Actual source code: ex1.c
2: static char help[] = "Tests VecView() contour plotting for 2d DMDAs.\n\n";
4: /*
5: MATLAB must be installed to configure PETSc to have MATLAB engine.
6: Unless you have specific important reasons for using the MATLAB engine, we do not
7: recommend it. If you want to use MATLAB for visualization and maybe a little post processing
8: then you can use the socket viewer and send the data to MATLAB via that.
10: VecView() on DMDA vectors first puts the Vec elements into global natural ordering before printing (or plotting)
11: them. In 2d 5 by 2 DMDA this means the numbering is
13: 5 6 7 8 9
14: 0 1 2 3 4
16: Now the default split across 2 processors with the DM is (by rank)
18: 0 0 0 1 1
19: 0 0 0 1 1
21: So the global PETSc ordering is
23: 3 4 5 8 9
24: 0 1 2 6 7
26: Use the options
27: -da_grid_x <nx> - number of grid points in x direction, if M < 0
28: -da_grid_y <ny> - number of grid points in y direction, if N < 0
29: -da_processors_x <MX> number of processors in x directio
30: -da_processors_y <MY> number of processors in x direction
31: */
33: #include <petscdm.h>
34: #include <petscdmda.h>
36: int main(int argc,char **argv)
37: {
38: PetscMPIInt rank;
39: PetscInt M = 10,N = 8;
40: PetscBool flg = PETSC_FALSE;
41: DM da;
42: PetscViewer viewer;
43: Vec local,global;
44: PetscScalar value;
45: DMBoundaryType bx = DM_BOUNDARY_NONE,by = DM_BOUNDARY_NONE;
46: DMDAStencilType stype = DMDA_STENCIL_BOX;
47: #if defined(PETSC_HAVE_MATLAB_ENGINE)
48: PetscViewer mviewer;
49: PetscMPIInt size;
50: #endif
52: PetscInitialize(&argc,&argv,(char*)0,help);
53: PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer);
54: #if defined(PETSC_HAVE_MATLAB_ENGINE)
55: MPI_Comm_size(PETSC_COMM_WORLD,&size);
56: if (size == 1) {
57: PetscViewerMatlabOpen(PETSC_COMM_WORLD,"tmp.mat",FILE_MODE_WRITE,&mviewer);
58: }
59: #endif
61: PetscOptionsGetBool(NULL,NULL,"-star_stencil",&flg,NULL);
62: if (flg) stype = DMDA_STENCIL_STAR;
64: /* Create distributed array and get vectors */
65: DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&da);
66: DMSetFromOptions(da);
67: DMSetUp(da);
68: DMCreateGlobalVector(da,&global);
69: DMCreateLocalVector(da,&local);
71: value = -3.0;
72: VecSet(global,value);
73: DMGlobalToLocalBegin(da,global,INSERT_VALUES,local);
74: DMGlobalToLocalEnd(da,global,INSERT_VALUES,local);
76: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
77: value = rank+1;
78: VecScale(local,value);
79: DMLocalToGlobalBegin(da,local,ADD_VALUES,global);
80: DMLocalToGlobalEnd(da,local,ADD_VALUES,global);
82: flg = PETSC_FALSE;
83: PetscOptionsGetBool(NULL,NULL, "-view_global", &flg,NULL);
84: if (flg) { /* view global vector in natural ordering */
85: VecView(global,PETSC_VIEWER_STDOUT_WORLD);
86: }
87: DMView(da,viewer);
88: VecView(global,viewer);
89: #if defined(PETSC_HAVE_MATLAB_ENGINE)
90: if (size == 1) {
91: DMView(da,mviewer);
92: VecView(global,mviewer);
93: }
94: #endif
96: /* Free memory */
97: #if defined(PETSC_HAVE_MATLAB_ENGINE)
98: if (size == 1) {
99: PetscViewerDestroy(&mviewer);
100: }
101: #endif
102: PetscViewerDestroy(&viewer);
103: VecDestroy(&local);
104: VecDestroy(&global);
105: DMDestroy(&da);
106: PetscFinalize();
107: return 0;
108: }
110: /*TEST
112: test:
113: requires: x
114: nsize: 2
115: args: -nox
117: TEST*/