xref: /petsc/src/dm/tutorials/ex1.c (revision b122ec5aa1bd4469eb4e0673542fb7de3f411254)
1c4762a1bSJed Brown 
2c4762a1bSJed Brown static char help[] = "Tests VecView() contour plotting for 2d DMDAs.\n\n";
3c4762a1bSJed Brown 
4c4762a1bSJed Brown /*
5c4762a1bSJed Brown   MATLAB must be installed to configure PETSc to have MATLAB engine.
6c4762a1bSJed Brown Unless you have specific important reasons for using the MATLAB engine, we do not
7c4762a1bSJed Brown recommend it. If you want to use MATLAB for visualization and maybe a little post processing
8c4762a1bSJed Brown then you can use the socket viewer and send the data to MATLAB via that.
9c4762a1bSJed Brown 
10c4762a1bSJed Brown   VecView() on DMDA vectors first puts the Vec elements into global natural ordering before printing (or plotting)
11c4762a1bSJed Brown them. In 2d 5 by 2 DMDA this means the numbering is
12c4762a1bSJed Brown 
13c4762a1bSJed Brown      5  6   7   8   9
14c4762a1bSJed Brown      0  1   2   3   4
15c4762a1bSJed Brown 
16c4762a1bSJed Brown Now the default split across 2 processors with the DM  is (by rank)
17c4762a1bSJed Brown 
18c4762a1bSJed Brown     0  0   0  1   1
19c4762a1bSJed Brown     0  0   0  1   1
20c4762a1bSJed Brown 
21c4762a1bSJed Brown So the global PETSc ordering is
22c4762a1bSJed Brown 
23c4762a1bSJed Brown     3  4  5   8  9
24c4762a1bSJed Brown     0  1  2   6  7
25c4762a1bSJed Brown 
26c4762a1bSJed Brown Use the options
27c4762a1bSJed Brown      -da_grid_x <nx> - number of grid points in x direction, if M < 0
28c4762a1bSJed Brown      -da_grid_y <ny> - number of grid points in y direction, if N < 0
29c4762a1bSJed Brown      -da_processors_x <MX> number of processors in x directio
30c4762a1bSJed Brown      -da_processors_y <MY> number of processors in x direction
31c4762a1bSJed Brown */
32c4762a1bSJed Brown 
33c4762a1bSJed Brown #include <petscdm.h>
34c4762a1bSJed Brown #include <petscdmda.h>
35c4762a1bSJed Brown 
36c4762a1bSJed Brown int main(int argc,char **argv)
37c4762a1bSJed Brown {
38c4762a1bSJed Brown   PetscMPIInt      rank;
39c4762a1bSJed Brown   PetscInt         M = 10,N = 8;
40c4762a1bSJed Brown   PetscBool        flg = PETSC_FALSE;
41c4762a1bSJed Brown   DM               da;
42c4762a1bSJed Brown   PetscViewer      viewer;
43c4762a1bSJed Brown   Vec              local,global;
44c4762a1bSJed Brown   PetscScalar      value;
45c4762a1bSJed Brown   DMBoundaryType   bx    = DM_BOUNDARY_NONE,by = DM_BOUNDARY_NONE;
46c4762a1bSJed Brown   DMDAStencilType  stype = DMDA_STENCIL_BOX;
47c4762a1bSJed Brown #if defined(PETSC_HAVE_MATLAB_ENGINE)
48c4762a1bSJed Brown   PetscViewer      mviewer;
49c4762a1bSJed Brown   PetscMPIInt      size;
50c4762a1bSJed Brown #endif
51c4762a1bSJed Brown 
52*b122ec5aSJacob Faibussowitsch   CHKERRQ(PetscInitialize(&argc,&argv,(char*)0,help));
535f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer));
54c4762a1bSJed Brown #if defined(PETSC_HAVE_MATLAB_ENGINE)
555f80ce2aSJacob Faibussowitsch   CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
56c4762a1bSJed Brown   if (size == 1) {
575f80ce2aSJacob Faibussowitsch     CHKERRQ(PetscViewerMatlabOpen(PETSC_COMM_WORLD,"tmp.mat",FILE_MODE_WRITE,&mviewer));
