xref: /petsc/src/mat/tests/ex11.c (revision 40badf4fbc550ac1f60bd080eaff6de6d55b946d)
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   PetscErrorCode ierr;
11   PetscScalar    v,five = 5.0;
12   IS             isrow;
13   PetscBool      keepnonzeropattern;
14 
15   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
16   /* create the matrix for the five point stencil, YET AGAIN*/
17   CHKERRQ(MatCreate(PETSC_COMM_SELF,&C));
18   CHKERRQ(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
19   CHKERRQ(MatSetFromOptions(C));
20   CHKERRQ(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; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
25       if (i<m-1) {J = Ii + n; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
26       if (j>0)   {J = Ii - 1; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
27       if (j<n-1) {J = Ii + 1; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
28       v = 4.0; CHKERRQ(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
29     }
30   }
31   CHKERRQ(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
32   CHKERRQ(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
33 
34   CHKERRQ(ISCreateStride(PETSC_COMM_SELF,(m*n)/2,0,2,&isrow));
35 
36   CHKERRQ(PetscOptionsHasName(NULL,NULL,"-keep_nonzero_pattern",&keepnonzeropattern));
37   if (keepnonzeropattern) {
38     CHKERRQ(MatSetOption(C,MAT_KEEP_NONZERO_PATTERN,PETSC_TRUE));
39   }
40 
41   CHKERRQ(MatZeroRowsIS(C,isrow,five,0,0));
42 
43   CHKERRQ(MatView(C,PETSC_VIEWER_STDOUT_SELF));
44 
45   CHKERRQ(ISDestroy(&isrow));
46   CHKERRQ(MatDestroy(&C));
47   ierr = PetscFinalize();
48   return ierr;
49 }
50 
51 /*TEST
52 
53    test:
54 
55    test:
56       suffix: 2
57       args: -mat_type seqbaij -mat_block_size 5
58 
59    test:
60       suffix: 3
61       args: -keep_nonzero_pattern
62 
63    test:
64       suffix: 4
65       args: -keep_nonzero_pattern -mat_type seqbaij -mat_block_size 5
66 
67 TEST*/
68