e957b86ca2
From llvm-project/pstl @ 0b2e0e80d96 libstdc++-v3/ChangeLog: * include/pstl/algorithm_impl.h: Update file. * include/pstl/execution_impl.h: Likewise. * include/pstl/glue_algorithm_impl.h: Likewise. * include/pstl/glue_memory_impl.h: Likewise. * include/pstl/glue_numeric_impl.h: Likewise. * include/pstl/memory_impl.h: Likewise. * include/pstl/numeric_impl.h: Likewise. * include/pstl/parallel_backend.h: Likewise. * include/pstl/parallel_backend_serial.h: Likewise. * include/pstl/parallel_backend_tbb.h: Likewise. * include/pstl/parallel_backend_utils.h: Likewise. * include/pstl/pstl_config.h: Likewise. * include/pstl/unseq_backend_simd.h: Likewise.
1292 lines
43 KiB
C++
1292 lines
43 KiB
C++
// -*- C++ -*-
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//===-- parallel_backend_tbb.h --------------------------------------------===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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#ifndef _PSTL_PARALLEL_BACKEND_TBB_H
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#define _PSTL_PARALLEL_BACKEND_TBB_H
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#include <algorithm>
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#include <type_traits>
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#include "parallel_backend_utils.h"
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// Bring in minimal required subset of Intel TBB
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#include <tbb/blocked_range.h>
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#include <tbb/parallel_for.h>
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#include <tbb/parallel_reduce.h>
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#include <tbb/parallel_scan.h>
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#include <tbb/parallel_invoke.h>
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#include <tbb/task_arena.h>
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#include <tbb/tbb_allocator.h>
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#include <tbb/task.h>
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#if TBB_INTERFACE_VERSION < 10000
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# error Intel(R) Threading Building Blocks 2018 is required; older versions are not supported.
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#endif
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namespace __pstl
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{
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namespace __tbb_backend
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{
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//! Raw memory buffer with automatic freeing and no exceptions.
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/** Some of our algorithms need to start with raw memory buffer,
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not an initialize array, because initialization/destruction
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would make the span be at least O(N). */
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// tbb::allocator can improve performance in some cases.
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template <typename _Tp>
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class __buffer
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{
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tbb::tbb_allocator<_Tp> _M_allocator;
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_Tp* _M_ptr;
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const std::size_t _M_buf_size;
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__buffer(const __buffer&) = delete;
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void
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operator=(const __buffer&) = delete;
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public:
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//! Try to obtain buffer of given size to store objects of _Tp type
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__buffer(std::size_t n) : _M_allocator(), _M_ptr(_M_allocator.allocate(n)), _M_buf_size(n) {}
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//! True if buffer was successfully obtained, zero otherwise.
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operator bool() const { return _M_ptr != NULL; }
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//! Return pointer to buffer, or NULL if buffer could not be obtained.
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_Tp*
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get() const
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{
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return _M_ptr;
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}
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//! Destroy buffer
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~__buffer() { _M_allocator.deallocate(_M_ptr, _M_buf_size); }
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};
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// Wrapper for tbb::task
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inline void
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__cancel_execution()
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{
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#if TBB_INTERFACE_VERSION <= 12000
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tbb::task::self().group()->cancel_group_execution();
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#else
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tbb::task::current_context()->cancel_group_execution();
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#endif
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}
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//------------------------------------------------------------------------
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// parallel_for
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//------------------------------------------------------------------------
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template <class _Index, class _RealBody>
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class __parallel_for_body
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{
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public:
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__parallel_for_body(const _RealBody& __body) : _M_body(__body) {}
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__parallel_for_body(const __parallel_for_body& __body) : _M_body(__body._M_body) {}
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void
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operator()(const tbb::blocked_range<_Index>& __range) const
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{
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_M_body(__range.begin(), __range.end());
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}
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private:
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_RealBody _M_body;
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};
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//! Evaluation of brick f[i,j) for each subrange [i,j) of [first,last)
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// wrapper over tbb::parallel_for
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template <class _ExecutionPolicy, class _Index, class _Fp>
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void
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__parallel_for(_ExecutionPolicy&&, _Index __first, _Index __last, _Fp __f)
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{
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tbb::this_task_arena::isolate([=]() {
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tbb::parallel_for(tbb::blocked_range<_Index>(__first, __last), __parallel_for_body<_Index, _Fp>(__f));
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});
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}
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//! Evaluation of brick f[i,j) for each subrange [i,j) of [first,last)
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// wrapper over tbb::parallel_reduce
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template <class _ExecutionPolicy, class _Value, class _Index, typename _RealBody, typename _Reduction>
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_Value
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__parallel_reduce(_ExecutionPolicy&&, _Index __first, _Index __last, const _Value& __identity,
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const _RealBody& __real_body, const _Reduction& __reduction)
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{
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return tbb::this_task_arena::isolate([__first, __last, &__identity, &__real_body, &__reduction]() -> _Value {
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return tbb::parallel_reduce(
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tbb::blocked_range<_Index>(__first, __last), __identity,
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[__real_body](const tbb::blocked_range<_Index>& __r, const _Value& __value) -> _Value {
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return __real_body(__r.begin(), __r.end(), __value);
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},
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__reduction);
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});
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}
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//------------------------------------------------------------------------
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// parallel_transform_reduce
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//
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// Notation:
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// r(i,j,init) returns reduction of init with reduction over [i,j)
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// u(i) returns f(i,i+1,identity) for a hypothetical left identity element of r
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// c(x,y) combines values x and y that were the result of r or u
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//------------------------------------------------------------------------
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template <class _Index, class _Up, class _Tp, class _Cp, class _Rp>
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struct __par_trans_red_body
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{
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alignas(_Tp) char _M_sum_storage[sizeof(_Tp)]; // Holds generalized non-commutative sum when has_sum==true
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_Rp _M_brick_reduce; // Most likely to have non-empty layout
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_Up _M_u;
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_Cp _M_combine;
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bool _M_has_sum; // Put last to minimize size of class
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_Tp&
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sum()
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{
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_PSTL_ASSERT_MSG(_M_has_sum, "sum expected");
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return *(_Tp*)_M_sum_storage;
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}
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__par_trans_red_body(_Up __u, _Tp __init, _Cp __c, _Rp __r)
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: _M_brick_reduce(__r), _M_u(__u), _M_combine(__c), _M_has_sum(true)
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{
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new (_M_sum_storage) _Tp(__init);
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}
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__par_trans_red_body(__par_trans_red_body& __left, tbb::split)
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: _M_brick_reduce(__left._M_brick_reduce), _M_u(__left._M_u), _M_combine(__left._M_combine), _M_has_sum(false)
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{
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}
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~__par_trans_red_body()
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{
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// 17.6.5.12 tells us to not worry about catching exceptions from destructors.
