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//----------------------------------------------------------------------------
/// @file block_indirect_sort.hpp
/// @brief block indirect sort algorithm
///
/// @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_BLOCK_INDIRECT_SORT_HPP
#define __BOOST_SORT_PARALLEL_DETAIL_BLOCK_INDIRECT_SORT_HPP
#include <atomic>
#include <boost/sort/block_indirect_sort/blk_detail/merge_blocks.hpp>
#include <boost/sort/block_indirect_sort/blk_detail/move_blocks.hpp>
#include <boost/sort/block_indirect_sort/blk_detail/parallel_sort.hpp>
#include <boost/sort/pdqsort/pdqsort.hpp>
#include <boost/sort/common/util/traits.hpp>
#include <boost/sort/common/util/algorithm.hpp>
#include <future>
#include <iterator>
// This value is the minimal number of threads for to use the
// block_indirect_sort algorithm
#define BOOST_NTHREAD_BORDER 6
namespace boost
{
namespace sort
{
namespace blk_detail
{
//---------------------------------------------------------------------------
// USING SENTENCES
//---------------------------------------------------------------------------
namespace bs = boost::sort;
namespace bsc = bs::common;
namespace bscu = bsc::util;
using bscu::compare_iter;
using bscu::value_iter;
using bsc::range;
using bsc::destroy;
using bsc::initialize;
using bscu::nbits64;
using bs::pdqsort;
using bscu::enable_if_string;
using bscu::enable_if_not_string;
using bscu::tmsb;
//
///---------------------------------------------------------------------------
/// @struct block_indirect_sort
/// @brief This class is the entry point of the block indirect sort. The code
/// of this algorithm is divided in several classes:
/// bis/block.hpp : basic structures used in the algorithm
/// bis/backbone.hpp : data used by all the classes
/// bis/merge_blocks.hpp : merge the internal blocks
/// bis/move_blocks.hpp : move the blocks, and obtain all the elements
/// phisicaly sorted
/// bis/parallel_sort.hpp : make the parallel sort of each part in the
/// initial division of the data
///
//----------------------------------------------------------------------------
template<uint32_t Block_size, uint32_t Group_size, class Iter_t,
class Compare = compare_iter<Iter_t> >
struct block_indirect_sort
{
//------------------------------------------------------------------------
// D E F I N I T I O N S
//------------------------------------------------------------------------
typedef typename std::iterator_traits<Iter_t>::value_type value_t;
typedef std::atomic<uint32_t> atomic_t;
typedef range<size_t> range_pos;
typedef range<Iter_t> range_it;
typedef range<value_t *> range_buf;
typedef std::function<void(void)> function_t;
// classes used in the internal operations of the algorithm
typedef block_pos block_pos_t;
typedef block<Block_size, Iter_t> block_t;
typedef backbone<Block_size, Iter_t, Compare> backbone_t;
typedef parallel_sort<Block_size, Iter_t, Compare> parallel_sort_t;
typedef merge_blocks<Block_size, Group_size, Iter_t, Compare> merge_blocks_t;
typedef move_blocks<Block_size, Group_size, Iter_t, Compare> move_blocks_t;
typedef compare_block_pos<Block_size, Iter_t, Compare> compare_block_pos_t;
//
//------------------------------------------------------------------------
// V A R I A B L E S A N D C O N S T A N T S
//------------------------------------------------------------------------
// contains the data and the internal data structures of the algorithm for
// to be shared between the classes which are part of the algorithm
backbone_t bk;
// atomic counter for to detect the end of the works created inside
// the object
atomic_t counter;
// pointer to the uninitialized memory used for the thread buffers
value_t *ptr;
// indicate if the memory pointed by ptr is initialized
bool construct;
// range from extract the buffers for the threads
range_buf rglobal_buf;
// number of threads to use
uint32_t nthread;
//
//------------------------------------------------------------------------
// F U N C T I O N S
//------------------------------------------------------------------------
block_indirect_sort(Iter_t first, Iter_t last, Compare cmp, uint32_t nthr);
block_indirect_sort(Iter_t first, Iter_t last) :
block_indirect_sort(first, last, Compare(),
std::thread::hardware_concurrency()) { }
block_indirect_sort(Iter_t first, Iter_t last, Compare cmp) :
block_indirect_sort(first, last, cmp,
std::thread::hardware_concurrency()) { }
block_indirect_sort(Iter_t first, Iter_t last, uint32_t nthread) :
block_indirect_sort(first, last, Compare(), nthread){}
//
//------------------------------------------------------------------------
// function :destroy_all
/// @brief destructor all the data structures of the class (if the memory
/// is constructed, is destroyed) and return the uninitialized
/// memory
//------------------------------------------------------------------------
void destroy_all(void)
{
if (ptr != nullptr)
{
if (construct)
{
destroy(rglobal_buf);
construct = false;
};
std::return_temporary_buffer(ptr);
ptr = nullptr;
};
}
//
//------------------------------------------------------------------------
// function :~block_indirect_sort
/// @brief destructor of the class (if the memory is constructed, is
/// destroyed) and return the uninitialized memory
//------------------------------------------------------------------------
~block_indirect_sort(void)
{
destroy_all();
}
void split_range(size_t pos_index1, size_t pos_index2,
uint32_t level_thread);
void start_function(void);
//-------------------------------------------------------------------------
}; // End class block_indirect_sort
//----------------------------------------------------------------------------
//
