Actual source code: sfgatherv.c

petsc-3.15.0 2021-04-05
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  2: #include <../src/vec/is/sf/impls/basic/gatherv/sfgatherv.h>

  4: /* Reuse the type. The difference is some fields (displs, recvcounts) are only significant
  5:    on rank 0 in Gatherv. On other ranks they are harmless NULL.
  6:  */
  7: typedef PetscSF_Allgatherv PetscSF_Gatherv;

  9: PETSC_INTERN PetscErrorCode PetscSFBcastBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,const void *rootdata,PetscMemType leafmtype,void *leafdata,MPI_Op op)
 10: {
 11:   PetscErrorCode       ierr;
 12:   PetscSFLink          link;
 13:   PetscMPIInt          sendcount;
 14:   MPI_Comm             comm;
 15:   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
 16:   void                 *rootbuf = NULL,*leafbuf = NULL; /* buffer seen by MPI */
 17:   MPI_Request          *req;

 20:   PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_BCAST,&link);
 21:   PetscSFLinkPackRootData(sf,link,PETSCSF_REMOTE,rootdata);
 22:   PetscSFLinkCopyRootBufferInCaseNotUseGpuAwareMPI(sf,link,PETSC_TRUE/* device2host before sending */);
 23:   PetscObjectGetComm((PetscObject)sf,&comm);
 24:   PetscMPIIntCast(sf->nroots,&sendcount);
 25:   PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_../../../../../..2LEAF,&rootbuf,&leafbuf,&req,NULL);
 26:   PetscSFLinkSyncStreamBeforeCallMPI(sf,link,PETSCSF_../../../../../..2LEAF);
 27:   MPIU_Igatherv(rootbuf,sendcount,unit,leafbuf,dat->recvcounts,dat->displs,unit,0/*rank 0*/,comm,req);
 28:   return(0);
 29: }

 31: static PetscErrorCode PetscSFReduceBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op)
 32: {
 33:   PetscErrorCode       ierr;
 34:   PetscSFLink          link;
 35:   PetscMPIInt          recvcount;
 36:   MPI_Comm             comm;
 37:   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
 38:   void                 *rootbuf = NULL,*leafbuf = NULL; /* buffer seen by MPI */
 39:   MPI_Request          *req;

 42:   PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_REDUCE,&link);
 43:   PetscSFLinkPackLeafData(sf,link,PETSCSF_REMOTE,leafdata);
 44:   PetscSFLinkCopyLeafBufferInCaseNotUseGpuAwareMPI(sf,link,PETSC_TRUE/* device2host before sending */);
 45:   PetscObjectGetComm((PetscObject)sf,&comm);
 46:   PetscMPIIntCast(sf->nroots,&recvcount);
 47:   PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_LEAF2../../../../../..,&rootbuf,&leafbuf,&req,NULL);
 48:   PetscSFLinkSyncStreamBeforeCallMPI(sf,link,PETSCSF_LEAF2../../../../../..);
 49:   MPIU_Iscatterv(leafbuf,dat->recvcounts,dat->displs,unit,rootbuf,recvcount,unit,0,comm,req);
 50:   return(0);
 51: }

 53: PETSC_INTERN PetscErrorCode PetscSFFetchAndOpBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,void *rootdata,PetscMemType leafmtype,const void *leafdata,void *leafupdate,MPI_Op op)
 54: {
 55:   PetscErrorCode      ierr;

 58:   /* In Gatherv, each root only has one leaf. So we just need to bcast rootdata to leafupdate and then reduce leafdata to rootdata */
 59:   PetscSFBcastBegin(sf,unit,rootdata,leafupdate,MPI_REPLACE);
 60:   PetscSFBcastEnd(sf,unit,rootdata,leafupdate,MPI_REPLACE);
 61:   PetscSFReduceBegin(sf,unit,leafdata,rootdata,op);
 62:   return(0);
 63: }

 65: PETSC_INTERN PetscErrorCode PetscSFCreate_Gatherv(PetscSF sf)
 66: {
 67:   PetscErrorCode  ierr;
 68:   PetscSF_Gatherv *dat = (PetscSF_Gatherv*)sf->data;

 71:   sf->ops->BcastEnd        = PetscSFBcastEnd_Basic;
 72:   sf->ops->ReduceEnd       = PetscSFReduceEnd_Basic;

 74:   /* Inherit from Allgatherv */
 75:   sf->ops->SetUp           = PetscSFSetUp_Allgatherv;
 76:   sf->ops->Reset           = PetscSFReset_Allgatherv;
 77:   sf->ops->Destroy         = PetscSFDestroy_Allgatherv;
 78:   sf->ops->GetGraph        = PetscSFGetGraph_Allgatherv;
 79:   sf->ops->GetLeafRanks    = PetscSFGetLeafRanks_Allgatherv;
 80:   sf->ops->GetRootRanks    = PetscSFGetRootRanks_Allgatherv;
 81:   sf->ops->FetchAndOpEnd   = PetscSFFetchAndOpEnd_Allgatherv;
 82:   sf->ops->CreateLocalSF   = PetscSFCreateLocalSF_Allgatherv;

 84:   /* Gatherv stuff */
 85:   sf->ops->BcastBegin      = PetscSFBcastBegin_Gatherv;
 86:   sf->ops->ReduceBegin     = PetscSFReduceBegin_Gatherv;
 87:   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Gatherv;

 89:   PetscNewLog(sf,&dat);
 90:   sf->data = (void*)dat;
 91:   return(0);
 92: }