mirror of https://github.com/CGAL/cgal
207 lines
7.8 KiB
C++
207 lines
7.8 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); 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; version 2.1 of the License.
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// See the file LICENSE.LGPL distributed with CGAL.
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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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//
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// Author: Luis Peñaranda <luis.penaranda@gmx.com>
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// This file contains the simplest refiner, that bisects the interval a given
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// number of times.
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#ifndef CGAL_RS_BISECTION_REFINER_1_H
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#define CGAL_RS_BISECTION_REFINER_1_H
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#include <CGAL/Polynomial_traits_d.h>
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#include "signat_1.h"
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namespace CGAL{
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template <class Polynomial_,class Bound_>
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struct Bisection_refiner_1{
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typedef CGAL::RS_AK1::Signat_1<Polynomial_,Bound_> Signat;
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void operator()(const Polynomial_&,Bound_&,Bound_&,int);
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}; // class Bisection_refiner_1
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// TODO: Write in a generic way, if possible (see next function).
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template <class Polynomial_,class Bound_>
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void
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Bisection_refiner_1<Polynomial_,Bound_>::
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operator()(const Polynomial_&,Bound_&,Bound_&,int){
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CGAL_error_msg("bisection refiner not implemented for these types");
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return;
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}
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// This works with any type of polynomial, but only for Gmpfr bounds.
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// TODO: Beyond writing generically, optimize this function. This would
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// remove the need for the next function, which essentially the same.
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template<>
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void
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Bisection_refiner_1<Polynomial<Gmpz>,Gmpfr>::
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operator()(const Polynomial<Gmpz> &pol,Gmpfr &left,Gmpfr &right,int prec){
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typedef Polynomial<Gmpz> Polynomial;
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typedef Polynomial_traits_d<Polynomial> Ptraits;
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typedef Ptraits::Make_square_free Sfpart;
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typedef CGAL::RS_AK1::Signat_1<Polynomial,Gmpfr>
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Signat;
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CGAL_precondition(left<=right);
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// TODO: add precondition to check whether the interval is a point
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// or the evaluations on its endpoints have different signs
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//std::cout<<"refining ["<<left<<","<<right<<"]"<<std::endl;
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#ifndef CGAL_GMPFR_NO_REFCOUNT
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// Make sure the endpoints do not share references. If some of them
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// does, copy it.
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if(!left.is_unique()){
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Gmpfr new_left(0,left.get_precision());
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mpfr_set(new_left.fr(),left.fr(),GMP_RNDN);
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left=new_left;
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CGAL_assertion_code(new_left=Gmpfr();)
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CGAL_assertion(left.is_unique());
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}
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if(!right.is_unique()){
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Gmpfr new_right(0,right.get_precision());
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mpfr_set(new_right.fr(),right.fr(),GMP_RNDN);
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right=new_right;
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CGAL_assertion_code(new_right=Gmpfr();)
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CGAL_assertion(right.is_unique());
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}
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#endif // CGAL_GMPFR_NO_REFCOUNT
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Polynomial sfpp=Sfpart()(pol);
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Signat signof(sfpp);
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CGAL::Sign sl,sc;
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mp_prec_t pl,pc;
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mpfr_t center;
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sl=signof(left);
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if(sl==ZERO)
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return;
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pl=left.get_precision();
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pc=right.get_precision();
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pc=(pl>pc?pl:pc)+(mp_prec_t)prec;
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mpfr_init2(center,pc);
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CGAL_assertion_code(int round=)
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mpfr_prec_round(left.fr(),pc,GMP_RNDN);
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CGAL_assertion(!round);
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CGAL_assertion_code(round=)
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mpfr_prec_round(right.fr(),pc,GMP_RNDN);
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CGAL_assertion(!round);
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for(int i=0;i<prec;++i){
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CGAL_assertion_code(round=)
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mpfr_add(center,left.fr(),right.fr(),GMP_RNDN);
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CGAL_assertion(!round);
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CGAL_assertion_code(round=)
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mpfr_div_2ui(center,center,1,GMP_RNDN);
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CGAL_assertion(!round);
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sc=signof(Gmpfr(center));
