xref: /petsc/src/dm/tests/ex51.c (revision 40badf4fbc550ac1f60bd080eaff6de6d55b946d)
1 
2 static char help[] = "Tests DMDAGlobalToNaturalAllCreate() using contour plotting for 2d DMDAs.\n\n";
3 
4 #include <petscdm.h>
5 #include <petscdmda.h>
6 #include <petscdraw.h>
7 
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   PetscErrorCode   ierr;
13   PetscBool        flg = PETSC_FALSE;
14   DM               da;
15   PetscViewer      viewer;
16   Vec              localall,global;
17   PetscScalar      value,*vlocal;
18   DMBoundaryType   bx    = DM_BOUNDARY_NONE,by = DM_BOUNDARY_NONE;
19   DMDAStencilType  stype = DMDA_STENCIL_BOX;
20   VecScatter       tolocalall,fromlocalall;
21   PetscInt         start,end;
22 
23   ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
24   CHKERRQ(PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer));
25 
26   /* Read options */
27   CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL));
28   CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-N",&N,NULL));
29   CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL));
30   CHKERRQ(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
31   CHKERRQ(PetscOptionsGetBool(NULL,NULL,"-star_stencil",&flg,NULL));
32   if (flg) stype = DMDA_STENCIL_STAR;
33 
34   /* Create distributed array and get vectors */
35   CHKERRQ(DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,m,n,1,1,NULL,NULL,&da));
36   CHKERRQ(DMSetFromOptions(da));
37   CHKERRQ(DMSetUp(da));
38 
39   CHKERRQ(DMCreateGlobalVector(da,&global));
40   CHKERRQ(VecCreateSeq(PETSC_COMM_SELF,M*N,&localall));
41 
42   CHKERRMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
43   CHKERRQ(VecGetOwnershipRange(global,&start,&end));
44   for (i=start; i<end; i++) {
45     value = 5.0*rank;
46     CHKERRQ(VecSetValues(global,1,&i,&value,INSERT_VALUES));
47   }
48   CHKERRQ(VecView(global,viewer));
49 
50   /*
51      Create Scatter from global DMDA parallel vector to local vector that
52    contains all entries
53   */
54   CHKERRQ(DMDAGlobalToNaturalAllCreate(da,&tolocalall));
55   CHKERRQ(DMDANaturalAllToGlobalCreate(da,&fromlocalall));
56 
57   CHKERRQ(VecScatterBegin(tolocalall,global,localall,INSERT_VALUES,SCATTER_FORWARD));
58   CHKERRQ(VecScatterEnd(tolocalall,global,localall,INSERT_VALUES,SCATTER_FORWARD));
59 
60   CHKERRQ(VecGetArray(localall,&vlocal));
61   for (j=0; j<N; j++) {
62     for (i=0; i<M; i++) {
63       *vlocal++ += i + j*M;
64     }
65   }
66   CHKERRQ(VecRestoreArray(localall,&vlocal));
67 
68   /* scatter back to global vector */
69   CHKERRQ(VecScatterBegin(fromlocalall,localall,global,INSERT_VALUES,SCATTER_FORWARD));
70   CHKERRQ(VecScatterEnd(fromlocalall,localall,global,INSERT_VALUES,SCATTER_FORWARD));
71 
72   CHKERRQ(VecView(global,viewer));
73 
74   /* Free memory */
75   CHKERRQ(VecScatterDestroy(&tolocalall));
76   CHKERRQ(VecScatterDestroy(&fromlocalall));
77   CHKERRQ(PetscViewerDestroy(&viewer));
78   CHKERRQ(VecDestroy(&localall));
79   CHKERRQ(VecDestroy(&global));
80   CHKERRQ(DMDestroy(&da));
81   ierr = PetscFinalize();
82   return ierr;
83 }
84 
85 /*TEST
86 
87    build:
88      requires: !complex
89 
90    test:
91       nsize: 3
92 
93 TEST*/
94