         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

         AUTHOR
              Werner von Bloh (bloh@pik-potsdam.de)

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