Actual source code: ex3.c
2: static char help[] = "Demonstrates creating a blocked index set.\n\n";
4: #include <petscis.h>
5: #include <petscviewer.h>
7: int main(int argc, char **argv)
8: {
9: PetscInt i, n = 4, inputindices[] = {0, 1, 3, 4}, bs = 3, issize;
10: const PetscInt *indices;
11: IS set;
12: PetscBool isblock;
15: PetscInitialize(&argc, &argv, (char *)0, help);
17: /*
18: Create a block index set. The index set has 4 blocks each of size 3.
19: The indices are {0,1,2,3,4,5,9,10,11,12,13,14}
20: Note each processor is generating its own index set
21: (in this case they are all identical)
22: */
23: ISCreateBlock(PETSC_COMM_SELF, bs, n, inputindices, PETSC_COPY_VALUES, &set);
24: ISView(set, PETSC_VIEWER_STDOUT_SELF);
26: /*
27: Extract indices from set.
28: */
29: ISGetLocalSize(set, &issize);
30: ISGetIndices(set, &indices);
31: PetscPrintf(PETSC_COMM_SELF, "Printing indices directly\n");
32: for (i = 0; i < issize; i++) PetscPrintf(PETSC_COMM_SELF, "%" PetscInt_FMT "\n", indices[i]);
33: ISRestoreIndices(set, &indices);
35: /*
36: Extract the block indices. This returns one index per block.
37: */
38: ISBlockGetIndices(set, &indices);
39: PetscPrintf(PETSC_COMM_SELF, "Printing block indices directly\n");
40: for (i = 0; i < n; i++) PetscPrintf(PETSC_COMM_SELF, "%" PetscInt_FMT "\n", indices[i]);
41: ISBlockRestoreIndices(set, &indices);
43: /*
44: Check if this is really a block index set
45: */
46: PetscObjectTypeCompare((PetscObject)set, ISBLOCK, &isblock);
49: /*
50: Determine the block size of the index set
51: */
52: ISGetBlockSize(set, &bs);
55: /*
56: Get the number of blocks
57: */
58: ISBlockGetLocalSize(set, &n);
61: ISDestroy(&set);
62: PetscFinalize();
63: return 0;
64: }
66: /*TEST
68: test:
70: TEST*/