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if(sc==ZERO){ // we have a root
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CGAL_assertion_code(round=)
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mpfr_set(left.fr(),center,GMP_RNDN);
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CGAL_assertion(!round);
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mpfr_swap(right.fr(),center);
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break;
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}
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if(sc==sl)
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mpfr_swap(left.fr(),center);
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else
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mpfr_swap(right.fr(),center);
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}
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mpfr_clear(center);
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CGAL_postcondition(left<=right);
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//std::cout<<"ref root is ["<<left<<","<<right<<"]"<<std::endl;
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return;
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}
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template<>
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void
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Bisection_refiner_1<Polynomial<Gmpq>,Gmpfr>::
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operator()(const Polynomial<Gmpq> &pol,Gmpfr &left,Gmpfr &right,int prec){
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typedef Polynomial<Gmpq> Polynomial;
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typedef Polynomial_traits_d<Polynomial> Ptraits;
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typedef Ptraits::Make_square_free Sfpart;
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typedef CGAL::RS_AK1::Signat_1<Polynomial,Gmpfr>
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Signat;
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CGAL_precondition(left<=right);
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// TODO: add precondition to check whether the interval is a point
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// or the evaluations on its endpoints have different signs
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//std::cout<<"refining ["<<left<<","<<right<<"]"<<std::endl;
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#ifndef CGAL_GMPFR_NO_REFCOUNT
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// Make sure the endpoints do not share references. If some of them
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// does, copy it.
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if(!left.is_unique()){
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Gmpfr new_left(0,left.get_precision());
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mpfr_set(new_left.fr(),left.fr(),GMP_RNDN);
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left=new_left;
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CGAL_assertion_code(new_left=Gmpfr();)
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CGAL_assertion(left.is_unique());
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}
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if(!right.is_unique()){
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Gmpfr new_right(0,right.get_precision());
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mpfr_set(new_right.fr(),right.fr(),GMP_RNDN);
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right=new_right;
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CGAL_assertion_code(new_right=Gmpfr();)
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CGAL_assertion(right.is_unique());
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}
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#endif // CGAL_GMPFR_NO_REFCOUNT
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Polynomial sfpp=Sfpart()(pol);
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Signat signof(sfpp);
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CGAL::Sign sl,sc;
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mp_prec_t pl,pc;
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mpfr_t center;
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sl=signof(left);
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if(sl==ZERO)
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return;
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pl=left.get_precision();
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pc=right.get_precision();
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pc=(pl>pc?pl:pc)+(mp_prec_t)prec;
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mpfr_init2(center,pc);
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CGAL_assertion_code(int round=)
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mpfr_prec_round(left.fr(),pc,GMP_RNDN);
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CGAL_assertion(!round);
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CGAL_assertion_code(round=)
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mpfr_prec_round(right.fr(),pc,GMP_RNDN);
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CGAL_assertion(!round);
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for(int i=0;i<prec;++i){
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CGAL_assertion_code(round=)
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mpfr_add(center,left.fr(),right.fr(),GMP_RNDN);
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CGAL_assertion(!round);
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CGAL_assertion_code(round=)
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mpfr_div_2ui(center,center,1,GMP_RNDN);
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CGAL_assertion(!round);
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sc=signof(Gmpfr(center));
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if(sc==ZERO){ // we have a root
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CGAL_assertion_code(round=)
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mpfr_set(left.fr(),center,GMP_RNDN);
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CGAL_assertion(!round);
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mpfr_swap(right.fr(),center);
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break;
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}
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if(sc==sl)
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mpfr_swap(left.fr(),center);
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else
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mpfr_swap(right.fr(),center);
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}
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mpfr_clear(center);
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CGAL_postcondition(left<=right);
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//std::cout<<"ref root is ["<<left<<","<<right<<"]"<<std::endl;
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return;
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}
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} // namespace CGAL
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#endif // CGAL_RS_BISECTION_REFINER_1_H
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