// Copyright (C) 2013 Andreas Hehn <hehn@phys.ethz.ch>, ETH Zurich

// Use, modification and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)

// A test of communicators created from groups.

#include <boost/mpi/environment.hpp>
#include <boost/mpi/communicator.hpp>
#include <boost/mpi/group.hpp>
#include <vector>
#include <algorithm>

#include "mpi_test_utils.hpp"

namespace mpi = boost::mpi;

template <typename T>
struct iota
{
    iota() : state(0){};
    T operator()()
    {
        return state++;
    }
    T state;
};

int
group_test(const mpi::communicator& comm)
{
  int failed = 0;
  std::vector<int> grp_a_ranks(comm.size() / 2);
  std::generate(grp_a_ranks.begin(),grp_a_ranks.end(),iota<int>());
  
  mpi::group grp_a = comm.group().include(grp_a_ranks.begin(),grp_a_ranks.end());
  mpi::group grp_b = comm.group().exclude(grp_a_ranks.begin(),grp_a_ranks.end());
  
  mpi::communicator part_a(comm,grp_a);
  mpi::communicator part_b(comm,grp_b);
  
  if(part_a)
    {
      std::cout << "comm rank: " << comm.rank() << " -> part_a rank:" << part_a.rank() << std::endl;
      BOOST_MPI_CHECK(part_a.rank() == comm.rank(), failed);
    }
  if(part_b)
    {
      std::cout << "comm rank: " << comm.rank() << " -> part_b rank:" << part_b.rank() << std::endl;
      BOOST_MPI_CHECK(part_b.rank() == comm.rank() - comm.size()/2, failed);
    }
  return failed;
}

int main()
{
  mpi::environment env;
  mpi::communicator comm;
  int failed = 0;
  BOOST_MPI_COUNT_FAILED(group_test(comm), failed);
  return failed;
}