xref: /petsc/src/vec/is/sf/impls/basic/gatherv/sfgatherv.c (revision 6a98f8dc3f2c9149905a87dc2e9d0fedaf64e09a)
1 
2 #include <../src/vec/is/sf/impls/basic/gatherv/sfgatherv.h>
3 
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;
8 
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;
18 
19   PetscFunctionBegin;
20   ierr = PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_BCAST,&link);CHKERRQ(ierr);
21   ierr = PetscSFLinkPackRootData(sf,link,PETSCSF_REMOTE,rootdata);CHKERRQ(ierr);
22   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
23   ierr = PetscMPIIntCast(sf->nroots,&sendcount);CHKERRQ(ierr);
24   ierr = PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_ROOT2LEAF,&rootbuf,&leafbuf,&req,NULL);CHKERRQ(ierr);
25   ierr = MPIU_Igatherv(rootbuf,sendcount,unit,leafbuf,dat->recvcounts,dat->displs,unit,0/*rank 0*/,comm,req);CHKERRQ(ierr);
26   PetscFunctionReturn(0);
27 }
28 
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;
38 
39   PetscFunctionBegin;
40   ierr = PetscSFLinkCreate(sf,unit,rootmtype,rootdata,leafmtype,leafdata,op,PETSCSF_REDUCE,&link);CHKERRQ(ierr);
41   ierr = PetscSFLinkPackLeafData(sf,link,PETSCSF_REMOTE,leafdata);CHKERRQ(ierr);
42   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
43   ierr = PetscMPIIntCast(sf->nroots,&recvcount);CHKERRQ(ierr);
44   ierr = PetscSFLinkGetMPIBuffersAndRequests(sf,link,PETSCSF_LEAF2ROOT,&rootbuf,&leafbuf,&req,NULL);CHKERRQ(ierr);
45   ierr = MPIU_Iscatterv(leafbuf,dat->recvcounts,dat->displs,unit,rootbuf,recvcount,unit,0,comm,req);CHKERRQ(ierr);
46   PetscFunctionReturn(0);
47 }
48 
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;
52 
53   PetscFunctionBegin;
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   ierr = PetscSFBcastAndOpBegin(sf,unit,rootdata,leafupdate,MPIU_REPLACE);CHKERRQ(ierr);
56   ierr = PetscSFBcastAndOpEnd(sf,unit,rootdata,leafupdate,MPIU_REPLACE);CHKERRQ(ierr);
57   ierr = PetscSFReduceBegin(sf,unit,leafdata,rootdata,op);CHKERRQ(ierr);
58   PetscFunctionReturn(0);
59 }
60 
61 PETSC_INTERN PetscErrorCode PetscSFCreate_Gatherv(PetscSF sf)
62 {
63   PetscErrorCode  ierr;
64   PetscSF_Gatherv *dat = (PetscSF_Gatherv*)sf->data;
65 
66   PetscFunctionBegin;
67   sf->ops->BcastAndOpEnd   = PetscSFBcastAndOpEnd_Basic;
68   sf->ops->ReduceEnd       = PetscSFReduceEnd_Basic;
69 
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;
79 
80   /* Gatherv stuff */
81   sf->ops->BcastAndOpBegin = PetscSFBcastAndOpBegin_Gatherv;
82   sf->ops->ReduceBegin     = PetscSFReduceBegin_Gatherv;
83   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Gatherv;
84 
85   ierr = PetscNewLog(sf,&dat);CHKERRQ(ierr);
86   sf->data = (void*)dat;
87   PetscFunctionReturn(0);
88 }
89