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if (_M_has_sum)
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sum().~_Tp();
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}
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void
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join(__par_trans_red_body& __rhs)
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{
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sum() = _M_combine(sum(), __rhs.sum());
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}
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void
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operator()(const tbb::blocked_range<_Index>& __range)
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{
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_Index __i = __range.begin();
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_Index __j = __range.end();
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if (!_M_has_sum)
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{
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_PSTL_ASSERT_MSG(__range.size() > 1, "there should be at least 2 elements");
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new (&_M_sum_storage)
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_Tp(_M_combine(_M_u(__i), _M_u(__i + 1))); // The condition i+1 < j is provided by the grain size of 3
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_M_has_sum = true;
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std::advance(__i, 2);
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if (__i == __j)
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return;
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}
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sum() = _M_brick_reduce(__i, __j, sum());
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}
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};
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template <class _ExecutionPolicy, class _Index, class _Up, class _Tp, class _Cp, class _Rp>
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_Tp
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__parallel_transform_reduce(_ExecutionPolicy&&, _Index __first, _Index __last, _Up __u, _Tp __init, _Cp __combine,
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_Rp __brick_reduce)
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{
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__tbb_backend::__par_trans_red_body<_Index, _Up, _Tp, _Cp, _Rp> __body(__u, __init, __combine, __brick_reduce);
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// The grain size of 3 is used in order to provide mininum 2 elements for each body
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tbb::this_task_arena::isolate(
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[__first, __last, &__body]() { tbb::parallel_reduce(tbb::blocked_range<_Index>(__first, __last, 3), __body); });
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return __body.sum();
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}
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//------------------------------------------------------------------------
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// parallel_scan
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//------------------------------------------------------------------------
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template <class _Index, class _Up, class _Tp, class _Cp, class _Rp, class _Sp>
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class __trans_scan_body
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{
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alignas(_Tp) char _M_sum_storage[sizeof(_Tp)]; // Holds generalized non-commutative sum when has_sum==true
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_Rp _M_brick_reduce; // Most likely to have non-empty layout
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_Up _M_u;
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_Cp _M_combine;
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_Sp _M_scan;
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bool _M_has_sum; // Put last to minimize size of class
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public:
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__trans_scan_body(_Up __u, _Tp __init, _Cp __combine, _Rp __reduce, _Sp __scan)
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: _M_brick_reduce(__reduce), _M_u(__u), _M_combine(__combine), _M_scan(__scan), _M_has_sum(true)
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{
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new (_M_sum_storage) _Tp(__init);
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}
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__trans_scan_body(__trans_scan_body& __b, tbb::split)
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: _M_brick_reduce(__b._M_brick_reduce), _M_u(__b._M_u), _M_combine(__b._M_combine), _M_scan(__b._M_scan),
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_M_has_sum(false)
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{
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}
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~__trans_scan_body()
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{
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// 17.6.5.12 tells us to not worry about catching exceptions from destructors.
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if (_M_has_sum)
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sum().~_Tp();
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}
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_Tp&
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sum() const
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{
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_PSTL_ASSERT_MSG(_M_has_sum, "sum expected");
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return *const_cast<_Tp*>(reinterpret_cast<_Tp const*>(_M_sum_storage));
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}
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void
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operator()(const tbb::blocked_range<_Index>& __range, tbb::pre_scan_tag)
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{
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_Index __i = __range.begin();
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_Index __j = __range.end();
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if (!_M_has_sum)
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{
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new (&_M_sum_storage) _Tp(_M_u(__i));
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_M_has_sum = true;
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++__i;
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if (__i == __j)
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return;
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}
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sum() = _M_brick_reduce(__i, __j, sum());
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}
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void
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operator()(const tbb::blocked_range<_Index>& __range, tbb::final_scan_tag)
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{
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sum() = _M_scan(__range.begin(), __range.end(), sum());
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}
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void
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reverse_join(__trans_scan_body& __a)
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{
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if (_M_has_sum)
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{
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sum() = _M_combine(__a.sum(), sum());
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}
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else
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{
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new (&_M_sum_storage) _Tp(__a.sum());
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_M_has_sum = true;
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}
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}
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void
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assign(__trans_scan_body& __b)
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{
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sum() = __b.sum();
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}
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};
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template <typename _Index>
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_Index
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__split(_Index __m)
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{
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_Index __k = 1;
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while (2 * __k < __m)
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__k *= 2;
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return __k;
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}
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//------------------------------------------------------------------------
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// __parallel_strict_scan
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//------------------------------------------------------------------------
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template <typename _Index, typename _Tp, typename _Rp, typename _Cp>
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void
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__upsweep(_Index __i, _Index __m, _Index __tilesize, _Tp* __r, _Index __lastsize, _Rp __reduce, _Cp __combine)
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{
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if (__m == 1)
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__r[0] = __reduce(__i * __tilesize, __lastsize);
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else
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{
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_Index __k = __split(__m);
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tbb::parallel_invoke(
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[=] { __tbb_backend::__upsweep(__i, __k, __tilesize, __r, __tilesize, __reduce, __combine); },
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[=] {
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__tbb_backend::__upsweep(__i + __k, __m - __k, __tilesize, __r + __k, __lastsize, __reduce, __combine);
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});
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if (__m == 2 * __k)
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__r[__m - 1] = __combine(__r[__k - 1], __r[__m - 1]);
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}
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}
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template <typename _Index, typename _Tp, typename _Cp, typename _Sp>
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void
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__downsweep(_Index __i, _Index __m, _Index __tilesize, _Tp* __r, _Index __lastsize, _Tp __initial, _Cp __combine,
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_Sp __scan)
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{
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if (__m == 1)
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__scan(__i * __tilesize, __lastsize, __initial);
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else
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{
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const _Index __k = __split(__m);
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tbb::parallel_invoke(
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[=] { __tbb_backend::__downsweep(__i, __k, __tilesize, __r, __tilesize, __initial, __combine, __scan); },
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// Assumes that __combine never throws.
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//TODO: Consider adding a requirement for user functors to be constant.
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[=, &__combine] {
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__tbb_backend::__downsweep(__i + __k, __m - __k, __tilesize, __r + __k, __lastsize,
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__combine(__initial, __r[__k - 1]), __combine, __scan);
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});
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}
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}
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// Adapted from Intel(R) Cilk(TM) version from cilkpub.
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// Let i:len denote a counted interval of length n starting at i. s denotes a generalized-sum value.
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// Expected actions of the functors are:
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// reduce(i,len) -> s -- return reduction value of i:len.
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// combine(s1,s2) -> s -- return merged sum
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// apex(s) -- do any processing necessary between reduce and scan.
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// scan(i,len,initial) -- perform scan over i:len starting with initial.
