Actual source code: ex4.c
1: static char help[] = "Demonstrates using ISLocalToGlobalMappings.\n\n";
3: #include <petscis.h>
4: #include <petscviewer.h>
6: int main(int argc, char **argv)
7: {
8: PetscInt i, n = 4, indices[] = {0, 3, 9, 12}, m = 2, input[] = {0, 2};
9: PetscInt output[2], inglobals[13], outlocals[13];
10: ISLocalToGlobalMapping mapping;
12: PetscFunctionBeginUser;
13: PetscCall(PetscInitialize(&argc, &argv, NULL, help));
15: /*
16: Create a local to global mapping. Each processor independently
17: creates a mapping
18: */
19: PetscCall(ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD, 1, n, indices, PETSC_COPY_VALUES, &mapping));
20: PetscCall(ISLocalToGlobalMappingSetFromOptions(mapping));
22: /*
23: Map a set of local indices to their global values
24: */
25: PetscCall(ISLocalToGlobalMappingApply(mapping, m, input, output));
26: PetscCall(PetscIntView(m, output, PETSC_VIEWER_STDOUT_WORLD));
28: /*
29: Map some global indices to local, retaining the ones without a local index by -1
30: */
31: for (i = 0; i < 13; i++) inglobals[i] = i;
32: PetscCall(ISGlobalToLocalMappingApply(mapping, IS_GTOLM_MASK, 13, inglobals, NULL, outlocals));
33: PetscCall(PetscIntView(13, outlocals, PETSC_VIEWER_STDOUT_WORLD));
35: /*
36: Map some global indices to local, dropping the ones without a local index.
37: */
38: PetscCall(ISGlobalToLocalMappingApply(mapping, IS_GTOLM_DROP, 13, inglobals, &m, outlocals));
39: PetscCall(PetscIntView(m, outlocals, PETSC_VIEWER_STDOUT_WORLD));
41: PetscCall(ISLocalToGlobalMappingView(mapping, PETSC_VIEWER_STDOUT_WORLD));
42: /*
43: Free the space used by the local to global mapping
44: */
45: PetscCall(ISLocalToGlobalMappingDestroy(&mapping));
47: PetscCall(PetscFinalize());
48: return 0;
49: }
51: /*TEST
53: test:
55: test:
56: suffix: 2
57: args: -islocaltoglobalmapping_type hash
59: TEST*/