xref: /petsc/src/dm/tests/ex51.c (revision 030f984af8d8bb4c203755d35bded3c05b3d83ce)
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   ierr = PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer);CHKERRQ(ierr);
25 
26   /* Read options */
27   ierr = PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL);CHKERRQ(ierr);
28   ierr = PetscOptionsGetInt(NULL,NULL,"-N",&N,NULL);CHKERRQ(ierr);
29   ierr = PetscOptionsGetInt(NULL,NULL,"-m",&m,NULL);CHKERRQ(ierr);
30   ierr = PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);CHKERRQ(ierr);
31   ierr = PetscOptionsGetBool(NULL,NULL,"-star_stencil",&flg,NULL);CHKERRQ(ierr);
32   if (flg) stype = DMDA_STENCIL_STAR;
33 
34   /* Create distributed array and get vectors */
35   ierr = DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,m,n,1,1,NULL,NULL,&da);CHKERRQ(ierr);
36   ierr = DMSetFromOptions(da);CHKERRQ(ierr);
37   ierr = DMSetUp(da);CHKERRQ(ierr);
38 
39   ierr = DMCreateGlobalVector(da,&global);CHKERRQ(ierr);
40   ierr = VecCreateSeq(PETSC_COMM_SELF,M*N,&localall);CHKERRQ(ierr);
41 
42   ierr = MPI_Comm_rank(PETSC_COMM_WORLD,&rank);CHKERRMPI(ierr);
43   ierr = VecGetOwnershipRange(global,&start,&end);CHKERRQ(ierr);
44   for (i=start; i<end; i++) {
45     value = 5.0*rank;
46     ierr  = VecSetValues(global,1,&i,&value,INSERT_VALUES);CHKERRQ(ierr);
47   }
48   ierr = VecView(global,viewer);CHKERRQ(ierr);
49 
50   /*
51      Create Scatter from global DMDA parallel vector to local vector that
52    contains all entries
53   */
54   ierr = DMDAGlobalToNaturalAllCreate(da,&tolocalall);CHKERRQ(ierr);
55   ierr = DMDANaturalAllToGlobalCreate(da,&fromlocalall);CHKERRQ(ierr);
56 
57   ierr = VecScatterBegin(tolocalall,global,localall,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
58   ierr = VecScatterEnd(tolocalall,global,localall,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
59 
60   ierr = VecGetArray(localall,&vlocal);CHKERRQ(ierr);
61   for (j=0; j<N; j++) {
62     for (i=0; i<M; i++) {
63       *vlocal++ += i + j*M;
64     }
65   }
66   ierr = VecRestoreArray(localall,&vlocal);CHKERRQ(ierr);
67 
68   /* scatter back to global vector */
69   ierr = VecScatterBegin(fromlocalall,localall,global,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
70   ierr = VecScatterEnd(fromlocalall,localall,global,INSERT_VALUES,SCATTER_FORWARD);CHKERRQ(ierr);
71 
72   ierr = VecView(global,viewer);CHKERRQ(ierr);
73 
74   /* Free memory */
75   ierr = VecScatterDestroy(&tolocalall);CHKERRQ(ierr);
76   ierr = VecScatterDestroy(&fromlocalall);CHKERRQ(ierr);
77   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
78   ierr = VecDestroy(&localall);CHKERRQ(ierr);
79   ierr = VecDestroy(&global);CHKERRQ(ierr);
80   ierr = DMDestroy(&da);CHKERRQ(ierr);
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