Actual source code: ex24.c

  1: /*$Id: ex24.c,v 1.15 2001/08/07 03:03:07 balay Exp $*/

  3: static char help[] = "Tests copying an AIJ matrix.nn";

 5:  #include petscmat.h

  7: int main(int argc,char **args)
  8: {
  9:   Mat         C,A;
 10:   int         i,j,m = 5,n = 5,I,J,ierr;
 11:   PetscScalar v;

 13:   PetscInitialize(&argc,&args,(char *)0,help);

 15:   /* create the matrix for the five point stencil, YET AGAIN*/
 16:   MatCreateSeqAIJ(PETSC_COMM_SELF,m*n,m*n,5,PETSC_NULL,&C);
 17:   for (i=0; i<m; i++) {
 18:     for (j=0; j<n; j++) {
 19:       v = -1.0;  I = j + n*i;
 20:       if (i>0)   {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 21:       if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 22:       if (j>0)   {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 23:       if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 24:       v = 4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
 25:     }
 26:   }
 27:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 28:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

 30:   MatConvert(C,MATSAME,&A);

 32:   for (i=0; i<m; i++) {
 33:     for (j=0; j<n; j++) {
 34:       v = -1.0;  I = j + n*i;
 35:       if (i>0)   {J = I - n; MatSetValues(A,1,&I,1,&J,&v,ADD_VALUES);}
 36:       if (i<m-1) {J = I + n; MatSetValues(A,1,&I,1,&J,&v,ADD_VALUES);}
 37:       if (j>0)   {J = I - 1; MatSetValues(A,1,&I,1,&J,&v,ADD_VALUES);}
 38:       if (j<n-1) {J = I + 1; MatSetValues(A,1,&I,1,&J,&v,ADD_VALUES);}
 39:       v = 4.0; MatSetValues(A,1,&I,1,&I,&v,ADD_VALUES);
 40:     }
 41:   }
 42:   MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
 43:   MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);

 45:   MatView(A,PETSC_VIEWER_STDOUT_SELF);

 47:   MatDestroy(C);
 48:   MatDestroy(A);
 49:   PetscFinalize();
 50:   return 0;
 51: }