ceph/src/boost/boost/mpi/collectives/scatterv.hpp

   1 // Copyright (C) 2011 Júlio Hoffimann.
   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 4.6. Scatterv
   8 #ifndef BOOST_MPI_SCATTERV_HPP
   9 #define BOOST_MPI_SCATTERV_HPP
  10
  11 #include <boost/scoped_array.hpp>
  12 #include <boost/mpi/collectives/scatter.hpp>
  13 #include <boost/mpi/detail/offsets.hpp>
  14 #include <boost/mpi/detail/antiques.hpp>
  15
  16 namespace boost { namespace mpi {
  17
  18 namespace detail {
  19
  20 //////////////////////////////////////////////
  21 /// Implementation for MPI primitive types ///
  22 //////////////////////////////////////////////
  23
  24 // We're scattering from the root for a type that has an associated MPI
  25 // datatype, so we'll use MPI_Scatterv to do all of the work.
  26 template<typename T>
  27 void
  28 scatterv_impl(const communicator& comm, const T* in_values, T* out_values, int out_size,
  29               const int* sizes, const int* displs, int root, mpl::true_)
  30 {
  31   assert(!sizes || out_size == sizes[comm.rank()]);
  32   assert(bool(sizes) == bool(in_values));
  33
  34   scoped_array<int> new_offsets_mem(make_offsets(comm, sizes, displs, root));
  35   if (new_offsets_mem) displs = new_offsets_mem.get();
  36   MPI_Datatype type = get_mpi_datatype<T>(*in_values);
  37   BOOST_MPI_CHECK_RESULT(MPI_Scatterv,
  38                          (const_cast<T*>(in_values), const_cast<int*>(sizes),
  39                           const_cast<int*>(displs), type,
  40                           out_values, out_size, type, root, comm));
  41 }
  42
  43 // We're scattering from a non-root for a type that has an associated MPI
  44 // datatype, so we'll use MPI_Scatterv to do all of the work.
  45 template<typename T>
  46 void
  47 scatterv_impl(const communicator& comm, T* out_values, int out_size, int root,
  48               mpl::true_ is_mpi_type)
  49 {
  50   scatterv_impl(comm, (T const*)0, out_values, out_size,
  51                 (const int*)0, (const int*)0, root, is_mpi_type);
  52 }
  53
  54 //////////////////////////////////////////////////
  55 /// Implementation for non MPI primitive types ///
  56 //////////////////////////////////////////////////
  57
  58 // We're scattering from the root for a type that does not have an
  59 // associated MPI datatype, so we'll need to serialize it.
  60 template<typename T>
  61 void
  62 scatterv_impl(const communicator& comm, const T* in_values, T* out_values, int out_size,
  63               int const* sizes, int const* displs, int root, mpl::false_)
  64 {
  65   packed_oarchive::buffer_type sendbuf;
  66   bool is_root = comm.rank() == root;
  67   int nproc = comm.size();
  68   std::vector<int> archsizes;
  69   if (is_root) {
  70     assert(out_size == sizes[comm.rank()]);
  71     archsizes.resize(nproc);
  72     std::vector<int> skipped;
  73     if (displs) {
  74       skipped.resize(nproc);
  75       offsets2skipped(sizes, displs, c_data(skipped), nproc);
  76       displs = c_data(skipped);
  77     }
  78     fill_scatter_sendbuf(comm, in_values, sizes, (int const*)0, sendbuf, archsizes);
  79   }
  80   dispatch_scatter_sendbuf(comm, sendbuf, archsizes, (T const*)0, out_values, out_size, root);
  81 }
  82
  83 // We're scattering to a non-root for a type that does not have an
  84 // associated MPI datatype. input data not needed.
  85 // it.
  86 template<typename T>
  87 void
  88 scatterv_impl(const communicator& comm, T* out_values, int n, int root,
  89               mpl::false_ isnt_mpi_type)
  90 {
  91   assert(root != comm.rank());
  92   scatterv_impl(comm, (T const*)0, out_values, n, (int const*)0, (int const*)0, root, isnt_mpi_type);
  93 }
  94
  95 } // end namespace detail
  96
  97 template<typename T>
  98 void
  99 scatterv(const communicator& comm, const T* in_values,
 100          const std::vector<int>& sizes, const std::vector<int>& displs,
 101          T* out_values, int out_size, int root)
 102 {
 103   using detail::c_data;
 104   detail::scatterv_impl(comm, in_values, out_values, out_size, c_data(sizes), c_data(displs),
 105                 root, is_mpi_datatype<T>());
 106 }
 107
 108 template<typename T>
 109 void
 110 scatterv(const communicator& comm, const std::vector<T>& in_values,
 111          const std::vector<int>& sizes, const std::vector<int>& displs,
 112          T* out_values, int out_size, int root)
 113 {
 114   using detail::c_data;
 115   ::boost::mpi::scatterv(comm, c_data(in_values), sizes, displs,
 116                          out_values, out_size, root);
 117 }
 118
 119 template<typename T>
 120 void scatterv(const communicator& comm, T* out_values, int out_size, int root)
 121 {
 122   BOOST_ASSERT(comm.rank() != root);
 123   detail::scatterv_impl(comm, out_values, out_size, root, is_mpi_datatype<T>());
 124 }
 125
 126 ///////////////////////
 127 // common use versions
 128 ///////////////////////
 129 template<typename T>
 130 void
 131 scatterv(const communicator& comm, const T* in_values,
 132          const std::vector<int>& sizes, T* out_values, int root)
 133 {
 134   using detail::c_data;
 135   detail::scatterv_impl(comm, in_values, out_values, sizes[comm.rank()],
 136                         c_data(sizes), (int const*)0,
 137                         root, is_mpi_datatype<T>());
 138 }
 139
 140 template<typename T>
 141 void
 142 scatterv(const communicator& comm, const std::vector<T>& in_values,
 143          const std::vector<int>& sizes, T* out_values, int root)
 144 {
 145   ::boost::mpi::scatterv(comm, &in_values[0], sizes, out_values, root);
 146 }
 147
 148 template<typename T>
 149 void
 150 scatterv(const communicator& comm, const T* in_values,
 151          T* out_values, int n, int root)
 152 {
 153   detail::scatterv_impl(comm, in_values, out_values, n, (int const*)0, (int const*)0,
 154                 root, is_mpi_datatype<T>());
 155 }
 156
 157 template<typename T>
 158 void
 159 scatterv(const communicator& comm, const std::vector<T>& in_values,
 160          T* out_values, int out_size, int root)
 161 {
 162   ::boost::mpi::scatterv(comm, &in_values[0], out_values, out_size, root);
 163 }
 164
 165 } } // end namespace boost::mpi
 166
 167 #endif // BOOST_MPI_SCATTERV_HPP