boost/histogram/axis/variable.hpp
// Copyright 2015-2018 Hans Dembinski // // Distributed under the Boost Software License, Version 1.0. // (See accompanying file LICENSE_1_0.txt // or copy at http://www.boost.org/LICENSE_1_0.txt) #ifndef BOOST_HISTOGRAM_AXIS_VARIABLE_HPP #define BOOST_HISTOGRAM_AXIS_VARIABLE_HPP #include <algorithm> #include <boost/assert.hpp> #include <boost/histogram/axis/interval_view.hpp> #include <boost/histogram/axis/iterator.hpp> #include <boost/histogram/axis/option.hpp> #include <boost/histogram/detail/compressed_pair.hpp> #include <boost/histogram/detail/meta.hpp> #include <boost/histogram/fwd.hpp> #include <boost/throw_exception.hpp> #include <cmath> #include <limits> #include <memory> #include <stdexcept> #include <type_traits> #include <utility> #include <vector> namespace boost { namespace histogram { namespace axis { /** Axis for non-equidistant bins on the real line. Binning is a O(log(N)) operation. If speed matters and the problem domain allows it, prefer a regular axis, possibly with a transform. @tparam Value input value type, must be floating point. @tparam MetaData type to store meta data. @tparam Options see boost::histogram::axis::option (all values allowed). @tparam Allocator allocator to use for dynamic memory management. */ template <class Value, class MetaData, class Options, class Allocator> class variable : public iterator_mixin<variable<Value, MetaData, Options, Allocator>> { static_assert(std::is_floating_point<Value>::value, "variable axis requires floating point type"); using value_type = Value; using metadata_type = detail::replace_default<MetaData, std::string>; using options_type = detail::replace_default<Options, decltype(option::underflow | option::overflow)>; using allocator_type = Allocator; using vec_type = std::vector<Value, allocator_type>; public: explicit variable(allocator_type alloc = {}) : vec_meta_(std::move(alloc)) {} /** Construct from iterator range of bin edges. * * \param begin begin of edge sequence. * \param end end of edge sequence. * \param meta description of the axis. * \param alloc allocator instance to use. */ template <class It, class = detail::requires_iterator<It>> variable(It begin, It end, metadata_type meta = {}, allocator_type alloc = {}) : vec_meta_(vec_type(std::move(alloc)), std::move(meta)) { if (std::distance(begin, end) <= 1) BOOST_THROW_EXCEPTION(std::invalid_argument("bins > 0 required")); auto& v = vec_meta_.first(); v.reserve(std::distance(begin, end)); v.emplace_back(*begin++); while (begin != end) { if (*begin <= v.back()) BOOST_THROW_EXCEPTION( std::invalid_argument("input sequence must be strictly ascending")); v.emplace_back(*begin++); } } /** Construct variable axis from iterable range of bin edges. * * \param iterable iterable range of bin edges. * \param meta description of the axis. * \param alloc allocator instance to use. */ template <class U, class = detail::requires_iterable<U>> variable(const U& iterable, metadata_type meta = {}, allocator_type alloc = {}) : variable(std::begin(iterable), std::end(iterable), std::move(meta), std::move(alloc)) {} /** Construct variable axis from initializer list of bin edges. * * @param list `std::initializer_list` of bin edges. * @param meta description of the axis. * @param alloc allocator instance to use. */ template <class U> variable(std::initializer_list<U> list, metadata_type meta = {}, allocator_type alloc = {}) : variable(list.begin(), list.end(), std::move(meta), std::move(alloc)) {} /// Constructor used by algorithm::reduce to shrink and rebin (not for users). variable(const variable& src, index_type begin, index_type end, unsigned merge) : vec_meta_(vec_type(src.get_allocator()), src.metadata()) { BOOST_ASSERT((end - begin) % merge == 0); if (options_type::test(option::circular) && !