Actual source code: ex7.c

petsc-3.7.7 2017-09-25
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  2: static char help[] = "Tests DMLocalToLocalxxx() for DMDA.\n\n";

  4: #include <petscdmda.h>

  8: int main(int argc,char **argv)
  9: {
 10:   PetscMPIInt      rank;
 11:   PetscInt         M=8,dof=1,stencil_width=1,i,start,end,P=5,N = 6,m=PETSC_DECIDE,n=PETSC_DECIDE,p=PETSC_DECIDE,pt = 0,st = 0;
 12:   PetscErrorCode   ierr;
 13:   PetscBool        flg = PETSC_FALSE,flg2,flg3;
 14:   DMBoundaryType   periodic;
 15:   DMDAStencilType  stencil_type;
 16:   DM               da;
 17:   Vec              local,global,local_copy;
 18:   PetscScalar      value;
 19:   PetscReal        norm,work;
 20:   PetscViewer      viewer;
 21:   char             filename[64];
 22:   FILE             *file;

 24:   PetscInitialize(&argc,&argv,(char*)0,help);

 26:   PetscOptionsGetInt(NULL,NULL,"-M",&M,NULL);
 27:   PetscOptionsGetInt(NULL,NULL,"-N",&N,NULL);
 28:   PetscOptionsGetInt(NULL,NULL,"-dof",&dof,NULL);
 29:   PetscOptionsGetInt(NULL,NULL,"-stencil_width",&stencil_width,NULL);
 30:   PetscOptionsGetInt(NULL,NULL,"-periodic",&pt,NULL);

 32:   periodic = (DMBoundaryType) pt;

 34:   PetscOptionsGetInt(NULL,NULL,"-stencil_type",&st,NULL);

 36:   stencil_type = (DMDAStencilType) st;

 38:   PetscOptionsHasName(NULL,NULL,"-grid2d",&flg2);
 39:   PetscOptionsHasName(NULL,NULL,"-grid3d",&flg3);
 40:   if (flg2) {
 41:     DMDACreate2d(PETSC_COMM_WORLD,periodic,periodic,stencil_type,M,N,m,n,dof,stencil_width,
 42:                         NULL,NULL,&da);
 43:   } else if (flg3) {
 44:     DMDACreate3d(PETSC_COMM_WORLD,periodic,periodic,periodic,stencil_type,M,N,P,m,n,p,dof,stencil_width,
 45:                         NULL,NULL,NULL,&da);
 46:   } else {
 47:     DMDACreate1d(PETSC_COMM_WORLD,periodic,M,dof,stencil_width,NULL,&da);
 48:   }

 50:   DMCreateGlobalVector(da,&global);
 51:   DMCreateLocalVector(da,&local);
 52:   VecDuplicate(local,&local_copy);


 55:   /* zero out vectors so that ghostpoints are zero */
 56:   value = 0;
 57:   VecSet(local,value);
 58:   VecSet(local_copy,value);

 60:   VecGetOwnershipRange(global,&start,&end);
 61:   for (i=start; i<end; i++) {
 62:     value = i + 1;
 63:     VecSetValues(global,1,&i,&value,INSERT_VALUES);
 64:   }
 65:   VecAssemblyBegin(global);
 66:   VecAssemblyEnd(global);

 68:   DMGlobalToLocalBegin(da,global,INSERT_VALUES,local);
 69:   DMGlobalToLocalEnd(da,global,INSERT_VALUES,local);


 72:   DMLocalToLocalBegin(da,local,INSERT_VALUES,local_copy);
 73:   DMLocalToLocalEnd(da,local,INSERT_VALUES,local_copy);


 76:   PetscOptionsGetBool(NULL,NULL,"-save",&flg,NULL);
 77:   if (flg) {
 78:     MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
 79:     sprintf(filename,"local.%d",rank);
 80:     PetscViewerASCIIOpen(PETSC_COMM_SELF,filename,&viewer);
 81:     PetscViewerASCIIGetPointer(viewer,&file);
 82:     VecView(local,viewer);
 83:     fprintf(file,"Vector with correct ghost points\n");
 84:     VecView(local_copy,viewer);
 85:     PetscViewerDestroy(&viewer);
 86:   }

 88:   VecAXPY(local_copy,-1.0,local);
 89:   VecNorm(local_copy,NORM_MAX,&work);
 90:   MPI_Allreduce(&work,&norm,1,MPIU_REAL,MPIU_MAX,PETSC_COMM_WORLD);
 91:   PetscPrintf(PETSC_COMM_WORLD,"Norm of difference %g should be zero\n",(double)norm);

 93:   VecDestroy(&local_copy);
 94:   VecDestroy(&local);
 95:   VecDestroy(&global);
 96:   DMDestroy(&da);
 97:   PetscFinalize();
 98:   return 0;
 99: }