variable.hpp
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// 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/core/nvp.hpp>
#include <boost/histogram/axis/interval_view.hpp>
#include <boost/histogram/axis/iterator.hpp>
#include <boost/histogram/axis/metadata_base.hpp>
#include <boost/histogram/axis/option.hpp>
#include <boost/histogram/detail/convert_integer.hpp>
#include <boost/histogram/detail/detect.hpp>
#include <boost/histogram/detail/limits.hpp>
#include <boost/histogram/detail/relaxed_equal.hpp>
#include <boost/histogram/detail/replace_type.hpp>
#include <boost/histogram/fwd.hpp>
#include <boost/throw_exception.hpp>
#include <cassert>
#include <cmath>
#include <limits>
#include <memory>
#include <stdexcept>
#include <string>
#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.
If the axis has an overflow bin (the default), a value on the upper edge of the last
bin is put in the overflow bin. The axis range represents a semi-open interval.
If the overflow bin is deactivated, then a value on the upper edge of the last bin is
still counted towards the last bin. The axis range represents a closed interval. This
is the desired behavior for random numbers drawn from a bounded interval, which is
usually closed.
@tparam Value input value type, must be floating point.
@tparam MetaData type to store meta data.
@tparam Options see boost::histogram::axis::option.
@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>>,
public metadata_base_t<MetaData> {
// these must be private, so that they are not automatically inherited
using value_type = Value;
using metadata_base = metadata_base_t<MetaData>;
using metadata_type = typename metadata_base::metadata_type;
using options_type =
detail::replace_default<Options, decltype(option::underflow | option::overflow)>;
using allocator_type = Allocator;
using vector_type = std::vector<Value, allocator_type>;
static_assert(
std::is_floating_point<value_type>::value,
"current version of variable axis requires floating point type; "
"if you need a variable axis with an integral type, please submit an issue");
static_assert(
(!options_type::test(option::circular) && !options_type::test(option::growth)) ||
(options_type::test(option::circular) ^ options_type::test(option::growth)),
"circular and growth options are mutually exclusive");
public:
constexpr variable() = default;
explicit variable(allocator_type alloc) : vec_(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 (optional).
@param options see boost::histogram::axis::option (optional).
@param alloc allocator instance to use (optional).
*/
template <class It, class = detail::requires_iterator<It>>
variable(It begin, It end, metadata_type meta = {}, options_type options = {},
allocator_type alloc = {})
: metadata_base(std::move(meta)), vec_(std::move(alloc)) {
(void)options;
if (std::distance(begin, end) < 2)
BOOST_THROW_EXCEPTION(std::invalid_argument("bins > 0 required"));
vec_.reserve(std::distance(begin, end));
vec_.emplace_back(*begin++);
bool strictly_ascending = true;
for (; begin != end; ++begin) {
strictly_ascending &= vec_.back() < *begin;
vec_.emplace_back(*begin);
}
if (!strictly_ascending)
BOOST_THROW_EXCEPTION(
std::invalid_argument("input sequence must be strictly ascending"));
}
// kept for backward compatibility
template <class It, class = detail::requires_iterator<It>>
variable(It begin, It end, metadata_type meta, allocator_type alloc)
: variable(begin, end, std::move(meta), {}, std::move(alloc)) {}
/** Construct variable axis from iterable range of bin edges.
@param iterable iterable range of bin edges.
@param meta description of the axis (optional).
@param options see boost::histogram::axis::option (optional).
@param alloc allocator instance to use (optional).
*/
template <class U, class = detail::requires_iterable<U>>
variable(const U& iterable, metadata_type meta = {}, options_type options = {},
allocator_type alloc = {})
: variable(std::begin(iterable), std::end(iterable), std::move(meta), options,
std::move(alloc)) {}
// kept for backward compatibility
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 (optional).
@param options see boost::histogram::axis::option (optional).
@param alloc allocator instance to use (optional).
