boost/histogram/axis/integer.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_INTEGER_HPP
#define BOOST_HISTOGRAM_AXIS_INTEGER_HPP
#include <boost/histogram/axis/iterator.hpp>
#include <boost/histogram/axis/option.hpp>
#include <boost/histogram/detail/compressed_pair.hpp>
#include <boost/histogram/detail/convert_integer.hpp>
#include <boost/histogram/detail/limits.hpp>
#include <boost/histogram/detail/relaxed_equal.hpp>
#include <boost/histogram/detail/replace_default.hpp>
#include <boost/histogram/detail/static_if.hpp>
#include <boost/histogram/fwd.hpp>
#include <boost/throw_exception.hpp>
#include <cmath>
#include <limits>
#include <stdexcept>
#include <string>
#include <type_traits>
#include <utility>
namespace boost {
namespace histogram {
namespace axis {
/**
Axis for an interval of integer values with unit steps.
Binning is a O(1) operation. This axis bins faster than a regular axis.
@tparam Value input value type. Must be integer or floating point.
@tparam MetaData type to store meta data.
@tparam Options see boost::histogram::axis::option (all values allowed).
*/
template <class Value, class MetaData, class Options>
class integer : public iterator_mixin<integer<Value, MetaData, Options>> {
static_assert(std::is_integral<Value>::value || std::is_floating_point<Value>::value,
"integer axis requires type floating point or integral type");
using value_type = Value;
using local_index_type = std::conditional_t<std::is_integral<value_type>::value,
index_type, real_index_type>;
using metadata_type = detail::replace_default<MetaData, std::string>;
using options_type =
detail::replace_default<Options, decltype(option::underflow | option::overflow)>;
static_assert(!options_type::test(option::circular) ||
std::is_floating_point<value_type>::value ||
!options_type::test(option::overflow),
"integer axis with integral type cannot have overflow");
public:
constexpr integer() = default;
integer(const integer&) = default;
integer& operator=(const integer&) = default;
integer(integer&& o) noexcept : size_meta_(std::move(o.size_meta_)), min_(o.min_) {
// std::string explicitly guarantees nothrow only in C++17
static_assert(std::is_same<metadata_type, std::string>::value ||
std::is_nothrow_move_constructible<metadata_type>::value,
"");
}
integer& operator=(integer&& o) noexcept {
// std::string explicitly guarantees nothrow only in C++17
static_assert(std::is_same<metadata_type, std::string>::value ||
std::is_nothrow_move_assignable<metadata_type>::value,
"");
size_meta_ = std::move(o.size_meta_);
min_ = o.min_;
return *this;
}
/** Construct over semi-open integer interval [start, stop).
*
* \param start first integer of covered range.
* \param stop one past last integer of covered range.
* \param meta description of the axis.
*/
integer(value_type start, value_type stop, metadata_type meta = {})
: size_meta_(static_cast<index_type>(stop - start), std::move(meta)), min_(start) {
if (stop <= start) BOOST_THROW_EXCEPTION(std::invalid_argument("bins > 0 required"));
}
/// Constructor used by algorithm::reduce to shrink and rebin.
integer(const integer& src, index_type begin, index_type end, unsigned merge)
: integer(src.value(begin), src.value(end), src.metadata()) {
if (merge > 1)
BOOST_THROW_EXCEPTION(std::invalid_argument("cannot merge bins for integer axis"));
if (options_type::test(option::circular) && !(begin == 0 && end == src.size()))
BOOST_THROW_EXCEPTION(std::invalid_argument("cannot shrink circular axis"));
}
/// Return index for value argument.
index_type index(value_type x) const noexcept {
return index_impl(std::is_floating_point<value_type>(), x);
}
/// Returns index and shift (if axis has grown) for the passed argument.
auto update(value_type x) noexcept {
auto impl = [this](long x) {
const auto i = x - min_;
if (i >= 0) {
const auto k = static_cast<axis::index_type>(i);
if (k < size()) return std::make_pair(k, 0);
const auto n = k - size() + 1;
size_meta_.first() += n;
return std::make_pair(k, -n);
}
const auto k = static_cast<axis::index_type>(
detail::static_if<std::is_floating_point<value_type>>(
[](auto x) { return std::floor(x); }, [](auto x) { return x; }, i));
min_ += k;
size_meta_.first() -= k;
return std::make_pair(0, -k);
};
return detail::static_if<std::is_floating_point<value_type>>(
[this, impl](auto x) {
if (std::isfinite(x)) return impl(static_cast<long>(std::floor(x)));
// this->size() is workaround for gcc-5 bug
return std::make_pair(x < 0 ? -1 : this->size(), 0);
},
impl, x);
}
/// Return value for index argument.
value_type value(local_index_type i) const noexcept {
if (!options_type::test(option::circular)) {
if (i < 0) return detail::lowest<value_type>();
if (i > size()) { return detail::highest<value_type>(); }
}
return min_ + i;
}
/// Return bin for index argument.
decltype(auto) bin(index_type idx) const noexcept {
return detail::static_if<std::is_floating_point<local_index_type>>(
[this](auto idx) { return interval_view<integer>(*this, idx); },
[this](auto idx) { return this->value(idx); }, idx);
}
/// Returns the number of bins, without over- or underflow.
index_type size() const noexcept { return size_meta_.first(); }
/// Returns the options.
static constexpr unsigned options() noexcept { return options_type::value; }
/// Returns reference to metadata.
metadata_type& metadata() noexcept { return size_meta_.second(); }
/// Returns reference to const metadata.
const metadata_type& metadata() const noexcept { return size_meta_.second(); }
template <class V, class M, class O>
bool operator==(const integer<V, M, O>& o) const noexcept {
return size() == o.size() && detail::relaxed_equal(metadata(), o.metadata()) &&
min_ == o.min_;
}
template <class V, class M, class O>
bool operator!=(const integer<V, M, O>& o) const noexcept {
return !operator==(o);
}
template <class Archive>
void serialize(Archive&, unsigned);
private:
index_type index_impl(std::false_type, int x) const noexcept {
const auto z = x - min_;
if (options_type::test(option::circular))
return static_cast<index_type>(z - std::floor(float(z) / size()) * size());
if (z < size()) return z >= 0 ? z : -1;
return size();
}
template <typename T>
index_type index_impl(std::true_type, T x) const noexcept {
// need to handle NaN, cannot simply cast to int and call int-implementation
const auto z = x - min_;
if (options_type::test(option::circular)) {
if (std::isfinite(z))
return static_cast<index_type>(std::floor(z) - std::floor(z / size()) * size());
} else if (z < size()) {
return z >= 0 ? static_cast<index_type>(z) : -1;
}
return size();
}
detail::compressed_pair<index_type, metadata_type> size_meta_{0};
value_type min_{0};
template <class V, class M, class O>
friend class integer;
};
#if __cpp_deduction_guides >= 201606
template <class T>
integer(T, T)->integer<detail::convert_integer<T, index_type>>;
template <class T>
integer(T, T, const char*)->integer<detail::convert_integer<T, index_type>>;
template <class T, class M>
integer(T, T, M)->integer<detail::convert_integer<T, index_type>, M>;
#endif
} // namespace axis
} // namespace histogram
} // namespace boost
#endif