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;

 14:   PetscInitialize(&argc, &argv, (char *)0, help);

 16:   /*
 17:       Create a local to global mapping. Each processor independently
 18:      creates a mapping
 19:   */
 20:   ISLocalToGlobalMappingCreate(PETSC_COMM_WORLD, 1, n, indices, PETSC_COPY_VALUES, &mapping);
 21:   ISLocalToGlobalMappingSetFromOptions(mapping);

 23:   /*
 24:      Map a set of local indices to their global values
 25:   */
 26:   ISLocalToGlobalMappingApply(mapping, m, input, output);
 27:   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:   ISGlobalToLocalMappingApply(mapping, IS_GTOLM_MASK, 13, inglobals, NULL, outlocals);
 34:   PetscIntView(13, outlocals, PETSC_VIEWER_STDOUT_WORLD);

 36:   /*
 37:      Map some global indices to local, dropping the ones without a local index.
 38:   */
 39:   ISGlobalToLocalMappingApply(mapping, IS_GTOLM_DROP, 13, inglobals, &m, outlocals);
 40:   PetscIntView(m, outlocals, PETSC_VIEWER_STDOUT_WORLD);

 42:   ISLocalToGlobalMappingView(mapping, PETSC_VIEWER_STDOUT_WORLD);
 43:   /*
 44:      Free the space used by the local to global mapping
 45:   */
 46:   ISLocalToGlobalMappingDestroy(&mapping);

 48:   PetscFinalize();
 49:   return 0;
 50: }

 52: /*TEST

 54:    test:

 56:    test:
 57:       suffix: 2
 58:       args: -islocaltoglobalmapping_type hash

 60: TEST*/