NAME
          pnet_exchg - Exchange input and output data

     SYNOPSIS
          #include <mpi.h>
          #include "pnet.h"

          void pnet_exchg(Pnet *pnet);

     DESCRIPTION
          Function call collective communication function
          MPI_AlltoAllv in order to exchange the data from the output
          to the input buffer. Is implemented as a macro. Must be
          called after pnet_setup.  The argument of pnet_setup is:

          pnet Pointer to initialized Pnet struct

     RETURN VALUE
          None

     AUTHORS
          For authors and contributors see AUTHORS file


     COPYRIGHT
          (C) Potsdam Institute for Climate Impact Research (PIK), see
          COPYRIGHT file


     SEE ALSO
          pnet_setup(3), pnet_init(3), pnet_addconnect(3),
          pnet_free(3),  pnet_lo(3), pnet_hi(3), pnet_nodes(3)