49 lines
1.8 KiB
C++
49 lines
1.8 KiB
C++
// Copyright Alain Miniussi 2014.
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// Distributed under the Boost Software License, Version 1.0.
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// (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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// Authors: Alain Miniussi
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#ifndef BOOST_MPI_OFFSETS_HPP
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#define BOOST_MPI_OFFSETS_HPP
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#include <vector>
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#include <boost/mpi/config.hpp>
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#include <boost/mpi/communicator.hpp>
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namespace boost { namespace mpi {
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namespace detail {
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// Convert a sequence of sizes [S0..Sn] to a sequence displacement
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// [O0..On] where O[0] = 0 and O[k+1] = O[k]+S[k].
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void BOOST_MPI_DECL sizes2offsets(int const* sizes, int* offsets, int n);
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// Same as size2offset(sizes.data(), offsets.data(), sizes.size())
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void BOOST_MPI_DECL sizes2offsets(std::vector<int> const& sizes, std::vector<int>& offsets);
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// Given a sequence of sizes (typically the number of records dispatched
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// to each process in a scater) and a sequence of displacements (typically the
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// slot index at with those record starts), convert the later to a number
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// of skipped slots.
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void offsets2skipped(int const* sizes, int const* offsets, int* skipped, int n);
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// Reconstruct offsets from sizes assuming no padding.
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// Only takes place if on the root process and if
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// displs are not already provided.
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// If memory was allocated, returns a pointer to it
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// otherwise null.
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int* make_offsets(communicator const& comm, int const* sizes, int const* displs, int root = -1);
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// Reconstruct skip slots from sizes and offsets.
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// Only takes place if on the root process and if
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// displs are provided.
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// If memory was allocated, returns a pointer to it
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// otherwise null.
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int* make_skipped_slots(communicator const& comm, int const* sizes, int const* displs, int root = -1);
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}
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}}// end namespace boost::mpi
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#endif // BOOST_MPI_OFFSETS_HPP
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