Hi Mike, Matthias, We could rewrite the affinity module as a C extension using Cython like in shapely/speedups/_speedups.pyx. It would certainly be faster.
Can one of you create an issue at https://github.com/Toblerity/Shapely/issues if you're seriously interested? On Thu, Dec 5, 2013 at 1:00 PM, Mike Toews <mwto...@gmail.com> wrote: > Hi Matthias, > > The bottleneck is due to reading coordinates from a geometry, doing > the transform on each vertex/point, then re-creating a new geometry. > This is done in Python. > > A faster approach would be to do an in-place geometry edit, where the > coordinate sequences are modified without requiring the geometry to be > re-created. One way to do this is to implement this with GEOS, but > that development won't happen quickly or easily (requires lots of C++ > and C-API patching). > > There might be a way to use the existing GEOSGeom_getCoordSeq then > GEOSCoordSeq_setX/Y/Z to modify coordinates of geometries in-place. I > have no idea if this could work, or if it would be faster. > > -Mike > > On 4 December 2013 03:07, Matthias Blaicher <matth...@blaicher.com> wrote: > > Hello, > > > > I'm currently using Shapely for optical computer chip design and the > > first prototypes work great. The only thing I am not satisfied with is > > the speed. I first assumed this to be caused by all the geometry > > operations I do, but after profiling it looks like most of the time is > > spent doing simple affine transformations, especially in > affine_transform. > > > > Is this just my own impression or is it a known area which needs > > performance improvements? > > > > Best, > > Matthias > > _______________________________________________ > > Community mailing list > > Community@lists.gispython.org > > http://lists.gispython.org/mailman/listinfo/community > _______________________________________________ > Community mailing list > Community@lists.gispython.org > http://lists.gispython.org/mailman/listinfo/community > -- Sean Gillies
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