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 PetscSFBcastAndOpBegin_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:   PetscObjectGetComm((PetscObject)sf,&comm);
 23:   PetscMPIIntCast(sf->nroots,&sendcount);
 24:   PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_../../../../../..2LEAF,&rootbuf,&leafbuf,&req,NULL);
 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:   PetscErrorCode       ierr;
 32:   PetscSFLink          link;
 33:   PetscMPIInt          recvcount;
 34:   MPI_Comm             comm;
 35:   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
 36:   void                 *rootbuf = NULL,*leafbuf = NULL; /* buffer seen by MPI */
 37:   MPI_Request          *req;

 40:   PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_REDUCE,&link);
 41:   PetscSFLinkPackLeafData(sf,link,PETSCSF_REMOTE,leafdata);
 42:   PetscObjectGetComm((PetscObject)sf,&comm);
 43:   PetscMPIIntCast(sf->nroots,&recvcount);
 44:   PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_LEAF2../../../../../..,&rootbuf,&leafbuf,&req,NULL);
 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:   PetscErrorCode      ierr;

 54:   /* In Gatherv, each root only has one leaf. So we just need to bcast rootdata to leafupdate and then reduce leafdata to rootdata */
 55:   PetscSFBcastAndOpBegin(sf,unit,rootdata,leafupdate,MPIU_REPLACE);
 56:   PetscSFBcastAndOpEnd(sf,unit,rootdata,leafupdate,MPIU_REPLACE);
 57:   PetscSFReduceBegin(sf,unit,leafdata,rootdata,op);
 58:   return(0);
 59: }

 61: PETSC_INTERN PetscErrorCode PetscSFCreate_Gatherv(PetscSF sf)
 62: {
 63:   PetscErrorCode  ierr;
 64:   PetscSF_Gatherv *dat = (PetscSF_Gatherv*)sf->data;

 67:   sf->ops->BcastAndOpEnd   = PetscSFBcastAndOpEnd_Basic;
 68:   sf->ops->ReduceEnd       = PetscSFReduceEnd_Basic;

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

 80:   /* Gatherv stuff */
 81:   sf->ops->BcastAndOpBegin = PetscSFBcastAndOpBegin_Gatherv;
 82:   sf->ops->ReduceBegin     = PetscSFReduceBegin_Gatherv;
 83:   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Gatherv;

 85:   PetscNewLog(sf,&dat);
 86:   sf->data = (void*)dat;
 87:   return(0);
 88: }