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// The initial range 0:n is partitioned into consecutive subranges.
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// reduce and scan are each called exactly once per subrange.
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// Thus callers can rely upon side effects in reduce.
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// combine must not throw an exception.
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// apex is called exactly once, after all calls to reduce and before all calls to scan.
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// For example, it's useful for allocating a __buffer used by scan but whose size is the sum of all reduction values.
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// T must have a trivial constructor and destructor.
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template <class _ExecutionPolicy, typename _Index, typename _Tp, typename _Rp, typename _Cp, typename _Sp, typename _Ap>
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void
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__parallel_strict_scan(_ExecutionPolicy&&, _Index __n, _Tp __initial, _Rp __reduce, _Cp __combine, _Sp __scan,
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_Ap __apex)
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{
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tbb::this_task_arena::isolate([=, &__combine]() {
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if (__n > 1)
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{
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_Index __p = tbb::this_task_arena::max_concurrency();
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const _Index __slack = 4;
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_Index __tilesize = (__n - 1) / (__slack * __p) + 1;
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_Index __m = (__n - 1) / __tilesize;
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__buffer<_Tp> __buf(__m + 1);
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_Tp* __r = __buf.get();
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__tbb_backend::__upsweep(_Index(0), _Index(__m + 1), __tilesize, __r, __n - __m * __tilesize, __reduce,
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__combine);
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// When __apex is a no-op and __combine has no side effects, a good optimizer
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// should be able to eliminate all code between here and __apex.
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// Alternatively, provide a default value for __apex that can be
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// recognized by metaprogramming that conditionlly executes the following.
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size_t __k = __m + 1;
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_Tp __t = __r[__k - 1];
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while ((__k &= __k - 1))
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__t = __combine(__r[__k - 1], __t);
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__apex(__combine(__initial, __t));
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__tbb_backend::__downsweep(_Index(0), _Index(__m + 1), __tilesize, __r, __n - __m * __tilesize, __initial,
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__combine, __scan);
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return;
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}
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// Fewer than 2 elements in sequence, or out of memory. Handle has single block.
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_Tp __sum = __initial;
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if (__n)
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__sum = __combine(__sum, __reduce(_Index(0), __n));
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__apex(__sum);
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if (__n)
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__scan(_Index(0), __n, __initial);
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});
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}
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template <class _ExecutionPolicy, class _Index, class _Up, class _Tp, class _Cp, class _Rp, class _Sp>
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_Tp
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__parallel_transform_scan(_ExecutionPolicy&&, _Index __n, _Up __u, _Tp __init, _Cp __combine, _Rp __brick_reduce,
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_Sp __scan)
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{
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__trans_scan_body<_Index, _Up, _Tp, _Cp, _Rp, _Sp> __body(__u, __init, __combine, __brick_reduce, __scan);
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auto __range = tbb::blocked_range<_Index>(0, __n);
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tbb::this_task_arena::isolate([__range, &__body]() { tbb::parallel_scan(__range, __body); });
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return __body.sum();
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}
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//------------------------------------------------------------------------
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// parallel_stable_sort
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//------------------------------------------------------------------------
