Actual source code: ex20.c
2: static char help[] = "Tests converting a matrix to another format with MatConvert().\n\n";
4: #include <petscmat.h>
6: int main(int argc, char **args)
7: {
8: Mat C, A;
9: PetscInt i, j, m = 5, n = 4, Ii, J;
10: PetscMPIInt rank, size;
11: PetscScalar v;
12: char mtype[256];
14: PetscFunctionBeginUser;
15: PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
16: PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD, &rank));
18: /* This example does not work correctly for np > 2 */
19: PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD, &size));
20: PetscCheck(size <= 2, PETSC_COMM_WORLD, PETSC_ERR_WRONG_MPI_SIZE, "Use np <= 2");
22: /* Create the matrix for the five point stencil, YET AGAIN */
23: PetscCall(MatCreate(PETSC_COMM_WORLD, &C));
24: PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
25: PetscCall(MatSetFromOptions(C));
26: PetscCall(MatSetUp(C));
27: for (i = 0; i < m; i++) {
28: for (j = 2 * rank; j < 2 * rank + 2; j++) {
29: v = -1.0;
30: Ii = j + n * i;
31: if (i > 0) {
32: J = Ii - n;
33: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
34: }
35: if (i < m - 1) {
36: J = Ii + n;
37: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
38: }
39: if (j > 0) {
40: J = Ii - 1;
41: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
42: }
43: if (j < n - 1) {
44: J = Ii + 1;
45: PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
46: }
47: v = 4.0;
48: PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
49: }
50: }
52: PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
53: PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
54: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
55: PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
56: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
57: PetscCall(MatView(C, PETSC_VIEWER_STDOUT_WORLD));
59: PetscCall(PetscStrncpy(mtype, MATSAME, sizeof(mtype)));
60: PetscCall(PetscOptionsGetString(NULL, NULL, "-conv_mat_type", mtype, sizeof(mtype), NULL));
61: PetscCall(MatConvert(C, mtype, MAT_INITIAL_MATRIX, &A));
62: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_INFO));
63: PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
64: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
65: PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD, PETSC_VIEWER_ASCII_IMPL));
66: PetscCall(MatView(A, PETSC_VIEWER_STDOUT_WORLD));
67: PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
69: /* Free data structures */
70: PetscCall(MatDestroy(&A));
71: PetscCall(MatDestroy(&C));
73: PetscCall(PetscFinalize());
74: return 0;
75: }
77: /*TEST
79: test:
80: args: -conv_mat_type seqaij
82: TEST*/