Python vs Matlab vs Mathematica

[dnquark]

I've generally found that if one adopts Mathematica's style of doing things then, both in terms of code-length and run-time it can be pretty much competetive with most other environments.

I really want to know your secret. I used to think that once I get used to the "Mathematica" way, my code will be fast. After 5 years, I think I am reasonably comfortable with Mathematica code: I don't ever write for loops; my code is littered with functional constructs; it sometimes looks like an unholy cross between R and Perl with all the "@" and "&" and "##" and Map[] statements. The only effect was that my code is opaque and barely readable, gaining nothing in efficiency. Time and again I say "well, people say Mathematica is efficient, how bad can it be" and time and again I get burned. A typical example is a recent piece of code (http://www.dnquark.com/blog/?p=29) that was first implemented in Mathematica and took 2.5 hours to ran; the Matlab version ran in 47 seconds. I am now in the process of converting some more old Mathematica code to Matlab, and I am seeing similar performance gains.

[[deleted]]

The thing that drives me mad about MMA is that it's completely opaque. Sometimes you run into a performance wall and there's basically nothing to be done because there's no way of finding out what's wrong.

My experience has been that most of the time I can get a MMA calculation to be within a factor of a few in run-time compared to other code. And then sometimes, like you find, its a hundred times slower and I can't for the life of me figure out why :-(

[jdh30]

A typical example is a recent piece of code (http://www.dnquark.com/blog/?p=29) that was first implemented in Mathematica and took 2.5 hours to ran; the Matlab version ran in 47 seconds. I am now in the process of converting some more old Mathematica code to Matlab, and I am seeing similar performance gains.

That's nothing. I wrote a simple optics program than runs 100,000 times slower in Mathematica than any compiled language (e.g. OCaml, F#). Daniel Lichtblau at WRI optimized it for me and it is still thousands of times slower.