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//------------------------------------------------------------------------
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// stable_sort utilities
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//
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// These are used by parallel implementations but do not depend on them.
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//------------------------------------------------------------------------
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#define _PSTL_MERGE_CUT_OFF 2000
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template <typename _Func>
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class __func_task;
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template <typename _Func>
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class __root_task;
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#if TBB_INTERFACE_VERSION <= 12000
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class __task : public tbb::task
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{
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public:
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template <typename _Fn>
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__task*
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make_continuation(_Fn&& __f)
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{
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return new (allocate_continuation()) __func_task<typename std::decay<_Fn>::type>(std::forward<_Fn>(__f));
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}
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template <typename _Fn>
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__task*
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make_child_of(__task* parent, _Fn&& __f)
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{
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return new (parent->allocate_child()) __func_task<typename std::decay<_Fn>::type>(std::forward<_Fn>(__f));
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}
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template <typename _Fn>
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__task*
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make_additional_child_of(tbb::task* parent, _Fn&& __f)
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{
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return new (tbb::task::allocate_additional_child_of(*parent))
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__func_task<typename std::decay<_Fn>::type>(std::forward<_Fn>(__f));
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}
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inline void
|
|
recycle_as_continuation()
|
|
{
|
|
tbb::task::recycle_as_continuation();
|
|
}
|
|
|
|
inline void
|
|
recycle_as_child_of(__task* parent)
|
|
{
|
|
tbb::task::recycle_as_child_of(*parent);
|
|
}
|
|
|
|
inline void
|
|
spawn(__task* __t)
|
|
{
|
|
tbb::task::spawn(*__t);
|
|
}
|
|
|
|
template <typename _Fn>
|
|
static inline void
|
|
spawn_root_and_wait(__root_task<_Fn>& __root)
|
|
{
|
|
tbb::task::spawn_root_and_wait(*__root._M_task);
|
|
}
|
|
};
|
|
|
|
template <typename _Func>
|
|
class __func_task : public __task
|
|
{
|
|
_Func _M_func;
|
|
|
|
tbb::task*
|
|
execute()
|
|
{
|
|
return _M_func(this);
|
|
};
|
|
|
|
public:
|
|
template <typename _Fn>
|
|
__func_task(_Fn&& __f) : _M_func{std::forward<_Fn>(__f)}
|
|
{
|
|
}
|
|
|
|
_Func&
|
|
body()
|
|
{
|
|
return _M_func;
|
|
}
|
|
};
|
|
|
|
template <typename _Func>
|
|
class __root_task
|
|
{
|
|
tbb::task* _M_task;
|
|
|
|
public:
|
|
template <typename... Args>
|
|
__root_task(Args&&... args)
|
|
: _M_task{new (tbb::task::allocate_root()) __func_task<_Func>{_Func(std::forward<Args>(args)...)}}
|
|
{
|
|
}
|
|
|
|
friend class __task;
|
|
friend class __func_task<_Func>;
|
|
};
|
|
|
|
#else // TBB_INTERFACE_VERSION <= 12000
|
|
class __task : public tbb::detail::d1::task
|
|
{
|
|
protected:
|
|
tbb::detail::d1::small_object_allocator _M_allocator{};
|
|
tbb::detail::d1::execution_data* _M_execute_data{};
|
|
__task* _M_parent{};
|
|
std::atomic<int> _M_refcount{};
|
|
bool _M_recycle{};
|
|
|
|
template <typename _Fn>
|
|
__task*
|
|
allocate_func_task(_Fn&& __f)
|
|
{
|
|
_PSTL_ASSERT(_M_execute_data != nullptr);
|
|
tbb::detail::d1::small_object_allocator __alloc{};
|
|
auto __t =
|
|
__alloc.new_object<__func_task<typename std::decay<_Fn>::type>>(*_M_execute_data, std::forward<_Fn>(__f));
|
|
__t->_M_allocator = __alloc;
|
|
return __t;
|
|
}
|
|
|
|
public:
|
|
__task*
|
|
parent()
|
|
{
|
|
return _M_parent;
|
|
}
|
|
|
|
void
|
|
set_ref_count(int __n)
|
|
{
|
|
_M_refcount.store(__n, std::memory_order_release);
|
|
}
|
|
|
|
template <typename _Fn>
|
|
__task*
|
|
make_continuation(_Fn&& __f)
|
|
{
|
|
auto __t = allocate_func_task(std::forward<_Fn&&>(__f));
|
|
__t->_M_parent = _M_parent;
|
|
_M_parent = nullptr;
|
|
return __t;
|
|
}
|
|
|
|
template <typename _Fn>
|
|
__task*
|
|
make_child_of(__task* __parent, _Fn&& __f)
|
|
{
|
|
auto __t = allocate_func_task(std::forward<_Fn&&>(__f));
|
|
__t->_M_parent = __parent;
|
|
return __t;
|
|
}
|
|
|
|
template <typename _Fn>
|
|
__task*
|
|
make_additional_child_of(__task* __parent, _Fn&& __f)
|
|
{
|
|
auto __t = make_child_of(__parent, std::forward<_Fn>(__f));
|
|
_PSTL_ASSERT(__parent->_M_refcount.load(std::memory_order_relaxed) > 0);
|
|
++__parent->_M_refcount;
|
|
return __t;
|
|
}
|
|
|
|
inline void
|
|
recycle_as_continuation()
|
|
