Actual source code: ex38.c
petsc-3.12.4 2020-02-04
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      2: static char help[] = "Tests DMGlobalToLocal() for 3d DA with stencil width of 2.\n\n";

      4:  #include <petscdm.h>
      5:  #include <petscdmda.h>

      7: int main(int argc,char **argv)
      8: {
      9:   PetscInt         N             = 3,M=2,P=4,dof=1,rstart,rend,i;
     10:   PetscInt         stencil_width = 2;
     11:   PetscErrorCode   ierr;
     12:   PetscMPIInt      rank;
     13:   DMBoundaryType   bx           = DM_BOUNDARY_NONE,by = DM_BOUNDARY_NONE,bz = DM_BOUNDARY_NONE;
     14:   DMDAStencilType  stencil_type = DMDA_STENCIL_STAR;
     15:   DM               da;
     16:   Vec              global,local;

     19:   PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
     20:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
     21:   PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL);
     22:   PetscOptionsGetInt(NULL,NULL,"-N",&N,NULL);
     23:   PetscOptionsGetInt(NULL,NULL,"-P",&P,NULL);
     24:   PetscOptionsGetInt(NULL,NULL,"-dof",&dof,NULL);
     25:   PetscOptionsGetInt(NULL,NULL,"-stencil_width",&stencil_width,NULL);
     26:   PetscOptionsGetInt(NULL,NULL,"-stencil_type",(PetscInt*)&stencil_type,NULL);

     28:   DMDACreate3d(PETSC_COMM_WORLD,bx,by,bz,stencil_type,M,N,P,PETSC_DECIDE,PETSC_DECIDE,PETSC_DECIDE,dof,stencil_width,0,0,0,&da);
     29:   DMSetFromOptions(da);
     30:   DMSetUp(da);
     31:   DMCreateGlobalVector(da,&global);
     32:   VecGetOwnershipRange(global,&rstart,&rend);
     33:   for (i=rstart; i<rend; i++) {VecSetValue(global,i,(PetscReal)(i + 100*rank),INSERT_VALUES);}
     34:   VecAssemblyBegin(global);
     35:   VecAssemblyEnd(global);
     36:   DMCreateLocalVector(da,&local);
     37:   VecSet(local,-1);
     38:   DMGlobalToLocalBegin(da,global,INSERT_VALUES,local);
     39:   DMGlobalToLocalEnd(da,global,INSERT_VALUES,local);
     40:   if (!rank) {VecView(local,0);}
     41:   DMDestroy(&da);
     42:   VecDestroy(&local);
     43:   VecDestroy(&global);
     44:   PetscFinalize();
     45:   return ierr;
     46: }