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: