1 // Copyright Alain Miniussi 2014. 2 // Distributed under the Boost Software License, Version 1.0. 3 // (See accompanying file LICENSE_1_0.txt or copy at 4 // http://www.boost.org/LICENSE_1_0.txt) 5 6 // Authors: Alain Miniussi 7 8 #ifndef BOOST_MPI_OFFSETS_HPP 9 #define BOOST_MPI_OFFSETS_HPP 10 11 #include <vector> 12 #include <boost/mpi/config.hpp> 13 #include <boost/mpi/communicator.hpp> 14 15 namespace boost { namespace mpi { 16 namespace detail { 17 18 // Convert a sequence of sizes [S0..Sn] to a sequence displacement 19 // [O0..On] where O[0] = 0 and O[k+1] = O[k]+S[k]. 20 void BOOST_MPI_DECL sizes2offsets(int const* sizes, int* offsets, int n); 21 22 // Same as size2offset(sizes.data(), offsets.data(), sizes.size()) 23 void BOOST_MPI_DECL sizes2offsets(std::vector<int> const& sizes, std::vector<int>& offsets); 24 25 // Given a sequence of sizes (typically the number of records dispatched 26 // to each process in a scater) and a sequence of displacements (typically the 27 // slot index at with those record starts), convert the later to a number 28 // of skipped slots. 29 void offsets2skipped(int const* sizes, int const* offsets, int* skipped, int n); 30 31 // Reconstruct offsets from sizes assuming no padding. 32 // Only takes place if on the root process and if 33 // displs are not already provided. 34 // If memory was allocated, returns a pointer to it 35 // otherwise null. 36 int* make_offsets(communicator const& comm, int const* sizes, int const* displs, int root = -1); 37 38 // Reconstruct skip slots from sizes and offsets. 39 // Only takes place if on the root process and if 40 // displs are provided. 41 // If memory was allocated, returns a pointer to it 42 // otherwise null. 43 int* make_skipped_slots(communicator const& comm, int const* sizes, int const* displs, int root = -1); 44 45 } 46 }}// end namespace boost::mpi 47 48 #endif // BOOST_MPI_OFFSETS_HPP 49