mirror of https://github.com/CGAL/cgal
150 lines
4.5 KiB
C++
150 lines
4.5 KiB
C++
// Copyright (c) 2006 Fernando Luis Cacciola Carballal. 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.
|
|
//
|
|
// $URL$
|
|
// $Id$
|
|
//
|
|
// Author(s) : Fernando Cacciola <fernando_cacciola@ciudad.com.ar>
|
|
//
|
|
#ifndef CGAL_CERTIFIED_QUOTIENT_PREDICATES_H
|
|
#define CGAL_CERTIFIED_QUOTIENT_PREDICATES_H
|
|
|
|
#include <CGAL/certified_numeric_predicates.h>
|
|
#include <CGAL/Quotient.h>
|
|
|
|
CGAL_BEGIN_NAMESPACE
|
|
|
|
template <class NT>
|
|
inline Uncertain<bool> certified_quotient_is_positive(const Quotient<NT>& x)
|
|
{
|
|
Uncertain<Sign> signum = CGAL_NTS certified_sign(x.num) ;
|
|
Uncertain<Sign> sigden = CGAL_NTS certified_sign(x.den) ;
|
|
Uncertain<Sign> zero(ZERO);
|
|
return signum != zero & signum == sigden ;
|
|
}
|
|
|
|
template <class NT>
|
|
inline Uncertain<bool> certified_quotient_is_negative(const Quotient<NT>& x)
|
|
{
|
|
Uncertain<Sign> signum = CGAL_NTS certified_sign(x.num) ;
|
|
Uncertain<Sign> sigden = CGAL_NTS certified_sign(x.den) ;
|
|
Uncertain<Sign> zero(ZERO);
|
|
|
|
return signum != zero & signum != sigden ;
|
|
}
|
|
|
|
template <class NT>
|
|
inline Uncertain<bool> certified_quotient_is_zero(const Quotient<NT>& x)
|
|
{
|
|
return CGAL_NTS certified_is_zero(x.num) ;
|
|
}
|
|
|
|
template <class NT>
|
|
CGAL_MEDIUM_INLINE
|
|
Uncertain<Sign> certified_quotient_sign(const Quotient<NT>& x)
|
|
{
|
|
Uncertain<Sign> r = Uncertain<Sign>::indeterminate();
|
|
|
|
Uncertain<Sign> signum = CGAL_NTS certified_sign(x.num) ;
|
|
Uncertain<Sign> sigden = CGAL_NTS certified_sign(x.den) ;
|
|
|
|
// No assumptions on the sign of den are made
|
|
|
|
// code assumes this
|
|
CGAL_precondition( NEGATIVE == static_cast<Sign>(-1)
|
|
&& ZERO == static_cast<Sign>(0)
|
|
&& POSITIVE == static_cast<Sign>(1)
|
|
);
|
|
|
|
if ( !is_indeterminate(signum) && !is_indeterminate(sigden) )
|
|
r = make_uncertain( static_cast<Sign>(signum * sigden) ) ;
|
|
|
|
return r ;
|
|
}
|
|
|
|
template <class NT1, class NT2>
|
|
CGAL_MEDIUM_INLINE
|
|
Uncertain<Comparison_result> certified_quotient_compare(const Quotient<NT1>& x, const Quotient<NT2>& y)
|
|
{
|
|
Uncertain<Comparison_result> r = Uncertain<Comparison_result>::indeterminate();
|
|
|
|
// No assumptions on the sign of den are made
|
|
|
|
// code assumes that SMALLER == - 1;
|
|
CGAL_precondition( SMALLER == static_cast<Comparison_result>(-1) );
|
|
|
|
Uncertain<Sign> xnumsign = CGAL_NTS certified_sign(x.num) ;
|
|
Uncertain<Sign> xdensign = CGAL_NTS certified_sign(x.den) ;
|
|
Uncertain<Sign> ynumsign = CGAL_NTS certified_sign(y.num) ;
|
|
Uncertain<Sign> ydensign = CGAL_NTS certified_sign(y.den) ;
|
|
|
|
if ( !is_indeterminate(xnumsign)
|
|
&& !is_indeterminate(xdensign)
|
|
&& !is_indeterminate(ynumsign)
|
|
&& !is_indeterminate(ydensign)
|
|
)
|
|
{
|
|
int xsign = xnumsign * xdensign ;
|
|
int ysign = ynumsign * ydensign ;
|
|
if (xsign == 0) return make_uncertain(static_cast<Comparison_result>(-ysign));
|
|
if (ysign == 0) return make_uncertain(static_cast<Comparison_result>(xsign));
|
|
// now (x != 0) && (y != 0)
|
|
int diff = xsign - ysign;
|
|
if (diff == 0)
|
|
{
|
|
int msign = xdensign * ydensign;
|
|
NT1 leftop = x.num * y.den * msign;
|
|
NT1 rightop = y.num * x.den * msign;
|
|
r = certified_compare(leftop, rightop);
|
|
}
|
|
else
|
|
{
|
|
r = make_uncertain((xsign < ysign) ? SMALLER : LARGER);
|
|
}
|
|
}
|
|
|
|
return r ;
|
|
}
|
|
|
|
template <class NT>
|
|
inline Uncertain<bool> certified_is_zero(const Quotient<NT>& n)
|
|
{
|
|
return certified_quotient_is_zero(n);
|
|
}
|
|
template <class NT>
|
|
inline Uncertain<bool> certified_is_positive(const Quotient<NT>& n)
|
|
{
|
|
return certified_quotient_is_positive(n);
|
|
}
|
|
template <class NT>
|
|
inline Uncertain<bool> certified_is_negative(const Quotient<NT>& n)
|
|
{
|
|
return certified_quotient_is_negative(n);
|
|
}
|
|
template <class NT>
|
|
inline Uncertain<Sign> certified_sign(const Quotient<NT>& n)
|
|
{
|
|
return certified_quotient_sign(n);
|
|
}
|
|
|
|
template <class NT1, class NT2>
|
|
inline Uncertain<Comparison_result> certified_compare(const Quotient<NT1>& n1, const Quotient<NT2>& n2)
|
|
{
|
|
return certified_quotient_compare(n1,n2);
|
|
}
|
|
|
|
CGAL_END_NAMESPACE
|
|
|
|
#endif // CGAL_CERTIFIED_QUOTIENT_PREDICATES_H
|
|
|