//############################################################################
// ##
// ##
// N O N I N L I N E F U N C T I O N S ##
// ##
// ##
//############################################################################
//
//-------------------------------------------------------------------------
// function : block_indirect_sort
/// @brief begin with the execution of the functions stored in works
/// @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 nthr : Number of threads to use in the process.When this value
/// is lower than 2, the sorting is done with 1 thread
//-------------------------------------------------------------------------
template<uint32_t Block_size, uint32_t Group_size, class Iter_t, class Compare>
block_indirect_sort<Block_size, Group_size, Iter_t, Compare>
::block_indirect_sort(Iter_t first, Iter_t last, Compare cmp, uint32_t nthr)
: bk(first, last, cmp), counter(0), ptr(nullptr), construct(false),
nthread(nthr)
{
try
{
assert((last - first) >= 0);
size_t nelem = size_t(last - first);
if (nelem == 0) return;
//------------------- check if sort -----------------------------------
bool sorted = true;
for (Iter_t it1 = first, it2 = first + 1; it2 != last and (sorted =
not bk.cmp(*it2, *it1)); it1 = it2++);
if (sorted) return;
//------------------- check if reverse sort ---------------------------
sorted = true;
for (Iter_t it1 = first, it2 = first + 1; it2 != last and (sorted =
not bk.cmp(*it1, *it2)); it1 = it2++);
if (sorted)
{
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;
};
//---------------- check if only single thread -----------------------
size_t nthreadmax = nelem / (Block_size * Group_size) + 1;
if (nthread > nthreadmax) nthread = (uint32_t) nthreadmax;
uint32_t nbits_size = (nbits64(sizeof(value_t)) >> 1);
if (nbits_size > 5) nbits_size = 5;
size_t max_per_thread = 1 << (18 - nbits_size);
if (nelem < (max_per_thread) or nthread < 2)
{
//intro_sort (first, last, bk.cmp);
pdqsort(first, last, bk.cmp);
return;
};
//----------- creation of the temporary buffer --------------------
ptr = std::get_temporary_buffer<value_t>(Block_size * nthread).first;
if (ptr == nullptr)
{
bk.error = true;
throw std::bad_alloc();
};
rglobal_buf = range_buf(ptr, ptr + (Block_size * nthread));
initialize(rglobal_buf, *first);
construct = true;
// creation of the buffers for the threads
std::vector<value_t *> vbuf(nthread);
for (uint32_t i = 0; i < nthread; ++i)
{
vbuf[i] = ptr + (i * Block_size);
};
// Insert the first work in the stack
bscu::atomic_write(counter, 1);
function_t f1 = [&]( )
{
start_function ( );
bscu::atomic_sub (counter, 1);
};
bk.works.emplace_back(f1);
//---------------------------------------------------------------------
// PROCESS
//---------------------------------------------------------------------
std::vector<std::future<void> > vfuture(nthread);
// The function launched with the futures is "execute the functions of
// the stack until this->counter is zero
// vbuf[i] is the memory from the main thread for to configure the
// thread local buffer
for (uint32_t i = 0; i < nthread; ++i)
{
auto f1 = [=, &vbuf]( )
{ bk.exec (vbuf[i], this->counter);};
vfuture[i] = std::async(std::launch::async, f1);
};
for (uint32_t i = 0; i < nthread; ++i)
vfuture[i].get();
if (bk.error) throw std::bad_alloc();
}
catch (std::bad_alloc &)
{
destroy_all();
throw;
}
};
//
//-----------------------------------------------------------------------------
// function : split_rage
/// @brief this function splits a range of positions in the index, and
/// depending of the size, sort directly or make to a recursive call
/// to split_range
/// @param pos_index1 : first position in the index
/// @param pos_index2 : position after the last in the index
/// @param level_thread : depth of the call. When 0 sort the blocks
//-----------------------------------------------------------------------------
template<uint32_t Block_size, uint32_t Group_size, class Iter_t, class Compare>
void block_indirect_sort<Block_size, Group_size, Iter_t, Compare>
::split_range(size_t pos_index1, size_t pos_index2, uint32_t level_thread)
{
size_t nblock = pos_index2 - pos_index1;
//-------------------------------------------------------------------------
// In the blocks not sorted, the physical position is the logical position
//-------------------------------------------------------------------------
Iter_t first = bk.get_block(pos_index1).first;
Iter_t last = bk.get_range(pos_index2 - 1).last;
if (nblock < Group_size)
{
pdqsort(first, last, bk.cmp);
return;
};
size_t pos_index_mid = pos_index1 + (nblock >> 1);
atomic_t son_counter(1);
//-------------------------------------------------------------------------
// Insert in the stack the work for the second part, and the actual thread,
// execute the first part
//-------------------------------------------------------------------------
if (level_thread != 0)
{
auto f1 = [=, &son_counter]( )
{
split_range (pos_index_mid, pos_index2, level_thread - 1);
bscu::atomic_sub (son_counter, 1);
};
bk.works.emplace_back(f1);
if (bk.error) return;
split_range(pos_index1, pos_index_mid, level_thread - 1);
}
else
{
Iter_t mid = first + ((nblock >> 1) * Block_size);
auto f1 = [=, &son_counter]( )
{
parallel_sort_t (bk, mid, last);
bscu::atomic_sub (son_counter, 1);
};
bk.works.emplace_back(f1);
if (bk.error) return;
parallel_sort_t(bk, first, mid);
};
bk.exec(son_counter);
if (bk.error) return;
merge_blocks_t(bk, pos_index1, pos_index_mid, pos_index2);
};
//
//-----------------------------------------------------------------------------
// function : start_function
/// @brief this function init the process. When the number of threads is lower
/// than a predefined value, sort the elements with a parallel pdqsort.
