Actual source code: ex10.c


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

  4: #include <petscmat.h>

  6: int main(int argc,char **args)
  7: {
  8:   Mat            C;
  9:   PetscInt       i,j,m = 5,n = 2,Ii,J;
 10:   PetscMPIInt    rank,size;
 11:   PetscScalar    v;

 13:   PetscInitialize(&argc,&args,(char*)0,help);
 14:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 15:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
 16:   n    = 2*size;

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

 48:   MatView(C,PETSC_VIEWER_STDOUT_WORLD);

 50:   MatDestroy(&C);
 51:   PetscFinalize();
 52:   return 0;
 53: }

 55: /*TEST

 57:    test:

 59: TEST*/