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- //----------------------------------------------------------------------------
- /// @file sample_sort.hpp
- /// @brief contains the class sample_sort
- ///
- /// @author Copyright (c) 2016 Francisco Jose Tapia (fjtapia@gmail.com )\n
- /// Distributed under the Boost Software License, Version 1.0.\n
- /// ( See accompanying file LICENSE_1_0.txt or copy at
- /// http://www.boost.org/LICENSE_1_0.txt )
- /// @version 0.1
- ///
- /// @remarks
- //-----------------------------------------------------------------------------
- #ifndef __BOOST_SORT_PARALLEL_DETAIL_SAMPLE_SORT_HPP
- #define __BOOST_SORT_PARALLEL_DETAIL_SAMPLE_SORT_HPP
- #include <functional>
- #include <future>
- #include <iterator>
- #include <memory>
- #include <type_traits>
- #include <vector>
- #include <algorithm>
- #include <boost/sort/spinsort/spinsort.hpp>
- #include <boost/sort/common/indirect.hpp>
- #include <boost/sort/common/util/atomic.hpp>
- #include <boost/sort/common/merge_four.hpp>
- #include <boost/sort/common/merge_vector.hpp>
- #include <boost/sort/common/range.hpp>
- namespace boost
- {
- namespace sort
- {
- namespace sample_detail
- {
- //---------------------------------------------------------------------------
- // USING SENTENCES
- //---------------------------------------------------------------------------
- namespace bsc = boost::sort::common;
- namespace bss = boost::sort::spin_detail;
- namespace bscu = boost::sort::common::util;
- using bsc::range;
- using bscu::atomic_add;
- using bsc::merge_vector4;
- using bsc::uninit_merge_level4;
- using bsc::less_ptr_no_null;
- //
- ///---------------------------------------------------------------------------
- /// @struct sample_sort
- /// @brief This a structure for to implement a sample sort, exception
- /// safe
- /// @tparam
- /// @remarks
- //----------------------------------------------------------------------------
- template<class Iter_t, class Compare>
- struct sample_sort
- {
- //------------------------------------------------------------------------
- // DEFINITIONS
- //------------------------------------------------------------------------
- typedef value_iter<Iter_t> value_t;
- typedef range<Iter_t> range_it;
- typedef range<value_t *> range_buf;
- typedef sample_sort<Iter_t, Compare> this_t;
- //------------------------------------------------------------------------
- // VARIABLES AND CONSTANTS
- //------------------------------------------------------------------------
- // minimun numbers of elements for to be sortd in parallel mode
- static const uint32_t thread_min = (1 << 16);
- // Number of threads to use in the algorithm
- // Number of intervals for to do the internal division of the data
- uint32_t nthread, ninterval;
- // Bool variables indicating if the auxiliary memory is constructed
- // and indicating in the auxiliary memory had been obtained inside the
- /// algorithm or had been received as a parameter
- bool construct = false, owner = false;
- // Comparison object for to compare two elements
- Compare comp;
- // Range with all the elements to sort
- range_it global_range;
- // range with the auxiliary memory
- range_buf global_buf;
- // vector of futures
- std::vector<std::future<void>> vfuture;
- // vector of vectors which contains the ranges to merge obtained in the
- // subdivision
- std::vector<std::vector<range_it>> vv_range_it;
- // each vector of ranges of the vv_range_it, need their corresponding buffer
- // for to do the merge
- std::vector<std::vector<range_buf>> vv_range_buf;
- // Initial vector of ranges
- std::vector<range_it> vrange_it_ini;
- // Initial vector of buffers
- std::vector<range_buf> vrange_buf_ini;
- // atomic counter for to know when are finished the function_t created
- // inside a function
- std::atomic<uint32_t> njob;
- // Indicate if an error in the algorithm for to undo all
- bool error;
- //------------------------------------------------------------------------
- // FUNCTIONS OF THE STRUCT
- //------------------------------------------------------------------------
- void initial_configuration(void);
- sample_sort (Iter_t first, Iter_t last, Compare cmp, uint32_t num_thread,
- value_t *paux, size_t naux);
- sample_sort(Iter_t first, Iter_t last)
- : sample_sort (first, last, Compare(), std::thread::hardware_concurrency(),
- nullptr, 0) { };
- sample_sort(Iter_t first, Iter_t last, Compare cmp)
- : sample_sort(first, last, cmp, std::thread::hardware_concurrency(),
- nullptr, 0) { };
- sample_sort(Iter_t first, Iter_t last, uint32_t num_thread)
- : sample_sort(first, last, Compare(), num_thread, nullptr, 0) { };
- sample_sort(Iter_t first, Iter_t last, Compare cmp, uint32_t num_thread)
- : sample_sort(first, last, cmp, num_thread, nullptr, 0) { };
