Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Are attack_to and attack from supposed to be incrementaly computed ?

Author: Robert Hyatt

Date: 21:16:10 10/22/04

Go up one level in this thread


On October 21, 2004 at 22:49:28, Mathieu Pagé wrote:

>I just read this paper by Robert Hyatt on rotated bitmap:
>
>http://www.cis.uab.edu/info/faculty/hyatt/bitmaps.html
>
>It describe how to generate attack_to[] and attack_from[] bitmaps. I think those
>tables are not updated incrementaly and are computed from scratch at each node.
>Am I right, or is there a efficient way to do it incrementaly ?
>
>Moreover, it seem to me that attack_to should be computed "on demand" only,
>since we will probably not use every square of it. So it could be a function :
>attack_to(int sq). Does this make sense ?
>
>Mathieu Pagé
>mathieu.page at gmail dot com


That is the point of "rotated bitmaps".  That you compute the attacks on demand.
 Early versions of crafty used the older chess 4.x approach of incrementally
updating things, but after fooling with that for a year, I came up with the idea
of rotated bitmaps to get rid of all the incremental computation...




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.