Actual source code: ex13.c
2: static char help[]= "Scatters from a sequential vector to a parallel vector. \n\
3: uses block index sets\n\n";
5: #include <petscvec.h>
7: int main(int argc,char **argv)
8: {
10: PetscInt bs=1,n=5,i,low;
11: PetscInt ix0[3] = {5,7,9},iy0[3] = {1,2,4},ix1[3] = {2,3,4},iy1[3] = {0,1,3};
12: PetscMPIInt size,rank;
13: PetscScalar *array;
14: Vec x,y;
15: IS isx,isy;
16: VecScatter ctx;
17: PetscViewer sviewer;
19: PetscInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
20: MPI_Comm_size(PETSC_COMM_WORLD,&size);
21: MPI_Comm_rank(PETSC_COMM_WORLD,&rank);
23: if (size <2) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"Must run more than one processor");
25: PetscOptionsGetInt(NULL,NULL,"-bs",&bs,NULL);
26: n = bs*n;
28: /* Create vector x over shared memory */
29: VecCreate(PETSC_COMM_WORLD,&x);
30: VecSetSizes(x,n,PETSC_DECIDE);
31: VecSetFromOptions(x);
33: VecGetOwnershipRange(x,&low,NULL);
34: VecGetArray(x,&array);
35: for (i=0; i<n; i++) {
36: array[i] = (PetscScalar)(i + low);
37: }
38: VecRestoreArray(x,&array);
40: /* Create a sequential vector y */
41: VecCreateSeq(PETSC_COMM_SELF,n,&y);
42: VecGetArray(y,&array);
43: for (i=0; i<n; i++) {
44: array[i] = (PetscScalar)(i + 100*rank);
45: }
46: VecRestoreArray(y,&array);
48: /* Create two index sets */
49: if (!rank) {
50: ISCreateBlock(PETSC_COMM_SELF,bs,3,ix0,PETSC_COPY_VALUES,&isx);
51: ISCreateBlock(PETSC_COMM_SELF,bs,3,iy0,PETSC_COPY_VALUES,&isy);
52: } else {
53: ISCreateBlock(PETSC_COMM_SELF,bs,3,ix1,PETSC_COPY_VALUES,&isx);
54: ISCreateBlock(PETSC_COMM_SELF,bs,3,iy1,PETSC_COPY_VALUES,&isy);
55: }
57: if (rank == 10) {
58: PetscPrintf(PETSC_COMM_SELF,"\n[%d] isx:\n",rank);
59: ISView(isx,PETSC_VIEWER_STDOUT_SELF);
60: }
62: VecScatterCreate(y,isy,x,isx,&ctx);
63: VecScatterSetFromOptions(ctx);
65: /* Test forward vecscatter */
66: VecSet(x,0.0);
67: VecScatterBegin(ctx,y,x,ADD_VALUES,SCATTER_FORWARD);
68: VecScatterEnd(ctx,y,x,ADD_VALUES,SCATTER_FORWARD);
69: VecView(x,PETSC_VIEWER_STDOUT_WORLD);
71: /* Test reverse vecscatter */
72: VecScale(x,-1.0);
73: VecScatterBegin(ctx,x,y,ADD_VALUES,SCATTER_REVERSE);
74: VecScatterEnd(ctx,x,y,ADD_VALUES,SCATTER_REVERSE);
75: PetscViewerGetSubViewer(PETSC_VIEWER_STDOUT_WORLD,PETSC_COMM_SELF,&sviewer);
76: if (rank == 1) {
77: VecView(y,sviewer);
78: }
79: PetscViewerRestoreSubViewer(PETSC_VIEWER_STDOUT_WORLD,PETSC_COMM_SELF,&sviewer);
81: /* Free spaces */
82: VecScatterDestroy(&ctx);
83: ISDestroy(&isx);
84: ISDestroy(&isy);
85: VecDestroy(&x);
86: VecDestroy(&y);
87: PetscFinalize();
88: return ierr;
89: }
91: /*TEST
93: test:
94: nsize: 3
96: TEST*/