Actual source code: ex6.c


  2: static char help[] = "Tests reordering a matrix.\n\n";

  4: #include <petscmat.h>

  6: int main(int argc,char **args)
  7: {
  8:   Mat            C;
  9:   PetscInt       i,j,m = 5,n = 5,Ii,J;
 10:   PetscScalar    v;
 11:   IS             perm,iperm;

 13:   PetscInitialize(&argc,&args,(char*)0,help);
 14:   MatCreate(PETSC_COMM_SELF,&C);
 15:   MatSetSizes(C,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n);
 16:   MatSetFromOptions(C);
 17:   MatSetUp(C);

 19:   /* create the matrix for the five point stencil, YET AGAIN*/
 20:   for (i=0; i<m; i++) {
 21:     for (j=0; j<n; j++) {
 22:       v = -1.0;  Ii = j + n*i;
 23:       if (i>0)   {J = Ii - n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
 24:       if (i<m-1) {J = Ii + n; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
 25:       if (j>0)   {J = Ii - 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
 26:       if (j<n-1) {J = Ii + 1; MatSetValues(C,1,&Ii,1,&J,&v,INSERT_VALUES);}
 27:       v = 4.0; MatSetValues(C,1,&Ii,1,&Ii,&v,INSERT_VALUES);
 28:     }
 29:   }
 30:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 31:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

 33:   MatGetOrdering(C,MATORDERINGND,&perm,&iperm);
 34:   ISView(perm,PETSC_VIEWER_STDOUT_SELF);
 35:   ISView(iperm,PETSC_VIEWER_STDOUT_SELF);
 36:   MatView(C,PETSC_VIEWER_STDOUT_SELF);

 38:   ISDestroy(&perm);
 39:   ISDestroy(&iperm);
 40:   MatDestroy(&C);
 41:   PetscFinalize();
 42:   return 0;
 43: }

 45: /*TEST

 47:    test:

 49: TEST*/