rational_translate_zero.h

很多二维 三维几何计算算法 C++ 类库

// Copyright (c) 2005  Stanford University (USA).
// 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 Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL distributed with CGAL.
//
// 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: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.3-branch/Kinetic_data_structures/include/CGAL/Polynomial/internal/Rational/Rational_translate_zero.h $
// $Id: Rational_translate_zero.h 28567 2006-02-16 14:30:13Z lsaboret $
// 
//
// Author(s)     : Daniel Russel <[e-mail]>

#ifndef CGAL_POLYNOMIAL_INTERNAL_TRANSLATE_ZERO_H
#define CGAL_POLYNOMIAL_INTERNAL_TRANSLATE_ZERO_H

#include <CGAL/Polynomial/basic.h>

CGAL_POLYNOMIAL_BEGIN_INTERNAL_NAMESPACE

//! Move 0 to -sh
template <class Polynomial>
class Rational_translate_zero
{
    public:
        typedef typename Polynomial::NT NT;
        typedef Polynomial argument_type;
        typedef Polynomial result_type;
        Rational_translate_zero(){}
        Rational_translate_zero(const NT &tr): tr_(tr){}

        void write(std::ostream &out) const
        {
            out << "translate_zero("<<tr_<<")";
        }

        Polynomial operator()(const Polynomial &f) const
        {
            if (f.degree()<1) return f;
//    Polynomial ret= f;
            unsigned int n= f.degree();

            std::vector<NT> ret_coef(n+1);

            for (unsigned int i = 0; i <= n; i++) {
                ret_coef[i] = f[i];
            }

            for (unsigned int i=1; i<=n; ++i) {
                for (unsigned int k=n-i; k<=n-1; ++k) {
                    ret_coef[k] = ret_coef[k]+tr_*ret_coef[k+1];
                }
            }

            Polynomial ret(ret_coef.begin(), ret_coef.end());
            return ret;
        }

    protected:
        NT tr_;
};

CGAL_POLYNOMIAL_END_INTERNAL_NAMESPACE
#endif