53 lines
1.8 KiB
C++
53 lines
1.8 KiB
C++
// Copyright (c) 2006-2013 INRIA Nancy-Grand Est (France). All rights reserved.
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//
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// This file is part of CGAL (www.cgal.org)
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//
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// $URL: https://github.com/CGAL/cgal/blob/v5.1/Algebraic_kernel_d/include/CGAL/RS/exact_signat_1.h $
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// $Id: exact_signat_1.h 52164b1 2019-10-19T15:34:59+02:00 Sébastien Loriot
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// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
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//
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// Author: Luis Peñaranda <luis.penaranda@gmx.com>
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#ifndef CGAL_RS_EXACT_SIGNAT_1_H
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#define CGAL_RS_EXACT_SIGNAT_1_H
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#include <CGAL/Polynomial_traits_d.h>
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#include "dyadic.h"
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namespace CGAL{
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namespace RS_AK1{
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template <class Polynomial_,class Bound_>
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struct ExactSignat_1{
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typedef Polynomial_ Polynomial;
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typedef Bound_ Bound;
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typedef CGAL::Polynomial_traits_d<Polynomial> PT;
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typedef typename PT::Degree Degree;
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Polynomial pol;
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ExactSignat_1(const Polynomial &p):pol(p){};
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CGAL::Sign operator()(const Bound&)const;
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}; // struct ExactSignat_1
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template <>
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inline CGAL::Sign
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ExactSignat_1<Polynomial<Gmpz>,Gmpfr>::operator()(const Gmpfr &x)const{
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int d=Degree()(pol);
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if(d==0)
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return pol[0].sign();
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// Construct a Gmpfr containing exactly the leading coefficient.
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Gmpfr h(pol[d],pol[d].bit_size());
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CGAL_assertion(h==pol[d]);
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// Horner's evaluation.
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for(int i=1;i<d;++i){
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CGALRS_dyadic_mul(h.fr(),h.fr(),x.fr());
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CGALRS_dyadic_add_z(h.fr(),h.fr(),pol[d-i].mpz());
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}
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// TODO: We can avoid doing the last addition.
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return h.sign();
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}
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} // namespace RS_AK1
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} // namespace CGAL
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#endif // CGAL_RS_EXACT_SIGNAT_1_H
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