(begin == 0 && end == src.size())) BOOST_THROW_EXCEPTION(std::invalid_argument("cannot shrink circular axis")); auto& vec = vec_meta_.first(); vec.reserve((end - begin) / merge); const auto beg = src.vec_meta_.first().begin(); for (index_type i = begin; i <= end; i += merge) vec.emplace_back(*(beg + i)); } /// Return index for value argument. index_type index(value_type x) const noexcept { const auto& v = vec_meta_.first(); if (options_type::test(option::circular)) { const auto a = v[0]; const auto b = v[size()]; x -= std::floor((x - a) / (b - a)) * (b - a); } return static_cast<index_type>(std::upper_bound(v.begin(), v.end(), x) - v.begin() - 1); } auto update(value_type x) noexcept { const auto i = index(x); if (std::isfinite(x)) { auto& vec = vec_meta_.first(); if (0 <= i) { if (i < size()) return std::make_pair(i, 0); const auto d = value(size()) - value(size() - 0.5); x = std::nextafter(x, std::numeric_limits<value_type>::max()); x = std::max(x, vec.back() + d); vec.push_back(x); return std::make_pair(i, -1); } const auto d = value(0.5) - value(0); x = std::min(x, value(0) - d); vec.insert(vec.begin(), x); return std::make_pair(0, -i); } return std::make_pair(x < 0 ? -1 : size(), 0); } /// Return value for fractional index argument. value_type value(real_index_type i) const noexcept { const auto& v = vec_meta_.first(); if (options_type::test(option::circular)) { auto shift = std::floor(i / size()); i -= shift * size(); double z; const auto k = static_cast<index_type>(std::modf(i, &z)); const auto a = v[0]; const auto b = v[size()]; return (1.0 - z) * v[k] + z * v[k + 1] + shift * (b - a); } if (i < 0) return detail::lowest<value_type>(); if (i == size()) return v.back(); if (i > size()) return detail::highest<value_type>(); const auto k = static_cast<index_type>(i); // precond: i >= 0 const real_index_type z = i - k; return (1.0 - z) * v[k] + z * v[k + 1]; } /// Return bin for index argument. auto bin(index_type idx) const noexcept { return interval_view<variable>(*this, idx); } /// Returns the number of bins, without over- or underflow. index_type size() const noexcept { return static_cast<index_type>(vec_meta_.first().size()) - 1; } /// Returns the options. static constexpr unsigned options() noexcept { return options_type::value; } /// Returns reference to metadata. metadata_type& metadata() noexcept { return vec_meta_.second(); } /// Returns reference to const metadata. const metadata_type& metadata() const noexcept { return vec_meta_.second(); } template <class V, class M, class O, class A> bool operator==(const variable<V, M, O, A>& o) const noexcept { const auto& a = vec_meta_.first(); const auto& b = o.vec_meta_.first(); return std::equal(a.begin(), a.end(), b.begin(), b.end()) && detail::relaxed_equal(metadata(), o.metadata()); } template <class V, class M, class O, class A> bool operator!=(const variable<V, M, O, A>& o) const noexcept { return !operator==(o); } /// Return allocator instance. auto get_allocator() const { return vec_meta_.first().get_allocator(); } template <class Archive> void serialize(Archive&, unsigned); private: detail::compressed_pair<vec_type, metadata_type> vec_meta_; template <class V, class M, class O, class A> friend class variable; }; #if __cpp_deduction_guides >= 201606 template <class U, class T = detail::convert_integer<U, double>> variable(std::initializer_list<U>)->variable<T>; template <class U, class T = detail::convert_integer<U, double>> variable(std::initializer_list<U>, const char*)->variable<T>; template <class U, class M, class T = detail::convert_integer<U, double>> variable(std::initializer_list<U>, M)->variable<T, M>; template < class Iterable, class T = detail::convert_integer< detail::remove_cvref_t<decltype(*std::begin(std::declval<Iterable&>()))>, double>> variable(Iterable)->variable<T>; template < class Iterable, class T = detail::convert_integer< detail::remove_cvref_t<decltype(*std::begin(std::declval<Iterable&>()))>, double>> variable(Iterable, const char*)->variable<T>; template < class Iterable, class M, class T = detail::convert_integer< detail::remove_cvref_t<decltype(*std::begin(std::declval<Iterable&>()))>, double>> variable(Iterable, M)->variable<T, M>; #endif } // namespace axis } // namespace histogram } // namespace boost #endif