Actual source code: ex10.c

  2: static char help[] = "Tests repeated use of assembly for matrices.\n\n";

 4:  #include petscmat.h

  8: int main(int argc,char **args)
  9: {
 10:   Mat            C;
 11:   PetscInt       i,j,m = 5,n = 2,I,J;
 13:   PetscMPIInt    rank,size;
 14:   PetscScalar    v;


 17:   PetscInitialize(&argc,&args,(char *)0,help);
 18:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 19:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
 20:   n = 2*size;

 22:   /* create the matrix for the five point stencil, YET AGAIN*/
 23:   MatCreate(PETSC_COMM_WORLD,PETSC_DECIDE,PETSC_DECIDE,m*n,m*n,&C);
 24:   MatSetFromOptions(C);
 25:   for (i=0; i<m; i++) {
 26:     for (j=2*rank; j<2*rank+2; j++) {
 27:       v = -1.0;  I = j + n*i;
 28:       if (i>0)   {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 29:       if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 30:       if (j>0)   {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 31:       if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 32:       v = 4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
 33:     }
 34:   }
 35:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 36:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);
 37:   for (i=0; i<m; i++) {
 38:     for (j=2*rank; j<2*rank+2; j++) {
 39:       v = 1.0;  I = j + n*i;
 40:       if (i>0)   {J = I - n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 41:       if (i<m-1) {J = I + n; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 42:       if (j>0)   {J = I - 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 43:       if (j<n-1) {J = I + 1; MatSetValues(C,1,&I,1,&J,&v,INSERT_VALUES);}
 44:       v = -4.0; MatSetValues(C,1,&I,1,&I,&v,INSERT_VALUES);
 45:     }
 46:   }
 47:   MatAssemblyBegin(C,MAT_FINAL_ASSEMBLY);
 48:   MatAssemblyEnd(C,MAT_FINAL_ASSEMBLY);

 50:   MatView(C,PETSC_VIEWER_STDOUT_WORLD);

 52:   MatDestroy(C);
 53:   PetscFinalize();
 54:   return 0;
 55: }