xref: /petsc/src/dm/tutorials/ex5.c (revision c4762a1b19cd2af06abeed90e8f9d34fb975dd94)
1*c4762a1bSJed Brown 
2*c4762a1bSJed Brown static char help[] = "Tests DMDAGetElements() and VecView() contour plotting for 2d DMDAs.\n\n";
3*c4762a1bSJed Brown 
4*c4762a1bSJed Brown 
5*c4762a1bSJed Brown #include <petscdm.h>
6*c4762a1bSJed Brown #include <petscdmda.h>
7*c4762a1bSJed Brown #include <petscdraw.h>
8*c4762a1bSJed Brown 
9*c4762a1bSJed Brown int main(int argc,char **argv)
10*c4762a1bSJed Brown {
11*c4762a1bSJed Brown   PetscInt         M = 10,N = 8,ne,nc,i;
12*c4762a1bSJed Brown   const PetscInt   *e;
13*c4762a1bSJed Brown   PetscErrorCode   ierr;
14*c4762a1bSJed Brown   PetscBool        flg = PETSC_FALSE;
15*c4762a1bSJed Brown   DM               da;
16*c4762a1bSJed Brown   PetscViewer      viewer;
17*c4762a1bSJed Brown   Vec              local,global;
18*c4762a1bSJed Brown   PetscScalar      value;
19*c4762a1bSJed Brown   DMBoundaryType   bx    = DM_BOUNDARY_NONE,by = DM_BOUNDARY_NONE;
20*c4762a1bSJed Brown   DMDAStencilType  stype = DMDA_STENCIL_BOX;
21*c4762a1bSJed Brown   PetscScalar      *lv;
22*c4762a1bSJed Brown 
23*c4762a1bSJed Brown   ierr = PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
24*c4762a1bSJed Brown   ierr = PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer);CHKERRQ(ierr);
25*c4762a1bSJed Brown 
26*c4762a1bSJed Brown   /* Read options */
27*c4762a1bSJed Brown   ierr = PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL);CHKERRQ(ierr);
28*c4762a1bSJed Brown   ierr = PetscOptionsGetInt(NULL,NULL,"-N",&N,NULL);CHKERRQ(ierr);
29*c4762a1bSJed Brown   ierr = PetscOptionsGetBool(NULL,NULL,"-star_stencil",&flg,NULL);CHKERRQ(ierr);
30*c4762a1bSJed Brown   if (flg) stype = DMDA_STENCIL_STAR;
31*c4762a1bSJed Brown 
32*c4762a1bSJed Brown   /* Create distributed array and get vectors */
33*c4762a1bSJed Brown   ierr = DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&da);CHKERRQ(ierr);
34*c4762a1bSJed Brown   ierr = DMSetFromOptions(da);CHKERRQ(ierr);
35*c4762a1bSJed Brown   ierr = DMSetUp(da);CHKERRQ(ierr);
36*c4762a1bSJed Brown   ierr = DMCreateGlobalVector(da,&global);CHKERRQ(ierr);
37*c4762a1bSJed Brown   ierr = DMCreateLocalVector(da,&local);CHKERRQ(ierr);
38*c4762a1bSJed Brown 
39*c4762a1bSJed Brown   value = -3.0;
40*c4762a1bSJed Brown   ierr  = VecSet(global,value);CHKERRQ(ierr);
41*c4762a1bSJed Brown   ierr  = DMGlobalToLocalBegin(da,global,INSERT_VALUES,local);CHKERRQ(ierr);
42*c4762a1bSJed Brown   ierr  = DMGlobalToLocalEnd(da,global,INSERT_VALUES,local);CHKERRQ(ierr);
43*c4762a1bSJed Brown 
44*c4762a1bSJed Brown   ierr = DMDASetElementType(da,DMDA_ELEMENT_P1);CHKERRQ(ierr);
45*c4762a1bSJed Brown   ierr = DMDAGetElements(da,&ne,&nc,&e);CHKERRQ(ierr);
46*c4762a1bSJed Brown   ierr = VecGetArray(local,&lv);CHKERRQ(ierr);
47*c4762a1bSJed Brown   for (i=0; i<ne; i++) {
48*c4762a1bSJed Brown     ierr       = PetscSynchronizedPrintf(PETSC_COMM_WORLD,"i %D e[3*i] %D %D %D\n",i,e[3*i],e[3*i+1],e[3*i+2]);CHKERRQ(ierr);
49*c4762a1bSJed Brown     lv[e[3*i]] = i;
50*c4762a1bSJed Brown   }
51*c4762a1bSJed Brown   ierr = PetscSynchronizedFlush(PETSC_COMM_WORLD,stdout);CHKERRQ(ierr);
52*c4762a1bSJed Brown   ierr = VecRestoreArray(local,&lv);CHKERRQ(ierr);
53*c4762a1bSJed Brown   ierr = DMDARestoreElements(da,&ne,&nc,&e);CHKERRQ(ierr);
54*c4762a1bSJed Brown 
55*c4762a1bSJed Brown   ierr = DMLocalToGlobalBegin(da,local,ADD_VALUES,global);CHKERRQ(ierr);
56*c4762a1bSJed Brown   ierr = DMLocalToGlobalEnd(da,local,ADD_VALUES,global);CHKERRQ(ierr);
57*c4762a1bSJed Brown 
58*c4762a1bSJed Brown   ierr = DMView(da,viewer);CHKERRQ(ierr);
59*c4762a1bSJed Brown   ierr = VecView(global,viewer);CHKERRQ(ierr);
60*c4762a1bSJed Brown 
61*c4762a1bSJed Brown   /* Free memory */
62*c4762a1bSJed Brown   ierr = PetscViewerDestroy(&viewer);CHKERRQ(ierr);
63*c4762a1bSJed Brown   ierr = VecDestroy(&local);CHKERRQ(ierr);
64*c4762a1bSJed Brown   ierr = VecDestroy(&global);CHKERRQ(ierr);
65*c4762a1bSJed Brown   ierr = DMDestroy(&da);CHKERRQ(ierr);
66*c4762a1bSJed Brown   ierr = PetscFinalize();
67*c4762a1bSJed Brown   return ierr;
68*c4762a1bSJed Brown }
69*c4762a1bSJed Brown 
70*c4762a1bSJed Brown 
71*c4762a1bSJed Brown 
72*c4762a1bSJed Brown /*TEST
73*c4762a1bSJed Brown 
74*c4762a1bSJed Brown    test:
75*c4762a1bSJed Brown      requires: x
76*c4762a1bSJed Brown 
77*c4762a1bSJed Brown    test:
78*c4762a1bSJed Brown      suffix: 2
79*c4762a1bSJed Brown      nsize: 2
80*c4762a1bSJed Brown      requires: x
81*c4762a1bSJed Brown 
82*c4762a1bSJed Brown TEST*/
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