[eigen] Ambiguous call

[Luis Peñaranda <luis.penaranda@xxxxxxx>]

Hello,

I have a problem with a simple call to the determinant of a 
Eigen::Matrix<NT,Eigen::Dynamic,Eigen::Dynamic> . This works for many 
different instantiations of NT, like mpq_class. The problem is when I 
try to use a rational number type from the CGAL library, CGAL::Gmpq. I 
get the following error from the compiler:

/usr/local/include/eigen3/Eigen/src/Core/Functors.h:284:90: error: call 
of overloaded ‘abs(const CGAL::Gmpq&)’ is ambiguous

The point is that the function abs(a) is also defined for CGAL::Gmpq. 
Digging inside the code, I found that the line 284 of the above file reads

  EIGEN_STRONG_INLINE const result_type operator() (const Scalar& a) 
const { return abs(a); }

This function is inside the namespace internal::, and I think what is 
intended here is to return internal::abs(a). Changing this line resulted 
in a correct compilation.

My question are two, then. Is it right what I am saying? Is it feasible 
to make this change permanent?

Thank you,

--
Luis