Actual source code: ex10.c

  1: /*$Id: ex10.c,v 1.18 2001/08/07 03:03:07 balay Exp $*/

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

 5:  #include petscmat.h

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


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

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

 49:   MatView(C,PETSC_VIEWER_STDOUT_WORLD);

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