127:   return(0);
    128: }

    130: static PetscErrorCode PetscSFBcastAndOpBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,const void *rootdata,PetscMemType leafmtype,void *leafdata,MPI_Op op)
    131: {
    132:   PetscErrorCode    ierr;
    133:   PetscSFLink       link = NULL;
    134:   MPI_Request       *rootreqs = NULL,*leafreqs = NULL;
    135:   PetscSF_Basic     *bas = (PetscSF_Basic*)sf->data;

    138:   /* Create a communication link, which provides buffers & MPI requests etc */
    139:   PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_BCAST,&link);
    140:   /* Get MPI requests from the link. We do not need buffers explicitly since we use persistent MPI */
    141:   PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_../../../../../..2LEAF,NULL,NULL,&rootreqs,&leafreqs);
    142:   /* Post Irecv for remote */
    143:   MPI_Startall_irecv(sf->leafbuflen[PETSCSF_REMOTE],unit,sf->nleafreqs,leafreqs);
    144:   /* Pack rootdata and do Isend for remote */
    145:   PetscSFLinkPackRootData(sf,link,PETSCSF_REMOTE,rootdata);
    146:   MPI_Startall_isend(bas->rootbuflen[PETSCSF_REMOTE],unit,bas->nrootreqs,rootreqs);
    147:   /* Do local BcastAndOp, which overlaps with the irecv/isend above */
    148:   PetscSFLinkBcastAndOpLocal(sf,link,rootdata,leafdata,op);
    149:   return(0);
    150: }

    152: PETSC_INTERN PetscErrorCode PetscSFBcastAndOpEnd_Basic(PetscSF sf,MPI_Datatype unit,const void *rootdata,void *leafdata,MPI_Op op)
    153: {
    154:   PetscErrorCode    ierr;
    155:   PetscSFLink       link = NULL;

    158:   /* Retrieve the link used in XxxBegin() with root/leafdata as key */
    159:   PetscSFLinkGetInUse(sf,unit,rootdata,leafdata,PETSC_OWN_POINTER,&link);
    160:   /* Wait for the completion of mpi */
    161:   PetscSFLinkMPIWaitall(sf,link,PETSCSF_../../../../../..2LEAF);
    162:   /* Unpack leafdata and reclaim the link */
    163:   PetscSFLinkUnpackLeafData(sf,link,PETSCSF_REMOTE,leafdata,op);
    164:   PetscSFLinkReclaim(sf,&link);
    165:   return(0);
    166: }

    168: /* Shared by ReduceBegin and FetchAndOpBegin */
    169: PETSC_STATIC_INLINE PetscErrorCode PetscSFLeafToRootBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op,PetscSFOperation sfop,PetscSFLink *out)
    170: {
    171:   PetscErrorCode    ierr;
    172:   PetscSFLink       link;
    173:   PetscSF_Basic     *bas = (PetscSF_Basic*)sf->data;
    174:   MPI_Request       *rootreqs = NULL,*leafreqs = NULL;

    177:   PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,sfop,&link);
    178:   PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_LEAF2../../../../../..,NULL,NULL,&rootreqs,&leafreqs);
    179:   MPI_Startall_irecv(bas->rootbuflen[PETSCSF_REMOTE],unit,bas->nrootreqs,rootreqs);
    180:   PetscSFLinkPackLeafData(sf,link,PETSCSF_REMOTE,leafdata);
    181:   MPI_Startall_isend(sf->leafbuflen[PETSCSF_REMOTE],unit,sf->nleafreqs,leafreqs);
    182:   *out = link;
    183:   return(0);
    184: }

    186: /* leaf -> root with reduction */
    187: static PetscErrorCode PetscSFReduceBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op)
    188: {
    189:   PetscErrorCode    ierr;
    190:   PetscSFLink       link = NULL;

    193:   PetscSFLeafToRootBegin_Basic(sf,unit,leafmtype,leafdata,rootmtype,rootdata,op,PETSCSF_REDUCE,&link);
    194:   PetscSFLinkReduceLocal(sf,link,leafdata,rootdata,op);
    195:   return(0);
    196: }

    198: PETSC_INTERN PetscErrorCode PetscSFReduceEnd_Basic(PetscSF sf,MPI_Datatype unit,const void *leafdata,void *rootdata,MPI_Op op)
    199: {
    200:   PetscErrorCode    ierr;
    201:   PetscSFLink       link = NULL;

