1 2 static char help[] = "Tests VecView() contour plotting for 2d DMDAs.\n\n"; 3 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. 9 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 12 13 5 6 7 8 9 14 0 1 2 3 4 15 16 Now the default split across 2 processors with the DM is (by rank) 17 18 0 0 0 1 1 19 0 0 0 1 1 20 21 So the global PETSc ordering is 22 23 3 4 5 8 9 24 0 1 2 6 7 25 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 */ 32 33 #include <petscdm.h> 34 #include <petscdmda.h> 35 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 51 52 CHKERRQ(PetscInitialize(&argc,&argv,(char*)0,help)); 53 CHKERRQ(PetscViewerDrawOpen(PETSC_COMM_WORLD,0,"",300,0,300,300,&viewer)); 54 #if defined(PETSC_HAVE_MATLAB_ENGINE) 55 CHKERRMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size)); 56 if (size == 1) { 57 CHKERRQ(PetscViewerMatlabOpen(PETSC_COMM_WORLD,"tmp.mat",FILE_MODE_WRITE,&mviewer)); 58 } 59 #endif 60 61 CHKERRQ(PetscOptionsGetBool(NULL,NULL,"-star_stencil",&flg,NULL)); 62 if (flg) stype = DMDA_STENCIL_STAR; 63 64 /* Create distributed array and get vectors */ 65 CHKERRQ(DMDACreate2d(PETSC_COMM_WORLD,bx,by,stype,M,N,PETSC_DECIDE,PETSC_DECIDE,1,1,NULL,NULL,&da)); 66 CHKERRQ(DMSetFromOptions(da)); 67 CHKERRQ(DMSetUp(da)); 68 CHKERRQ(DMCreateGlobalVector(da,&global)); 69 CHKERRQ(DMCreateLocalVector(da,&local)); 70 71 value = -3.0; 72 CHKERRQ(VecSet(global,value)); 73 CHKERRQ(DMGlobalToLocalBegin(da,global,INSERT_VALUES,local)); 74 CHKERRQ(DMGlobalToLocalEnd(da,global,INSERT_VALUES,local)); 75 76 CHKERRMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank)); 77 value = rank+1; 78 CHKERRQ(VecScale(local,value)); 79 CHKERRQ(DMLocalToGlobalBegin(da,local,ADD_VALUES,global)); 80 CHKERRQ(DMLocalToGlobalEnd(da,local,ADD_VALUES,global)); 81 82 flg = PETSC_FALSE; 83 CHKERRQ(PetscOptionsGetBool(NULL,NULL, "-view_global", &flg,NULL)); 84 if (flg) { /* view global vector in natural ordering */ 85 CHKERRQ(VecView(global,PETSC_VIEWER_STDOUT_WORLD)); 86 } 87 CHKERRQ(DMView(da,viewer)); 88 CHKERRQ(VecView(global,viewer)); 89 #if defined(PETSC_HAVE_MATLAB_ENGINE) 90 if (size == 1) { 91 CHKERRQ(DMView(da,mviewer)); 92 CHKERRQ(VecView(global,mviewer)); 93 } 94 #endif 95 96 /* Free memory */ 97 #if defined(PETSC_HAVE_MATLAB_ENGINE) 98 if (size == 1) { 99 CHKERRQ(PetscViewerDestroy(&mviewer)); 100 } 101 #endif 102 CHKERRQ(PetscViewerDestroy(&viewer)); 103 CHKERRQ(VecDestroy(&local)); 104 CHKERRQ(VecDestroy(&global)); 105 CHKERRQ(DMDestroy(&da)); 106 CHKERRQ(PetscFinalize()); 107 return 0; 108 } 109 110 /*TEST 111 112 test: 113 requires: x 114 nsize: 2 115 args: -nox 116 117 TEST*/ 118