CGAL users discussion list

["Laurent Rineau (GeometryFactory)" <>]

On Monday 27 April 2009 23:40:54 panayiotis foteinos wrote:
> Hello all.
>
> I am using the simple cartesian kernel with double precision and exact
> predicates.
>
> I observed that sometimes CGAL answers that the points p, q and
> CGAL::midpoint(p, q) are not collinear. Is this the expected behavior?

Yes. With double precision cordinates, the constructions cannot be exact. 
That 
said, midpoint(p, q) is not exactly on the middle point, and not exactly 
colinear with p and q.

-- 
Laurent Rineau, PhD
Engineer at GeometryFactory
http://www.geometryfactory.com/