    204:   PetscSFLinkGetInUse(sf,unit,rootdata,leafdata,PETSC_OWN_POINTER,&link);
    205:   PetscSFLinkMPIWaitall(sf,link,PETSCSF_LEAF2../../../../../..);
    206:   PetscSFLinkUnpackRootData(sf,link,PETSCSF_REMOTE,rootdata,op);
    207:   PetscSFLinkReclaim(sf,&link);
    208:   return(0);
    209: }

    211: PETSC_INTERN PetscErrorCode PetscSFFetchAndOpBegin_Basic(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,void *rootdata,PetscMemType leafmtype,const void *leafdata,void *leafupdate,MPI_Op op)
    212: {
    213:   PetscErrorCode    ierr;
    214:   PetscSFLink       link = NULL;

    217:   PetscSFLeafToRootBegin_Basic(sf,unit,leafmtype,leafdata,rootmtype,rootdata,op,PETSCSF_FETCH,&link);
    218:   PetscSFLinkFetchAndOpLocal(sf,link,rootdata,leafdata,leafupdate,op);
    219:   return(0);
    220: }

    222: static PetscErrorCode PetscSFFetchAndOpEnd_Basic(PetscSF sf,MPI_Datatype unit,void *rootdata,const void *leafdata,void *leafupdate,MPI_Op op)
    223: {
    224:   PetscErrorCode    ierr;
    225:   PetscSFLink       link = NULL;
    226:   MPI_Request       *rootreqs = NULL,*leafreqs = NULL;
    227:   PetscSF_Basic     *bas = (PetscSF_Basic*)sf->data;

    230:   PetscSFLinkGetInUse(sf,unit,rootdata,leafdata,PETSC_OWN_POINTER,&link);
    231:   /* This implementation could be changed to unpack as receives arrive, at the cost of non-determinism */
    232:   PetscSFLinkMPIWaitall(sf,link,PETSCSF_LEAF2../../../../../..);
    233:   /* Do fetch-and-op, the (remote) update results are in rootbuf */
    234:   PetscSFLinkFetchRootData(sf,link,PETSCSF_REMOTE,rootdata,op);

    236:   /* Bcast rootbuf to leafupdate */
    237:   PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_../../../../../..2LEAF,NULL,NULL,&rootreqs,&leafreqs);
    238:   /* Post leaf receives and root sends */
    239:   MPI_Startall_irecv(sf->leafbuflen[PETSCSF_REMOTE],unit,sf->nleafreqs,leafreqs);
    240:   MPI_Startall_isend(bas->rootbuflen[PETSCSF_REMOTE],unit,bas->nrootreqs,rootreqs);
    241:   /* Unpack and insert fetched data into leaves */
    242:   PetscSFLinkMPIWaitall(sf,link,PETSCSF_../../../../../..2LEAF);
    243:   PetscSFLinkUnpackLeafData(sf,link,PETSCSF_REMOTE,leafupdate,MPIU_REPLACE);
    244:   PetscSFLinkReclaim(sf,&link);
    245:   return(0);
    246: }

    248: PETSC_INTERN PetscErrorCode PetscSFGetLeafRanks_Basic(PetscSF sf,PetscInt *niranks,const PetscMPIInt **iranks,const PetscInt **ioffset,const PetscInt **irootloc)
    249: {
    250:   PetscSF_Basic *bas = (PetscSF_Basic*)sf->data;

    253:   if (niranks)  *niranks  = bas->niranks;
    254:   if (iranks)   *iranks   = bas->iranks;
    255:   if (ioffset)  *ioffset  = bas->ioffset;
    256:   if (irootloc) *irootloc = bas->irootloc;
    257:   return(0);
    258: }

    260: /* An optimized PetscSFCreateEmbeddedSF. We aggresively make use of the established communication on sf.
    261:    We need one bcast on sf, and no communication anymore to build the embedded sf. Note that selected[]
    262:    was sorted before calling the routine.
    263:  */
    264: PETSC_INTERN PetscErrorCode PetscSFCreateEmbeddedSF_Basic(PetscSF sf,PetscInt nselected,const PetscInt *selected,PetscSF *newsf)
    265: {
    266:   PetscSF           esf;
    267:   PetscInt          esf_nranks,esf_ndranks,*esf_roffset,*esf_rmine,*esf_rremote;
    268:   PetscInt          i,j,p,q,nroots,esf_nleaves,*new_ilocal,nranks,ndranks,niranks,ndiranks,minleaf,maxleaf,maxlocal;
    269:   char              *rootdata,*leafdata,*leafmem; /* Only stores 0 or 1, so we can save memory with char */
    270:   PetscMPIInt       *esf_ranks;
    271:   const PetscMPIInt *ranks,*iranks;
    272:   const PetscInt    *roffset,*rmine,*rremote,*ioffset,*irootloc;
    273:   PetscBool         connected;
    274:   PetscSFNode       *new_iremote;
    275:   PetscSF_Basic     *bas;
    276:   PetscErrorCode    ierr;

