From: nobu.nokada@...
Date: 2002-03-20T14:09:26+09:00
Subject: Re: Why is Ruby so slow? - Solution

Hi,

At Wed, 20 Mar 2002 11:01:34 +0900,
Christoph wrote:
> > Here I relied on the 'set difference' that returns an array of only
> > unique elements which then are counted. I have to warn you: this kind
> > of set operation is _unbelievably_ slow!
> 
> This depends. If you ``set subtract'' a one million element set from an
> other one million element set then the current Array#- implementation
> will be unbelievably fast.

Yes, current implementation is optimized for bigger arrays, it
takes O(N+M) time, but former was O(N*M), where arrays with N
and M size.  Perhaps, in this case, GC occurred several times
per each loops by 1,600,000 items hashes.

-- 
Nobu Nakada