Actual source code: ex13.c
1: /*$Id: ex13.c,v 1.51 2001/09/11 16:32:10 bsmith 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: PetscScalar 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: VecCreate(PETSC_COMM_WORLD,&y);
25: VecSetSizes(y,PETSC_DECIDE,N);
26: VecSetFromOptions(y);
27: VecCreateSeq(PETSC_COMM_SELF,N,&x);
29: /* create two index sets */
30: ISCreateStride(PETSC_COMM_SELF,N,0,1,&is1);
31: ISCreateStride(PETSC_COMM_SELF,N,0,1,&is2);
33: for (i=0; i<N; i++) {
34: value = (PetscScalar) i;
35: VecSetValues(x,1,&i,&value,INSERT_VALUES);
36: }
37: VecAssemblyBegin(x);
38: VecAssemblyEnd(x);
40: VecScatterCreate(x,is2,y,is1,&ctx);
41: VecScatterBegin(x,y,INSERT_VALUES,SCATTER_FORWARD,ctx);
42: VecScatterEnd(x,y,INSERT_VALUES,SCATTER_FORWARD,ctx);
43: VecScatterDestroy(ctx);
44:
45: VecView(y,PETSC_VIEWER_STDOUT_WORLD);
47: VecDestroy(x);
48: VecDestroy(y);
49: ISDestroy(is1);
50: ISDestroy(is2);
52: PetscFinalize();
53: return 0;
54: }
55: