Actual source code: ex24.c
2: static char help[] = "Scatters from a parallel vector to a sequential vector.\n\
3: Tests where the local part of the scatter is a copy.\n\n";
5: #include <petscvec.h>
7: int main(int argc, char **argv)
8: {
9: PetscMPIInt size, rank;
10: PetscInt n = 5, i, *blks, bs = 1, m = 2;
11: PetscScalar value;
12: Vec x, y;
13: IS is1, is2;
14: VecScatter ctx = 0;
15: PetscViewer sviewer;
18: PetscInitialize(&argc, &argv, (char *)0, help);
20: PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL);
21: PetscOptionsGetInt(NULL, NULL, "-bs", &bs, NULL);
23: MPI_Comm_size(PETSC_COMM_WORLD, &size);
24: MPI_Comm_rank(PETSC_COMM_WORLD, &rank);
26: /* create two vectors */
27: VecCreate(PETSC_COMM_WORLD, &x);
28: VecSetSizes(x, PETSC_DECIDE, size * bs * n);
29: VecSetFromOptions(x);
31: /* create two index sets */
32: if (rank < size - 1) m = n + 2;
33: else m = n;
35: PetscMalloc1(m, &blks);
36: blks[0] = n * rank;
37: for (i = 1; i < m; i++) blks[i] = blks[i - 1] + 1;
38: ISCreateBlock(PETSC_COMM_SELF, bs, m, blks, PETSC_COPY_VALUES, &is1);
39: PetscFree(blks);
41: VecCreateSeq(PETSC_COMM_SELF, bs * m, &y);
42: ISCreateStride(PETSC_COMM_SELF, bs * m, 0, 1, &is2);
44: /* each processor inserts the entire vector */
45: /* this is redundant but tests assembly */
46: for (i = 0; i < bs * n * size; i++) {
47: value = (PetscScalar)i;
48: VecSetValues(x, 1, &i, &value, INSERT_VALUES);
49: }
50: VecAssemblyBegin(x);
51: VecAssemblyEnd(x);
52: VecView(x, PETSC_VIEWER_STDOUT_WORLD);
54: VecScatterCreate(x, is1, y, is2, &ctx);
55: VecScatterBegin(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD);
56: VecScatterEnd(ctx, x, y, INSERT_VALUES, SCATTER_FORWARD);
58: PetscViewerASCIIPushSynchronized(PETSC_VIEWER_STDOUT_WORLD);
59: PetscViewerASCIISynchronizedPrintf(PETSC_VIEWER_STDOUT_WORLD, "----\n");
60: PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
61: VecView(y, sviewer);
62: fflush(stdout);
63: PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD, PETSC_COMM_SELF, &sviewer);
64: PetscViewerFlush(PETSC_VIEWER_STDOUT_WORLD);
65: PetscViewerASCIIPopSynchronized(PETSC_VIEWER_STDOUT_WORLD);
67: VecScatterDestroy(&ctx);
69: VecDestroy(&x);
70: VecDestroy(&y);
71: ISDestroy(&is1);
72: ISDestroy(&is2);
74: PetscFinalize();
75: return 0;
76: }
78: /*TEST
80: testset:
81: nsize: 3
82: output_file: output/ex24_1.out
83: filter: grep -v " type:"
84: test:
85: suffix: standard
86: args: -vec_type standard
87: test:
88: requires: cuda
89: suffix: cuda
90: args: -vec_type cuda
91: test:
92: requires: viennacl
93: suffix: viennacl
94: args: -vec_type viennacl
96: TEST*/