Re: [boost] Re: rationals initialization bug

From: Greg Colvin (gcolvin_at_[hidden])
Date: 2000-11-28 22:29:41

From: Lutz Kettner <kettner_at_[hidden]>
> Hi Paul,
> 
> > I agree up to a point. But I take a slightly more extreme view, that there
> > should be no construction from double at all. This is based on my not seeing
> > any use for it, admittedly. Your example seems to indicate that there is a
> > (rare) use for an exact conversion, but in general I feel that it would be
> > surprising more often than useful.
> 
> Yes, there is a good use in geometry, the data comes often in doubles
> (after reading it from a file or so). For example 3d meshes in graphics.
> So I would like to see the (exact) constructor from double, but I can
> also perfectly understand if it will be a cast-like function call.

Why not an explicit constructor?

> With CGAL we like to use LEDA (the library at 
> http://www.mpi-sb.mpg.de/LEDA/leda.html, not the language) that has 
> good number types. They convert doubles to leda_real and also 
> to leda_rational with constructors. I don't know internals though.
> 
> Best regards,
> 
> Lutz
> 
> 
> 
>