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.. Copyright (C) 2004-2009 The Trustees of Indiana University.
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)
============================
|Logo| MPI BSP Process Group
============================
.. contents::
Introduction
------------
The MPI ``mpi_process_group`` is an implementation of the `process
group`_ interface using the Message Passing Interface (MPI). It is the
primary process group used in the Parallel BGL at this time.
Where Defined
-------------
Header ``<boost/graph/distributed/mpi_process_group.hpp>``
Reference
---------
::
namespace boost { namespace graph { namespace distributed {
class mpi_process_group
{
public:
typedef boost::mpi::communicator communicator_type;
// Process group constructors
mpi_process_group(communicator_type comm = communicator_type());
mpi_process_group(std::size_t num_headers, std::size_t buffer_size,
communicator_type comm = communicator_type());
mpi_process_group();
mpi_process_group(const mpi_process_group&, boost::parallel::attach_distributed_object);
// Triggers
template<typename Type, typename Handler>
void trigger(int tag, const Handler& handler);
template<typename Type, typename Handler>
void trigger_with_reply(int tag, const Handler& handler);
trigger_receive_context trigger_context() const;
// Helper operations
void poll();
mpi_process_group base() const;
};
// Process query
int process_id(const mpi_process_group&);
int num_processes(const mpi_process_group&);
// Message transmission
template<typename T>
void send(const mpi_process_group& pg, int dest, int tag, const T& value);
template<typename T>
void receive(const mpi_process_group& pg, int source, int tag, T& value);
optional<std::pair<int, int> > probe(const mpi_process_group& pg);
// Synchronization
void synchronize(const mpi_process_group& pg);
// Out-of-band communication
template<typename T>
void send_oob(const mpi_process_group& pg, int dest, int tag, const T& value);
template<typename T, typename U>
void
send_oob_with_reply(const mpi_process_group& pg, int dest, int
tag, const T& send_value, U& receive_value);
template<typename T>
void receive_oob(const mpi_process_group& pg, int source, int tag, T& value);
} } }
Since the ``mpi_process_group`` is an implementation of the `process
group`_ interface, we omit the description of most of the functions in
the prototype. Two constructors need special mentioning:
::
mpi_process_group(communicator_type comm = communicator_type());
The constructor can take an optional MPI communicator. As default a communicator
constructed from MPI_COMM_WORLD is used.
::
mpi_process_group(std::size_t num_headers, std::size_t buffer_size,
communicator_type comm = communicator_type());
For performance fine tuning the maximum number of headers in a message batch
(num_headers) and the maximum combined size of batched messages (buffer_size)
can be specified. The maximum message size of a batch is
16*num_headers+buffer_size. Sensible default values have been found by optimizing
a typical application on a cluster with Ethernet network, and are num_header=64k
and buffer_size=1MB, for a total maximum batches message size of 2MB.
-----------------------------------------------------------------------------
Copyright (C) 2007 Douglas Gregor
Copyright (C) 2007 Matthias Troyer
.. |Logo| image:: pbgl-logo.png
:align: middle
:alt: Parallel BGL
:target: http://www.osl.iu.edu/research/pbgl
.. _process group: process_group.html
|
