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From: "John B. Matthews" <nospam@nospam.invalid>
Newsgroups: comp.lang.ada
Subject: Re: Efficient Sequential Access to Arrays
Date: Mon, 16 Jul 2012 15:43:54 -0400
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Date: 2012-07-16T15:43:54-04:00
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In article <4c86d54d-dfeb-44f1-9638-3c416ea51d74@googlegroups.com>,
 Keean Schupke <keean.schupke@googlemail.com> wrote:

> > On Mon, 16 Jul 2012 03:16:09 -0700 (PDT), Keean Schupke wrote:
> > 
> > &gt; On Monday, 16 July 2012 08:47:01 UTC+1, Dmitry A. Kazakov  wrote:
> > > > On Sun, 15 Jul 2012 13:03:12 -0700 (PDT), Keean Schupke wrote:
> > > >  
> > > > Absolute figures tell little. How big is the relative difference?
> > > 
> > > About 25% (30k with indexing, 40k with relative addressing)
> > 
> > Which itself looks like a problem. It takes no less than 25% of 
> > overall performance for mere shuffling data in a task unrelated to 
> > stuff like recoding etc. This looks wrong to me. I would look for a 
> > better algorithm/structure.
> 
> I find this comment puzzling and does not match my experience. What 
> sort of algorithms do you work with. What algorithm for disjoint-set 
> do you suggest I use? Have a read of this:
> 
> http://www.cs.princeton.edu/~rs/AlgsDS07/01UnionFind.pdf

Apropos to this, may I impose on you to elaborate on your previous 
decision not to use WQUPC? In particular, is your application lookup 
dominated due in some part to the choice of algorithm itself?

Sorry if I've overlooked an intervening clarification.

<https://groups.google.com/d/msg/comp.lang.ada/EDgDNVw9tgc/bUYu34D_8LEJ>

> Can you come up with a faster algorithm? Until you have read it I 
> don't think you can comment on the quality of algorithm I am using.

-- 
John B. Matthews
trashgod at gmail dot com
<http://sites.google.com/site/drjohnbmatthews>