in reply to Perl PDL slower than python numpy

Three points.


It would be interesting to see some profiling results showing where the time is spent. For perl you can use Devel::NYTProf. I'm not sure about python.

I've profiled code with PDL in the past, and if there are many piddles being generated then the generation is a hotspot. Your profiling code regenerates the piddle each time.

This might also be relevant here:


Your code also includes the startup times, and PDL is a pretty heavy package that pulls in many dependencies. PDL::Lite is useful in such cases.

That said, the cross-posted question on the pdl-general mailing list has updated numbers in the thread: numpy is faster than PDL, but not by double. (Cross-posting is OK, but it helps if it is noted in any posts).


A last observation is that you appear to be running your code in a virtual machine. Does that have any effect on relative speed?