cgal/Interpolation/include/CGAL/sibson_gradient_fitting.h

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// Copyright (c) 2003 INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
// You can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL$
// $Id$
// SPDX-License-Identifier: GPL-3.0+
//
//
// Author(s) : Julia Floetotto
#ifndef CGAL_SIBSON_GRADIENT_FITTING_H
#define CGAL_SIBSON_GRADIENT_FITTING_H
#include <CGAL/license/Interpolation.h>
#include <CGAL/Origin.h>
#include <CGAL/interpolation_functions.h> // AF: for V2P
#include <CGAL/natural_neighbor_coordinates_2.h>
#include <CGAL/regular_neighbor_coordinates_2.h>
#include <iterator>
#include <utility>
namespace CGAL {
template < class ForwardIterator, class Functor, class Traits>
typename Traits::Vector_d
sibson_gradient_fitting(ForwardIterator first,
ForwardIterator beyond,
const typename
std::iterator_traits<ForwardIterator>::
value_type::second_type& norm,
const typename Traits::Point_d& bare_p,
const typename Functor::result_type::first_type fn,
Functor function_value,
const Traits& traits)
{
Interpolation::internal::V2P<Traits> v2p(traits);
CGAL_precondition( first!=beyond && norm!=0);
typedef typename Traits::Aff_transformation_d Aff_transformation;
typedef typename Traits::FT Coord_type;
typename Traits::Vector_d pn =
traits.construct_vector_d_object()(NULL_VECTOR);
Aff_transformation scaling, m,
Hn(traits.construct_null_matrix_d_object()());
for(;first!=beyond; ++first)
{
const typename Traits::Point_d& bare_f = v2p(first->first);
Coord_type square_dist = traits.compute_squared_distance_d_object()(bare_f, bare_p);
CGAL_assertion(square_dist != 0);
Coord_type scale = first->second / (norm*square_dist);
typename Traits::Vector_d d = traits.construct_vector_d_object()(bare_p, bare_f);
//compute the vector pn:
typename Functor::result_type f = function_value(first->first);
CGAL_assertion(f.second);//function value of first->first is valid
pn = pn + traits.construct_scaled_vector_d_object()
(d,scale * (f.first - fn));
//compute the matrix Hn:
m = traits.construct_outer_product_d_object()(d);
scaling = traits.construct_scaling_matrix_d_object()(scale);
Hn = traits.construct_sum_matrix_d_object()(Hn, scaling * m);
}
return Hn.inverse().transform(pn);
}
template < class Triangul, class ForwardIterator, class Functor, class Traits, class VH>
typename Traits::Vector_d
sibson_gradient_fitting(const Triangul& tr,
ForwardIterator first,
ForwardIterator beyond,
const typename
std::iterator_traits<ForwardIterator>::
value_type::second_type& norm,
VH vh,
Functor function_value,
const Traits& traits,
const typename Traits::Point_d& ignored)
{
const typename Traits::Point_d& bare_p = traits.construct_point_d_object()(vh->point());
typename Functor::result_type fn = function_value(bare_p);
CGAL_assertion(fn.second);
return sibson_gradient_fitting(first,
beyond,
norm,
bare_p,
fn.first,
function_value,
traits);
}
template < class Triangul, class ForwardIterator, class Functor, class Traits, class VH>
typename Traits::Vector_d
sibson_gradient_fitting(const Triangul& tr,
ForwardIterator first,
ForwardIterator beyond,
const typename
std::iterator_traits<ForwardIterator>::
value_type::second_type& norm,
VH vh,
Functor function_value,
const Traits& traits,
typename Triangul::Vertex_handle ignored)
{
const typename Traits::Point_d& bare_p = traits.construct_point_d_object()(vh->point());
typename Functor::result_type fn = function_value(vh);
CGAL_assertion(fn.second);
return sibson_gradient_fitting(first,
beyond,
norm,
bare_p,
fn.first,
function_value,
traits);
}
template < class Triangul, class OutputIterator, class Functor,
class CoordFunctor, class OIF, class Traits>
OutputIterator
sibson_gradient_fitting_internal(const Triangul& tr,
OutputIterator out,
Functor function_value,
CoordFunctor compute_coordinates,
OIF fct,
const Traits& traits)
{
typedef typename Traits::FT Coord_type;
std::vector< std::pair< typename Functor::argument_type, Coord_type> > coords;
Coord_type norm;
typedef typename Interpolation::internal::Output_iterator_functor_selector<Triangul, Traits,
typename Functor::argument_type,
Coord_type>::type Coord_OIF;
typename Triangul::Finite_vertices_iterator vit = tr.finite_vertices_begin();
for(; vit != tr.finite_vertices_end(); ++vit){
//test if vit is a convex hull vertex, otherwise do nothing
if (!tr.is_edge(vit, tr.infinite_vertex()))
{
norm = compute_coordinates(tr, vit, std::back_inserter(coords), Coord_OIF()).second;
*out++ = fct(std::make_pair(vit,
sibson_gradient_fitting(tr,
coords.begin(),
coords.end(),
norm,
vit,
function_value,
traits,
typename Functor::argument_type())));
coords.clear();
}
}
return out;
}
//the following functions allow to fit the gradients for all points in
// a triangulation except the convex hull points.
// -> _nn2: natural_neighbor_coordinates_2
// -> _rn2: regular_neighbor_coordinates_2
// -> _sn2_3: surface_neighbor_coordinates_2_3
template < class Dt, class OutputIterator, class Functor, class OIF, class Traits>
OutputIterator
sibson_gradient_fitting_nn_2(const Dt& dt,
OutputIterator out,
Functor function_value,
OIF fct,
const Traits& traits)
{
typedef typename std::back_insert_iterator<
std::vector<
std::pair< typename Functor::argument_type,
typename Traits::FT > > > CoordInserter;
typedef typename Interpolation::internal::Output_iterator_functor_selector<Dt, Traits,
typename Functor::argument_type,
typename Traits::FT>::type Coord_OIF;
return sibson_gradient_fitting_internal(dt, out, function_value,
natural_neighbor_coordinates_2_object<Dt,
CoordInserter,
Coord_OIF>(),
fct,
traits);
}
template < class Dt, class OutputIterator, class Functor, class Traits>
OutputIterator
sibson_gradient_fitting_nn_2(const Dt& dt,
OutputIterator out,
Functor function_value,
const Traits& traits)
{
return sibson_gradient_fitting_nn_2(dt, out, function_value,
Interpolation::internal::Vertex2Point<Dt, typename Traits::Vector_d>(), traits);
}
template < class Rt, class OutputIterator, class Functor, class Traits>
OutputIterator
sibson_gradient_fitting_rn_2(const Rt& rt,
OutputIterator out,
Functor function_value,
const Traits& traits)
{
typedef typename std::back_insert_iterator<
std::vector<
std::pair< typename Traits::Weighted_point_d,
typename Traits::FT > > > CoordInserter;
return sibson_gradient_fitting(rt, out, function_value,
regular_neighbor_coordinates_2_object< Rt,
CoordInserter >(),
traits);
}
} //namespace CGAL
#endif // CGAL_SIBSON_GRADIENT_FITTING_H