130 lines
4.4 KiB
C++
Executable File
130 lines
4.4 KiB
C++
Executable File
// Copyright (c) 2005 INRIA Sophia-Antipolis (France).
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// All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
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// modify it under the terms of the GNU Lesser General Public License as
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// published by the Free Software Foundation; either version 3 of the License,
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// or (at your option) any later version.
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//
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// Licensees holding a valid commercial license may use this file in
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// accordance with the commercial license agreement provided with the software.
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//
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// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
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// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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//
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// $URL$
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// $Id$
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// SPDX-License-Identifier: LGPL-3.0+
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//
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//
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// Author(s) : Sylvain Pion
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#ifndef CGAL_BARYCENTER_H
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#define CGAL_BARYCENTER_H
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#include <CGAL/basic.h>
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#include <CGAL/Origin.h>
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#include <iterator>
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#include <CGAL/Kernel_traits.h>
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#include <CGAL/Kernel/Dimension_utils.h>
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#include <CGAL/Dimension.h>
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// Functions to compute the point given its barycentric coordinates.
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// Works in 2D and 3D (and dD ?).
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// Special case for the centroid.
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// TODO : Note : more numerically stable variants could be implemented as well.
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// TODO : Specify a traits class concept ? Maybe not for these computations.
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// TODO : Grep for "barycenter" and "centroid" in CGAL to check existing usages.
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// TODO : Add barycentric_coordinates() (to the kernel, this time).
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namespace CGAL {
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// This one takes an iterator range over std::pair<K::Point_[23], K::FT>
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template < typename InputIterator, typename K >
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typename std::iterator_traits<InputIterator>::value_type::first_type
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barycenter(InputIterator begin, InputIterator end, const K & )
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{
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typedef typename std::iterator_traits<InputIterator>::value_type pair;
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typedef typename pair::second_type FT;
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typedef typename pair::first_type Point;
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typedef typename Access::Vector<K, typename Ambient_dimension<Point, K>::type>::type Vector;
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CGAL_precondition(begin != end);
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Vector v = NULL_VECTOR;
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FT norm = 0;
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while (begin != end) {
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pair p = *begin++;
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v = v + p.second * (p.first - ORIGIN);
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norm += p.second;
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}
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CGAL_assertion( norm != 0 );
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return ORIGIN + v / norm;
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}
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// This one takes an iterator range over K::Point_[23],
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// and an iterator over K::FT.
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template < typename PointInputIterator, typename WeightInputIterator,
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typename K >
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typename std::iterator_traits<PointInputIterator>::value_type
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barycenter(PointInputIterator begin, PointInputIterator end,
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WeightInputIterator wbegin, const K & )
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{
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typedef typename std::iterator_traits<PointInputIterator>::value_type Point;
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typedef typename std::iterator_traits<WeightInputIterator>::value_type FT;
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typedef typename Access::Vector<K, typename Ambient_dimension<Point, K>::type>::type Vector;
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CGAL_precondition(begin != end);
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Vector v = NULL_VECTOR;
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FT norm = 0;
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while (begin != end) {
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FT weight = *wbegin++;
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v = v + weight * (*begin++ - ORIGIN);
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norm += weight;
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}
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CGAL_assertion( norm != 0 );
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return ORIGIN + v / norm;
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}
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// This one takes an iterator range over std::pair<K::Point_[23], K::FT>
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// And it uses Kernel_traits<> to find out its kernel.
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template < typename InputIterator >
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inline
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typename std::iterator_traits<InputIterator>::value_type::first_type
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barycenter(InputIterator begin, InputIterator end)
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{
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typedef typename std::iterator_traits<InputIterator>::value_type pair;
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typedef typename pair::first_type Point;
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typedef typename Kernel_traits<Point>::Kernel K;
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return CGAL::barycenter(begin, end, K());
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}
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// This one takes an iterator range over K::Point_[23],
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// and an iterator over K::FT.
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// And it uses Kernel_traits<> to find out its kernel.
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// To differentiate it from the others, it takes an "int" as K parameter
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template < typename PointInputIterator, typename WeightInputIterator >
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inline
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typename std::iterator_traits<PointInputIterator>::value_type
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barycenter(PointInputIterator begin, PointInputIterator end,
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WeightInputIterator wbegin, int)
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{
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typedef typename std::iterator_traits<PointInputIterator>::value_type Point;
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typedef typename Kernel_traits<Point>::Kernel K;
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return CGAL::barycenter(begin, end, wbegin, K());
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}
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} //namespace CGAL
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#endif
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