From: "Bartosz Dziewoński" <matma.rex@...>
Date: 2012-03-25T02:11:31+09:00
Subject: Re: Ruby speed compared to C in a simple calculations.

W dniu 24 marca 2012 17:45 użytkownik Роман Ткаленко
<rain.roman@gmail.com> napisał:
> #works for 3.55 mins
> <snip>
> Code written in C gives me the solution in only 2 seconds. I suppose that
> it's called not by ruby slowlyness, but my shitty coding abilities. Cuold
> tou please tell me the weaknesse of the code?

It took 51 seconds for me on Ruby 1.9.3, on a laptop; the 1.9 series
is much faster than 1.8.

Ruby, overall, is unfortunately very slow. There are many reasons for
this (for example, every operator is your code becomes a method call,
and every method call requires looking up the relevant code in a
method table - this adds up), and not much can be done.

For some reason even the bare "(0 .. P).each do | i |" loop (with
everything inside removed) takes 30 seconds to run, and so does a
P.times or a while loop (negligible time difference).  You just can't
do fast computation in Ruby now, at all. (Note that JRuby or Rubinius
might be faster for numeric computation - try yourself, if you care.)


-- Matma Rex