Actual source code: ex13.c

  1: /*$Id: ex13.c,v 1.48 2001/03/23 23:21:30 balay Exp $*/

  3: static char help[] = "Scatters from a sequential vector to a parallel vector.  Inn
  4: this case each local vector is as long as the entire parallel vector.n";

  6: #include "petscvec.h"
  7: #include "petscsys.h"

  9: int main(int argc,char **argv)
 10: {
 11:   int           n = 5,ierr;
 12:   int           size,rank,i,N;
 13:   Scalar        value;
 14:   Vec           x,y;
 15:   IS            is1,is2;
 16:   VecScatter    ctx = 0;

 18:   PetscInitialize(&argc,&argv,(char*)0,help);
 19:   MPI_Comm_size(PETSC_COMM_WORLD,&size);
 20:   MPI_Comm_rank(PETSC_COMM_WORLD,&rank);

 22:   /* create two vectors */
 23:   N = size*n;
 24:   VecCreateMPI(PETSC_COMM_WORLD,PETSC_DECIDE,N,&y);
 25:   VecCreateSeq(PETSC_COMM_SELF,N,&x);

 27:   /* create two index sets */
 28:   ISCreateStride(PETSC_COMM_SELF,N,0,1,&is1);
 29:   ISCreateStride(PETSC_COMM_SELF,N,0,1,&is2);

 31:   for (i=0; i<N; i++) {
 32:     value = (Scalar) i;
 33:     VecSetValues(x,1,&i,&value,INSERT_VALUES);
 34:   }
 35:   VecAssemblyBegin(x);
 36:   VecAssemblyEnd(x);

 38:   VecScatterCreate(x,is2,y,is1,&ctx);
 39:   VecScatterBegin(x,y,INSERT_VALUES,SCATTER_FORWARD,ctx);
 40:   VecScatterEnd(x,y,INSERT_VALUES,SCATTER_FORWARD,ctx);
 41:   VecScatterDestroy(ctx);
 42: 
 43:   VecView(y,PETSC_VIEWER_STDOUT_WORLD);

 45:   VecDestroy(x);
 46:   VecDestroy(y);
 47:   ISDestroy(is1);
 48:   ISDestroy(is2);

 50:   PetscFinalize();
 51:   return 0;
 52: }
 53: