Actual source code: ex2.c
1: static char help[] = "Tests vector scatter-gather operations. Input arguments are\n\
2: -n <length> : vector length\n\n";
4: #include <petscvec.h>
6: int main(int argc, char **argv)
7: {
8: PetscInt n = 5, idx1[2] = {0, 3}, idx2[2] = {1, 4};
9: PetscScalar one = 1.0, two = 2.0;
10: Vec x, y;
11: IS is1, is2;
12: VecScatter ctx = 0;
14: PetscFunctionBeginUser;
15: PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
16: PetscCall(PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL));
18: /* create two vector */
19: PetscCall(VecCreateSeq(PETSC_COMM_SELF, n, &x));
20: PetscCall(VecDuplicate(x, &y));
22: /* create two index sets */
23: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, 2, idx1, PETSC_COPY_VALUES, &is1));
24: PetscCall(ISCreateGeneral(PETSC_COMM_SELF, 2, idx2, PETSC_COPY_VALUES, &is2));
26: PetscCall(VecSet(x, one));
27: PetscCall(VecSet(y, two));
28: PetscCall(VecScatterCreate(x, is1, y, is2, &ctx));
29: PetscCall(VecScatterBegin(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD));
30: PetscCall(VecScatterEnd(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD));
32: PetscCall(VecView(y, PETSC_VIEWER_STDOUT_SELF));
34: PetscCall(VecScatterBegin(ctx, y, x, INSERT_VALUES, SCATTER_FORWARD));
35: PetscCall(VecScatterEnd(ctx, y, x, INSERT_VALUES, SCATTER_FORWARD));
36: PetscCall(VecScatterDestroy(&ctx));
38: PetscCall(PetscPrintf(PETSC_COMM_SELF, "-------\n"));
39: PetscCall(VecView(x, PETSC_VIEWER_STDOUT_SELF));
41: PetscCall(ISDestroy(&is1));
42: PetscCall(ISDestroy(&is2));
44: PetscCall(VecDestroy(&x));
45: PetscCall(VecDestroy(&y));
47: PetscCall(PetscFinalize());
48: return 0;
49: }
51: /*TEST
53: test:
55: TEST*/