xref: /petsc/src/mat/tests/ex13.c (revision 6ffe77eaecce1557e50d00ca5347a7f48e598865)
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   PetscCall(PetscInitialize(&argc,&args,(char*)0,help));
14   PetscCall(MatCreateSeqAIJ(PETSC_COMM_SELF,m*n,m*n,5,NULL,&C));
15   /* create the matrix for the five point stencil, YET AGAIN*/
16   for (i=0; i<m; i++) {
17     for (j=0; j<n; j++) {
18       v = -1.0;  Ii = j + n*i;
19       if (i>0)   {J = Ii - n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
20       if (i<m-1) {J = Ii + n; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
21       if (j>0)   {J = Ii - 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
22       if (j<n-1) {J = Ii + 1; PetscCall(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
23       v = 4.0; PetscCall(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
24     }
25   }
26   PetscCall(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
27   PetscCall(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
28 
29   PetscCall(MatConvert(C,MATSAME,MAT_INITIAL_MATRIX,&A));
30 
31   PetscCall(MatGetOrdering(A,MATORDERINGND,&perm,&iperm));
32   PetscCall(ISView(perm,PETSC_VIEWER_STDOUT_SELF));
33   PetscCall(ISView(iperm,PETSC_VIEWER_STDOUT_SELF));
34   PetscCall(MatView(A,PETSC_VIEWER_STDOUT_SELF));
35 
36   PetscCall(ISDestroy(&perm));
37   PetscCall(ISDestroy(&iperm));
38   PetscCall(MatDestroy(&C));
39   PetscCall(MatDestroy(&A));
40   PetscCall(PetscFinalize());
41   return 0;
42 }
43 
44 /*TEST
45 
46    test:
47       filter: grep -v " MPI process"
48 
49 TEST*/
50