Actual source code: ex6.c
2: static char help[] = "Tests reordering a matrix.\n\n";
4: #include <petscmat.h>
6: int main(int argc, char **args)
7: {
8: Mat C;
9: PetscInt i, j, m = 5, n = 5, Ii, J;
10: PetscScalar v;
11: IS perm, iperm;
14: PetscInitialize(&argc, &args, (char *)0, help);
15: MatCreate(PETSC_COMM_SELF, &C);
16: MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n);
17: MatSetFromOptions(C);
18: MatSetUp(C);
20: /* create the matrix for the five point stencil, YET AGAIN*/
21: for (i = 0; i < m; i++) {
22: for (j = 0; j < n; j++) {
23: v = -1.0;
24: Ii = j + n * i;
25: if (i > 0) {
26: J = Ii - n;
27: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
28: }
29: if (i < m - 1) {
30: J = Ii + n;
31: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
32: }
33: if (j > 0) {
34: J = Ii - 1;
35: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
36: }
37: if (j < n - 1) {
38: J = Ii + 1;
39: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
40: }
41: v = 4.0;
42: MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES);
43: }
44: }
45: MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY);
46: MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY);
48: MatGetOrdering(C, MATORDERINGND, &perm, &iperm);
49: ISView(perm, PETSC_VIEWER_STDOUT_SELF);
50: ISView(iperm, PETSC_VIEWER_STDOUT_SELF);
51: MatView(C, PETSC_VIEWER_STDOUT_SELF);
53: ISDestroy(&perm);
54: ISDestroy(&iperm);
55: MatDestroy(&C);
56: PetscFinalize();
57: return 0;
58: }
60: /*TEST
62: test:
64: TEST*/