Author: Ed Schröder
Date: 14:48:29 11/27/03
Go up one level in this thread
On November 27, 2003 at 15:34:24, Tord Romstad wrote: >On November 27, 2003 at 12:39:06, Ed Schröder wrote: > >>On November 27, 2003 at 07:54:50, martin fierz wrote: >> >>>am i missing something here, or is this just another inaccuracy that such a >>>table-based SEE has (like not resolving xray attacks)? is it simply unimportant >>>to resolve such details? >>It depends how you are planning to use the information, it is great for >>move-ordering, q-search, static selective search, pruning, extensions, >>reductions, eval. >I've always wondered how you manage with only one bit for knights and bishop >in your eval, for instance when using the attack table for static mate >detection. How is this done? Static mate detection, why should one do this when you have q-search? I have done so at the very beginning, on the Z80 I had a working static checkmate algorithm which was called everytime a move gave a check, those were the days I never heard of q-search and I evaluated hanging pieces on a static base. >My attack tables are similar to yours, but >the way my eval currently works I need 9 bits instead of 8 because of the >important distinction between knights and bishops. My system was developed on the Z80 from the early 80's, 9-bits was a non option at that time :) I agree that with an 8-bit system to extract the information is more complicated than with a 9-bit system nevertheless it is doable. I am pretty sure the error margin in practice is somewhere between 0.1% and 0.01% which is more than satisfying. >Another question: How did you do hanging piece detection and similar >stuff at the time when the memory for lookup tables was limited (like >on the ChessMachine version of Rebel and on versions for various Mephisto >standalone units)? I used code, later I precalculated the results. Actually the speed gain was disappointing, less than 1%, probably due to the extra use of the PC's data cache. >Thank you very much for making your ideas public! Your Rebel pages >is the most valuable chess programming resource out there, IMHO. They >contain loads of interesting and useful information. Thank you, that was the intend. My best, Ed
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.