CGAL users discussion list

[Marc Glisse <>]

On Thu, 26 Apr 2018, houes wrote:

> Hello. I have a bunch of Plane_3 objects in std::vector, However, there are
> some duplicates among them. I need to eliminate the duplicates.
>
> I thought of two methods:
> (1) sort and unique using std. However this requires me to design a
> comparator for Plane_3, anyone know what would be a good comparator for
> Plane_3 like?
> (2) add items into a hashset one by one. However, this requires me to design
> a hash function for Plane_3, and I wonder what is a good hash function for
> Plane_3.
>
> Efficiency speaking, method (2) would be better, because it take O(n) time,
> where n is the number of input Planes. Method (1) takes O(nlogn) due to
> sorting.
>
> Therefore, I would like to know what a good hashing function for Plane_3 is
> like.

Numerical issues make this problematic.
Are you using Epick or Epeck?
Are your duplicates copies originating from the same object, or are they 
possibly created separately?

--
Marc Glisse