Actual source code: ex33.c

petsc-3.10.2 2018-10-09
Report Typos and Errors

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

  4: /*T
  5:    requires: x
  6: T*/

  8:  #include <petscvec.h>

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

 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:   /* create two vectors */
 24:   VecCreateMPI(PETSC_COMM_WORLD,PETSC_DECIDE,size*n,&x);

 26:   /* each processor inserts its values */

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

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

 42:   /* Cannot view the above vector with VecView(), so place it in an MPI Vec
 43:      and do a VecView() */
 44:   VecGetArray(y,&yy);
 45:   VecGetLocalSize(y,&len);
 46:   VecCreateMPIWithArray(PETSC_COMM_WORLD,1,len,PETSC_DECIDE,yy,&y_t);
 47:   VecView(y_t,PETSC_VIEWER_STDOUT_WORLD);
 48:   VecDestroy(&y_t);
 49:   VecRestoreArray(y,&yy);

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

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

 66:   VecDestroy(&x);
 67:   VecDestroy(&y);

 69:   PetscFinalize();
 70:   return ierr;
 71: }



 75: /*TEST

 77:    test:
 78:       nsize: 4

 80: TEST*/