{
|
|
_M_recycle = true;
|
|
}
|
|
|
|
inline void
|
|
recycle_as_child_of(__task* parent)
|
|
{
|
|
_M_recycle = true;
|
|
_M_parent = parent;
|
|
}
|
|
|
|
inline void
|
|
spawn(__task* __t)
|
|
{
|
|
_PSTL_ASSERT(_M_execute_data != nullptr);
|
|
tbb::detail::d1::spawn(*__t, *_M_execute_data->context);
|
|
}
|
|
|
|
template <typename _Fn>
|
|
static inline void
|
|
spawn_root_and_wait(__root_task<_Fn>& __root)
|
|
{
|
|
tbb::detail::d1::execute_and_wait(*__root._M_func_task, __root._M_context, __root._M_wait_object,
|
|
__root._M_context);
|
|
}
|
|
|
|
template <typename _Func>
|
|
friend class __func_task;
|
|
};
|
|
|
|
template <typename _Func>
|
|
class __func_task : public __task
|
|
{
|
|
_Func _M_func;
|
|
|
|
__task*
|
|
execute(tbb::detail::d1::execution_data& __ed) override
|
|
{
|
|
_M_execute_data = &__ed;
|
|
_M_recycle = false;
|
|
__task* __next = _M_func(this);
|
|
return finalize(__next);
|
|
};
|
|
|
|
__task*
|
|
cancel(tbb::detail::d1::execution_data& __ed) override
|
|
{
|
|
return finalize(nullptr);
|
|
}
|
|
|
|
__task*
|
|
finalize(__task* __next)
|
|
{
|
|
bool __recycle = _M_recycle;
|
|
_M_recycle = false;
|
|
|
|
if (__recycle)
|
|
{
|
|
return __next;
|
|
}
|
|
|
|
auto __parent = _M_parent;
|
|
auto __alloc = _M_allocator;
|
|
auto __ed = _M_execute_data;
|
|
|
|
this->~__func_task();
|
|
|
|
_PSTL_ASSERT(__parent != nullptr);
|
|
_PSTL_ASSERT(__parent->_M_refcount.load(std::memory_order_relaxed) > 0);
|
|
if (--__parent->_M_refcount == 0)
|
|
{
|
|
_PSTL_ASSERT(__next == nullptr);
|
|
__alloc.deallocate(this, *__ed);
|
|
return __parent;
|
|
}
|
|
|
|
return __next;
|
|
}
|
|
|
|
friend class __root_task<_Func>;
|
|
|
|
public:
|
|
template <typename _Fn>
|
|
__func_task(_Fn&& __f) : _M_func(std::forward<_Fn>(__f))
|
|
{
|
|
}
|
|
|
|
_Func&
|
|
body()
|
|
{
|
|
return _M_func;
|
|
}
|
|
};
|
|
|
|
template <typename _Func>
|
|
class __root_task : public __task
|
|
{
|
|
__task*
|
|
execute(tbb::detail::d1::execution_data& __ed) override
|
|
{
|
|
_M_wait_object.release();
|
|
return nullptr;
|
|
};
|
|
|
|
__task*
|
|
cancel(tbb::detail::d1::execution_data& __ed) override
|
|
{
|
|
_M_wait_object.release();
|
|
return nullptr;
|
|
}
|
|
|
|
__func_task<_Func>* _M_func_task{};
|
|
tbb::detail::d1::wait_context _M_wait_object{0};
|
|
tbb::task_group_context _M_context{};
|
|
|
|
public:
|
|
template <typename... Args>
|
|
__root_task(Args&&... args) : _M_wait_object{1}
|
|
{
|
|
tbb::detail::d1::small_object_allocator __alloc{};
|
|
_M_func_task = __alloc.new_object<__func_task<_Func>>(_Func(std::forward<Args>(args)...));
|
|
_M_func_task->_M_allocator = __alloc;
|
|
_M_func_task->_M_parent = this;
|
|
_M_refcount.store(1, std::memory_order_relaxed);
|
|
}
|
|
|
|
friend class __task;
|
|
};
|
|
#endif // TBB_INTERFACE_VERSION <= 12000
|
|
|
|
template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _Compare, typename _Cleanup,
|
|
typename _LeafMerge>
|
|
class __merge_func
|
|
{
|
|
typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
|
|
typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
|
|
typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
|
|
typedef typename std::iterator_traits<_RandomAccessIterator1>::value_type _ValueType;
|
|
|
|
_RandomAccessIterator1 _M_x_beg;
|
|
_RandomAccessIterator2 _M_z_beg;
|
|
|
|
_SizeType _M_xs, _M_xe;
|
|
_SizeType _M_ys, _M_ye;
|
|
_SizeType _M_zs;
|
|
_Compare _M_comp;
|
|
_LeafMerge _M_leaf_merge;
|
|
_SizeType _M_nsort; //number of elements to be sorted for partial_sort alforithm
|
|
|
|
static const _SizeType __merge_cut_off = _PSTL_MERGE_CUT_OFF;
|
|
|
|
bool _root; //means a task is merging root task
|
|
bool _x_orig; //"true" means X(or left ) subrange is in the original container; false - in the buffer
|
|
bool _y_orig; //"true" means Y(or right) subrange is in the original container; false - in the buffer
|
|
bool _split; //"true" means a merge task is a split task for parallel merging, the execution logic differs
|
|
|
|
bool
|
|
is_partial() const
|
|
{
|
|
return _M_nsort > 0;
|
|
}
|
|
|
|
struct __move_value
|
|
{
|
|
template <typename Iterator1, typename Iterator2>
|
|
void
|
|
operator()(Iterator1 __x, Iterator2 __z)
|
|
{
|
|
*__z = std::move(*__x);
|
|
}
|
|
};
|
|
|
|
struct __move_value_construct
|
|
{
|
|
template <typename Iterator1, typename Iterator2>
|
|
void
|
|
operator()(Iterator1 __x, Iterator2 __z)
|
|
{
|
|
::new (std::addressof(*__z)) _ValueType(std::move(*__x));
|
|
}
|
|
};
|
|
|
|
struct __move_range
|
|
{
|
|
template <typename Iterator1, typename Iterator2>
|
|
Iterator2
|
|
operator()(Iterator1 __first1, Iterator1 __last1, Iterator2 __first2)
|
|
{
|
|
if (__last1 - __first1 < __merge_cut_off)
|
|
return std::move(__first1, __last1, __first2);
|
|
|
|
auto __n = __last1 - __first1;
|
|
tbb::parallel_for(tbb::blocked_range<_SizeType>(0, __n, __merge_cut_off),
|
|
[__first1, __first2](const tbb::blocked_range<_SizeType>& __range) {
|
|
std::move(__first1 + __range.begin(), __first1 + __range.end(),
|
|
__first2 + __range.begin());
|
|
});
|
|
return __first2 + __n;
|
|
}
|
|
};
|
|
|
|
struct __move_range_construct
|
|
{
|
|
template <typename Iterator1, typename Iterator2>
|
|
Iterator2
|
|
operator()(Iterator1 __first1, Iterator1 __last1, Iterator2 __first2)
|
|
{
|
|
if (__last1 - __first1 < __merge_cut_off)
|
|
{
|
|
for (; __first1 != __last1; ++__first1, ++__first2)
|
|
__move_value_construct()(__first1, __first2);
|
|
return __first2;
|
|
}
|
|
|
|
auto __n = __last1 - __first1;
|
|
tbb::parallel_for(tbb::blocked_range<_SizeType>(0, __n, __merge_cut_off),
|
|
[__first1, __first2](const tbb::blocked_range<_SizeType>& __range) {
|
|
