mirror of https://github.com/CGAL/cgal
112 lines
2.6 KiB
C++
112 lines
2.6 KiB
C++
// ============================================================================
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//
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// Copyright (c) 2001-2006 Max-Planck-Institut Saarbruecken (Germany).
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// All rights reserved.
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//
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// This file is part of EXACUS (http://www.mpi-inf.mpg.de/projects/EXACUS/);
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// you may redistribute it under the terms of the Q Public License version 1.0.
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// See the file LICENSE.QPL distributed with EXACUS.
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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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// ----------------------------------------------------------------------------
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//
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// Library : CGAL
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// File : include/CGAL/wang.h
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// CGAL_release : $Name: $
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// Revision : $Revision$
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// Revision_date : $Date$
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//
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// Author(s) : Dominik Huelse <dominik.huelse@gmx.de>
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// Michael Hemmer <hemmer@mpi-inf.mpg.de>
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//
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//
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// ============================================================================
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/*! \file CGAL/wang.h
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* \brief Wang's algorithm for Rational Reconstruction.
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*/
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#ifndef CGAL_WANG_H
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#define CGAL_WANG_H 1
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#include <cmath>
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#include <CGAL/basic.h>
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//#include <CGAL/number_type_utils.h>
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#include <cstdlib>
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namespace CGAL {
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namespace CGALi{
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template<typename Integer>
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inline
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bool wang_general(const Integer& u, const Integer& m,
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Integer& n, Integer& d,
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const Integer& N, const Integer& D) {
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Integer r0,r1,t0,t1,q,hilf;
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// std::cout<<" wang general "<<std::endl;
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Integer u1 = u;
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if(u1<0){
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u1=u1+m;
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}
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CGAL_precondition(u1>=0);
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CGAL_precondition((m>u) && (2*N*D<m));
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r0=m;
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t0=0;
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r1=u1;
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t1=1;
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while(r1>N){
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q = CGAL::div(r0,r1);
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hilf=r0;
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r0=r1;
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r1=hilf-q*r1;
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hilf=t0;
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t0=t1;
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t1=hilf-q*t1;
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}
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n=r1;
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d=t1;
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if(d<0){
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n=-n;
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d=-d;
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}
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if(d<=D && (CGAL::gcd(n,d))==1)
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return true;
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else{
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return false;
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}
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} // wang_general
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} // namespace CGALi
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/*!
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* \brief Wang's algorithm for Rational Reconstruction
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*/
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template<typename Integer>
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bool wang( const Integer& u, const Integer& m,
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Integer& n, Integer& d ){
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typename CGAL::Algebraic_structure_traits<Integer>::Sqrt sqrt;
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// set N and D to wang's default values
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Integer N = sqrt(CGAL::div(m,Integer(2)));
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Integer D = N-Integer(1);
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return CGALi::wang_general(u, m, n, d, N, D);
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}// wang
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} // namespace CGAL
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#endif // CGAL_WANG_H
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// EOF
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