//-----------------------------------------------------------------------------
template<uint32_t Block_size, uint32_t Group_size, class Iter_t, class Compare>
void block_indirect_sort<Block_size, Group_size, Iter_t, Compare>
::start_function(void)
{
if (nthread < BOOST_NTHREAD_BORDER)
{
parallel_sort_t(bk, bk.global_range.first, bk.global_range.last);
}
else
{
size_t level_thread = nbits64(nthread - 1) - 1;
split_range(0, bk.nblock, level_thread - 1);
if (bk.error) return;
move_blocks_t k(bk);
};
};
///---------------------------------------------------------------------------
// function block_indirect_sort_call
/// @brief This class is select the block size in the block_indirect_sort
/// algorithm depending of the type and size of the data to sort
///
//----------------------------------------------------------------------------
template <class Iter_t, class Compare,
enable_if_string<value_iter<Iter_t>> * = nullptr>
inline void block_indirect_sort_call(Iter_t first, Iter_t last, Compare cmp,
uint32_t nthr)
{
block_indirect_sort<128, 128, Iter_t, Compare>(first, last, cmp, nthr);
};
template<size_t Size>
struct block_size
{
static constexpr const uint32_t BitsSize =
(Size == 0) ? 0 : (Size > 256) ? 9 : tmsb[Size - 1];
static constexpr const uint32_t sz[10] =
{ 4096, 4096, 4096, 4096, 2048, 1024, 768, 512, 256, 128 };
static constexpr const uint32_t data = sz[BitsSize];
};
//
///---------------------------------------------------------------------------
/// @struct block_indirect_sort_call
/// @brief This class is select the block size in the block_indirect_sort
/// algorithm depending of the type and size of the data to sort
///
//----------------------------------------------------------------------------
template <class Iter_t, class Compare,
enable_if_not_string<value_iter<Iter_t>> * = nullptr>
inline void block_indirect_sort_call (Iter_t first, Iter_t last, Compare cmp,
uint32_t nthr)
{
block_indirect_sort<block_size<sizeof (value_iter<Iter_t> )>::data, 64,
Iter_t, Compare> (first, last, cmp, nthr);
};
//
//****************************************************************************
}; // End namespace blk_detail
//****************************************************************************
//
namespace bscu = boost::sort::common::util;
//
//############################################################################
// ##
// ##
// B L O C K _ I N D I R E C T _ S O R T ##
// ##
// ##
//############################################################################
//
//-----------------------------------------------------------------------------
// function : block_indirect_sort
/// @brief invocation of block_indirtect_sort with 2 parameters
///
/// @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 block_indirect_sort(Iter_t first, Iter_t last)
{
typedef bscu::compare_iter<Iter_t> Compare;
blk_detail::block_indirect_sort_call (first, last, Compare(),
std::thread::hardware_concurrency());
}
//
//-----------------------------------------------------------------------------
// function : block_indirect_sort
/// @brief invocation of block_indirtect_sort with 3 parameters. The third is
/// the number of threads
///
/// @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 block_indirect_sort(Iter_t first, Iter_t last, uint32_t nthread)
{
typedef bscu::compare_iter<Iter_t> Compare;
blk_detail::block_indirect_sort_call(first, last, Compare(), nthread);
}
//
//-----------------------------------------------------------------------------
// function : block_indirect_sort
/// @brief invocation of block_indirtect_sort with 3 parameters. The third is
/// the comparison object
///
/// @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 block_indirect_sort(Iter_t first, Iter_t last, Compare comp)
{
blk_detail::block_indirect_sort_call (first, last, comp,
std::thread::hardware_concurrency());
}
//
//-----------------------------------------------------------------------------
// function : block_indirect_sort
/// @brief invocation of block_indirtect_sort with 4 parameters.
///
/// @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 block_indirect_sort (Iter_t first, Iter_t last, Compare comp,
uint32_t nthread)
{
blk_detail::block_indirect_sort_call(first, last, comp, nthread);
}
//
//****************************************************************************
}; // End namespace sort
}; // End namespace boost
//****************************************************************************
//
#endif
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