xref: /petsc/src/vec/is/sf/impls/basic/gatherv/sfgatherv.c (revision ad227fea26420e7a31ef041a9fa1418814d171a8)
1dd5b3ca6SJunchao Zhang 
2dd5b3ca6SJunchao Zhang #include <../src/vec/is/sf/impls/basic/gatherv/sfgatherv.h>
3dd5b3ca6SJunchao Zhang 
4eb02082bSJunchao Zhang /* Reuse the type. The difference is some fields (displs, recvcounts) are only significant
5eb02082bSJunchao Zhang    on rank 0 in Gatherv. On other ranks they are harmless NULL.
6eb02082bSJunchao Zhang  */
7eb02082bSJunchao Zhang typedef PetscSF_Allgatherv PetscSF_Gatherv;
8eb02082bSJunchao Zhang 
9*ad227feaSJunchao Zhang PETSC_INTERN PetscErrorCode PetscSFBcastBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,const void *rootdata,PetscMemType leafmtype,void *leafdata,MPI_Op op)
10dd5b3ca6SJunchao Zhang {
11dd5b3ca6SJunchao Zhang   PetscErrorCode       ierr;
12cd620004SJunchao Zhang   PetscSFLink          link;
13855db38dSJunchao Zhang   PetscMPIInt          sendcount;
14dd5b3ca6SJunchao Zhang   MPI_Comm             comm;
15dd5b3ca6SJunchao Zhang   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
16cd620004SJunchao Zhang   void                 *rootbuf = NULL,*leafbuf = NULL; /* buffer seen by MPI */
17cd620004SJunchao Zhang   MPI_Request          *req;
18dd5b3ca6SJunchao Zhang 
19dd5b3ca6SJunchao Zhang   PetscFunctionBegin;
20cd620004SJunchao Zhang   ierr = PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_BCAST,&link);CHKERRQ(ierr);
21cd620004SJunchao Zhang   ierr = PetscSFLinkPackRootData(sf,link,PETSCSF_REMOTE,rootdata);CHKERRQ(ierr);
22dd5b3ca6SJunchao Zhang   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
23dd5b3ca6SJunchao Zhang   ierr = PetscMPIIntCast(sf->nroots,&sendcount);CHKERRQ(ierr);
24cd620004SJunchao Zhang   ierr = PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_ROOT2LEAF,&rootbuf,&leafbuf,&req,NULL);CHKERRQ(ierr);
25cd620004SJunchao Zhang   ierr = MPIU_Igatherv(rootbuf,sendcount,unit,leafbuf,dat->recvcounts,dat->displs,unit,0/*rank 0*/,comm,req);CHKERRQ(ierr);
26dd5b3ca6SJunchao Zhang   PetscFunctionReturn(0);
27dd5b3ca6SJunchao Zhang }
28dd5b3ca6SJunchao Zhang 
29eb02082bSJunchao Zhang static PetscErrorCode PetscSFReduceBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op)
30dd5b3ca6SJunchao Zhang {
31dd5b3ca6SJunchao Zhang   PetscErrorCode       ierr;
32cd620004SJunchao Zhang   PetscSFLink          link;
33dd5b3ca6SJunchao Zhang   PetscMPIInt          recvcount;
34dd5b3ca6SJunchao Zhang   MPI_Comm             comm;
35dd5b3ca6SJunchao Zhang   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
36cd620004SJunchao Zhang   void                 *rootbuf = NULL,*leafbuf = NULL; /* buffer seen by MPI */
37cd620004SJunchao Zhang   MPI_Request          *req;
38dd5b3ca6SJunchao Zhang 
39dd5b3ca6SJunchao Zhang   PetscFunctionBegin;
40cd620004SJunchao Zhang   ierr = PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_REDUCE,&link);CHKERRQ(ierr);
41cd620004SJunchao Zhang   ierr = PetscSFLinkPackLeafData(sf,link,PETSCSF_REMOTE,leafdata);CHKERRQ(ierr);
42dd5b3ca6SJunchao Zhang   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
43dd5b3ca6SJunchao Zhang   ierr = PetscMPIIntCast(sf->nroots,&recvcount);CHKERRQ(ierr);