58c4762a1bSJed Brown   }
59c4762a1bSJed Brown #endif
60c4762a1bSJed Brown 
615f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscOptionsGetBool(NULL,NULL,"-star_stencil",&flg,NULL));
62c4762a1bSJed Brown   if (flg) stype = DMDA_STENCIL_STAR;
63c4762a1bSJed Brown 
64c4762a1bSJed Brown   /* Create distributed array and get vectors */
655f80ce2aSJacob Faibussowitsch   CHKERRQ(DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&da));
665f80ce2aSJacob Faibussowitsch   CHKERRQ(DMSetFromOptions(da));
675f80ce2aSJacob Faibussowitsch   CHKERRQ(DMSetUp(da));
685f80ce2aSJacob Faibussowitsch   CHKERRQ(DMCreateGlobalVector(da,&global));
695f80ce2aSJacob Faibussowitsch   CHKERRQ(DMCreateLocalVector(da,&local));
70c4762a1bSJed Brown 
71c4762a1bSJed Brown   value = -3.0;
725f80ce2aSJacob Faibussowitsch   CHKERRQ(VecSet(global,value));
735f80ce2aSJacob Faibussowitsch   CHKERRQ(DMGlobalToLocalBegin(da,global,INSERT_VALUES,local));
745f80ce2aSJacob Faibussowitsch   CHKERRQ(DMGlobalToLocalEnd(da,global,INSERT_VALUES,local));
75c4762a1bSJed Brown 
765f80ce2aSJacob Faibussowitsch   CHKERRMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
77c4762a1bSJed Brown   value = rank+1;
785f80ce2aSJacob Faibussowitsch   CHKERRQ(VecScale(local,value));
795f80ce2aSJacob Faibussowitsch   CHKERRQ(DMLocalToGlobalBegin(da,local,ADD_VALUES,global));
805f80ce2aSJacob Faibussowitsch   CHKERRQ(DMLocalToGlobalEnd(da,local,ADD_VALUES,global));
81c4762a1bSJed Brown 
82c4762a1bSJed Brown   flg  = PETSC_FALSE;
835f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscOptionsGetBool(NULL,NULL, "-view_global", &flg,NULL));
84c4762a1bSJed Brown   if (flg) { /* view global vector in natural ordering */
855f80ce2aSJacob Faibussowitsch     CHKERRQ(VecView(global,PETSC_VIEWER_STDOUT_WORLD));
86c4762a1bSJed Brown   }
875f80ce2aSJacob Faibussowitsch   CHKERRQ(DMView(da,viewer));
885f80ce2aSJacob Faibussowitsch   CHKERRQ(VecView(global,viewer));
89c4762a1bSJed Brown #if defined(PETSC_HAVE_MATLAB_ENGINE)
90c4762a1bSJed Brown   if (size == 1) {
915f80ce2aSJacob Faibussowitsch     CHKERRQ(DMView(da,mviewer));
925f80ce2aSJacob Faibussowitsch     CHKERRQ(VecView(global,mviewer));
93c4762a1bSJed Brown   }
94c4762a1bSJed Brown #endif
95c4762a1bSJed Brown 
96c4762a1bSJed Brown   /* Free memory */
97c4762a1bSJed Brown #if defined(PETSC_HAVE_MATLAB_ENGINE)
98c4762a1bSJed Brown   if (size == 1) {
995f80ce2aSJacob Faibussowitsch     CHKERRQ(PetscViewerDestroy(&mviewer));
100c4762a1bSJed Brown   }
101c4762a1bSJed Brown #endif
1025f80ce2aSJacob Faibussowitsch   CHKERRQ(PetscViewerDestroy(&viewer));
1035f80ce2aSJacob Faibussowitsch   CHKERRQ(VecDestroy(&local));
1045f80ce2aSJacob Faibussowitsch   CHKERRQ(VecDestroy(&global));
1055f80ce2aSJacob Faibussowitsch   CHKERRQ(DMDestroy(&da));
106*b122ec5aSJacob Faibussowitsch   CHKERRQ(PetscFinalize());
107*b122ec5aSJacob Faibussowitsch   return 0;
108c4762a1bSJed Brown }
109c4762a1bSJed Brown 
110c4762a1bSJed Brown /*TEST
111c4762a1bSJed Brown 
112c4762a1bSJed Brown    test:
113c4762a1bSJed Brown       requires: x
114c4762a1bSJed Brown       nsize: 2
115c4762a1bSJed Brown       args: -nox
116c4762a1bSJed Brown 
117c4762a1bSJed Brown TEST*/
118