2: static char help[] = "Tests saving DMDA vectors to files.\n\n";

  4: /*
  5:     ex13.c reads in the DMDA and vector written by this program.
  6: */

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

 11: int main(int argc,char **argv)
 12: {
 13:   PetscMPIInt    rank;
 14:   PetscInt       M = 10,N = 8,m = PETSC_DECIDE,n = PETSC_DECIDE, dof = 1;
 16:   DM             da;
 17:   Vec            local,global,natural;
 18:   PetscScalar    value;
 19:   PetscViewer    bviewer;

 21:   PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
 22:   PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL);
 23:   PetscOptionsGetInt(NULL,NULL,"-N",&N,NULL);
 24:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 25:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 26:   PetscOptionsGetInt(NULL,NULL,"-dof",&dof,NULL);

 28:   /* Create distributed array and get vectors */
 29:   DMDACreate2d(PETSC_COMM_WORLD, DM_BOUNDARY_NONE, DM_BOUNDARY_NONE,DMDA_STENCIL_BOX,M,N,m,n,dof,1,NULL,NULL,&da);
 30:   DMSetFromOptions(da);
 31:   DMSetUp(da);
 32:   DMCreateGlobalVector(da,&global);
 33:   DMCreateLocalVector(da,&local);

 35:   value = -3.0;
 36:   VecSet(global,value);
 37:   DMGlobalToLocalBegin(da,global,INSERT_VALUES,local);
 38:   DMGlobalToLocalEnd(da,global,INSERT_VALUES,local);

 40:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 41:   value = rank+1;
 42:   VecScale(local,value);
 43:   DMLocalToGlobalBegin(da,local,ADD_VALUES,global);
 44:   DMLocalToGlobalEnd(da,local,ADD_VALUES,global);

 46:   DMDACreateNaturalVector(da,&natural);
 47:   DMDAGlobalToNaturalBegin(da,global,INSERT_VALUES,natural);
 48:   DMDAGlobalToNaturalEnd(da,global,INSERT_VALUES,natural);

 50:   DMDASetFieldName(da,0,"First field");
 51:   /*  VecView(global,PETSC_VIEWER_DRAW_WORLD); */

 53:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,"daoutput",FILE_MODE_WRITE,&bviewer);
 54:   DMView(da,bviewer);
 55:   VecView(global,bviewer);
 56:   PetscViewerDestroy(&bviewer);

 58:   /* Free memory */
 59:   VecDestroy(&local);
 60:   VecDestroy(&global);
 61:   VecDestroy(&natural);
 62:   DMDestroy(&da);
 63:   PetscFinalize();
 64:   return ierr;
 65: }