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[Myirci <>]

Bonjour,

I'm using segment delaunay graphs and conics arrangements. At some point of my program I need to convert Ring Type variables to Rational variables to create the conic arcs. My original code is very long, but I generated the same condition in the program below. How can I do the conversion? For just one simple parabola I can supply the Rational coefficients by hand but in my original program, the numbers are not so simple and the coefficients are calculated in run time.

Bonne journée

Merci beaucoup 

#include <iostream>

#include <CGAL/Exact_predicates_exact_constructions_kernel.h>

#include <CGAL/Segment_Delaunay_graph_2.h>

#include <CGAL/Segment_Delaunay_graph_traits_2.h>

typedef CGAL::Exact_predicates_exact_constructions_kernel Kernel;

typedef CGAL::Segment_Delaunay_graph_traits_without_intersections_2<

Kernel,

CGAL::Integral_domain_without_division_tag> Gt;

typedef Gt::Point_2 Point_2;

typedef CGAL::Segment_Delaunay_graph_2<Gt> SDG_2;

#include <CGAL/basic.h>

#include <CGAL/Cartesian.h>

#include <CGAL/CORE_algebraic_number_traits.h>

#include <CGAL/Arrangement_2.h>

#include <CGAL/Arr_conic_traits_2.h>

typedef CGAL::CORE_algebraic_number_traits Nt_traits;

typedef Nt_traits::Rational Rational;

typedef Nt_traits::Algebraic Algebraic;

typedef CGAL::Cartesian<Rational> Rat_kernel;

typedef CGAL::Cartesian<Algebraic> Alg_kernel;

typedef CGAL::Arr_conic_traits_2<Rat_kernel, Alg_kernel, Nt_traits> Traits_2;

typedef Traits_2::Curve_2 Conic_arc_2;

typedef CGAL::Arrangement_2<Traits_2> Arrangement_2;

int main(void) {

// Parabola: y = -3/4x²

Gt::RT r = 0.75;

Gt::RT s = 0;

Gt::RT t = 0;

Gt::RT u = 0;

Gt::RT v = 1;

Gt::RT w = 0;

Point_2 ps = Point_2(2, -3);

Point_2 pt = Point_2(-1, 0.75);

// Does not compile: RT number type must be converted to Rational! How?

Conic_arc_2 arc(r,s,t,u,v,w, CGAL::COUNTERCLOCKWISE, ps, pt);

if(!arc.is_valid()) { std::cout << "NOT VALID" << std::endl; }

return 0;

}
--
Murat Yirci