xref: /petsc/src/mat/tests/ex11.c (revision df4cd43f92eaa320656440c40edb1046daee8f75)
1 
2 static char help[] = "Tests the use of MatZeroRows() for uniprocessor matrices.\n\n";
3 
4 #include <petscmat.h>
5 
6 int main(int argc, char **args)
7 {
8   Mat         C;
9   PetscInt    i, j, m = 5, n = 5, Ii, J;
10   PetscScalar v, five = 5.0;
11   IS          isrow;
12   PetscBool   keepnonzeropattern;
13 
14   PetscFunctionBeginUser;
15   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
16   /* create the matrix for the five point stencil, YET AGAIN*/
17   PetscCall(MatCreate(PETSC_COMM_SELF, &C));
18   PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
19   PetscCall(MatSetFromOptions(C));
20   PetscCall(MatSetUp(C));
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         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
28       }
29       if (i < m - 1) {
30         J = Ii + n;
31         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
32       }
33       if (j > 0) {
34         J = Ii - 1;
35         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
36       }
37       if (j < n - 1) {
38         J = Ii + 1;
39         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
40       }
41       v = 4.0;
42       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
43     }
44   }
45   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
46   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
47 
48   PetscCall(ISCreateStride(PETSC_COMM_SELF, (m * n) / 2, 0, 2, &isrow));
49 
50   PetscCall(PetscOptionsHasName(NULL, NULL, "-keep_nonzero_pattern", &keepnonzeropattern));
51   if (keepnonzeropattern) PetscCall(MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE));
52 
53   PetscCall(MatZeroRowsIS(C, isrow, five, 0, 0));
54 
55   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_SELF));
56 
57   PetscCall(ISDestroy(&isrow));
58   PetscCall(MatDestroy(&C));
59   PetscCall(PetscFinalize());
60   return 0;
61 }
62 
63 /*TEST
64 
65    test:
66 
67    test:
68       suffix: 2
69       args: -mat_type seqbaij -mat_block_size 5
70 
71    test:
72       suffix: 3
73       args: -keep_nonzero_pattern
74 
75    test:
76       suffix: 4
77       args: -keep_nonzero_pattern -mat_type seqbaij -mat_block_size 5
78 
79 TEST*/
80