for (auto i = __range.begin(); i != __range.end(); ++i)
|
|
__move_value_construct()(__first1 + i, __first2 + i);
|
|
});
|
|
return __first2 + __n;
|
|
}
|
|
};
|
|
|
|
struct __cleanup_range
|
|
{
|
|
template <typename Iterator>
|
|
void
|
|
operator()(Iterator __first, Iterator __last)
|
|
{
|
|
if (__last - __first < __merge_cut_off)
|
|
_Cleanup()(__first, __last);
|
|
else
|
|
{
|
|
auto __n = __last - __first;
|
|
tbb::parallel_for(tbb::blocked_range<_SizeType>(0, __n, __merge_cut_off),
|
|
[__first](const tbb::blocked_range<_SizeType>& __range) {
|
|
_Cleanup()(__first + __range.begin(), __first + __range.end());
|
|
});
|
|
}
|
|
}
|
|
};
|
|
|
|
public:
|
|
__merge_func(_SizeType __xs, _SizeType __xe, _SizeType __ys, _SizeType __ye, _SizeType __zs, _Compare __comp,
|
|
_Cleanup, _LeafMerge __leaf_merge, _SizeType __nsort, _RandomAccessIterator1 __x_beg,
|
|
_RandomAccessIterator2 __z_beg, bool __x_orig, bool __y_orig, bool __root)
|
|
: _M_xs(__xs), _M_xe(__xe), _M_ys(__ys), _M_ye(__ye), _M_zs(__zs), _M_x_beg(__x_beg), _M_z_beg(__z_beg),
|
|
_M_comp(__comp), _M_leaf_merge(__leaf_merge), _M_nsort(__nsort), _root(__root),
|
|
_x_orig(__x_orig), _y_orig(__y_orig), _split(false)
|
|
{
|
|
}
|
|
|
|
bool
|
|
is_left(_SizeType __idx) const
|
|
{
|
|
return _M_xs == __idx;
|
|
}
|
|
|
|
template <typename IndexType>
|
|
void
|
|
set_odd(IndexType __idx, bool __on_off)
|
|
{
|
|
if (is_left(__idx))
|
|
_x_orig = __on_off;
|
|
else
|
|
_y_orig = __on_off;
|
|
}
|
|
|
|
__task*
|
|
operator()(__task* __self);
|
|
|
|
private:
|
|
__merge_func*
|
|
parent_merge(__task* __self) const
|
|
{
|
|
return _root ? nullptr : &static_cast<__func_task<__merge_func>*>(__self->parent())->body();
|
|
}
|
|
bool
|
|
x_less_y()
|
|
{
|
|
const auto __nx = (_M_xe - _M_xs);
|
|
const auto __ny = (_M_ye - _M_ys);
|
|
_PSTL_ASSERT(__nx > 0 && __ny > 0);
|
|
|
|
_PSTL_ASSERT(_x_orig == _y_orig);
|
|
_PSTL_ASSERT(!is_partial());
|
|
|
|
if (_x_orig)
|
|
{
|
|
_PSTL_ASSERT(std::is_sorted(_M_x_beg + _M_xs, _M_x_beg + _M_xe, _M_comp));
|
|
_PSTL_ASSERT(std::is_sorted(_M_x_beg + _M_ys, _M_x_beg + _M_ye, _M_comp));
|
|
return !_M_comp(*(_M_x_beg + _M_ys), *(_M_x_beg + _M_xe - 1));
|
|
}
|
|
|
|
_PSTL_ASSERT(std::is_sorted(_M_z_beg + _M_xs, _M_z_beg + _M_xe, _M_comp));
|
|
_PSTL_ASSERT(std::is_sorted(_M_z_beg + _M_ys, _M_z_beg + _M_ye, _M_comp));
|
|
return !_M_comp(*(_M_z_beg + _M_zs + __nx), *(_M_z_beg + _M_zs + __nx - 1));
|
|
}
|
|
void
|
|
move_x_range()
|
|
{
|
|
const auto __nx = (_M_xe - _M_xs);
|
|
const auto __ny = (_M_ye - _M_ys);
|
|
_PSTL_ASSERT(__nx > 0 && __ny > 0);
|
|
|
|
if (_x_orig)
|
|
__move_range_construct()(_M_x_beg + _M_xs, _M_x_beg + _M_xe, _M_z_beg + _M_zs);
|
|
else
|
|
{
|
|
__move_range()(_M_z_beg + _M_zs, _M_z_beg + _M_zs + __nx, _M_x_beg + _M_xs);
|
|
__cleanup_range()(_M_z_beg + _M_zs, _M_z_beg + _M_zs + __nx);
|
|
}
|
|
|
|
_x_orig = !_x_orig;
|
|
}
|
|
void
|
|
move_y_range()
|
|
{
|
|
const auto __nx = (_M_xe - _M_xs);
|
|
const auto __ny = (_M_ye - _M_ys);
|
|
|
|
if (_y_orig)
|
|
__move_range_construct()(_M_x_beg + _M_ys, _M_x_beg + _M_ye, _M_z_beg + _M_zs + __nx);
|
|
else
|
|
{
|
|
__move_range()(_M_z_beg + _M_zs + __nx, _M_z_beg + _M_zs + __nx + __ny, _M_x_beg + _M_ys);
|
|
__cleanup_range()(_M_z_beg + _M_zs + __nx, _M_z_beg + _M_zs + __nx + __ny);
|
|
}
|
|
|
|
_y_orig = !_y_orig;
|
|
}
|
|
__task*
|
|
merge_ranges(__task* __self)
|
|
{
|
|
_PSTL_ASSERT(_x_orig == _y_orig); //two merged subrange must be lie into the same buffer
|
|
|
|
const auto __nx = (_M_xe - _M_xs);
|
|
const auto __ny = (_M_ye - _M_ys);
|
|
const auto __n = __nx + __ny;
|
|
|
|
// need to merge {x} and {y}
|
|
if (__n > __merge_cut_off)
|
|
return split_merging(__self);
|
|
|
|
//merge to buffer
|
|
if (_x_orig)
|
|
{
|
|
_M_leaf_merge(_M_x_beg + _M_xs, _M_x_beg + _M_xe, _M_x_beg + _M_ys, _M_x_beg + _M_ye, _M_z_beg + _M_zs,
|
|
_M_comp, __move_value_construct(), __move_value_construct(), __move_range_construct(),
|
|
__move_range_construct());
|
|
_PSTL_ASSERT(parent_merge(__self)); //not root merging task
|
|
}
|
|
//merge to "origin"
|
|
else
|
|
{
|
|
_PSTL_ASSERT(_x_orig == _y_orig);
|
|
|
|
_PSTL_ASSERT(is_partial() || std::is_sorted(_M_z_beg + _M_xs, _M_z_beg + _M_xe, _M_comp));
|
|
_PSTL_ASSERT(is_partial() || std::is_sorted(_M_z_beg + _M_ys, _M_z_beg + _M_ye, _M_comp));
|
|
|
|
const auto __nx = (_M_xe - _M_xs);
|
|
const auto __ny = (_M_ye - _M_ys);
|
|
|
|
_M_leaf_merge(_M_z_beg + _M_xs, _M_z_beg + _M_xe, _M_z_beg + _M_ys, _M_z_beg + _M_ye, _M_x_beg + _M_zs,
|
|
_M_comp, __move_value(), __move_value(), __move_range(), __move_range());
|
|
|
|
__cleanup_range()(_M_z_beg + _M_xs, _M_z_beg + _M_xe);
|
|
__cleanup_range()(_M_z_beg + _M_ys, _M_z_beg + _M_ye);
|
|
}
|
|
return nullptr;
|
|
}
|
|
|
|
__task*
|
|
process_ranges(__task* __self)
|
|
{
|
|
_PSTL_ASSERT(_x_orig == _y_orig);
|
|
_PSTL_ASSERT(!_split);
|
|
|
|
auto p = parent_merge(__self);
|
|
|
|
if (!p)
|
|
{ //root merging task
|
|
|
|
//optimization, just for sort algorithm, //{x} <= {y}
|
|
if (!is_partial() && x_less_y()) //we have a solution
|
|
{
|
|
if (!_x_orig)
|
|
{ //we have to move the solution to the origin
|
|
move_x_range(); //parallel moving
|
|
move_y_range(); //parallel moving
|
|
}
|
|
return nullptr;
|
|
}
|
|
//else: if we have data in the origin,
|
|
//we have to move data to the buffer for final merging into the origin.
|
|
if (_x_orig)
|
|
{
|
|
move_x_range(); //parallel moving
|
|
move_y_range(); //parallel moving
|
|
}
|
|
// need to merge {x} and {y}.
|
|
return merge_ranges(__self);
|
|
}
|
|
//else: not root merging task (parent_merge() == NULL)
|
|
//optimization, just for sort algorithm, //{x} <= {y}
