/usr/include/CGAL/RS/sign_1.h is in libcgal-dev 4.2-5ubuntu1.
This file is owned by root:root, with mode 0o644.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 | // Copyright (c) 2006-2010 Inria Lorraine (France). 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; either version 3 of the License,
// or (at your option) any later version.
//
// 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: Luis Peñaranda <luis.penaranda@gmx.com>
#ifndef CGAL_RS_SIGN_1_H
#define CGAL_RS_SIGN_1_H
#include <gmp.h>
#include <mpfr.h>
#include <mpfi.h>
#include <CGAL/RS/basic.h>
#include <CGAL/RS/dyadic.h>
#include <CGAL/RS/polynomial_1.h>
#include <CGAL/RS/algebraic_1.h>
#include <CGAL/RS/solve_1.h>
#include <CGAL/assertions.h>
namespace CGAL{
struct RSSign{
// This function calculates the sign of the evaluation of a polynomial
// at a given algebraic number. If it is impossible to know the sign
// evaluating the interval, it calls sign_1_rs, which uses RS to do it.
static CGAL::Sign sign_1(const RS_polynomial_1 &p,const Algebraic_1 &x){
RS::rs_sign s=p.sign_mpfi(x.mpfi());
if(s!=RS::RS_UNKNOWN)
return RS::convert_rs_sign(s);
return sign_1_rs(p,x);
}
// compute the sign of the polynomial at a given dyadic
static inline CGAL::Sign
exactsignatdyadic(const RS_polynomial_1 &p,CGALRS_dyadic_srcptr d){
return p.sign_dyadic(d);
}
// compute the sign of the polynomial at a given mpfr
static inline CGAL::Sign
exactsignat(const RS_polynomial_1 &p,mpfr_srcptr m){
return p.sign_mpfr(m);
}
// This function uses interval arithmetic to calculate the sign of the
// evaluation. First, it converts the given mpfr number to an mpfi
// interval with the given precision. Later, it evaluates the
// polynomial in the interval an looks for the sign. If it is not able
// to determine it, it calls the exact signat function.
static CGAL::Sign quicksignat
(const RS_polynomial_1 &p,mpfr_srcptr xcoord,mp_prec_t prec){
mpfi_t x_approx;
RS::rs_sign s;
mpfi_init2(x_approx,prec);
mpfi_set_fr(x_approx,xcoord);
s=p.sign_mpfi(x_approx);
mpfi_clear(x_approx);
if(s!=RS::RS_UNKNOWN)
return RS::convert_rs_sign(s);
return p.sign_mpfr(xcoord);
}
// This function is supposed to return the signat calculated in
// the best way.
static CGAL::Sign signat(const RS_polynomial_1 &p,mpfr_srcptr xcoord){
mp_prec_t xprec=mpfr_get_prec(xcoord);
if(xprec>>(mp_prec_t)12) // switch to exact if xprec>=8192
return p.sign_mpfr(xcoord);
return quicksignat(p,xcoord,xprec);
}
}; // struct RSSign
} // namespace CGAL
#endif // CGAL_RS_SIGN_1_H
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