- sample_sort(Iter_t first, Iter_t last, Compare cmp, uint32_t num_thread,
- range_buf range_buf_initial)
- : sample_sort(first, last, cmp, num_thread,
- range_buf_initial.first, range_buf_initial.size()) { };
- void destroy_all(void);
- //
- //-----------------------------------------------------------------------------
- // function :~sample_sort
- /// @brief destructor of the class. The utility is to destroy the temporary
- /// buffer used in the sorting process
- //-----------------------------------------------------------------------------
- ~sample_sort(void) { destroy_all(); };
- //
- //-----------------------------------------------------------------------
- // function : execute first
- /// @brief this a function to assign to each thread in the first merge
- //-----------------------------------------------------------------------
- void execute_first(void)
- {
- uint32_t job = 0;
- while ((job = atomic_add(njob, 1)) < ninterval)
- {
- uninit_merge_level4(vrange_buf_ini[job], vv_range_it[job],
- vv_range_buf[job], comp);
- };
- };
- //
- //-----------------------------------------------------------------------
- // function : execute
- /// @brief this is a function to assignt each thread the final merge
- //-----------------------------------------------------------------------
- void execute(void)
- {
- uint32_t job = 0;
- while ((job = atomic_add(njob, 1)) < ninterval)
- {
- merge_vector4(vrange_buf_ini[job], vrange_it_ini[job],
- vv_range_buf[job], vv_range_it[job], comp);
- };
- };
- //
- //-----------------------------------------------------------------------
- // function : first merge
- /// @brief Implement the merge of the initially sparse ranges
- //-----------------------------------------------------------------------
- void first_merge(void)
- { //---------------------------------- begin --------------------------
- njob = 0;
- for (uint32_t i = 0; i < nthread; ++i)
- {
- vfuture[i] = std::async(std::launch::async, &this_t::execute_first,
- this);
- };
- for (uint32_t i = 0; i < nthread; ++i)
- vfuture[i].get();
- };
- //
- //-----------------------------------------------------------------------
- // function : final merge
- /// @brief Implement the final merge of the ranges
- //-----------------------------------------------------------------------
- void final_merge(void)
- { //---------------------------------- begin --------------------------
- njob = 0;
- for (uint32_t i = 0; i < nthread; ++i)
- {
- vfuture[i] = std::async(std::launch::async, &this_t::execute, this);
- };
- for (uint32_t i = 0; i < nthread; ++i)
- vfuture[i].get();
- };
- //----------------------------------------------------------------------------
- };
- // End class sample_sort
- //----------------------------------------------------------------------------
- //
- //############################################################################
- // ##
- // N O N I N L I N E F U N C T I O N S ##
- // ##
- // ##
- //############################################################################
- //
- //-----------------------------------------------------------------------------
- // function : sample_sort
- /// @brief constructor of the class
- ///
- /// @param first : iterator to the first element of the range to sort
- /// @param last : iterator after the last element to the range to sort
- /// @param cmp : object for to compare two elements pointed by Iter_t iterators
- /// @param num_thread : Number of threads to use in the process. When this value
- /// is lower than 2, the sorting is done with 1 thread
- /// @param paux : pointer to the auxiliary memory. If nullptr, the memory is
- /// created inside the class
- /// @param naux : number of elements of the memory pointed by paux
- //-----------------------------------------------------------------------------
- template<class Iter_t, typename Compare>
- sample_sort<Iter_t, Compare>
- ::sample_sort (Iter_t first, Iter_t last, Compare cmp, uint32_t num_thread,
- value_t *paux, size_t naux)
- : nthread(num_thread), owner(false), comp(cmp), global_range(first, last),
- global_buf(nullptr, nullptr), error(false)
- {
- assert((last - first) >= 0);
- size_t nelem = size_t(last - first);
- construct = false;
- njob = 0;
- vfuture.resize(nthread);
- // Adjust when have many threads and only a few elements
- while (nelem > thread_min and (nthread * nthread) > (nelem >> 3))
- {
- nthread /= 2;
- };
- ninterval = (nthread << 3);
- if (nthread < 2 or nelem <= (thread_min))
- {
- bss::spinsort<Iter_t, Compare>(first, last, comp);
- return;
- };
- //------------------- check if sort --------------------------------------
- bool sw = true;
- for (Iter_t it1 = first, it2 = first + 1;
- it2 != last and (sw = not comp(*it2, *it1)); it1 = it2++);
- if (sw) return;
- //------------------- check if reverse sort ---------------------------
