ceph/src/boost/libs/graph_parallel/doc/mpi_bsp_process_group.rst

   1 .. Copyright (C) 2004-2009 The Trustees of Indiana University.
   2    Use, modification and distribution is subject to the Boost Software
   3    License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   4    http://www.boost.org/LICENSE_1_0.txt)
   5
   6 ============================
   7 |Logo| MPI BSP Process Group
   8 ============================
   9
  10 .. contents::
  11
  12 Introduction
  13 ------------
  14
  15 The MPI ``mpi_process_group`` is an implementation of the `process
  16 group`_ interface using the Message Passing Interface (MPI). It is the
  17 primary process group used in the Parallel BGL at this time.
  18
  19 Where Defined
  20 -------------
  21
  22 Header ``<boost/graph/distributed/mpi_process_group.hpp>``
  23
  24 Reference
  25 ---------
  26
  27 ::
  28
  29   namespace boost { namespace graph { namespace distributed {
  30
  31   class mpi_process_group
  32   {
  33   public:
  34     typedef boost::mpi::communicator communicator_type;
  35
  36     // Process group constructors
  37     mpi_process_group(communicator_type comm = communicator_type());
  38     mpi_process_group(std::size_t num_headers, std::size_t buffer_size,
  39                       communicator_type comm = communicator_type());
  40
  41     mpi_process_group();
  42     mpi_process_group(const mpi_process_group&, boost::parallel::attach_distributed_object);
  43
  44     // Triggers
  45     template<typename Type, typename Handler>
  46       void trigger(int tag, const Handler& handler);
  47
  48     template<typename Type, typename Handler>
  49       void trigger_with_reply(int tag, const Handler& handler);
  50
  51     trigger_receive_context trigger_context() const;
  52
  53     // Helper operations
  54     void poll();
  55     mpi_process_group base() const;
  56   };
  57
  58   // Process query
  59   int process_id(const mpi_process_group&);
  60   int num_processes(const mpi_process_group&);
  61
  62   // Message transmission
  63   template<typename T>
  64     void send(const mpi_process_group& pg, int dest, int tag, const T& value);
  65
  66   template<typename T>
  67     void receive(const mpi_process_group& pg, int source, int tag, T& value);
  68
  69   optional<std::pair<int, int> > probe(const mpi_process_group& pg);
  70
  71   // Synchronization
  72   void synchronize(const mpi_process_group& pg);
  73
  74   // Out-of-band communication
  75   template<typename T>
  76     void send_oob(const mpi_process_group& pg, int dest, int tag, const T& value);
  77
  78   template<typename T, typename U>
  79     void
  80     send_oob_with_reply(const mpi_process_group& pg, int dest, int
  81                         tag, const T& send_value, U& receive_value);
  82
  83   template<typename T>
  84     void receive_oob(const mpi_process_group& pg, int source, int tag, T& value);
  85
  86   } } }
  87
  88 Since the ``mpi_process_group`` is an implementation of the `process
  89 group`_ interface, we omit the description of most of the functions in
  90 the prototype. Two constructors need special mentioning:
  91
  92 ::
  93
  94       mpi_process_group(communicator_type comm = communicator_type());
  95
  96 The constructor can take an optional MPI communicator. As default a communicator
  97 constructed from MPI_COMM_WORLD is used.
  98
  99 ::
 100
 101     mpi_process_group(std::size_t num_headers, std::size_t buffer_size,
 102                       communicator_type comm = communicator_type());
 103
 104
 105 For performance fine tuning the maximum number of headers in a message batch
 106 (num_headers) and the maximum combined size of batched messages (buffer_size)
 107 can be specified. The maximum message size of a batch is
 108 16*num_headers+buffer_size. Sensible default values have been found by optimizing
 109 a typical application on a cluster with Ethernet network, and are num_header=64k
 110 and buffer_size=1MB, for a total maximum batches message size of 2MB.
 111
 112
 113
 114 -----------------------------------------------------------------------------
 115
 116 Copyright (C) 2007 Douglas Gregor
 117
 118 Copyright (C) 2007 Matthias Troyer
 119
 120 .. |Logo| image:: pbgl-logo.png
 121             :align: middle
 122             :alt: Parallel BGL
 123             :target: http://www.osl.iu.edu/research/pbgl
 124
 125 .. _process group: process_group.html