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:   PetscSFLink          link;
 12:   PetscMPIInt          sendcount;
 13:   MPI_Comm             comm;
 14:   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
 15:   void                 *rootbuf = NULL,*leafbuf = NULL; /* buffer seen by MPI */
 16:   MPI_Request          *req;

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

 29: static PetscErrorCode PetscSFReduceBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op)
 30: {
 31:   PetscSFLink          link;
 32:   PetscMPIInt          recvcount;
 33:   MPI_Comm             comm;
 34:   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
 35:   void                 *rootbuf = NULL,*leafbuf = NULL; /* buffer seen by MPI */
 36:   MPI_Request          *req;

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

 49: PETSC_INTERN PetscErrorCode PetscSFFetchAndOpBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,void *rootdata,PetscMemType leafmtype,const void *leafdata,void *leafupdate,MPI_Op op)
 50: {
 51:   /* In Gatherv, each root only has one leaf. So we just need to bcast rootdata to leafupdate and then reduce leafdata to rootdata */
 52:   PetscSFBcastBegin(sf,unit,rootdata,leafupdate,MPI_REPLACE);
 53:   PetscSFBcastEnd(sf,unit,rootdata,leafupdate,MPI_REPLACE);
 54:   PetscSFReduceBegin(sf,unit,leafdata,rootdata,op);
 55:   return 0;
 56: }

 58: PETSC_INTERN PetscErrorCode PetscSFCreate_Gatherv(PetscSF sf)
 59: {
 60:   PetscSF_Gatherv *dat = (PetscSF_Gatherv*)sf->data;

 62:   sf->ops->BcastEnd        = PetscSFBcastEnd_Basic;
 63:   sf->ops->ReduceEnd       = PetscSFReduceEnd_Basic;

 65:   /* Inherit from Allgatherv */
 66:   sf->ops->SetUp           = PetscSFSetUp_Allgatherv;
 67:   sf->ops->Reset           = PetscSFReset_Allgatherv;
 68:   sf->ops->Destroy         = PetscSFDestroy_Allgatherv;
 69:   sf->ops->GetGraph        = PetscSFGetGraph_Allgatherv;
 70:   sf->ops->GetLeafRanks    = PetscSFGetLeafRanks_Allgatherv;
 71:   sf->ops->GetRootRanks    = PetscSFGetRootRanks_Allgatherv;
 72:   sf->ops->FetchAndOpEnd   = PetscSFFetchAndOpEnd_Allgatherv;
 73:   sf->ops->CreateLocalSF   = PetscSFCreateLocalSF_Allgatherv;

 75:   /* Gatherv stuff */
 76:   sf->ops->BcastBegin      = PetscSFBcastBegin_Gatherv;
 77:   sf->ops->ReduceBegin     = PetscSFReduceBegin_Gatherv;
 78:   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Gatherv;

 80:   PetscNewLog(sf,&dat);
 81:   sf->data = (void*)dat;
 82:   return 0;
 83: }