From: Jon Harrop <jon@...>
Date: 2006-08-04T11:00:12+09:00
Subject: Re: For performance, write it in OCaml

William James wrote:
> Here's a faster version of my program.
> 
> Eliminated a "not" in a loop by replacing the array of booleans
> that shows incompatibility of two rows with an array that shows
> compatibility.

Heh, should've thought of that. :-)

> Borrowed you idea of creating an output line ahead of time and
> modifying it in place.
> 
> Timings:
> 1.11  yours
> 1.04  mine

I get the opposite order:

0.394s yours
0.390s mine

but your timings are probably more accurate because your computer is so
slow. ;-)

You can make it slightly faster by factoring out the CSE "compatible
(latest)", giving:

0.382s

That's actually faster than the C here. Woohoo! :-)

Using bitvectors may also improve things, depending if skipping a bunch of
comparisons in that loop is significant. However, I think it is time we
searched for a new task to optimise. Ray tracer anyone? ;-)

-- 
Dr Jon D Harrop, Flying Frog Consultancy
Objective CAML for Scientists
http://www.ffconsultancy.com/products/ocaml_for_scientists