Actual source code: ex4.c
2: static char help[] = "Demonstrates using ISLocalToGlobalMappings.\n\n";
4: #include <petscis.h>
5: #include <petscviewer.h>
7: int main(int argc, char **argv)
8: {
9: PetscInt i, n = 4, indices[] = {0, 3, 9, 12}, m = 2, input[] = {0, 2};
10: PetscInt output[2], inglobals[13], outlocals[13];
11: ISLocalToGlobalMapping mapping;
13: PetscFunctionBeginUser;
14: PetscCall(PetscInitialize(&argc, &argv, (char *)0, help));
16: /*
17: Create a local to global mapping. Each processor independently
18: creates a mapping
19: */
20: PetscCall(ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD, 1, n, indices, PETSC_COPY_VALUES, &mapping));
21: PetscCall(ISLocalToGlobalMappingSetFromOptions(mapping));
23: /*
24: Map a set of local indices to their global values
25: */
26: PetscCall(ISLocalToGlobalMappingApply(mapping, m, input, output));
27: PetscCall(PetscIntView(m, output, PETSC_VIEWER_STDOUT_WORLD));
29: /*
30: Map some global indices to local, retaining the ones without a local index by -1
31: */
32: for (i = 0; i < 13; i++) inglobals[i] = i;
33: PetscCall(ISGlobalToLocalMappingApply(mapping, IS_GTOLM_MASK, 13, inglobals, NULL, outlocals));
34: PetscCall(PetscIntView(13, outlocals, PETSC_VIEWER_STDOUT_WORLD));
36: /*
37: Map some global indices to local, dropping the ones without a local index.
38: */
39: PetscCall(ISGlobalToLocalMappingApply(mapping, IS_GTOLM_DROP, 13, inglobals, &m, outlocals));
40: PetscCall(PetscIntView(m, outlocals, PETSC_VIEWER_STDOUT_WORLD));
42: PetscCall(ISLocalToGlobalMappingView(mapping, PETSC_VIEWER_STDOUT_WORLD));
43: /*
44: Free the space used by the local to global mapping
45: */
46: PetscCall(ISLocalToGlobalMappingDestroy(&mapping));
48: PetscCall(PetscFinalize());
49: return 0;
50: }
52: /*TEST
54: test:
56: test:
57: suffix: 2
58: args: -islocaltoglobalmapping_type hash
60: TEST*/