From: Bill Kelly <billk@...>
Date: 2003-03-03T09:26:21+09:00
Subject: Re: Is Ruby slower?

Hi,

From: "Mauricio Fern�ndez" <batsman.geo@yahoo.com>

>  * however, a perf. increase of 1-3% can be achieved by setting the
>    number of bins in the hash to be a power of 2, so that we can later
>    use bitwise AND instead of the modulus operator [I assume our hash is
>    good enough not to increase the num. of collisions a lot]

Sorry if this contribution is "newbie-like" as I'm not an expert
in any kind of mathematical/analytical field, but... Just wanted
to mention that my Sedgewick algorithms book goes into a bit of
detail on why prime numbers should generate better distributed
hash values using the modulo operator than powers-of-two...


HTH,

Bill