xref: /petsc/src/mat/tests/ex13.c (revision d5b43468fb8780a8feea140ccd6fa3e6a50411cc)
1 
2 static char help[] = "Tests copying and ordering uniprocessor row-based sparse matrices.\n\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc, char **args)
7 {
8   Mat         C, A;
9   PetscInt    i, j, m = 5, n = 5, Ii, J;
10   PetscScalar v;
11   IS          perm, iperm;
12 
13   PetscFunctionBeginUser;
14   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
15   PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF, m * n, m * n, 5, NULL, &C));
16   /* create the matrix for the five point stencil, YET AGAIN*/
17   for (i = 0; i < m; i++) {
18     for (j = 0; j < n; j++) {
19       v  = -1.0;
20       Ii = j + n * i;
21       if (i > 0) {
22         J = Ii - n;
23         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
24       }
25       if (i < m - 1) {
26         J = Ii + n;
27         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
28       }
29       if (j > 0) {
30         J = Ii - 1;
31         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
32       }
33       if (j < n - 1) {
34         J = Ii + 1;
35         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
36       }
37       v = 4.0;
38       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
39     }
40   }
41   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
42   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
43 
44   PetscCall(MatConvert(C, MATSAME, MAT_INITIAL_MATRIX, &A));
45 
46   PetscCall(MatGetOrdering(A, MATORDERINGND, &perm, &iperm));
47   PetscCall(ISView(perm, PETSC_VIEWER_STDOUT_SELF));
48   PetscCall(ISView(iperm, PETSC_VIEWER_STDOUT_SELF));
49   PetscCall(MatView(A, PETSC_VIEWER_STDOUT_SELF));
50 
51   PetscCall(ISDestroy(&perm));
52   PetscCall(ISDestroy(&iperm));
53   PetscCall(MatDestroy(&C));
54   PetscCall(MatDestroy(&A));
55   PetscCall(PetscFinalize());
56   return 0;
57 }
58 
59 /*TEST
60 
61    test:
62       filter: grep -v " MPI process"
63 
64 TEST*/
65