Actual source code: ex33.c

  1: /*$Id: ex33.c,v 1.1 2001/09/24 21:04:45 balay Exp $*/

  3: static char help[] = "Tests the routines VecScatterCreateToAll(), VecScatterCreateToZero()\n\n";

 5:  #include petscvec.h

  9: int main(int argc,char **argv)
 10: {
 11:   PetscInt       n = 3,i,len,start,end;
 13:   PetscMPIInt    size,rank;
 14:   PetscScalar    value,*yy;
 15:   Vec            x,y,z,y_t;
 16:   VecScatter     toall,tozero;

 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:   VecCreateMPI(PETSC_COMM_WORLD,PETSC_DECIDE,size*n,&x);

 25:   /* each processor inserts its values */

 27:   VecGetOwnershipRange(x,&start,&end);
 28:   for (i=start; i<end; i++) {
 29:     value = (PetscScalar) i;
 30:     VecSetValues(x,1,&i,&value,INSERT_VALUES);
 31:   }
 32:   VecAssemblyBegin(x);
 33:   VecAssemblyEnd(x);
 34:   VecView(x,PETSC_VIEWER_STDOUT_WORLD);

 36:   VecScatterCreateToAll(x,&toall,&y);
 37:   VecScatterBegin(toall,x,y,INSERT_VALUES,SCATTER_FORWARD);
 38:   VecScatterEnd(toall,x,y,INSERT_VALUES,SCATTER_FORWARD);
 39:   VecScatterDestroy(toall);

 41:   /* Cannot view the above vector with VecView(), so place it in an MPI Vec
 42:      and do a VecView() */
 43:   VecGetArray(y,&yy);
 44:   VecGetLocalSize(y,&len);
 45:   VecCreateMPIWithArray(PETSC_COMM_WORLD,len,PETSC_DECIDE,yy,&y_t);
 46:   VecView(y_t,PETSC_VIEWER_STDOUT_WORLD);
 47:   VecDestroy(y_t);
 48:   VecRestoreArray(y,&yy);

 50:   VecScatterCreateToAll(x,&tozero,&z);
 51:   VecScatterBegin(tozero,x,z,INSERT_VALUES,SCATTER_FORWARD);
 52:   VecScatterEnd(tozero,x,z,INSERT_VALUES,SCATTER_FORWARD);
 53:   VecScatterDestroy(tozero);
 54:   if (!rank) {
 55:     VecView(z,PETSC_VIEWER_STDOUT_SELF);
 56:   }
 57:   VecDestroy(z);

 59:   VecScatterCreateToZero(x,&tozero,&z);
 60:   VecScatterBegin(tozero,x,z,INSERT_VALUES,SCATTER_FORWARD);
 61:   VecScatterEnd(tozero,x,z,INSERT_VALUES,SCATTER_FORWARD);
 62:   VecScatterDestroy(tozero);
 63:   VecDestroy(z);

 65:   VecDestroy(x);
 66:   VecDestroy(y);

 68:   PetscFinalize();
 69:   return 0;
 70: }
 71: