Py 2.5 on Language Shootout

[pgarrone at acay.com.au]

Alioth is a great site for selecting the language in which to implement
primitives. Usually it's C.

Two of the alioth benchmarks, Partial-sums and Spectral-norm, could be
done using Numarray, or would be done with Numarray if most of the
program was in Python and there was a need to implement a similar
numerical procedure. The speed would be up near the compiled language
benchmarks. However the specific wording of these benchmarks prohibits
this approach. Spectral-norm must pretend the dataset is infinite, and
Partial-sums has to be implemented in a simple dumb loop.

Looking over the benchmarks, one gains the impression that Python is a
slow language.
My first serious Python programming exercise involved converting a 900
line Bash Shell program to a 500 line Python program, with a speedup
factor of 17. Using Python allowed an OO structure and advanced
containers, meaning the program was more maintainable and portable,
which were the main aims of the exercise. The speedup was a surprising
and welcome side benefit. I think it was mosly because the Python
byte-code interpreter is probably an order of magnitude faster than
Bash's direct interpretation, and because in Python system calls to
recurse directories and create symbolic links were not forked to
separate processes. In fact I would guess that the overall speed of the
Python program would be little less than a C program, given that most
of the time would be spent in system calls.

Its almost possible to make a large Python program arbitrarily fast by
profiling it and implementing slow bits as primitives. Size is probably
of greater concern.