xref: /petsc/src/vec/is/sf/tests/ex17.c (revision ebead697dbf761eb322f829370bbe90b3bd93fa3)
1 static const char help[] = "Test PetscSF with MPI large count (more than 2 billion elements in messages)\n\n";
2 
3 #include <petscsys.h>
4 #include <petscsf.h>
5 
6 int main(int argc,char **argv)
7 {
8   PetscSF           sf;
9   PetscInt          i,nroots,nleaves;
10   PetscInt          n = (1ULL<<31) + 1024; /* a little over 2G elements */
11   PetscSFNode       *iremote = NULL;
12   PetscMPIInt       rank,size;
13   char              *rootdata=NULL,*leafdata=NULL;
14   Vec               x,y;
15   VecScatter        vscat;
16   PetscInt          rstart,rend;
17   IS                ix;
18   const PetscScalar *xv;
19 
20   PetscFunctionBeginUser;
21   PetscCall(PetscInitialize(&argc,&argv,NULL,help));
22   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
23   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
24   PetscCheck(size == 2,PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"The test can only run with two MPI ranks");
25 
26   /* Test PetscSF */
27   PetscCall(PetscSFCreate(PETSC_COMM_WORLD,&sf));
28   PetscCall(PetscSFSetFromOptions(sf));
29 
30   if (rank == 0) {
31     nroots  = n;
32     nleaves = 0;
33   } else {
34     nroots  = 0;
35     nleaves = n;
36     PetscCall(PetscMalloc1(nleaves,&iremote));
37     for (i=0; i<nleaves; i++) {
38       iremote[i].rank  = 0;
39       iremote[i].index = i;
40     }
41   }
42   PetscCall(PetscSFSetGraph(sf,nroots,nleaves,NULL,PETSC_COPY_VALUES,iremote,PETSC_COPY_VALUES));
43   PetscCall(PetscMalloc2(nroots,&rootdata,nleaves,&leafdata));
44   if (rank == 0) {
45     memset(rootdata,11,nroots);
46     rootdata[nroots-1] = 12; /* Use a different value at the end */
47   }
48 
49   PetscCall(PetscSFBcastBegin(sf,MPI_SIGNED_CHAR,rootdata,leafdata,MPI_REPLACE)); /* rank 0->1, bcast rootdata to leafdata */
50   PetscCall(PetscSFBcastEnd(sf,MPI_SIGNED_CHAR,rootdata,leafdata,MPI_REPLACE));
51   PetscCall(PetscSFReduceBegin(sf,MPI_SIGNED_CHAR,leafdata,rootdata,MPI_SUM)); /* rank 1->0, add leafdata to rootdata */
52   PetscCall(PetscSFReduceEnd(sf,MPI_SIGNED_CHAR,leafdata,rootdata,MPI_SUM));
53   PetscCheck(rank != 0 || (rootdata[0] == 22 && rootdata[nroots-1] == 24),PETSC_COMM_SELF,PETSC_ERR_PLIB,"SF: wrong results");
54 
55   PetscCall(PetscFree2(rootdata,leafdata));
56   PetscCall(PetscFree(iremote));
57   PetscCall(PetscSFDestroy(&sf));
58 
59   /* Test VecScatter */
60   PetscCall(VecCreate(PETSC_COMM_WORLD,&x));
61   PetscCall(VecCreate(PETSC_COMM_WORLD,&y));
62   PetscCall(VecSetSizes(x,rank==0? n : 64,PETSC_DECIDE));
63   PetscCall(VecSetSizes(y,rank==0? 64 : n,PETSC_DECIDE));
64   PetscCall(VecSetFromOptions(x));
65   PetscCall(VecSetFromOptions(y));
66 
67   PetscCall(VecGetOwnershipRange(x,&rstart,&rend));
68   PetscCall(ISCreateStride(PETSC_COMM_SELF,rend-rstart,rstart,1,&ix));
69   PetscCall(VecScatterCreate(x,ix,y,ix,&vscat));
70 
71   PetscCall(VecSet(x,3.0));
72   PetscCall(VecScatterBegin(vscat,x,y,INSERT_VALUES,SCATTER_FORWARD));
73   PetscCall(VecScatterEnd(vscat,x,y,INSERT_VALUES,SCATTER_FORWARD));
74 
75   PetscCall(VecScatterBegin(vscat,y,x,ADD_VALUES,SCATTER_REVERSE));
76   PetscCall(VecScatterEnd(vscat,y,x,ADD_VALUES,SCATTER_REVERSE));
77 
78   PetscCall(VecGetArrayRead(x,&xv));
79   PetscCheck(xv[0] == 6.0,PETSC_COMM_SELF,PETSC_ERR_PLIB,"VecScatter: wrong results");
80   PetscCall(VecRestoreArrayRead(x,&xv));
81   PetscCall(VecDestroy(&x));
82   PetscCall(VecDestroy(&y));
83   PetscCall(VecScatterDestroy(&vscat));
84   PetscCall(ISDestroy(&ix));
85 
86   PetscCall(PetscFinalize());
87   return 0;
88 }
89 
90 /**TEST
91    test:
92      requires: defined(PETSC_HAVE_MPI_LARGE_COUNT) defined(PETSC_USE_64BIT_INDICES)
93      TODO: need a machine with big memory (~150GB) to run the test
94      nsize: 2
95      args: -sf_type {{basic neighbor}}
96 
97 TEST**/
98