125 lines
4.2 KiB
C++
125 lines
4.2 KiB
C++
// Boost.Geometry Index
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//
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// minmaxdist used in R-tree k nearest neighbors query
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//
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// Copyright (c) 2011-2014 Adam Wulkiewicz, Lodz, Poland.
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//
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// This file was modified by Oracle on 2020.
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// Modifications copyright (c) 2020 Oracle and/or its affiliates.
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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//
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_MINMAXDIST_HPP
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#define BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_MINMAXDIST_HPP
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#include <boost/geometry/algorithms/distance.hpp>
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#include <boost/geometry/algorithms/comparable_distance.hpp>
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#include <boost/geometry/core/static_assert.hpp>
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#include <boost/geometry/index/detail/algorithms/diff_abs.hpp>
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#include <boost/geometry/index/detail/algorithms/sum_for_indexable.hpp>
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#include <boost/geometry/index/detail/algorithms/smallest_for_indexable.hpp>
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namespace boost { namespace geometry { namespace index { namespace detail {
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struct minmaxdist_tag {};
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template <
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typename Point,
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typename BoxIndexable,
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size_t DimensionIndex>
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struct smallest_for_indexable_dimension<Point, BoxIndexable, box_tag, minmaxdist_tag, DimensionIndex>
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{
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typedef typename geometry::default_comparable_distance_result<Point, BoxIndexable>::type result_type;
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inline static result_type apply(Point const& pt, BoxIndexable const& i, result_type const& maxd)
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{
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typedef typename coordinate_type<Point>::type point_coord_t;
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typedef typename coordinate_type<BoxIndexable>::type indexable_coord_t;
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point_coord_t pt_c = geometry::get<DimensionIndex>(pt);
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indexable_coord_t ind_c_min = geometry::get<geometry::min_corner, DimensionIndex>(i);
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indexable_coord_t ind_c_max = geometry::get<geometry::max_corner, DimensionIndex>(i);
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indexable_coord_t ind_c_avg = ind_c_min + (ind_c_max - ind_c_min) / 2;
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// TODO: awulkiew - is (ind_c_min + ind_c_max) / 2 safe?
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// TODO: awulkiew - optimize! don't calculate 2x pt_c <= ind_c_avg
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// take particular case pt_c == ind_c_avg into account
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result_type closer_comp = 0;
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if ( pt_c <= ind_c_avg )
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closer_comp = detail::diff_abs(pt_c, ind_c_min); // unsigned values protection
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else
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closer_comp = ind_c_max - pt_c;
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result_type further_comp = 0;
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if ( ind_c_avg <= pt_c )
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further_comp = pt_c - ind_c_min;
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else
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further_comp = detail::diff_abs(pt_c, ind_c_max); // unsigned values protection
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return (maxd + closer_comp * closer_comp) - further_comp * further_comp;
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}
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};
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template <typename Point, typename Indexable, typename IndexableTag>
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struct minmaxdist_impl
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{
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BOOST_GEOMETRY_STATIC_ASSERT_FALSE(
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"Not implemented for this Indexable type.",
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Point, Indexable, IndexableTag);
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};
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template <typename Point, typename Indexable>
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struct minmaxdist_impl<Point, Indexable, point_tag>
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{
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typedef typename geometry::default_comparable_distance_result<Point, Indexable>::type result_type;
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inline static result_type apply(Point const& pt, Indexable const& i)
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{
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return geometry::comparable_distance(pt, i);
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}
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};
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template <typename Point, typename Indexable>
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struct minmaxdist_impl<Point, Indexable, box_tag>
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{
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typedef typename geometry::default_comparable_distance_result<Point, Indexable>::type result_type;
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inline static result_type apply(Point const& pt, Indexable const& i)
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{
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result_type maxd = geometry::comparable_distance(pt, i);
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return smallest_for_indexable<
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Point,
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Indexable,
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box_tag,
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minmaxdist_tag,
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dimension<Indexable>::value
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>::apply(pt, i, maxd);
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}
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};
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/**
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* This is comparable distace.
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*/
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template <typename Point, typename Indexable>
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typename geometry::default_comparable_distance_result<Point, Indexable>::type
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minmaxdist(Point const& pt, Indexable const& i)
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{
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return detail::minmaxdist_impl<
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Point,
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Indexable,
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typename tag<Indexable>::type
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>::apply(pt, i);
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}
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}}}} // namespace boost::geometry::index::detail
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#endif // BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_MINMAXDIST_HPP
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