CGAL users discussion list

[Andreas Fabri <>]

Thomas Zangl - Home wrote:
>  
> Am Thu, 03 Jul 2008 14:03:55 +0200, schrieb "Andreas Fabri" <>:
>
>
> Hi!
>
> > > > The lazy exact kernel stores DAGs (directed acyclic graph) of geometric and
> > > > arithmetic operations.
>
> And the Filtered_Kernel only uses interval arithmetic for some
> pre-defined predicates?

For all predicates

> Sorry, but I did not get yet what the *main* difference between the
> Lazy_kernel and Filtered_kernel is. 

The main difference is that
The lazy kernel is exact_predicates_exact_constructions
The Filtered kernel is only exact_predicates

andreas
> As far as I was able to extract from docs, sources and papers is:
>
> Filtered_kernel:
>
> * Interval arithmetic and maybe static-filters (if not disabled)
>
> Lazy_kernel:
>
> * Stores DAGs of arithmetic operations, geometric constructions  
> and predicates. 
> * Uses interval arithmetic (''Approximate'') and reverts back to exact
> computations if the IA is unsure 
>
> Is that correct? So, is the use of caching DAGs the only difference
> between the Lazy_kernel and the Filtered_kernel?
>
> TIA!,