    279:   PetscSFCreate(PetscObjectComm((PetscObject)sf),&esf);
    280:   PetscSFSetFromOptions(esf);
    281:   PetscSFSetType(esf,PETSCSFBASIC); /* This optimized routine can only create a basic sf */

    283:   /* Find out which leaves are still connected to roots in the embedded sf by doing a Bcast */
    284:   PetscSFGetGraph(sf,&nroots,NULL,NULL,NULL);
    285:   PetscSFGetLeafRange(sf,&minleaf,&maxleaf);
    286:   maxlocal = maxleaf - minleaf + 1;
    287:   PetscCalloc2(nroots,&rootdata,maxlocal,&leafmem);
    288:   leafdata = leafmem - minleaf;
    289:   /* Tag selected roots */
    290:   for (i=0; i<nselected; ++i) rootdata[selected[i]] = 1;

    292:   PetscSFBcastBegin(sf,MPI_CHAR,rootdata,leafdata);
    293:   PetscSFBcastEnd(sf,MPI_CHAR,rootdata,leafdata);
    294:   PetscSFGetLeafInfo_Basic(sf,&nranks,&ndranks,&ranks,&roffset,&rmine,&rremote); /* Get send info */
    295:   esf_nranks = esf_ndranks = esf_nleaves = 0;
    296:   for (i=0; i<nranks; i++) {
    297:     connected = PETSC_FALSE; /* Is this process still connected to this remote root rank? */
    298:     for (j=roffset[i]; j<roffset[i+1]; j++) {if (leafdata[rmine[j]]) {esf_nleaves++; connected = PETSC_TRUE;}}
    299:     if (connected) {esf_nranks++; if (i < ndranks) esf_ndranks++;}
    300:   }

    302:   /* Set graph of esf and also set up its outgoing communication (i.e., send info), which is usually done by PetscSFSetUpRanks */
    303:   PetscMalloc1(esf_nleaves,&new_ilocal);
    304:   PetscMalloc1(esf_nleaves,&new_iremote);
    305:   PetscMalloc4(esf_nranks,&esf_ranks,esf_nranks+1,&esf_roffset,esf_nleaves,&esf_rmine,esf_nleaves,&esf_rremote);
    306:   p    = 0; /* Counter for connected root ranks */
    307:   q    = 0; /* Counter for connected leaves */
    308:   esf_roffset[0] = 0;
    309:   for (i=0; i<nranks; i++) { /* Scan leaf data again to fill esf arrays */
    310:     connected = PETSC_FALSE;
    311:     for (j=roffset[i]; j<roffset[i+1]; j++) {
    312:       if (leafdata[rmine[j]]) {
    313:         esf_rmine[q]         = new_ilocal[q] = rmine[j];
    314:         esf_rremote[q]       = rremote[j];
    315:         new_iremote[q].index = rremote[j];
    316:         new_iremote[q].rank  = ranks[i];
    317:         connected            = PETSC_TRUE;
    318:         q++;
    319:       }
    320:     }
    321:     if (connected) {
    322:       esf_ranks[p]     = ranks[i];
    323:       esf_roffset[p+1] = q;
    324:       p++;
    325:     }
    326:   }

    328:   /* SetGraph internally resets the SF, so we only set its fields after the call */
    329:   PetscSFSetGraph(esf,nroots,esf_nleaves,new_ilocal,PETSC_OWN_POINTER,new_iremote,PETSC_OWN_POINTER);
    330:   esf->nranks    = esf_nranks;
    331:   esf->ndranks   = esf_ndranks;
    332:   esf->ranks     = esf_ranks;
    333:   esf->roffset   = esf_roffset;
    334:   esf->rmine     = esf_rmine;
    335:   esf->rremote   = esf_rremote;
    336:   esf->nleafreqs = esf_nranks - esf_ndranks;

