113 lines
3.3 KiB
C++
113 lines
3.3 KiB
C++
// Copyright 2015-2018 Hans Dembinski
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//
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// Distributed under the Boost Software License, version 1.0.
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// (See accompanying file LICENSE_1_0.txt
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// or copy at http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_HISTOGRAM_ACCUMULATORS_WEIGHTED_SUM_HPP
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#define BOOST_HISTOGRAM_ACCUMULATORS_WEIGHTED_SUM_HPP
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#include <boost/histogram/fwd.hpp>
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#include <type_traits>
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namespace boost {
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namespace histogram {
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namespace accumulators {
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/// Holds sum of weights and its variance estimate
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template <typename RealType>
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class weighted_sum {
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public:
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weighted_sum() = default;
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explicit weighted_sum(const RealType& value) noexcept
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: sum_of_weights_(value), sum_of_weights_squared_(value) {}
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weighted_sum(const RealType& value, const RealType& variance) noexcept
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: sum_of_weights_(value), sum_of_weights_squared_(variance) {}
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/// Increment by one.
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weighted_sum& operator++() { return operator+=(1); }
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/// Increment by value.
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template <typename T>
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weighted_sum& operator+=(const T& value) {
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sum_of_weights_ += value;
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sum_of_weights_squared_ += value * value;
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return *this;
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}
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/// Added another weighted sum.
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template <typename T>
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weighted_sum& operator+=(const weighted_sum<T>& rhs) {
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sum_of_weights_ += static_cast<RealType>(rhs.sum_of_weights_);
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sum_of_weights_squared_ += static_cast<RealType>(rhs.sum_of_weights_squared_);
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return *this;
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}
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/// Scale by value.
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weighted_sum& operator*=(const RealType& x) {
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sum_of_weights_ *= x;
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sum_of_weights_squared_ *= x * x;
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return *this;
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}
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bool operator==(const RealType& rhs) const noexcept {
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return sum_of_weights_ == rhs && sum_of_weights_squared_ == rhs;
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}
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template <typename T>
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bool operator==(const weighted_sum<T>& rhs) const noexcept {
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return sum_of_weights_ == rhs.sum_of_weights_ &&
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sum_of_weights_squared_ == rhs.sum_of_weights_squared_;
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}
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template <typename T>
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bool operator!=(const T& rhs) const noexcept {
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return !operator==(rhs);
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}
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/// Return value of the sum.
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const RealType& value() const noexcept { return sum_of_weights_; }
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/// Return estimated variance of the sum.
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const RealType& variance() const noexcept { return sum_of_weights_squared_; }
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// lossy conversion must be explicit
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template <class T>
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explicit operator T() const {
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return static_cast<T>(sum_of_weights_);
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}
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template <class Archive>
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void serialize(Archive&, unsigned /* version */);
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private:
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RealType sum_of_weights_ = RealType();
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RealType sum_of_weights_squared_ = RealType();
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};
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} // namespace accumulators
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} // namespace histogram
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} // namespace boost
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#ifndef BOOST_HISTOGRAM_DOXYGEN_INVOKED
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namespace std {
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template <class T, class U>
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struct common_type<boost::histogram::accumulators::weighted_sum<T>,
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boost::histogram::accumulators::weighted_sum<U>> {
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using type = boost::histogram::accumulators::weighted_sum<common_type_t<T, U>>;
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};
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template <class T, class U>
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struct common_type<boost::histogram::accumulators::weighted_sum<T>, U> {
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using type = boost::histogram::accumulators::weighted_sum<common_type_t<T, U>>;
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};
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template <class T, class U>
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struct common_type<T, boost::histogram::accumulators::weighted_sum<U>> {
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using type = boost::histogram::accumulators::weighted_sum<common_type_t<T, U>>;
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};
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} // namespace std
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#endif
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#endif
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