44cd620004SJunchao Zhang   ierr = PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_LEAF2ROOT,&rootbuf,&leafbuf,&req,NULL);CHKERRQ(ierr);
45cd620004SJunchao Zhang   ierr = MPIU_Iscatterv(leafbuf,dat->recvcounts,dat->displs,unit,rootbuf,recvcount,unit,0,comm,req);CHKERRQ(ierr);
46dd5b3ca6SJunchao Zhang   PetscFunctionReturn(0);
47dd5b3ca6SJunchao Zhang }
48dd5b3ca6SJunchao Zhang 
49eb02082bSJunchao Zhang PETSC_INTERN PetscErrorCode PetscSFFetchAndOpBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,void *rootdata,PetscMemType leafmtype,const void *leafdata,void *leafupdate,MPI_Op op)
50dd5b3ca6SJunchao Zhang {
51dd5b3ca6SJunchao Zhang   PetscErrorCode      ierr;
52dd5b3ca6SJunchao Zhang 
53dd5b3ca6SJunchao Zhang   PetscFunctionBegin;
54dd5b3ca6SJunchao Zhang   /* In Gatherv, each root only has one leaf. So we just need to bcast rootdata to leafupdate and then reduce leafdata to rootdata */
55*ad227feaSJunchao Zhang   ierr = PetscSFBcastBegin(sf,unit,rootdata,leafupdate,MPI_REPLACE);CHKERRQ(ierr);
56*ad227feaSJunchao Zhang   ierr = PetscSFBcastEnd(sf,unit,rootdata,leafupdate,MPI_REPLACE);CHKERRQ(ierr);
57dd5b3ca6SJunchao Zhang   ierr = PetscSFReduceBegin(sf,unit,leafdata,rootdata,op);CHKERRQ(ierr);
58dd5b3ca6SJunchao Zhang   PetscFunctionReturn(0);
59dd5b3ca6SJunchao Zhang }
60dd5b3ca6SJunchao Zhang 
61dd5b3ca6SJunchao Zhang PETSC_INTERN PetscErrorCode PetscSFCreate_Gatherv(PetscSF sf)
62dd5b3ca6SJunchao Zhang {
63dd5b3ca6SJunchao Zhang   PetscErrorCode  ierr;
64dd5b3ca6SJunchao Zhang   PetscSF_Gatherv *dat = (PetscSF_Gatherv*)sf->data;
65dd5b3ca6SJunchao Zhang 
66dd5b3ca6SJunchao Zhang   PetscFunctionBegin;
67*ad227feaSJunchao Zhang   sf->ops->BcastEnd        = PetscSFBcastEnd_Basic;
68cd620004SJunchao Zhang   sf->ops->ReduceEnd       = PetscSFReduceEnd_Basic;
69cd620004SJunchao Zhang 
70dd5b3ca6SJunchao Zhang   /* Inherit from Allgatherv */
71dd5b3ca6SJunchao Zhang   sf->ops->SetUp           = PetscSFSetUp_Allgatherv;
72dd5b3ca6SJunchao Zhang   sf->ops->Reset           = PetscSFReset_Allgatherv;
73dd5b3ca6SJunchao Zhang   sf->ops->Destroy         = PetscSFDestroy_Allgatherv;
74dd5b3ca6SJunchao Zhang   sf->ops->GetGraph        = PetscSFGetGraph_Allgatherv;
75dd5b3ca6SJunchao Zhang   sf->ops->GetLeafRanks    = PetscSFGetLeafRanks_Allgatherv;
76dd5b3ca6SJunchao Zhang   sf->ops->GetRootRanks    = PetscSFGetRootRanks_Allgatherv;
77dd5b3ca6SJunchao Zhang   sf->ops->FetchAndOpEnd   = PetscSFFetchAndOpEnd_Allgatherv;
78dd5b3ca6SJunchao Zhang   sf->ops->CreateLocalSF   = PetscSFCreateLocalSF_Allgatherv;
79dd5b3ca6SJunchao Zhang 
80dd5b3ca6SJunchao Zhang   /* Gatherv stuff */
81*ad227feaSJunchao Zhang   sf->ops->BcastBegin      = PetscSFBcastBegin_Gatherv;
82dd5b3ca6SJunchao Zhang   sf->ops->ReduceBegin     = PetscSFReduceBegin_Gatherv;
83dd5b3ca6SJunchao Zhang   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Gatherv;
84dd5b3ca6SJunchao Zhang 
85dd5b3ca6SJunchao Zhang   ierr = PetscNewLog(sf,&dat);CHKERRQ(ierr);
86dd5b3ca6SJunchao Zhang   sf->data = (void*)dat;
87dd5b3ca6SJunchao Zhang   PetscFunctionReturn(0);
88dd5b3ca6SJunchao Zhang }
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