[geos-devel] count of signOfDet2x2 calls in JTS

[Norman Vine]

Martin Davis writes:

> Here's the results.  (Note these are for the SineStar^2 test, comparing two offset sine stars of the same size).
> 
> Good news: there's lots of calls to signOfDet2x2 , so GEOS looks like it's mirroring JTS
> Bad news: why so many calls? 
> 
> I'll try and figure out the reason for the bad news...   8^(

Hmm...  the patch I posted should help a bit

Note there are two separate early out tricks

the first is the obvious 'trivial reject' 
the other is doing the orientationIndex() on 'Qp'
only after testing for an early reject on 'Pq'

this should save ~30% of the tests or better

Hopefully there are bigger gains to be had elsewhere too :-)

Norman