Actual source code: ex14.c
1: /*$Id: ex14.c,v 1.47 2001/03/23 23:21:30 balay Exp $*/
3: static char help[] = "Scatters from a sequential vector to a parallel vector.n
4: This does the tricky case.nn";
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,N;
13: Scalar value,zero = 0.0;
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,rank,1,&is2);
31: value = rank+1;
32: VecSet(&value,x);
33: VecSet(&zero,y);
35: VecScatterCreate(x,is1,y,is2,&ctx);
36: VecScatterBegin(x,y,ADD_VALUES,SCATTER_FORWARD,ctx);
37: VecScatterEnd(x,y,ADD_VALUES,SCATTER_FORWARD,ctx);
38: VecScatterDestroy(ctx);
39:
40: VecView(y,PETSC_VIEWER_STDOUT_WORLD);
42: VecDestroy(x);
43: VecDestroy(y);
44: ISDestroy(is1);
45: ISDestroy(is2);
47: PetscFinalize();
48: return 0;
49: }
50: