66 lines
3.1 KiB
C++
Executable File
66 lines
3.1 KiB
C++
Executable File
// ======================================================================== //
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// Copyright 2009-2014 Intel Corporation //
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// //
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// Licensed under the Apache License, Version 2.0 (the "License"); //
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// you may not use this file except in compliance with the License. //
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// You may obtain a copy of the License at //
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// //
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// http://www.apache.org/licenses/LICENSE-2.0 //
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// //
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// Unless required by applicable law or agreed to in writing, software //
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// distributed under the License is distributed on an "AS IS" BASIS, //
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. //
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// See the License for the specific language governing permissions and //
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// limitations under the License. //
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// ======================================================================== //
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#pragma once
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#include "parallel_for.h"
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namespace embree
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{
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value sequential_reduce( const Index first, const Index last, const Value& identity, const Func& func, const Reduction& reduction )
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{
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return func(range<Index>(first,last));
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value sequential_reduce( const Index first, const Index last, const Index minStepSize, const Value& identity, const Func& func, const Reduction& reduction )
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{
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return func(range<Index>(first,last));
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value parallel_reduce( const Index first, const Index last, const Index minStepSize, const Value& identity, const Func& func, const Reduction& reduction )
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{
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/* fast path for small number of iterations */
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size_t taskCount = (last-first+minStepSize-1)/minStepSize;
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if (taskCount == 1) {
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return func(range<Index>(first,last));
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}
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const size_t maxTasks = 256;
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taskCount = min(taskCount,LockStepTaskScheduler::instance()->getNumThreads(),maxTasks);
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/* parallel invokation of all tasks */
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Value values[maxTasks];
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parallel_for(taskCount, [&](const size_t taskIndex) {
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const size_t k0 = first+(taskIndex+0)*(last-first)/taskCount;
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const size_t k1 = first+(taskIndex+1)*(last-first)/taskCount;
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values[taskIndex] = func(range<Index>(k0,k1));
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});
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/* perform reduction over all tasks */
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Value v = identity;
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for (size_t i=0; i<taskCount; i++) v = reduction(v,values[i]);
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return v;
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value parallel_reduce( const Index first, const Index last, const Value& identity, const Func& func, const Reduction& reduction )
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{
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return parallel_reduce(first,last,1,identity,func,reduction);
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}
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}
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