Author: Dieter Buerssner
Date: 01:48:42 09/29/00
Go up one level in this thread
On September 29, 2000 at 03:08:25, Bernhard Bauer wrote: >On September 28, 2000 at 10:18:53, Dieter Buerssner wrote: > >>On September 28, 2000 at 04:26:54, Bernhard Bauer wrote: >> >>[much snipped] >> >>>My modification has also to do with null move, but I do another change. >>>Instead of the original statement in search.c >>>if (do_null && !tree->in_check[ply] && pieces >>> && (pieces>5 || depth<421)) { >>> >>>I use the following statement >>>if (do_null && !tree->in_check[ply] && pieces>0 && depth>60 && >>> && (pieces>9 || depth>301) ) { >> >>This is interesting. The original Crafty code uses null move at the leaves of >>the tree, when close to the endgame. Your code uses null move at at the front of >>the tree. Has this shown to be better in test suites or in games? >> >>Also, you don't allow null moves at the last ply. Does this reach higher depth >>with the same node count? Bernhard, I really read your source snippet different, then your description. >For many pieces (pieces>5) the original Crafty code will always use null move. Yes, this is like I read the source snippet of original Crafty. >I don't use null move for the first ply hoping to get a better move ordering. But wouldn't this mean to use "&& ply > 1" instead of and "depth > 60" >If only a few pieces remain I don't do null move for the first 5 plies. Again, wouldn't this mean to use "&& ply > 5" instead of "&& depht > 301" For your description I would use: if (do_null && !tree->in_check[ply] && pieces>0 && ply>1 /* No null move at first ply */ && (pieces>9 || ply>5) /* Little material: not for the first 5 plies */ ) { Where is my misunderstanding? Nevertheless, I think depth instead of ply seems superior, for example because of hash table consistency. But then your ">" seems the wrong way around. Remember that depth is the remaining depth, or have you changed the meaning of depth? I would read "depth > 60" only one ply is remaining (which could make sense, because there is not much you can cut off in the last ply). -- Dieter
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.