Actual source code: ex20.c
1: static char help[] = "Tests converting a matrix to another format with MatConvert().\n\n";
3: #include <petscmat.h>
5: int main(int argc, char **args)
6: {
7: Mat C, A;
8: PetscInt i, j, m = 5, n = 4, Ii, J;
9: PetscMPIInt rank, size;
10: PetscScalar v;
11: char mtype[256];
13: PetscFunctionBeginUser;
14: PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
15: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
17: /* This example does not work correctly for np > 2 */
18: PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
19: PetscCheck(size <= 2, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Use np <= 2");
21: /* Create the matrix for the five point stencil, YET AGAIN */
22: PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
23: PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
24: PetscCall(MatSetFromOptions(C));
25: PetscCall(MatSetUp(C));
26: for (i = 0; i < m; i++) {
27: for (j = 2 * rank; j < 2 * rank + 2; j++) {
28: v = -1.0;
29: Ii = j + n * i;
30: if (i > 0) {
31: J = Ii - n;
32: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
33: }
34: if (i < m - 1) {
35: J = Ii + n;
36: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
37: }
38: if (j > 0) {
39: J = Ii - 1;
40: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
41: }
42: if (j < n - 1) {
43: J = Ii + 1;
44: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
45: }
46: v = 4.0;
47: PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
48: }
49: }
51: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
52: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
53: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
54: PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
55: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
56: PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
58: PetscCall(PetscStrncpy(mtype, MATSAME, sizeof(mtype)));
59: PetscCall(PetscOptionsGetString(NULL, NULL, "-conv_mat_type", mtype, sizeof(mtype), NULL));
60: PetscCall(MatConvert(C, mtype, MAT_INITIAL_MATRIX, &A));
61: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
62: PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
63: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
64: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_IMPL));
65: PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
66: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
68: /* Free data structures */
69: PetscCall(MatDestroy(&A));
70: PetscCall(MatDestroy(&C));
72: PetscCall(PetscFinalize());
73: return 0;
74: }
76: /*TEST
78: test:
79: args: -conv_mat_type seqaij
81: TEST*/