|
|
if (!is_partial() && x_less_y())
|
|
{
|
|
const auto id_range = _M_zs;
|
|
p->set_odd(id_range, _x_orig);
|
|
return nullptr;
|
|
}
|
|
//else: we have to revert "_x(y)_orig" flag of the parent merging task
|
|
const auto id_range = _M_zs;
|
|
p->set_odd(id_range, !_x_orig);
|
|
|
|
return merge_ranges(__self);
|
|
}
|
|
|
|
//splitting as merge task into 2 of the same level
|
|
__task*
|
|
split_merging(__task* __self)
|
|
{
|
|
_PSTL_ASSERT(_x_orig == _y_orig);
|
|
const auto __nx = (_M_xe - _M_xs);
|
|
const auto __ny = (_M_ye - _M_ys);
|
|
|
|
_SizeType __xm{};
|
|
_SizeType __ym{};
|
|
if (__nx < __ny)
|
|
{
|
|
__ym = _M_ys + __ny / 2;
|
|
|
|
if (_x_orig)
|
|
__xm = std::upper_bound(_M_x_beg + _M_xs, _M_x_beg + _M_xe, *(_M_x_beg + __ym), _M_comp) - _M_x_beg;
|
|
else
|
|
__xm = std::upper_bound(_M_z_beg + _M_xs, _M_z_beg + _M_xe, *(_M_z_beg + __ym), _M_comp) - _M_z_beg;
|
|
}
|
|
else
|
|
{
|
|
__xm = _M_xs + __nx / 2;
|
|
|
|
if (_y_orig)
|
|
__ym = std::lower_bound(_M_x_beg + _M_ys, _M_x_beg + _M_ye, *(_M_x_beg + __xm), _M_comp) - _M_x_beg;
|
|
else
|
|
__ym = std::lower_bound(_M_z_beg + _M_ys, _M_z_beg + _M_ye, *(_M_z_beg + __xm), _M_comp) - _M_z_beg;
|
|
}
|
|
|
|
auto __zm = _M_zs + ((__xm - _M_xs) + (__ym - _M_ys));
|
|
__merge_func __right_func(__xm, _M_xe, __ym, _M_ye, __zm, _M_comp, _Cleanup(), _M_leaf_merge, _M_nsort,
|
|
_M_x_beg, _M_z_beg, _x_orig, _y_orig, _root);
|
|
__right_func._split = true;
|
|
auto __merge_task = __self->make_additional_child_of(__self->parent(), std::move(__right_func));
|
|
__self->spawn(__merge_task);
|
|
__self->recycle_as_continuation();
|
|
|
|
_M_xe = __xm;
|
|
_M_ye = __ym;
|
|
_split = true;
|
|
|
|
return __self;
|
|
}
|
|
};
|
|
|
|
template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename __M_Compare, typename _Cleanup,
|
|
typename _LeafMerge>
|
|
__task*
|
|
__merge_func<_RandomAccessIterator1, _RandomAccessIterator2, __M_Compare, _Cleanup, _LeafMerge>::
|
|
operator()(__task* __self)
|
|
{
|
|
//a. split merge task into 2 of the same level; the special logic,
|
|
//without processing(process_ranges) adjacent sub-ranges x and y
|
|
if (_split)
|
|
return merge_ranges(__self);
|
|
|
|
//b. General merging of adjacent sub-ranges x and y (with optimization in case of {x} <= {y} )
|
|
|
|
//1. x and y are in the even buffer
|
|
//2. x and y are in the odd buffer
|
|
if (_x_orig == _y_orig)
|
|
return process_ranges(__self);
|
|
|
|
//3. x is in even buffer, y is in the odd buffer
|
|
//4. x is in odd buffer, y is in the even buffer
|
|
if (!parent_merge(__self))
|
|
{ //root merge task
|
|
if (_x_orig)
|
|
move_x_range();
|
|
else
|
|
move_y_range();
|
|
}
|
|
else
|
|
{
|
|
const _SizeType __nx = (_M_xe - _M_xs);
|
|
const _SizeType __ny = (_M_ye - _M_ys);
|
|
_PSTL_ASSERT(__nx > 0);
|
|
_PSTL_ASSERT(__nx > 0);
|
|
|
|
if (__nx < __ny)
|
|
move_x_range();
|
|
else
|
|
move_y_range();
|
|
}
|
|
|
|
return process_ranges(__self);
|
|
}
|
|
|
|
template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _Compare, typename _LeafSort>
|
|
class __stable_sort_func
|
|
{
|
|
public:
|
|
typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
|
|
typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
|
|
typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
|
|
|
|
private:
|
|
_RandomAccessIterator1 _M_xs, _M_xe, _M_x_beg;
|
|
_RandomAccessIterator2 _M_zs, _M_z_beg;
|
|
_Compare _M_comp;
|
|
_LeafSort _M_leaf_sort;
|
|
bool _M_root;
|
|
_SizeType _M_nsort; //zero or number of elements to be sorted for partial_sort alforithm
|
|
|
|
public:
|
|
__stable_sort_func(_RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe, _RandomAccessIterator2 __zs,
|
|
bool __root, _Compare __comp, _LeafSort __leaf_sort, _SizeType __nsort,
|
|
_RandomAccessIterator1 __x_beg, _RandomAccessIterator2 __z_beg)
|
|
: _M_xs(__xs), _M_xe(__xe), _M_x_beg(__x_beg), _M_zs(__zs), _M_z_beg(__z_beg), _M_comp(__comp),
|
|
_M_leaf_sort(__leaf_sort), _M_root(__root), _M_nsort(__nsort)
|
|
{
|
|
}
|
|
|
|
__task*
|
|
operator()(__task* __self);
|
|
};
|
|
|
|
#define _PSTL_STABLE_SORT_CUT_OFF 500
|
|
|
|
template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _Compare, typename _LeafSort>
|
|
__task*
|
|
__stable_sort_func<_RandomAccessIterator1, _RandomAccessIterator2, _Compare, _LeafSort>::operator()(__task* __self)
|
|
{
|
|
typedef __merge_func<_RandomAccessIterator1, _RandomAccessIterator2, _Compare, __utils::__serial_destroy,
|
|
__utils::__serial_move_merge>
|
|
_MergeTaskType;
|
|
|
|
const _SizeType __n = _M_xe - _M_xs;
|
|
const _SizeType __nmerge = _M_nsort > 0 ? _M_nsort : __n;
|
|
const _SizeType __sort_cut_off = _PSTL_STABLE_SORT_CUT_OFF;
|
|
if (__n <= __sort_cut_off)
|
|
{
|
|
_M_leaf_sort(_M_xs, _M_xe, _M_comp);
|
|
_PSTL_ASSERT(!_M_root);
|
|
return nullptr;
|
|
}
|
|
|
|
const _RandomAccessIterator1 __xm = _M_xs + __n / 2;
|
|
const _RandomAccessIterator2 __zm = _M_zs + (__xm - _M_xs);
|
|
const _RandomAccessIterator2 __ze = _M_zs + __n;
|
|
_MergeTaskType __m(_MergeTaskType(_M_xs - _M_x_beg, __xm - _M_x_beg, __xm - _M_x_beg, _M_xe - _M_x_beg,
|
|
_M_zs - _M_z_beg, _M_comp, __utils::__serial_destroy(),
|
|
__utils::__serial_move_merge(__nmerge), _M_nsort, _M_x_beg, _M_z_beg,
|
|
/*x_orig*/ true, /*y_orig*/ true, /*root*/ _M_root));
|
|
auto __parent = __self->make_continuation(std::move(__m));
|
|
__parent->set_ref_count(2);
|
|
auto __right = __self->make_child_of(
|
|
__parent, __stable_sort_func(__xm, _M_xe, __zm, false, _M_comp, _M_leaf_sort, _M_nsort, _M_x_beg, _M_z_beg));
|
|
__self->spawn(__right);
|
|
__self->recycle_as_child_of(__parent);
|
|
_M_root = false;
|
|
_M_xe = __xm;
|
|
|
|
