xref: /petsc/src/mat/tests/ex11.c (revision ebead697dbf761eb322f829370bbe90b3bd93fa3)
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;  Ii = j + n*i;
24       if (i>0)   {J = Ii - n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
25       if (i<m-1) {J = Ii + n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
26       if (j>0)   {J = Ii - 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
27       if (j<n-1) {J = Ii + 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
28       v = 4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
29     }
30   }
31   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
32   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
33 
34   PetscCall(ISCreateStride(PETSC_COMM_SELF,(m*n)/2,0,2,&isrow));
35 
36   PetscCall(PetscOptionsHasName(NULL,NULL,"-keep_nonzero_pattern",&keepnonzeropattern));
37   if (keepnonzeropattern) PetscCall(MatSetOption(C,MAT_KEEP_NONZERO_PATTERN,PETSC_TRUE));
38 
39   PetscCall(MatZeroRowsIS(C,isrow,five,0,0));
40 
41   PetscCall(MatView(C,PETSC_VIEWER_STDOUT_SELF));
42 
43   PetscCall(ISDestroy(&isrow));
44   PetscCall(MatDestroy(&C));
45   PetscCall(PetscFinalize());
46   return 0;
47 }
48 
49 /*TEST
50 
51    test:
52 
53    test:
54       suffix: 2
55       args: -mat_type seqbaij -mat_block_size 5
56 
57    test:
58       suffix: 3
59       args: -keep_nonzero_pattern
60 
61    test:
62       suffix: 4
63       args: -keep_nonzero_pattern -mat_type seqbaij -mat_block_size 5
64 
65 TEST*/
66