Actual source code: ex19.c


  2: static char help[] = "Tests DMDA with variable multiple degrees of freedom per node.\n\n";

  4: /*
  5:    This code only compiles with gcc, since it is not ANSI C
  6: */

  8: #include <petscdm.h>
  9: #include <petscdmda.h>

 11: PetscErrorCode doit(DM da,Vec global)
 12: {
 13:   PetscInt       i,j,k,M,N,dof;

 15:   DMDAGetInfo(da,0,&M,&N,0,0,0,0,&dof,0,0,0,0,0);
 16:   {
 17:     struct {PetscScalar inside[dof];} **mystruct;
 18:     DMDAVecGetArrayRead(da,global,(void*) &mystruct);
 19:     for (i=0; i<N; i++) {
 20:       for (j=0; j<M; j++) {
 21:         for (k=0; k<dof; k++) {
 22:           PetscPrintf(PETSC_COMM_WORLD,"%D %D %g\n",i,j,(double)mystruct[i][j].inside[0]);

 24:           mystruct[i][j].inside[1] = 2.1;
 25:         }
 26:       }
 27:     }
 28:     DMDAVecRestoreArrayRead(da,global,(void*) &mystruct);
 29:   }
 30:   return 0;
 31: }

 33: int main(int argc,char **argv)
 34: {
 35:   PetscInt       dof = 2,M = 3,N = 3,m = PETSC_DECIDE,n = PETSC_DECIDE;
 36:   DM             da;
 37:   Vec            global,local;

 39:   PetscInitialize(&argc,&argv,(char*)0,help);
 40:   PetscOptionsGetInt(NULL,0,"-dof",&dof,0);
 41:   /* Create distributed array and get vectors */
 42:   DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,DMDA_STENCIL_BOX,M,N,m,n,dof,1,NULL,NULL,&da);
 43:   DMSetFromOptions(da);
 44:   DMSetUp(da);
 45:   DMCreateGlobalVector(da,&global);
 46:   DMCreateLocalVector(da,&local);

 48:   doit(da,global);

 50:   VecView(global,0);

 52:   /* Free memory */
 53:   VecDestroy(&local);
 54:   VecDestroy(&global);
 55:   DMDestroy(&da);
 56:   PetscFinalize();
 57:   return 0;
 58: }