CGAL users discussion list

[Sylvain Pion <>]

Torchi Borchi wrote:
> i would like to try mpq_class but:
>
> #include <CGAL/gmpxx.h>
> typedef mpq_class RT;
> typedef CGAL::Cartesian<RT> K;

It should be correct.

> this does not work.

Can you expand a bit on "it does not work" ?

> how can use mpq_class to get a kernel?
> i cant find any documentation or example.
>
> i see also that #include <CGAL/gmpxx.h> is including
> #include <gmpxx.h>
>
> gmpxx.h is missing in CGAL-3.4-Setup.exe
>
> i downloaded gmp-4.3.1 and added the path to gmpxx.h.
> but i still dont know how to make a kernel out of mpq_class.

Note that you will also need to link against libgmpxx.

> Sylvain Pion schrieb:
> > torchi borchi wrote:
> > > i followed your suggestion and tried this:
> > >
> > > typedef CGAL::Gmpq RT;
> > > typedef CGAL::Simple_cartesian<RT> K;
> > >
> > > but it still crashes. is Gmpq using reference counting?
> >
> > Yes, it uses the same thread-unsafe mechanism.
> >
> > > i need exact constructions.
> >
> > Try mpq_class instead of Gmpq ?
> > Or Quotient<MP_Float>, but that can be much slower.
> >
> > Otherwise, someone needs to bite the bullet and fix
> > the reference counting mechanism (in <CGAL/Handle_for.h>).


--
Sylvain Pion
INRIA Sophia-Antipolis
Geometrica Project-Team
CGAL, http://cgal.org/