I was writing a data intensive code in Perl relying heavily on PDL for some statitical calculations (estimation of percentile points in some very BIG vectors, e.g. 100k to 1B elements), when I noticed that PDL was taking a very (and unusually long!) time to produce results compared to my experience in Python. This happened irrespective of whether one used the pct or oddpct functions in PDL::Ufunc.