xref: /petsc/src/mat/tests/ex11.c (revision 66af8762ec03dbef0e079729eb2a1734a35ed7ff)
1 static char help[] = "Tests the use of MatZeroRows() for uniprocessor matrices.\n\n";
2 
3 #include <petscmat.h>
4 
5 int main(int argc, char **args)
6 {
7   Mat         C;
8   PetscInt    i, j, m = 5, n = 5, Ii, J;
9   PetscScalar v, five = 5.0;
10   IS          isrow;
11   PetscBool   keepnonzeropattern;
12 
13   PetscFunctionBeginUser;
14   PetscCall(PetscInitialize(&argc, &args, (char *)0, help));
15   /* create the matrix for the five point stencil, YET AGAIN*/
16   PetscCall(MatCreate(PETSC_COMM_SELF, &C));
17   PetscCall(MatSetSizes(C, PETSC_DECIDE, PETSC_DECIDE, m * n, m * n));
18   PetscCall(MatSetFromOptions(C));
19   PetscCall(MatSetUp(C));
20   for (i = 0; i < m; i++) {
21     for (j = 0; j < n; j++) {
22       v  = -1.0;
23       Ii = j + n * i;
24       if (i > 0) {
25         J = Ii - n;
26         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
27       }
28       if (i < m - 1) {
29         J = Ii + n;
30         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
31       }
32       if (j > 0) {
33         J = Ii - 1;
34         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
35       }
36       if (j < n - 1) {
37         J = Ii + 1;
38         PetscCall(MatSetValues(C, 1, &Ii, 1, &J, &v, INSERT_VALUES));
39       }
40       v = 4.0;
41       PetscCall(MatSetValues(C, 1, &Ii, 1, &Ii, &v, INSERT_VALUES));
42     }
43   }
44   PetscCall(MatAssemblyBegin(C, MAT_FINAL_ASSEMBLY));
45   PetscCall(MatAssemblyEnd(C, MAT_FINAL_ASSEMBLY));
46 
47   PetscCall(ISCreateStride(PETSC_COMM_SELF, (m * n) / 2, 0, 2, &isrow));
48 
49   PetscCall(PetscOptionsHasName(NULL, NULL, "-keep_nonzero_pattern", &keepnonzeropattern));
50   if (keepnonzeropattern) PetscCall(MatSetOption(C, MAT_KEEP_NONZERO_PATTERN, PETSC_TRUE));
51 
52   PetscCall(MatZeroRowsIS(C, isrow, five, 0, 0));
53 
54   PetscCall(MatView(C, PETSC_VIEWER_STDOUT_SELF));
55 
56   PetscCall(ISDestroy(&isrow));
57   PetscCall(MatDestroy(&C));
58   PetscCall(PetscFinalize());
59   return 0;
60 }
61 
62 /*TEST
63 
64    test:
65 
66    test:
67       suffix: 2
68       args: -mat_type seqbaij -mat_block_size 5
69 
70    test:
71       suffix: 3
72       args: -keep_nonzero_pattern
73 
74    test:
75       suffix: 4
76       args: -keep_nonzero_pattern -mat_type seqbaij -mat_block_size 5
77 
78 TEST*/
79