boost/mpi/collectives/broadcast.hpp

   1 // Copyright (C) 2005, 2006 Douglas Gregor <doug.gregor -at- gmail.com>.
   2
   3 // Use, modification and distribution is subject to the Boost Software
   4 // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   5 // http://www.boost.org/LICENSE_1_0.txt)
   6
   7 // Message Passing Interface 1.1 -- Section 4.4. Broadcast
   8 #ifndef BOOST_MPI_BROADCAST_HPP
   9 #define BOOST_MPI_BROADCAST_HPP
  10
  11 #include <boost/mpi/collectives_fwd.hpp>
  12 #include <boost/mpi/exception.hpp>
  13 #include <boost/mpi/datatype.hpp>
  14 #include <boost/mpi/communicator.hpp>
  15
  16 namespace boost { namespace mpi {
  17
  18 /************************************************************************
  19  * Specializations                                                      *
  20  ************************************************************************/
  21
  22 /**
  23  * INTERNAL ONLY
  24  */
  25 template<>
  26 BOOST_MPI_DECL void
  27 broadcast<const packed_oarchive>(const communicator& comm,
  28                                  const packed_oarchive& oa,
  29                                  int root);
  30
  31 /**
  32  * INTERNAL ONLY
  33  */
  34 template<>
  35 BOOST_MPI_DECL void
  36 broadcast<packed_oarchive>(const communicator& comm, packed_oarchive& oa,
  37                            int root);
  38
  39 /**
  40  * INTERNAL ONLY
  41  */
  42 template<>
  43 BOOST_MPI_DECL void
  44 broadcast<packed_iarchive>(const communicator& comm, packed_iarchive& ia,
  45                            int root);
  46
  47 /**
  48  * INTERNAL ONLY
  49  */
  50 template<>
  51 BOOST_MPI_DECL void
  52 broadcast<const packed_skeleton_oarchive>(const communicator& comm,
  53                                           const packed_skeleton_oarchive& oa,
  54                                           int root);
  55
  56 /**
  57  * INTERNAL ONLY
  58  */
  59 template<>
  60 void
  61 broadcast<packed_skeleton_oarchive>(const communicator& comm,
  62                                     packed_skeleton_oarchive& oa, int root);
  63
  64 /**
  65  * INTERNAL ONLY
  66  */
  67 template<>
  68 void
  69 broadcast<packed_skeleton_iarchive>(const communicator& comm,
  70                                     packed_skeleton_iarchive& ia, int root);
  71
  72 /**
  73  * INTERNAL ONLY
  74  */
  75 template<>
  76 void broadcast<content>(const communicator& comm, content& c, int root);
  77
  78 /**
  79  * INTERNAL ONLY
  80  */
  81 template<>
  82 void broadcast<const content>(const communicator& comm, const content& c,
  83                               int root);
  84
  85 /************************************************************************
  86  * broadcast() implementation                                           *
  87  ************************************************************************/
  88 namespace detail {
  89   // We're sending a type that has an associated MPI datatype, so
  90   // we'll use MPI_Bcast to do all of the work.
  91   template<typename T>
  92   void
  93   broadcast_impl(const communicator& comm, T* values, int n, int root,
  94                  mpl::true_)
  95   {
  96     BOOST_MPI_CHECK_RESULT(MPI_Bcast,
  97                            (values, n,
  98                             boost::mpi::get_mpi_datatype<T>(*values),
  99                             root, MPI_Comm(comm)));
 100   }
 101
 102   // We're sending a type that does not have an associated MPI
 103   // datatype, so we'll need to serialize it. Unfortunately, this
 104   // means that we cannot use MPI_Bcast, so we'll just send from the
 105   // root to everyone else.
 106   template<typename T>
 107   void
 108   broadcast_impl(const communicator& comm, T* values, int n, int root,
 109                  mpl::false_)
 110   {
 111     if (comm.rank() == root) {
 112       packed_oarchive oa(comm);
 113       for (int i = 0; i < n; ++i)
 114         oa << values[i];
 115       broadcast(comm, oa, root);
 116     } else {
 117       packed_iarchive ia(comm);
 118       broadcast(comm, ia, root);
 119       for (int i = 0; i < n; ++i)
 120         ia >> values[i];
 121     }
 122   }
 123 } // end namespace detail
 124
 125 template<typename T>
 126 void broadcast(const communicator& comm, T& value, int root)
 127 {
 128   detail::broadcast_impl(comm, &value, 1, root, is_mpi_datatype<T>());
 129 }
 130
 131 template<typename T>
 132 void broadcast(const communicator& comm, T* values, int n, int root)
 133 {
 134   detail::broadcast_impl(comm, values, n, root, is_mpi_datatype<T>());
 135 }
 136
 137 } } // end namespace boost::mpi
 138
 139 // If the user has already included skeleton_and_content.hpp, include
 140 // the code to broadcast skeletons and content.
 141 #ifdef BOOST_MPI_SKELETON_AND_CONTENT_HPP
 142 #  include <boost/mpi/detail/broadcast_sc.hpp>
 143 #endif
 144
 145 #endif // BOOST_MPI_BROADCAST_HPP