    338:   /* Set up the incoming communication (i.e., recv info) stored in esf->data, which is usually done by PetscSFSetUp_Basic */
    339:   bas  = (PetscSF_Basic*)esf->data;
    340:   PetscSFGetRootInfo_Basic(sf,&niranks,&ndiranks,&iranks,&ioffset,&irootloc); /* Get recv info */
    341:   /* Embedded sf always has simpler communication than the original one. We might allocate longer arrays than needed here. But we
    342:      we do not care since these arrays are usually short. The benefit is we can fill these arrays by just parsing irootloc once.
    343:    */
    344:   PetscMalloc2(niranks,&bas->iranks,niranks+1,&bas->ioffset);
    345:   PetscMalloc1(ioffset[niranks],&bas->irootloc);
    346:   bas->niranks = bas->ndiranks = bas->ioffset[0] = 0;
    347:   p = 0; /* Counter for connected leaf ranks */
    348:   q = 0; /* Counter for connected roots */
    349:   for (i=0; i<niranks; i++) {
    350:     connected = PETSC_FALSE; /* Is the current process still connected to this remote leaf rank? */
    351:     for (j=ioffset[i]; j<ioffset[i+1]; j++) {
    352:       if (rootdata[irootloc[j]]) {
    353:         bas->irootloc[q++] = irootloc[j];
    354:         connected = PETSC_TRUE;
    355:       }
    356:     }
    357:     if (connected) {
    358:       bas->niranks++;
    359:       if (i<ndiranks) bas->ndiranks++; /* Note that order of ranks (including distinguished ranks) is kept */
    360:       bas->iranks[p]    = iranks[i];
    361:       bas->ioffset[p+1] = q;
    362:       p++;
    363:     }
    364:   }
    365:   bas->itotal     = q;
    366:   bas->nrootreqs  = bas->niranks - bas->ndiranks;
    367:   esf->persistent = PETSC_TRUE;
    368:   /* Setup packing related fields */
    369:   PetscSFSetUpPackFields(esf);

    371:   /* Copy from PetscSFSetUp(), since this method wants to skip PetscSFSetUp(). */
    372: #if defined(PETSC_HAVE_CUDA)
    373:   if (esf->backend == PETSCSF_BACKEND_CUDA) {
    374:     esf->ops->Malloc = PetscSFMalloc_Cuda;
    375:     esf->ops->Free   = PetscSFFree_Cuda;
    376:   }
    377: #endif

    379: #if defined(PETSC_HAVE_KOKKOS)
    380:   if (esf->backend == PETSCSF_BACKEND_KOKKOS) {
    381:     esf->ops->Malloc = PetscSFMalloc_Kokkos;
    382:     esf->ops->Free   = PetscSFFree_Kokkos;
    383:   }
    384: #endif
    385:   esf->setupcalled = PETSC_TRUE; /* We have done setup ourselves! */
    386:   PetscFree2(rootdata,leafmem);
    387:   *newsf = esf;
    388:   return(0);
    389: }

    391: PETSC_EXTERN PetscErrorCode PetscSFCreate_Basic(PetscSF sf)
    392: {
    393:   PetscSF_Basic  *dat;

    397:   sf->ops->SetUp                = PetscSFSetUp_Basic;
    398:   sf->ops->Reset                = PetscSFReset_Basic;
    399:   sf->ops->Destroy              = PetscSFDestroy_Basic;
    400:   sf->ops->View                 = PetscSFView_Basic;
    401:   sf->ops->BcastAndOpBegin      = PetscSFBcastAndOpBegin_Basic;
    402:   sf->ops->BcastAndOpEnd        = PetscSFBcastAndOpEnd_Basic;
    403:   sf->ops->ReduceBegin          = PetscSFReduceBegin_Basic;
    404:   sf->ops->ReduceEnd            = PetscSFReduceEnd_Basic;
    405:   sf->ops->FetchAndOpBegin      = PetscSFFetchAndOpBegin_Basic;
    406:   sf->ops->FetchAndOpEnd        = PetscSFFetchAndOpEnd_Basic;
    407:   sf->ops->GetLeafRanks         = PetscSFGetLeafRanks_Basic;
    408:   sf->ops->CreateEmbeddedSF     = PetscSFCreateEmbeddedSF_Basic;

    410:   PetscNewLog(sf,&dat);
    411:   sf->data = (void*)dat;
    412:   return(0);
    413: }