From: "Peña, Botp" <botp@...>
Date: 2002-03-20T11:03:10+09:00
Subject: RE: Why is Ruby so slow? - Solution

yes, and I'd like to know, too, how did Nobu knew that that line was the
culprit...

btw, you guys are cool...

Thanks,
-botp

> -----Original Message-----
> From: Jim Freeze [mailto:jim@freeze.org]
> Sent: Wednesday, March 20, 2002 5:26 AM
> To: ruby-talk@ruby-lang.org
> Subject: Re: Why is Ruby so slow? - Solution
> 
> 
> On Wed, Mar 20, 2002 at 05:26:27AM +0900, Venherm Borchers wrote:
> > Dear colleagues,
> > 
> > The solution
> > ------------
> > 
> > Nobu Nakada pointed out that the following line might be causing the
> > problem, and it indeed does:
> > 
> >         nitms = (@col[j]-['']).nitems
> > 
> > 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!
> > 
> How did you implement @col[j]-[''] to get a speed improvement?
> 
> 
> -- 
> Jim Freeze
> atto:       1e-18 = one quintillionth
> parsec:     3.258 light-years: 3.258 * 186000 * 364 * 24 * 
> 3600 * 5280 * 12
> attoparsec: atto * parsec =~ 1.20 inch
> My height:  62 inches / 1.2 = 51.7 attoparsecs
> ~
>