Author: Uri Blass
Date: 01:17:25 03/26/04
Go up one level in this thread
On March 26, 2004 at 03:02:04, Tord Romstad wrote: >On March 26, 2004 at 02:39:29, Johan de Koning wrote: > >>>I thought so, too, but after watching the first two games of a blitz match >>>between the normal version of my engine and an identical version with the >>>null move disabled I am already beginning to doubt it. The non-nullmove >>>version is leading by 2-0. >> >>IIRC it was only 2 days ago Will Singleton posted a funny remark about >>discarding null moves after 10 games. :-) > >Yes, I remember. :-) > >I wasn't really close to discarding null moves, of course, but I was surprised >that the version without null move had any chance at all, and that the >difference in search depth was not greater. I expect the null move version >to win by a clear margin when enough games are played, but it will be >interesting to see how big the difference is. After 8 games, it's 4-4. > >>>The difference in search depth isn't as big as I expected. In the middle >>>game, the null move version typically reaches about 12 plies, while the >>>version without null move reaches 11 plies. >> >>Hmmm... that sounds pretty incredible. >>We're not talking about 11 ply full-width here, are we? > >No, I do lots of pruning besides null-move, and reach rather high search >depths even without it. Here are the number of nodes I need to search >n plies (n from 1 to 13) with and without null move from the opening >position: > >Plies Nodes (null move off) Nodes (null move on) > 1 55 55 > 2 228 261 > 3 965 439 > 4 3,741 2,318 > 5 13,213 6,638 > 6 35,056 18,964 > 7 37,398 36,095 > 8 77,226 60,240 > 9 117,274 109,939 >10 239,355 237,775 >11 555,661 412,969 >12 1,942,523 1,084,089 >13 12,060,312 3,531,279 > >I have no good explanation for the bizarrely irregular effective >branching factor of my non-nullmove search here. I wonder how it is >possible that hardly any nodes are needed in the 7th iteration. > >Tord I find it strange that you have 55 nodes for searching depth 1 in the initial position. I think that 20 or 21 is the normal number. What extensions do you do that are relevant for the first ply? Uri
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.