Actual source code: ex8.c
2: static char help[] = "Tests automatic allocation of matrix storage space.\n\n";
4: #include <petscmat.h>
6: int main(int argc, char **args)
7: {
8: Mat C;
9: PetscInt i, j, m = 3, n = 3, Ii, J;
10: PetscScalar v;
11: MatInfo info;
14: PetscInitialize(&argc, &args, (char *)0, help);
15: PetscOptionsGetInt(NULL, NULL, "-m", &m, NULL);
16: PetscOptionsGetInt(NULL, NULL, "-n", &n, NULL);
18: /* create the matrix for the five point stencil, YET AGAIN */
19: MatCreate(PETSC_COMM_SELF, &C);
20: MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n);
21: MatSetFromOptions(C);
22: MatSetUp(C);
23: for (i = 0; i < m; i++) {
24: for (j = 0; j < n; j++) {
25: v = -1.0;
26: Ii = j + n * i;
27: if (i > 0) {
28: J = Ii - n;
29: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
30: }
31: if (i < m - 1) {
32: J = Ii + n;
33: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
34: }
35: if (j > 0) {
36: J = Ii - 1;
37: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
38: }
39: if (j < n - 1) {
40: J = Ii + 1;
41: MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES);
42: }
43: v = 4.0;
44: MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES);
45: }
46: }
47: MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY);
48: MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY);
49: MatView(C, PETSC_VIEWER_STDOUT_SELF);
51: MatGetInfo(C, MAT_LOCAL, &info);
52: PetscPrintf(PETSC_COMM_SELF, "matrix nonzeros = %" PetscInt_FMT ", allocated nonzeros = %" PetscInt_FMT "\n", (PetscInt)info.nz_used, (PetscInt)info.nz_allocated);
54: MatDestroy(&C);
55: PetscFinalize();
56: return 0;
57: }
59: /*TEST
61: test:
63: TEST*/