- sw = true;
- for (Iter_t it1 = first, it2 = first + 1;
- it2 != last and (sw = comp(*it2, *it1)); it1 = it2++);
- if (sw)
- {
- size_t nelem2 = nelem >> 1;
- Iter_t it1 = first, it2 = last - 1;
- for (size_t i = 0; i < nelem2; ++i)
- std::swap(*(it1++), *(it2--));
- return;
- };
- if (paux != nullptr)
- {
- assert(naux != 0);
- global_buf.first = paux;
- global_buf.last = paux + naux;
- owner = false;
- }
- else
- {
- value_t *ptr = std::get_temporary_buffer<value_t>(nelem).first;
- if (ptr == nullptr) throw std::bad_alloc();
- owner = true;
- global_buf = range_buf(ptr, ptr + nelem);
- };
- //------------------------------------------------------------------------
- // PROCESS
- //------------------------------------------------------------------------
- try
- {
- initial_configuration();
- } catch (std::bad_alloc &)
- {
- error = true;
- };
- if (not error)
- {
- first_merge();
- construct = true;
- final_merge();
- };
- if (error)
- {
- destroy_all();
- throw std::bad_alloc();
- };
- }
- ;
- //
- //-----------------------------------------------------------------------------
- // function : destroy_all
- /// @brief destructor of the class. The utility is to destroy the temporary
- /// buffer used in the sorting process
- //-----------------------------------------------------------------------------
- template<class Iter_t, typename Compare>
- void sample_sort<Iter_t, Compare>::destroy_all(void)
- {
- if (construct)
- {
- destroy(global_buf);
- construct = false;
- }
- if (global_buf.first != nullptr and owner)
- std::return_temporary_buffer(global_buf.first);
- }
- //
- //-----------------------------------------------------------------------------
- // function : initial_configuration
- /// @brief Create the internal data structures, and obtain the inital set of
- /// ranges to merge
- //-----------------------------------------------------------------------------
- template<class Iter_t, typename Compare>
- void sample_sort<Iter_t, Compare>::initial_configuration(void)
- {
- std::vector<range_it> vmem_thread;
- std::vector<range_buf> vbuf_thread;
- size_t nelem = global_range.size();
- //------------------------------------------------------------------------
- size_t cupo = nelem / nthread;
- Iter_t it_first = global_range.first;
- value_t *buf_first = global_buf.first;
- vmem_thread.reserve(nthread + 1);
- vbuf_thread.reserve(nthread + 1);
- for (uint32_t i = 0; i < (nthread - 1); ++i, it_first += cupo, buf_first +=
- cupo)
- {
- vmem_thread.emplace_back(it_first, it_first + cupo);
- vbuf_thread.emplace_back(buf_first, buf_first + cupo);
- };
- vmem_thread.emplace_back(it_first, global_range.last);
- vbuf_thread.emplace_back(buf_first, global_buf.last);
- //------------------------------------------------------------------------
- // Sorting of the ranges
- //------------------------------------------------------------------------
- std::vector<std::future<void>> vfuture(nthread);
- for (uint32_t i = 0; i < nthread; ++i)
- {
- auto func = [=]()
- {
- bss::spinsort<Iter_t, Compare> (vmem_thread[i].first,
- vmem_thread[i].last, comp,
- vbuf_thread[i]);
- };
- vfuture[i] = std::async(std::launch::async, func);
- };
- for (uint32_t i = 0; i < nthread; ++i)
- vfuture[i].get();
- //------------------------------------------------------------------------
- // Obtain the vector of milestones
- //------------------------------------------------------------------------
- std::vector<Iter_t> vsample;
- vsample.reserve(nthread * (ninterval - 1));
- for (uint32_t i = 0; i < nthread; ++i)
- {
- size_t distance = vmem_thread[i].size() / ninterval;
- for (size_t j = 1, pos = distance; j < ninterval; ++j, pos += distance)
- {
- vsample.push_back(vmem_thread[i].first + pos);
- };
- };
- typedef less_ptr_no_null<Iter_t, Compare> compare_ptr;
- typedef typename std::vector<Iter_t>::iterator it_to_it;
- bss::spinsort<it_to_it, compare_ptr>(vsample.begin(), vsample.end(),
- compare_ptr(comp));
- //------------------------------------------------------------------------
- // Create the final milestone vector
- //------------------------------------------------------------------------
- std::vector<Iter_t> vmilestone;
- vmilestone.reserve(ninterval);
- for (uint32_t pos = nthread >> 1; pos < vsample.size(); pos += nthread)
- {
- vmilestone.push_back(vsample[pos]);
- };
- //------------------------------------------------------------------------
- // Creation of the first vector of ranges
- //------------------------------------------------------------------------
- std::vector<std::vector<range<Iter_t>>>vv_range_first (nthread);
- for (uint32_t i = 0; i < nthread; ++i)
- {
- Iter_t itaux = vmem_thread[i].first;
- for (uint32_t k = 0; k < (ninterval - 1); ++k)
- {
- Iter_t it2 = std::upper_bound(itaux, vmem_thread[i].last,
- *vmilestone[k], comp);
