dust3d/thirdparty/cgal/CGAL-4.13/include/CGAL/Polynomial/Coercion_traits.h

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// Copyright (c) 2008 Max-Planck-Institute Saarbruecken (Germany)
//
// This file is part of CGAL (www.cgal.org); you can redistribute it and/or
// modify it under the terms of the GNU Lesser 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: LGPL-3.0+
//
//
// Author(s) : Michael Hemmer <hemmer@mpi-inf.mpg.de>
//
// ============================================================================
#ifndef CGAL_POLYNOMIAL_COERCION_TRAITS_H
#define CGAL_POLYNOMIAL_COERCION_TRAITS_H
// The coercion type of two polynomials is a polynomial in d=max(d1,d2)
// variables, where d1 and d2 are the number of variables the two
// polynomials. (This also includes the case of d1 = 0 or d2 = 0.)
// Moreover, the new Innermost_coefficient_type is the coercion type of the
// two Innermost_coefficient_types of the two involved polynomials.
// (Again, this is generalized if one of the involved types is just a scalar
// type)
// Though the coercion type is clear, the problem is how to match the
// variables. The recursive definition of Polynomial<Coeff> suggest that
// the coercion type of two polynomial types Polynomial<A> and Polynomial<B>
// is defined as Polynomial<C>, where C is the coercion type.
// However, this is not in line with the fact that a Polynomial<A>
// is interoperable with its coefficient type A, that is, if A is a polynomial
// the variables of A should not be moved outward while casting A to
// Polynomial<A>.
#include <CGAL/Polynomial/misc.h>
namespace CGAL {
namespace internal{
// A has less variables than B
template <typename A, typename B, bool less >
struct Coercion_traits_for_polynomial_comp_d
:public Coercion_traits_for_polynomial_comp_d< B, A , false >{};
// Polynomial<A> has more variables than B
template <typename A, typename B >
struct Coercion_traits_for_polynomial_comp_d< Polynomial<A>, B , false>{
typedef Coercion_traits<A,B> CT;
typedef CGAL::Tag_true Are_explicit_interoperable;
typedef CGAL::Tag_false Are_implicit_interoperable;
typedef Polynomial<typename CT::Type> Type;
struct Cast{
typedef Type result_type;
Type operator()(const Polynomial<A>& poly) const {
typename CT::Cast cast;
return Type(::boost::make_transform_iterator(poly.begin(),cast),
::boost::make_transform_iterator(poly.end() ,cast));
}
Type operator()(const B& x) const {
typename CT::Cast cast;
return Type(cast(x));
}
};
};
// number of variables is different
template <typename A, typename B, int a, int b>
struct Coercion_traits_for_polynomial_equal_d
:public Coercion_traits_for_polynomial_comp_d <A,B, a < b >{};
// number of variables is equal and at least one.
template <class A,class B, int d>
struct Coercion_traits_for_polynomial_equal_d<Polynomial<A>, Polynomial<B>, d, d >{
typedef Coercion_traits<A,B> CT;
typedef CGAL::Tag_true Are_explicit_interoperable;
typedef CGAL::Tag_false Are_implicit_interoperable;
typedef Polynomial<typename CT::Type> Type;
struct Cast{
typedef Type result_type;
Type operator()(const Polynomial<A>& poly) const {
typename CT::Cast cast;
return Type(::boost::make_transform_iterator(poly.begin(),cast),
::boost::make_transform_iterator(poly.end() ,cast));
}
Type operator()(const Polynomial<B>& poly) const {
typename CT::Cast cast;
return Type(::boost::make_transform_iterator(poly.begin(),cast),
::boost::make_transform_iterator(poly.end() ,cast));
}
};
};
// determine number of variables in each polynomial
template <typename A, typename B>
struct Coercion_traits_for_polynomial
: public Coercion_traits_for_polynomial_equal_d
< A , B , Dimension<A>::value, Dimension<B>::value >{};
}// namespace internal
template <class A,class B>
struct Coercion_traits_for_level< Polynomial<A> , Polynomial<B>, CTL_POLYNOMIAL >
:public internal::Coercion_traits_for_polynomial< Polynomial<A>, Polynomial<B> >
{};
template <class A,class B>
struct Coercion_traits_for_level< Polynomial<A> , B , CTL_POLYNOMIAL >
:public internal::Coercion_traits_for_polynomial< Polynomial<A>, B >
{};
template <class A,class B>
struct Coercion_traits_for_level< A , Polynomial<B> , CTL_POLYNOMIAL >
:public internal::Coercion_traits_for_polynomial< A , Polynomial<B> >
{};
#if 0
// COERCION_TRAITS BEGIN
//Coercion_traits_polynomial-----------------------------------
// If there is a Polynomial_traits, valid for more than one Polynomial
// class this part should be adapted, using a Polynomial_traits
// and the nesting_depth
template <class A,class B>
struct Coercion_traits_for_level<Polynomial<A>, Polynomial<B>, CTL_POLYNOMIAL >{
typedef Coercion_traits<A,B> CT;
typedef CGAL::Tag_true Are_explicit_interoperable;
typedef CGAL::Tag_false Are_implicit_interoperable;
typedef Polynomial<typename CT::Type> Type;
struct Cast{
typedef Type result_type;
Type operator()(const Polynomial<A>& poly) const {
typename CT::Cast cast;
return Type(::boost::make_transform_iterator(poly.begin(),cast),
::boost::make_transform_iterator(poly.end() ,cast));
}
Type operator()(const Polynomial<B>& poly) const {
typename CT::Cast cast;
return Type(::boost::make_transform_iterator(poly.begin(),cast),
::boost::make_transform_iterator(poly.end() ,cast));
}
};
};
template <class A,class B>
struct Coercion_traits_for_level<Polynomial<A>,B ,CTL_POLYNOMIAL >{
typedef Coercion_traits<A,B> CT;
typedef CGAL::Tag_true Are_explicit_interoperable;
typedef CGAL::Tag_false Are_implicit_interoperable;
typedef Polynomial<typename CT::Type> Type;
struct Cast{
typedef Type result_type;
Type operator()(const Polynomial<A>& poly) const {
typename CT::Cast cast;
return Type(::boost::make_transform_iterator(poly.begin(),cast),
::boost::make_transform_iterator(poly.end() ,cast));
}
Type operator()(const B& x) const {
typename CT::Cast cast;
return Type(cast(x));
}
};
};
template <class A,class B>
struct Coercion_traits_for_level<B,Polynomial<A>,CTL_POLYNOMIAL >
:public Coercion_traits_for_level<Polynomial<A>,B,CTL_POLYNOMIAL >
{};
#endif // 0
// COERCION_TRAITS END
} //namespace CGAL
#endif // CGAL_POLYNOMIAL_COERCION_TRAITS_H