*/
template <class U>
variable(std::initializer_list<U> list, metadata_type meta = {},
options_type options = {}, allocator_type alloc = {})
: variable(list.begin(), list.end(), std::move(meta), options, std::move(alloc)) {}
// kept for backward compatibility
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)
: metadata_base(src), vec_(src.get_allocator()) {
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"));
vec_.reserve((end - begin) / merge);
const auto beg = src.vec_.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 {
if (options_type::test(option::circular)) {
const auto a = vec_[0];
const auto b = vec_[size()];
x -= std::floor((x - a) / (b - a)) * (b - a);
}
// upper edge of last bin is inclusive if overflow bin is not present
if (!options_type::test(option::overflow) && x == vec_.back()) return size() - 1;
return static_cast<index_type>(std::upper_bound(vec_.begin(), vec_.end(), x) -
vec_.begin() - 1);
}
std::pair<index_type, index_type> update(value_type x) noexcept {
const auto i = index(x);
if (std::isfinite(x)) {
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 {i, -1};
}
const auto d = value(0.5) - value(0);
x = (std::min)(x, value(0) - d);
vec_.insert(vec_.begin(), x);
return {0, -i};
}
return {x < 0 ? -1 : size(), 0};
}
/// Return value for fractional index argument.
value_type value(real_index_type i) const noexcept {
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 = vec_[0];
const auto b = vec_[size()];
return (1.0 - z) * vec_[k] + z * vec_[k + 1] + shift * (b - a);
}
if (i < 0) return detail::lowest<value_type>();
if (i == size()) return vec_.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;
// check z == 0 needed to avoid returning nan when vec_[k + 1] is infinity
return (1.0 - z) * vec_[k] + (z == 0 ? 0 : z * vec_[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_.size()) - 1; }
/// Returns the options.
static constexpr unsigned options() noexcept { return options_type::value; }
template <class V, class M, class O, class A>
bool operator==(const variable<V, M, O, A>& o) const noexcept {
const auto& a = vec_;
const auto& b = o.vec_;
return std::equal(a.begin(), a.end(), b.begin(), b.end()) &&
detail::relaxed_equal{}(this->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_.get_allocator(); }
template <class Archive>
void serialize(Archive& ar, unsigned /* version */) {
ar& make_nvp("seq", vec_);
ar& make_nvp("meta", this->metadata());
}
private:
vector_type vec_;
template <class V, class M, class O, class A>
friend class variable;
};
#if __cpp_deduction_guides >= 201606
template <class T>
variable(std::initializer_list<T>)
-> variable<detail::convert_integer<T, double>, null_type>;
template <class T, class M>
variable(std::initializer_list<T>, M)
-> variable<detail::convert_integer<T, double>,
detail::replace_type<std::decay_t<M>, const char*, std::string>>;
template <class T, class M, unsigned B>
variable(std::initializer_list<T>, M, const option::bitset<B>&)
-> variable<detail::convert_integer<T, double>,
detail::replace_type<std::decay_t<M>, const char*, std::string>,
option::bitset<B>>;
template <class Iterable, class = detail::requires_iterable<Iterable>>
variable(Iterable) -> variable<
detail::convert_integer<
std::decay_t<decltype(*std::begin(std::declval<Iterable&>()))>, double>,
null_type>;
template <class Iterable, class M>
variable(Iterable, M) -> variable<
detail::convert_integer<
std::decay_t<decltype(*std::begin(std::declval<Iterable&>()))>, double>,
detail::replace_type<std::decay_t<M>, const char*, std::string>>;
template <class Iterable, class M, unsigned B>
variable(Iterable, M, const option::bitset<B>&) -> variable<
detail::convert_integer<
std::decay_t<decltype(*std::begin(std::declval<Iterable&>()))>, double>,
detail::replace_type<std::decay_t<M>, const char*, std::string>, option::bitset<B>>;
#endif
} // namespace axis
} // namespace histogram
} // namespace boost
#endif