return __self;
|
|
}
|
|
|
|
template <class _ExecutionPolicy, typename _RandomAccessIterator, typename _Compare, typename _LeafSort>
|
|
void
|
|
__parallel_stable_sort(_ExecutionPolicy&&, _RandomAccessIterator __xs, _RandomAccessIterator __xe, _Compare __comp,
|
|
_LeafSort __leaf_sort, std::size_t __nsort = 0)
|
|
{
|
|
tbb::this_task_arena::isolate([=, &__nsort]() {
|
|
//sorting based on task tree and parallel merge
|
|
typedef typename std::iterator_traits<_RandomAccessIterator>::value_type _ValueType;
|
|
typedef typename std::iterator_traits<_RandomAccessIterator>::difference_type _DifferenceType;
|
|
const _DifferenceType __n = __xe - __xs;
|
|
if (__nsort == __n)
|
|
__nsort = 0; // 'partial_sort' becames 'sort'
|
|
|
|
const _DifferenceType __sort_cut_off = _PSTL_STABLE_SORT_CUT_OFF;
|
|
if (__n > __sort_cut_off)
|
|
{
|
|
__buffer<_ValueType> __buf(__n);
|
|
__root_task<__stable_sort_func<_RandomAccessIterator, _ValueType*, _Compare, _LeafSort>> __root{
|
|
__xs, __xe, __buf.get(), true, __comp, __leaf_sort, __nsort, __xs, __buf.get()};
|
|
__task::spawn_root_and_wait(__root);
|
|
return;
|
|
}
|
|
//serial sort
|
|
__leaf_sort(__xs, __xe, __comp);
|
|
});
|
|
}
|
|
|
|
//------------------------------------------------------------------------
|
|
// parallel_merge
|
|
//------------------------------------------------------------------------
|
|
template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _RandomAccessIterator3,
|
|
typename _Compare, typename _LeafMerge>
|
|
class __merge_func_static
|
|
{
|
|
_RandomAccessIterator1 _M_xs, _M_xe;
|
|
_RandomAccessIterator2 _M_ys, _M_ye;
|
|
_RandomAccessIterator3 _M_zs;
|
|
_Compare _M_comp;
|
|
_LeafMerge _M_leaf_merge;
|
|
|
|
public:
|
|
__merge_func_static(_RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe, _RandomAccessIterator2 __ys,
|
|
_RandomAccessIterator2 __ye, _RandomAccessIterator3 __zs, _Compare __comp,
|
|
_LeafMerge __leaf_merge)
|
|
: _M_xs(__xs), _M_xe(__xe), _M_ys(__ys), _M_ye(__ye), _M_zs(__zs), _M_comp(__comp), _M_leaf_merge(__leaf_merge)
|
|
{
|
|
}
|
|
|
|
__task*
|
|
operator()(__task* __self);
|
|
};
|
|
|
|
//TODO: consider usage of parallel_for with a custom blocked_range
|
|
template <typename _RandomAccessIterator1, typename _RandomAccessIterator2, typename _RandomAccessIterator3,
|
|
typename __M_Compare, typename _LeafMerge>
|
|
__task*
|
|
__merge_func_static<_RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator3, __M_Compare, _LeafMerge>::
|
|
operator()(__task* __self)
|
|
{
|
|
typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
|
|
typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
|
|
typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
|
|
const _SizeType __n = (_M_xe - _M_xs) + (_M_ye - _M_ys);
|
|
const _SizeType __merge_cut_off = _PSTL_MERGE_CUT_OFF;
|
|
if (__n <= __merge_cut_off)
|
|
{
|
|
_M_leaf_merge(_M_xs, _M_xe, _M_ys, _M_ye, _M_zs, _M_comp);
|
|
return nullptr;
|
|
}
|
|
|
|
_RandomAccessIterator1 __xm;
|
|
_RandomAccessIterator2 __ym;
|
|
if (_M_xe - _M_xs < _M_ye - _M_ys)
|
|
{
|
|
__ym = _M_ys + (_M_ye - _M_ys) / 2;
|
|
__xm = std::upper_bound(_M_xs, _M_xe, *__ym, _M_comp);
|
|
}
|
|
else
|
|
{
|
|
__xm = _M_xs + (_M_xe - _M_xs) / 2;
|
|
__ym = std::lower_bound(_M_ys, _M_ye, *__xm, _M_comp);
|
|
}
|
|
const _RandomAccessIterator3 __zm = _M_zs + ((__xm - _M_xs) + (__ym - _M_ys));
|
|
auto __right = __self->make_additional_child_of(
|
|
__self->parent(), __merge_func_static(__xm, _M_xe, __ym, _M_ye, __zm, _M_comp, _M_leaf_merge));
|
|
__self->spawn(__right);
|
|
__self->recycle_as_continuation();
|
|
_M_xe = __xm;
|
|
_M_ye = __ym;
|
|
|
|
return __self;
|
|
}
|
|
|
|
template <class _ExecutionPolicy, typename _RandomAccessIterator1, typename _RandomAccessIterator2,
|
|
typename _RandomAccessIterator3, typename _Compare, typename _LeafMerge>
|
|
void
|
|
__parallel_merge(_ExecutionPolicy&&, _RandomAccessIterator1 __xs, _RandomAccessIterator1 __xe,
|
|
_RandomAccessIterator2 __ys, _RandomAccessIterator2 __ye, _RandomAccessIterator3 __zs, _Compare __comp,
|
|
_LeafMerge __leaf_merge)
|
|
{
|
|
typedef typename std::iterator_traits<_RandomAccessIterator1>::difference_type _DifferenceType1;
|
|
typedef typename std::iterator_traits<_RandomAccessIterator2>::difference_type _DifferenceType2;
|
|
typedef typename std::common_type<_DifferenceType1, _DifferenceType2>::type _SizeType;
|
|
const _SizeType __n = (__xe - __xs) + (__ye - __ys);
|
|
const _SizeType __merge_cut_off = _PSTL_MERGE_CUT_OFF;
|
|
if (__n <= __merge_cut_off)
|
|
{
|
|
// Fall back on serial merge
|
|
__leaf_merge(__xs, __xe, __ys, __ye, __zs, __comp);
|
|
}
|
|
else
|
|
{
|
|
tbb::this_task_arena::isolate([=]() {
|
|
typedef __merge_func_static<_RandomAccessIterator1, _RandomAccessIterator2, _RandomAccessIterator3,
|
|
_Compare, _LeafMerge>
|
|
_TaskType;
|
|
__root_task<_TaskType> __root{__xs, __xe, __ys, __ye, __zs, __comp, __leaf_merge};
|
|
__task::spawn_root_and_wait(__root);
|
|
});
|
|
}
|
|
}
|
|
|
|
//------------------------------------------------------------------------
|
|
// parallel_invoke
|
|
//------------------------------------------------------------------------
|
|
template <class _ExecutionPolicy, typename _F1, typename _F2>
|
|
void
|
|
__parallel_invoke(_ExecutionPolicy&&, _F1&& __f1, _F2&& __f2)
|
|
{
|
|
//TODO: a version of tbb::this_task_arena::isolate with variadic arguments pack should be added in the future
|
|
tbb::this_task_arena::isolate([&]() { tbb::parallel_invoke(std::forward<_F1>(__f1), std::forward<_F2>(__f2)); });
|
|
}
|
|
|
|
} // namespace __tbb_backend
|
|
} // namespace __pstl
|
|
|
|
#endif /* _PSTL_PARALLEL_BACKEND_TBB_H */
|