xref: /petsc/src/mat/tests/ex6.c (revision 5f80ce2ab25dff0f4601e710601cbbcecf323266)
1c4762a1bSJed Brown 
2c4762a1bSJed Brown static char help[] = "Tests reordering a matrix.\n\n";
3c4762a1bSJed Brown 
4c4762a1bSJed Brown #include <petscmat.h>
5c4762a1bSJed Brown 
6c4762a1bSJed Brown int main(int argc,char **args)
7c4762a1bSJed Brown {
8c4762a1bSJed Brown   Mat            C;
9c4762a1bSJed Brown   PetscInt       i,j,m = 5,n = 5,Ii,J;
10c4762a1bSJed Brown   PetscErrorCode ierr;
11c4762a1bSJed Brown   PetscScalar    v;
12c4762a1bSJed Brown   IS             perm,iperm;
13c4762a1bSJed Brown 
14c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&args,(char*)0,help);if (ierr) return ierr;
15*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatCreate(PETSC_COMM_SELF,&C));
16*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n));
17*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetFromOptions(C));
18*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatSetUp(C));
19c4762a1bSJed Brown 
20c4762a1bSJed Brown   /* create the matrix for the five point stencil, YET AGAIN*/
21c4762a1bSJed Brown   for (i=0; i<m; i++) {
22c4762a1bSJed Brown     for (j=0; j<n; j++) {
23c4762a1bSJed Brown       v = -1.0;  Ii = j + n*i;
24*5f80ce2aSJacob Faibussowitsch       if (i>0)   {J = Ii - n; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
25*5f80ce2aSJacob Faibussowitsch       if (i<m-1) {J = Ii + n; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
26*5f80ce2aSJacob Faibussowitsch       if (j>0)   {J = Ii - 1; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
27*5f80ce2aSJacob Faibussowitsch       if (j<n-1) {J = Ii + 1; CHKERRQ(MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES));}
28*5f80ce2aSJacob Faibussowitsch       v = 4.0; CHKERRQ(MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES));
29c4762a1bSJed Brown     }
30c4762a1bSJed Brown   }
31*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY));
32*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY));
33c4762a1bSJed Brown 
34*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatGetOrdering(C,MATORDERINGND,&perm,&iperm));
35*5f80ce2aSJacob Faibussowitsch   CHKERRQ(ISView(perm,PETSC_VIEWER_STDOUT_SELF));
36*5f80ce2aSJacob Faibussowitsch   CHKERRQ(ISView(iperm,PETSC_VIEWER_STDOUT_SELF));
37*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatView(C,PETSC_VIEWER_STDOUT_SELF));
38c4762a1bSJed Brown 
39*5f80ce2aSJacob Faibussowitsch   CHKERRQ(ISDestroy(&perm));
40*5f80ce2aSJacob Faibussowitsch   CHKERRQ(ISDestroy(&iperm));
41*5f80ce2aSJacob Faibussowitsch   CHKERRQ(MatDestroy(&C));
42c4762a1bSJed Brown   ierr = PetscFinalize();
43c4762a1bSJed Brown   return ierr;
44c4762a1bSJed Brown }
45c4762a1bSJed Brown 
46c4762a1bSJed Brown /*TEST
47c4762a1bSJed Brown 
48c4762a1bSJed Brown    test:
49c4762a1bSJed Brown 
50c4762a1bSJed Brown TEST*/
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