CGAL users discussion list

[Khue Le <>]

Hello,

I am using CGAL QP solver for my project, and get stuck at a numerical issue when getting the objective value:

typedef CGAL::Gmpzf ET;
...define a quadratic program qp here...
Solution s = CGAL::solve_quadratic_program(qp, ET());
assert (s.solves_quadratic_program(qp));
cout<<"QP objective = "<<s.objective_value()<<endl;
// The above returns a value of type CGAL::Quotient<ET>
// and I need to convert it to double
double n = s.objective_value_numerator().to_double();
double d = s.objective_value_denominator().to_double();
cout<<"QP objective 2 = "<<n/d<<endl;

With the above code, I got:

QP objective = -2.57497e-22/2.01459e-22 
QP objective 2 = -nan

Clearly I failed on the conversion step. 

Could you please suggest me a way to properly do the conversion?

Thank you very much in advance!

Regards,

Khue Le
(Lê Hữu Điền Khuê)
PhD Student in Applied Mathematics,
Center for Visual Computing,
Ecole Centrale Paris
Grande Voie des Vignes, 92 295 Châtenay-Malabry, France

www.khue.fr

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