[geos-devel] Why many calls to signOfDet2x2 and addIntersections
Norman Vine
nhv at cape.com
Wed Nov 20 15:26:56 EST 2002
Martin Davis writes:
>
> Ok, after refreshing my brain about the JTS algorithms I can now shed some light on the mystery of why there are so many calls to
RobustDeterminant::signOfDet2x2 and SegmentIntersector SegmentIntersector::addIntersections.
Martin
It seems from your instrumentation that the JAVA code
is making ~10 times npoints calls but it is hard to tell exactly
Could you please add some instrumentation inside of signOfDet2x2()
and post the results of the TOTAL calls per test.
> Probably the real message here is that JTS has lived quite happily doing this all the time. If GEOS is slower than JTS we have to
look elsewhere for the cause.
FWIW- My current TestLineSweep is running about
~20% faster then the Java results you posted
this is computed by elapsed_time * 733 / 1100
where my 733/1100 represents the speed of
my machine vs your machine
Of course this doesn't take into account lots of things
like different processors or memry speed
Norman
More information about the geos-devel
mailing list