Actual source code: ex5.c
petsc-3.4.5 2014-06-29
2: static char help[] = "Tests DMDAGetElements() and VecView() contour plotting for 2d DMDAs.\n\n";
4: #include <petscdmda.h>
5: #include <petscdraw.h>
9: int main(int argc,char **argv)
10: {
11: PetscInt M = 10,N = 8,m = PETSC_DECIDE,n = PETSC_DECIDE,ne,nc,i;
12: const PetscInt *e;
13: PetscErrorCode ierr;
14: PetscBool flg = PETSC_FALSE;
15: DM da;
16: PetscViewer viewer;
17: Vec local,global;
18: PetscScalar value;
19: DMDABoundaryType bx = DMDA_BOUNDARY_NONE,by = DMDA_BOUNDARY_NONE;
20: DMDAStencilType stype = DMDA_STENCIL_BOX;
21: PetscScalar *lv;
23: PetscInitialize(&argc,&argv,(char*)0,help);
24: PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer);
26: /* Read options */
27: PetscOptionsGetInt(NULL,"-M",&M,NULL);
28: PetscOptionsGetInt(NULL,"-N",&N,NULL);
29: PetscOptionsGetInt(NULL,"-m",&m,NULL);
30: PetscOptionsGetInt(NULL,"-n",&n,NULL);
31: PetscOptionsGetBool(NULL,"-star_stencil",&flg,NULL);
32: if (flg) stype = DMDA_STENCIL_STAR;
34: /* Create distributed array and get vectors */
35: DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,m,n,1,1,NULL,NULL,&da);
36: DMCreateGlobalVector(da,&global);
37: DMCreateLocalVector(da,&local);
39: value = -3.0;
40: VecSet(global,value);
41: DMGlobalToLocalBegin(da,global,INSERT_VALUES,local);
42: DMGlobalToLocalEnd(da,global,INSERT_VALUES,local);
44: DMDASetElementType(da,DMDA_ELEMENT_P1);
45: DMDAGetElements(da,&ne,&nc,&e);
46: VecGetArray(local,&lv);
47: for (i=0; i<ne; i++) {
48: PetscPrintf(PETSC_COMM_WORLD,"i %D e[3*i] %D %D %D\n",i,e[3*i],e[3*i+1],e[3*i+2]);
49: lv[e[3*i]] = i;
50: }
51: VecRestoreArray(local,&lv);
52: DMDARestoreElements(da,&ne,&nc,&e);
54: DMLocalToGlobalBegin(da,local,ADD_VALUES,global);
55: DMLocalToGlobalEnd(da,local,ADD_VALUES,global);
57: DMView(da,viewer);
58: VecView(global,viewer);
60: /* Free memory */
61: PetscViewerDestroy(&viewer);
62: VecDestroy(&local);
63: VecDestroy(&global);
64: DMDestroy(&da);
65: PetscFinalize();
66: return 0;
67: }