- vv_range_first[i].emplace_back(itaux, it2);
- itaux = it2;
- };
- vv_range_first[i].emplace_back(itaux, vmem_thread[i].last);
- };
- //------------------------------------------------------------------------
- // Copy in buffer and creation of the final matrix of ranges
- //------------------------------------------------------------------------
- vv_range_it.resize(ninterval);
- vv_range_buf.resize(ninterval);
- vrange_it_ini.reserve(ninterval);
- vrange_buf_ini.reserve(ninterval);
- for (uint32_t i = 0; i < ninterval; ++i)
- {
- vv_range_it[i].reserve(nthread);
- vv_range_buf[i].reserve(nthread);
- };
- Iter_t it = global_range.first;
- value_t *it_buf = global_buf.first;
- for (uint32_t k = 0; k < ninterval; ++k)
- {
- size_t nelem_interval = 0;
- for (uint32_t i = 0; i < nthread; ++i)
- {
- size_t nelem_range = vv_range_first[i][k].size();
- if (nelem_range != 0)
- {
- vv_range_it[k].push_back(vv_range_first[i][k]);
- };
- nelem_interval += nelem_range;
- };
- vrange_it_ini.emplace_back(it, it + nelem_interval);
- vrange_buf_ini.emplace_back(it_buf, it_buf + nelem_interval);
- it += nelem_interval;
- it_buf += nelem_interval;
- };
- }
- ;
- //
- //****************************************************************************
- }
- ;
- // End namespace sample_detail
- //****************************************************************************
- //
- namespace bscu = boost::sort::common::util;
- //
- //############################################################################
- // ##
- // ##
- // S A M P L E _ S O R T ##
- // ##
- // ##
- //############################################################################
- //
- //-----------------------------------------------------------------------------
- // function : sample_sort
- /// @brief parallel sample sort algorithm (stable sort)
- ///
- /// @param first : iterator to the first element of the range to sort
- /// @param last : iterator after the last element to the range to sort
- //-----------------------------------------------------------------------------
- template<class Iter_t>
- void sample_sort(Iter_t first, Iter_t last)
- {
- typedef compare_iter<Iter_t> Compare;
- sample_detail::sample_sort<Iter_t, Compare>(first, last);
- };
- //
- //-----------------------------------------------------------------------------
- // function : sample_sort
- /// @brief parallel sample sort algorithm (stable sort)
- ///
- /// @param first : iterator to the first element of the range to sort
- /// @param last : iterator after the last element to the range to sort
- /// @param nthread : Number of threads to use in the process. When this value
- /// is lower than 2, the sorting is done with 1 thread
- //-----------------------------------------------------------------------------
- template<class Iter_t>
- void sample_sort(Iter_t first, Iter_t last, uint32_t nthread)
- {
- typedef compare_iter<Iter_t> Compare;
- sample_detail::sample_sort<Iter_t, Compare>(first, last, nthread);
- };
- //
- //-----------------------------------------------------------------------------
- // function : sample_sort
- /// @brief parallel sample sort algorithm (stable sort)
- ///
- /// @param first : iterator to the first element of the range to sort
- /// @param last : iterator after the last element to the range to sort
- /// @param comp : object for to compare two elements pointed by Iter_t
- /// iterators
- //-----------------------------------------------------------------------------
- template<class Iter_t, class Compare, bscu::enable_if_not_integral<Compare> * =
- nullptr>
- void sample_sort(Iter_t first, Iter_t last, Compare comp)
- {
- sample_detail::sample_sort<Iter_t, Compare>(first, last, comp);
- };
- //
- //-----------------------------------------------------------------------------
- // function : sample_sort
- /// @brief parallel sample sort algorithm (stable sort)
- ///
- /// @param first : iterator to the first element of the range to sort
- /// @param last : iterator after the last element to the range to sort
- /// @param comp : object for to compare two elements pointed by Iter_t
- /// iterators
- /// @param nthread : Number of threads to use in the process. When this value
- /// is lower than 2, the sorting is done with 1 thread
- //-----------------------------------------------------------------------------
- template<class Iter_t, class Compare>
- void sample_sort(Iter_t first, Iter_t last, Compare comp, uint32_t nthread)
- {
- sample_detail::sample_sort<Iter_t, Compare>(first, last, comp, nthread);
- };
- //
- //****************************************************************************
- };// End namespace sort
- };// End namespace boost
- //****************************************************************************
- //
- #endif
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