xref: /petsc/src/vec/is/sf/impls/basic/gather/sfgather.c (revision 21e3ffae2f3b73c0bd738cf6d0a809700fc04bb0)
1 #include <../src/vec/is/sf/impls/basic/gatherv/sfgatherv.h>
2 #include <../src/vec/is/sf/impls/basic/allgather/sfallgather.h>
3 
4 /* Reuse the type. The difference is some fields (i.e., displs, recvcounts) are not used in Gather, which is not a big deal */
5 typedef PetscSF_Allgatherv PetscSF_Gather;
6 
7 PETSC_INTERN PetscErrorCode PetscSFBcastBegin_Gather(PetscSF sf, MPI_Datatype unit, PetscMemType rootmtype, const void *rootdata, PetscMemType leafmtype, void *leafdata, MPI_Op op)
8 {
9   PetscSFLink  link;
10   PetscMPIInt  sendcount;
11   MPI_Comm     comm;
12   void        *rootbuf = NULL, *leafbuf = NULL;
13   MPI_Request *req;
14 
15   PetscFunctionBegin;
16   PetscCall(PetscSFLinkCreate(sf, unit, rootmtype, rootdata, leafmtype, leafdata, op, PETSCSF_BCAST, &link));
17   PetscCall(PetscSFLinkPackRootData(sf, link, PETSCSF_REMOTE, rootdata));
18   PetscCall(PetscSFLinkCopyRootBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_TRUE /* device2host before sending */));
19   PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
20   PetscCall(PetscMPIIntCast(sf->nroots, &sendcount));
21   PetscCall(PetscSFLinkGetMPIBuffersAndRequests(sf, link, PETSCSF_ROOT2LEAF, &rootbuf, &leafbuf, &req, NULL));
22   PetscCall(PetscSFLinkSyncStreamBeforeCallMPI(sf, link, PETSCSF_ROOT2LEAF));
23   PetscCallMPI(MPIU_Igather(rootbuf == leafbuf ? MPI_IN_PLACE : rootbuf, sendcount, unit, leafbuf, sendcount, unit, 0 /*rank 0*/, comm, req));
24   PetscFunctionReturn(PETSC_SUCCESS);
25 }
26 
27 static PetscErrorCode PetscSFReduceBegin_Gather(PetscSF sf, MPI_Datatype unit, PetscMemType leafmtype, const void *leafdata, PetscMemType rootmtype, void *rootdata, MPI_Op op)
28 {
29   PetscSFLink  link;
30   PetscMPIInt  recvcount;
31   MPI_Comm     comm;
32   void        *rootbuf = NULL, *leafbuf = NULL;
33   MPI_Request *req;
34 
35   PetscFunctionBegin;
36   PetscCall(PetscSFLinkCreate(sf, unit, rootmtype, rootdata, leafmtype, leafdata, op, PETSCSF_REDUCE, &link));
37   PetscCall(PetscSFLinkPackLeafData(sf, link, PETSCSF_REMOTE, leafdata));
38   PetscCall(PetscSFLinkCopyLeafBufferInCaseNotUseGpuAwareMPI(sf, link, PETSC_TRUE /* device2host before sending */));
39   PetscCall(PetscObjectGetComm((PetscObject)sf, &comm));
40   PetscCall(PetscMPIIntCast(sf->nroots, &recvcount));
41   PetscCall(PetscSFLinkGetMPIBuffersAndRequests(sf, link, PETSCSF_LEAF2ROOT, &rootbuf, &leafbuf, &req, NULL));
42   PetscCall(PetscSFLinkSyncStreamBeforeCallMPI(sf, link, PETSCSF_LEAF2ROOT));
43   PetscCallMPI(MPIU_Iscatter(leafbuf, recvcount, unit, rootbuf == leafbuf ? MPI_IN_PLACE : rootbuf, recvcount, unit, 0 /*rank 0*/, comm, req));
44   PetscFunctionReturn(PETSC_SUCCESS);
45 }
46 
47 PETSC_INTERN PetscErrorCode PetscSFCreate_Gather(PetscSF sf)
48 {
49   PetscSF_Gather *dat = (PetscSF_Gather *)sf->data;
50 
51   PetscFunctionBegin;
52   sf->ops->BcastEnd  = PetscSFBcastEnd_Basic;
53   sf->ops->ReduceEnd = PetscSFReduceEnd_Basic;
54 
55   /* Inherit from Allgatherv */
56   sf->ops->Reset         = PetscSFReset_Allgatherv;
57   sf->ops->Destroy       = PetscSFDestroy_Allgatherv;
58   sf->ops->GetGraph      = PetscSFGetGraph_Allgatherv;
59   sf->ops->GetRootRanks  = PetscSFGetRootRanks_Allgatherv;
60   sf->ops->GetLeafRanks  = PetscSFGetLeafRanks_Allgatherv;
61   sf->ops->FetchAndOpEnd = PetscSFFetchAndOpEnd_Allgatherv;
62   sf->ops->CreateLocalSF = PetscSFCreateLocalSF_Allgatherv;
63 
64   /* Inherit from Allgather */
65   sf->ops->SetUp = PetscSFSetUp_Allgather;
66 
67   /* Inherit from Gatherv */
68   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Gatherv;
69 
70   /* Gather stuff */
71   sf->ops->BcastBegin  = PetscSFBcastBegin_Gather;
72   sf->ops->ReduceBegin = PetscSFReduceBegin_Gather;
73 
74   PetscCall(PetscNew(&dat));
75   sf->data = (void *)dat;
76   PetscFunctionReturn(PETSC_SUCCESS);
77 }
78