xref: /petsc/src/vec/is/sf/impls/basic/gatherv/sfgatherv.c (revision d2fd7bfc6f0fd2e1d083decbb7cc7d77e16824f0)
1 
2 #include <../src/vec/is/sf/impls/basic/gatherv/sfgatherv.h>
3 
4 #define PetscSFPackGet_Gatherv PetscSFPackGet_Allgatherv
5 
6 /* Reuse the type. The difference is some fields (displs, recvcounts) are only significant
7    on rank 0 in Gatherv. On other ranks they are harmless NULL.
8  */
9 typedef PetscSF_Allgatherv PetscSF_Gatherv;
10 
11 PETSC_INTERN PetscErrorCode PetscSFBcastAndOpBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,const void *rootdata,PetscMemType leafmtype,void *leafdata,MPI_Op op)
12 {
13   PetscErrorCode       ierr;
14   PetscSFPack          link;
15   PetscMPIInt          rank,sendcount;
16   MPI_Comm             comm;
17   char                 *recvbuf;
18   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
19 
20   PetscFunctionBegin;
21   ierr = PetscSFPackGet_Gatherv(sf,unit,rootmtype,rootdata,leafmtype,leafdata,&link);CHKERRQ(ierr);
22   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
23   ierr = PetscMPIIntCast(sf->nroots,&sendcount);CHKERRQ(ierr);
24   ierr = MPI_Comm_rank(comm,&rank);CHKERRQ(ierr);
25 
26   if (op == MPIU_REPLACE) {
27     recvbuf = (char*)leafdata;
28   } else {
29     if (!link->leafbuf[leafmtype] && !rank) {ierr = PetscMallocWithMemType(leafmtype,sf->nleaves*link->unitbytes,(void**)&link->leafbuf[leafmtype]);CHKERRQ(ierr);} /* Alloate leafbuf on rank 0 */
30     recvbuf = link->leafbuf[leafmtype];
31   }
32 
33   ierr = MPIU_Igatherv(rootdata,sendcount,unit,recvbuf,dat->recvcounts,dat->displs,unit,0/*rank 0*/,comm,link->rootreqs[PETSCSF_ROOT2LEAF_BCAST][rootmtype]);CHKERRQ(ierr);
34   PetscFunctionReturn(0);
35 }
36 
37 static PetscErrorCode PetscSFReduceBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType leafmtype,const void *leafdata,PetscMemType rootmtype,void *rootdata,MPI_Op op)
38 {
39   PetscErrorCode       ierr;
40   PetscSFPack          link;
41   PetscMPIInt          recvcount;
42   MPI_Comm             comm;
43   char                 *recvbuf;
44   PetscSF_Gatherv      *dat = (PetscSF_Gatherv*)sf->data;
45 
46   PetscFunctionBegin;
47   ierr = PetscSFPackGet_Gatherv(sf,unit,rootmtype,rootdata,leafmtype,leafdata,&link);CHKERRQ(ierr);
48   ierr = PetscObjectGetComm((PetscObject)sf,&comm);CHKERRQ(ierr);
49 
50   if (op == MPIU_REPLACE) {
51     recvbuf = (char*)rootdata;
52   } else {
53     if (!link->rootbuf[rootmtype]) {ierr = PetscMallocWithMemType(rootmtype,sf->nroots*link->unitbytes,(void**)&link->rootbuf[rootmtype]);CHKERRQ(ierr);}
54     recvbuf = link->rootbuf[rootmtype];
55   }
56 
57   ierr = PetscMPIIntCast(sf->nroots,&recvcount);CHKERRQ(ierr);
58   ierr = MPIU_Iscatterv(leafdata,dat->recvcounts,dat->displs,unit,recvbuf,recvcount,unit,0,comm,link->rootreqs[PETSCSF_LEAF2ROOT_REDUCE][rootmtype]);CHKERRQ(ierr);
59   PetscFunctionReturn(0);
60 }
61 
62 PETSC_INTERN PetscErrorCode PetscSFFetchAndOpBegin_Gatherv(PetscSF sf,MPI_Datatype unit,PetscMemType rootmtype,void *rootdata,PetscMemType leafmtype,const void *leafdata,void *leafupdate,MPI_Op op)
63 {
64   PetscErrorCode      ierr;
65 
66   PetscFunctionBegin;
67   /* In Gatherv, each root only has one leaf. So we just need to bcast rootdata to leafupdate and then reduce leafdata to rootdata */
68   ierr = PetscSFBcastAndOpBegin(sf,unit,rootdata,leafupdate,MPIU_REPLACE);CHKERRQ(ierr);
69   ierr = PetscSFBcastAndOpEnd(sf,unit,rootdata,leafupdate,MPIU_REPLACE);CHKERRQ(ierr);
70   ierr = PetscSFReduceBegin(sf,unit,leafdata,rootdata,op);CHKERRQ(ierr);
71   PetscFunctionReturn(0);
72 }
73 
74 PETSC_INTERN PetscErrorCode PetscSFCreate_Gatherv(PetscSF sf)
75 {
76   PetscErrorCode  ierr;
77   PetscSF_Gatherv *dat = (PetscSF_Gatherv*)sf->data;
78 
79   PetscFunctionBegin;
80   /* Inherit from Allgatherv */
81   sf->ops->SetUp           = PetscSFSetUp_Allgatherv;
82   sf->ops->Reset           = PetscSFReset_Allgatherv;
83   sf->ops->Destroy         = PetscSFDestroy_Allgatherv;
84   sf->ops->GetGraph        = PetscSFGetGraph_Allgatherv;
85   sf->ops->GetLeafRanks    = PetscSFGetLeafRanks_Allgatherv;
86   sf->ops->GetRootRanks    = PetscSFGetRootRanks_Allgatherv;
87   sf->ops->BcastAndOpEnd   = PetscSFBcastAndOpEnd_Allgatherv;
88   sf->ops->ReduceEnd       = PetscSFReduceEnd_Allgatherv;
89   sf->ops->FetchAndOpEnd   = PetscSFFetchAndOpEnd_Allgatherv;
90   sf->ops->CreateLocalSF   = PetscSFCreateLocalSF_Allgatherv;
91 
92   /* Gatherv stuff */
93   sf->ops->BcastAndOpBegin = PetscSFBcastAndOpBegin_Gatherv;
94   sf->ops->ReduceBegin     = PetscSFReduceBegin_Gatherv;
95   sf->ops->FetchAndOpBegin = PetscSFFetchAndOpBegin_Gatherv;
96 
97   ierr = PetscNewLog(sf,&dat);CHKERRQ(ierr);
98   sf->data = (void*)dat;
99   PetscFunctionReturn(0);
100 }
101