Actual source code: ex51.c


  2: static char help[] = "Tests DMDAGlobalToNaturalAllCreate() using contour plotting for 2d DMDAs.\n\n";

  4: #include <petscdm.h>
  5: #include <petscdmda.h>
  6: #include <petscdraw.h>

  8: int main(int argc,char **argv)
  9: {
 10:   PetscInt         i,j,M = 10,N = 8,m = PETSC_DECIDE,n = PETSC_DECIDE;
 11:   PetscMPIInt      rank;
 12:   PetscBool        flg = PETSC_FALSE;
 13:   DM               da;
 14:   PetscViewer      viewer;
 15:   Vec              localall,global;
 16:   PetscScalar      value,*vlocal;
 17:   DMBoundaryType   bx    = DM_BOUNDARY_NONE,by = DM_BOUNDARY_NONE;
 18:   DMDAStencilType  stype = DMDA_STENCIL_BOX;
 19:   VecScatter       tolocalall,fromlocalall;
 20:   PetscInt         start,end;

 22:   PetscInitialize(&argc,&argv,(char*)0,help);
 23:   PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer);

 25:   /* Read options */
 26:   PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL);
 27:   PetscOptionsGetInt(NULL,NULL,"-N",&N,NULL);
 28:   PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);
 29:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
 30:   PetscOptionsGetBool(NULL,NULL,"-star_stencil",&flg,NULL);
 31:   if (flg) stype = DMDA_STENCIL_STAR;

 33:   /* Create distributed array and get vectors */
 34:   DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,m,n,1,1,NULL,NULL,&da);
 35:   DMSetFromOptions(da);
 36:   DMSetUp(da);

 38:   DMCreateGlobalVector(da,&global);
 39:   VecCreateSeq(PETSC_COMM_SELF,M*N,&localall);

 41:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 42:   VecGetOwnershipRange(global,&start,&end);
 43:   for (i=start; i<end; i++) {
 44:     value = 5.0*rank;
 45:     VecSetValues(global,1,&i,&value,INSERT_VALUES);
 46:   }
 47:   VecView(global,viewer);

 49:   /*
 50:      Create Scatter from global DMDA parallel vector to local vector that
 51:    contains all entries
 52:   */
 53:   DMDAGlobalToNaturalAllCreate(da,&tolocalall);
 54:   DMDANaturalAllToGlobalCreate(da,&fromlocalall);

 56:   VecScatterBegin(tolocalall,global,localall,INSERT_VALUES,SCATTER_FORWARD);
 57:   VecScatterEnd(tolocalall,global,localall,INSERT_VALUES,SCATTER_FORWARD);

 59:   VecGetArray(localall,&vlocal);
 60:   for (j=0; j<N; j++) {
 61:     for (i=0; i<M; i++) {
 62:       *vlocal++ += i + j*M;
 63:     }
 64:   }
 65:   VecRestoreArray(localall,&vlocal);

 67:   /* scatter back to global vector */
 68:   VecScatterBegin(fromlocalall,localall,global,INSERT_VALUES,SCATTER_FORWARD);
 69:   VecScatterEnd(fromlocalall,localall,global,INSERT_VALUES,SCATTER_FORWARD);

 71:   VecView(global,viewer);

 73:   /* Free memory */
 74:   VecScatterDestroy(&tolocalall);
 75:   VecScatterDestroy(&fromlocalall);
 76:   PetscViewerDestroy(&viewer);
 77:   VecDestroy(&localall);
 78:   VecDestroy(&global);
 79:   DMDestroy(&da);
 80:   PetscFinalize();
 81:   return 0;
 82: }

 84: /*TEST

 86:    build:
 87:      requires: !complex

 89:    test:
 90:       nsize: 3

 92: TEST*/