id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
5849	all_to_all() passes invalid args to allocate when sending lots of data	Kelly Davis <kdavis@…>	Matthias Troyer	"For boost 1.47.0 code of the following form fails...
{{{
#!div style=""font-size: 80%""
  {{{#!c++
boost::mpi::communicator communicator;
std::vector< std::list<Thing*> > in_values(communicator.size());
std::vector< std::list<Thing*> > out_values(communicator.size());
// Point the lists in in_values to more than numeric_limits<int>::max() bytes of data
boost::mpi::all_to_all(communicator,in_values,out_values);
  }}}
}}}
Such code ends up passing the allocator, using openmpi-1.4.3, an invalid argument.

Looking at all_to_all.hpp and the method...
{{{
#!div style=""font-size: 80%""
  {{{#!c++
  template<typename T>
  void
  all_to_all_impl(const communicator& comm, const T* in_values, int n,
                  T* out_values, mpl::false_)
  {
      ...
  }
  }}}
}}}
I think I see why this happens. The method begins as follows...
{{{
#!div style=""font-size: 80%""
  {{{#!c++
    std::vector<int> send_sizes(size);

    // The displacements for each outgoing value.
    std::vector<int> send_disps(size);

    // The buffer that will store all of the outgoing values
    std::vector<char, allocator<char> > outgoing;

    // Pack the buffer with all of the outgoing values.
    for (int dest = 0; dest < size; ++dest) {
      // Keep track of the displacements
      send_disps[dest] = outgoing.size();

      // Our own value will never be transmitted, so don't pack it.
      if (dest != rank) {
        packed_oarchive oa(comm, outgoing);
        for (int i = 0; i < n; ++i)
          oa << in_values[dest * n + i];
      }

      // Keep track of the sizes
      send_sizes[dest] = outgoing.size() - send_disps[dest];
    }
  }}}
}}}
If outgoing.size() or (outgoing.size() - send_disps[dest]) is greater than
numeric_limits<int>::max(), then send_disps[dest]  or send_sizes[dest]
flips over to negative values or is simply junk. After that happens the rest
of the code in all_to_all_impl() doesn't really make any sense.

My guess is that instead of using int here...
{{{
#!div style=""font-size: 80%""
  {{{#!c++
  std::vector<int> send_sizes(size);
  std::vector<int> send_disps(size);
  std::vector<int> recv_sizes(size);
  ...
  }}}
}}}
you should use allocator::size_type."	Bugs	new	To Be Determined	mpi	Boost 1.47.0	Problem			kdavis@…