boost/accumulators/statistics/extended_p_square_quantile.hpp
///////////////////////////////////////////////////////////////////////////////
// extended_p_square_quantile.hpp
//
// Copyright 2005 Daniel Egloff. 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_ACCUMULATORS_STATISTICS_EXTENDED_SINGLE_QUANTILE_HPP_DE_01_01_2006
#define BOOST_ACCUMULATORS_STATISTICS_EXTENDED_SINGLE_QUANTILE_HPP_DE_01_01_2006
#include <vector>
#include <functional>
#include <boost/throw_exception.hpp>
#include <boost/range/begin.hpp>
#include <boost/range/end.hpp>
#include <boost/range/iterator_range.hpp>
#include <boost/iterator/transform_iterator.hpp>
#include <boost/iterator/counting_iterator.hpp>
#include <boost/iterator/permutation_iterator.hpp>
#include <boost/parameter/keyword.hpp>
#include <boost/mpl/placeholders.hpp>
#include <boost/type_traits/is_same.hpp>
#include <boost/accumulators/framework/accumulator_base.hpp>
#include <boost/accumulators/framework/extractor.hpp>
#include <boost/accumulators/numeric/functional.hpp>
#include <boost/accumulators/framework/parameters/sample.hpp>
#include <boost/accumulators/framework/depends_on.hpp>
#include <boost/accumulators/statistics_fwd.hpp>
#include <boost/accumulators/statistics/count.hpp>
#include <boost/accumulators/statistics/parameters/quantile_probability.hpp>
#include <boost/accumulators/statistics/extended_p_square.hpp>
#include <boost/accumulators/statistics/weighted_extended_p_square.hpp>
#include <boost/accumulators/statistics/times2_iterator.hpp>
#ifdef _MSC_VER
# pragma warning(push)
# pragma warning(disable: 4127) // conditional expression is constant
#endif
namespace boost { namespace accumulators
{
namespace impl
{
///////////////////////////////////////////////////////////////////////////////
// extended_p_square_quantile_impl
// single quantile estimation
/**
@brief Quantile estimation using the extended \f$P^2\f$ algorithm for weighted and unweighted samples
Uses the quantile estimates calculated by the extended \f$P^2\f$ algorithm to compute
intermediate quantile estimates by means of quadratic interpolation.
@param quantile_probability The probability of the quantile to be estimated.
*/
template<typename Sample, typename Impl1, typename Impl2> // Impl1: weighted/unweighted // Impl2: linear/quadratic
struct extended_p_square_quantile_impl
: accumulator_base
{
typedef typename numeric::functional::fdiv<Sample, std::size_t>::result_type float_type;
typedef std::vector<float_type> array_type;
typedef iterator_range<
detail::lvalue_index_iterator<
permutation_iterator<
typename array_type::const_iterator
, detail::times2_iterator
>
>
> range_type;
// for boost::result_of
typedef float_type result_type;
template<typename Args>
extended_p_square_quantile_impl(Args const &args)
: probabilities(
boost::begin(args[extended_p_square_probabilities])
, boost::end(args[extended_p_square_probabilities])
)
{
}
template<typename Args>
result_type result(Args const &args) const
{
typedef
typename mpl::if_<
is_same<Impl1, weighted>
, tag::weighted_extended_p_square
, tag::extended_p_square
>::type
extended_p_square_tag;
extractor<extended_p_square_tag> const some_extended_p_square = {};
array_type heights(some_extended_p_square(args).size());
std::copy(some_extended_p_square(args).begin(), some_extended_p_square(args).end(), heights.begin());
this->probability = args[quantile_probability];
typename array_type::const_iterator iter_probs = std::lower_bound(this->probabilities.begin(), this->probabilities.end(), this->probability);
std::size_t dist = std::distance(this->probabilities.begin(), iter_probs);
typename array_type::const_iterator iter_heights = heights.begin() + dist;
// If this->probability is not in a valid range return NaN or throw exception
if (this->probability < *this->probabilities.begin() || this->probability > *(this->probabilities.end() - 1))
{
if (std::numeric_limits<result_type>::has_quiet_NaN)
{
return std::numeric_limits<result_type>::quiet_NaN();
}
else
{
std::ostringstream msg;
msg << "probability = " << this->probability << " is not in valid range (";
msg << *this->probabilities.begin() << ", " << *(this->probabilities.end() - 1) << ")";
boost::throw_exception(std::runtime_error(msg.str()));
return Sample(0);
}
}
if (*iter_probs == this->probability)
{
return heights[dist];
}
else
{
result_type res;
if (is_same<Impl2, linear>::value)
{
/////////////////////////////////////////////////////////////////////////////////
// LINEAR INTERPOLATION
//
float_type p1 = *iter_probs;
float_type p0 = *(iter_probs - 1);
float_type h1 = *iter_heights;
float_type h0 = *(iter_heights - 1);
float_type a = numeric::fdiv(h1 - h0, p1 - p0);
float_type b = h1 - p1 * a;
res = a * this->probability + b;
}
else
{
/////////////////////////////////////////////////////////////////////////////////
// QUADRATIC INTERPOLATION
//
float_type p0, p1, p2;
float_type h0, h1, h2;
if ( (dist == 1 || *iter_probs - this->probability <= this->probability - *(iter_probs - 1) ) && dist != this->probabilities.size() - 1 )
