8bb54b04ef
FYI: find ortools \( -type d -name .git -prune \) -o -type f -print0 | xargs -0 sed -i 's/\(Copyright 2010\)-2018/\1-2021/g'
47 lines
1.3 KiB
C++
47 lines
1.3 KiB
C++
// Copyright 2010-2021 Google LLC
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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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#ifndef OR_TOOLS_BASE_ACCURATE_SUM_H_
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#define OR_TOOLS_BASE_ACCURATE_SUM_H_
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namespace operations_research {
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// Kahan summation compensation algorithm.
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//
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// http://en.wikipedia.org/wiki/Kahan_summation_algorithm
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template <typename FpNumber>
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class AccurateSum {
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public:
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// You may copy-construct an AccurateSum.
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AccurateSum() : sum_(), error_sum_() {}
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// Adds an FpNumber to the sum.
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void Add(const FpNumber& value) {
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error_sum_ += value;
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const FpNumber new_sum = sum_ + error_sum_;
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error_sum_ += sum_ - new_sum;
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sum_ = new_sum;
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}
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// Gets the value of the sum.
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FpNumber Value() const { return sum_; }
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private:
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FpNumber sum_;
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FpNumber error_sum_;
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};
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} // namespace operations_research
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#endif // OR_TOOLS_BASE_ACCURATE_SUM_H_
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