1 static char help[] = "Scatters from a sequential vector to a parallel vector. \n\
2 uses block index sets\n\n";
3
4 #include <petscvec.h>
5
main(int argc,char ** argv)6 int main(int argc, char **argv)
7 {
8 PetscInt bs = 1, n = 5, i, low;
9 PetscInt ix0[3] = {5, 7, 9}, iy0[3] = {1, 2, 4}, ix1[3] = {2, 3, 4}, iy1[3] = {0, 1, 3};
10 PetscMPIInt size, rank;
11 PetscScalar *array;
12 Vec x, y;
13 IS isx, isy;
14 VecScatter ctx;
15 PetscViewer sviewer;
16
17 PetscFunctionBeginUser;
18 PetscCall(PetscInitialize(&argc, &argv, NULL, help));
19 PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
20 PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
21
22 PetscCheck(size >= 2, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Must run more than one processor");
23
24 PetscCall(PetscOptionsGetInt(NULL, NULL, "-bs", &bs, NULL));
25 n = bs * n;
26
27 /* Create vector x over shared memory */
28 PetscCall(VecCreate(PETSC_COMM_WORLD, &x));
29 PetscCall(VecSetSizes(x, n, PETSC_DECIDE));
30 PetscCall(VecSetFromOptions(x));
31
32 PetscCall(VecGetOwnershipRange(x, &low, NULL));
33 PetscCall(VecGetArray(x, &array));
34 for (i = 0; i < n; i++) array[i] = (PetscScalar)(i + low);
35 PetscCall(VecRestoreArray(x, &array));
36
37 /* Create a sequential vector y */
38 PetscCall(VecCreateSeq(PETSC_COMM_SELF, n, &y));
39 PetscCall(VecGetArray(y, &array));
40 for (i = 0; i < n; i++) array[i] = (PetscScalar)(i + 100 * rank);
41 PetscCall(VecRestoreArray(y, &array));
42
43 /* Create two index sets */
44 if (rank == 0) {
45 PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, 3, ix0, PETSC_COPY_VALUES, &isx));
46 PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, 3, iy0, PETSC_COPY_VALUES, &isy));
47 } else {
48 PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, 3, ix1, PETSC_COPY_VALUES, &isx));
49 PetscCall(ISCreateBlock(PETSC_COMM_SELF, bs, 3, iy1, PETSC_COPY_VALUES, &isy));
50 }
51
52 if (rank == 10) {
53 PetscCall(PetscPrintf(PETSC_COMM_SELF, "\n[%d] isx:\n", rank));
54 PetscCall(ISView(isx, PETSC_VIEWER_STDOUT_SELF));
55 }
56
57 PetscCall(VecScatterCreate(y, isy, x, isx, &ctx));
58 PetscCall(VecScatterSetFromOptions(ctx));
59
60 /* Test forward vecscatter */
61 PetscCall(VecSet(x, 0.0));
62 PetscCall(VecScatterBegin(ctx, y, x, ADD_VALUES, SCATTER_FORWARD));
63 PetscCall(VecScatterEnd(ctx, y, x, ADD_VALUES, SCATTER_FORWARD));
64 PetscCall(VecView(x, PETSC_VIEWER_STDOUT_WORLD));
65
66 /* Test reverse vecscatter */
67 PetscCall(VecScale(x, -1.0));
68 PetscCall(VecScatterBegin(ctx, x, y, ADD_VALUES, SCATTER_REVERSE));
69 PetscCall(VecScatterEnd(ctx, x, y, ADD_VALUES, SCATTER_REVERSE));
70 PetscCall(PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
71 if (rank == 1) PetscCall(VecView(y, sviewer));
72 PetscCall(PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer));
73
74 /* Free spaces */
75 PetscCall(VecScatterDestroy(&ctx));
76 PetscCall(ISDestroy(&isx));
77 PetscCall(ISDestroy(&isy));
78 PetscCall(VecDestroy(&x));
79 PetscCall(VecDestroy(&y));
80 PetscCall(PetscFinalize());
81 return 0;
82 }
83
84 /*TEST
85
86 test:
87 nsize: 3
88
89 TEST*/
90