{
p0 = *(iter_probs - 1);
p1 = *iter_probs;
p2 = *(iter_probs + 1);
h0 = *(iter_heights - 1);
h1 = *iter_heights;
h2 = *(iter_heights + 1);
}
else
{
p0 = *(iter_probs - 2);
p1 = *(iter_probs - 1);
p2 = *iter_probs;
h0 = *(iter_heights - 2);
h1 = *(iter_heights - 1);
h2 = *iter_heights;
}
float_type hp21 = numeric::fdiv(h2 - h1, p2 - p1);
float_type hp10 = numeric::fdiv(h1 - h0, p1 - p0);
float_type p21 = numeric::fdiv(p2 * p2 - p1 * p1, p2 - p1);
float_type p10 = numeric::fdiv(p1 * p1 - p0 * p0, p1 - p0);
float_type a = numeric::fdiv(hp21 - hp10, p21 - p10);
float_type b = hp21 - a * p21;
float_type c = h2 - a * p2 * p2 - b * p2;
res = a * this->probability * this-> probability + b * this->probability + c;
}
return res;
}
}
private:
array_type probabilities;
mutable float_type probability;
};
} // namespace impl
///////////////////////////////////////////////////////////////////////////////
// tag::extended_p_square_quantile
//
namespace tag
{
struct extended_p_square_quantile
: depends_on<extended_p_square>
{
typedef accumulators::impl::extended_p_square_quantile_impl<mpl::_1, unweighted, linear> impl;
};
struct extended_p_square_quantile_quadratic
: depends_on<extended_p_square>
{
typedef accumulators::impl::extended_p_square_quantile_impl<mpl::_1, unweighted, quadratic> impl;
};
struct weighted_extended_p_square_quantile
: depends_on<weighted_extended_p_square>
{
typedef accumulators::impl::extended_p_square_quantile_impl<mpl::_1, weighted, linear> impl;
};
struct weighted_extended_p_square_quantile_quadratic
: depends_on<weighted_extended_p_square>
{
typedef accumulators::impl::extended_p_square_quantile_impl<mpl::_1, weighted, quadratic> impl;
};
}
///////////////////////////////////////////////////////////////////////////////
// extract::extended_p_square_quantile
// extract::weighted_extended_p_square_quantile
//
namespace extract
{
extractor<tag::extended_p_square_quantile> const extended_p_square_quantile = {};
extractor<tag::extended_p_square_quantile_quadratic> const extended_p_square_quantile_quadratic = {};
extractor<tag::weighted_extended_p_square_quantile> const weighted_extended_p_square_quantile = {};
extractor<tag::weighted_extended_p_square_quantile_quadratic> const weighted_extended_p_square_quantile_quadratic = {};
BOOST_ACCUMULATORS_IGNORE_GLOBAL(extended_p_square_quantile)
BOOST_ACCUMULATORS_IGNORE_GLOBAL(extended_p_square_quantile_quadratic)
BOOST_ACCUMULATORS_IGNORE_GLOBAL(weighted_extended_p_square_quantile)
BOOST_ACCUMULATORS_IGNORE_GLOBAL(weighted_extended_p_square_quantile_quadratic)
}
using extract::extended_p_square_quantile;
using extract::extended_p_square_quantile_quadratic;
using extract::weighted_extended_p_square_quantile;
using extract::weighted_extended_p_square_quantile_quadratic;
// extended_p_square_quantile(linear) -> extended_p_square_quantile
template<>
struct as_feature<tag::extended_p_square_quantile(linear)>
{
typedef tag::extended_p_square_quantile type;
};
// extended_p_square_quantile(quadratic) -> extended_p_square_quantile_quadratic
template<>
struct as_feature<tag::extended_p_square_quantile(quadratic)>
{
typedef tag::extended_p_square_quantile_quadratic type;
};
// weighted_extended_p_square_quantile(linear) -> weighted_extended_p_square_quantile
template<>
struct as_feature<tag::weighted_extended_p_square_quantile(linear)>
{
typedef tag::weighted_extended_p_square_quantile type;
};
// weighted_extended_p_square_quantile(quadratic) -> weighted_extended_p_square_quantile_quadratic
template<>
struct as_feature<tag::weighted_extended_p_square_quantile(quadratic)>
{
typedef tag::weighted_extended_p_square_quantile_quadratic type;
};
// for the purposes of feature-based dependency resolution,
// extended_p_square_quantile and weighted_extended_p_square_quantile
// provide the same feature as quantile
template<>
struct feature_of<tag::extended_p_square_quantile>
: feature_of<tag::quantile>
{
};
template<>
struct feature_of<tag::extended_p_square_quantile_quadratic>
: feature_of<tag::quantile>
{
};
// So that extended_p_square_quantile can be automatically substituted with
// weighted_extended_p_square_quantile when the weight parameter is non-void
template<>
struct as_weighted_feature<tag::extended_p_square_quantile>
{
typedef tag::weighted_extended_p_square_quantile type;
};
template<>
struct feature_of<tag::weighted_extended_p_square_quantile>
: feature_of<tag::extended_p_square_quantile>
{
};
// So that extended_p_square_quantile_quadratic can be automatically substituted with
// weighted_extended_p_square_quantile_quadratic when the weight parameter is non-void
template<>
struct as_weighted_feature<tag::extended_p_square_quantile_quadratic>
{
typedef tag::weighted_extended_p_square_quantile_quadratic type;
};
template<>
struct feature_of<tag::weighted_extended_p_square_quantile_quadratic>
: feature_of<tag::extended_p_square_quantile_quadratic>
{
};
}} // namespace boost::accumulators
#ifdef _MSC_VER
# pragma warning(pop)
#endif
#endif