Author: Sune Fischer
Date: 03:46:52 08/30/02
Go up one level in this thread
On August 30, 2002 at 06:29:37, Uri Blass wrote: >On August 30, 2002 at 05:51:37, Sune >>I don't know what a 'verification search' is, but I bet it isn't free to do, so >>in some positions they surely must be weaker because they 'waste' time on this >>verification. > >It is better to be 0.1% slower in order to avoid stupid mistakes even if the >mistakes happens only one time out of 500 games and there was one engine-engine >game when I saw a stupid mistake. > >I believe that they can do it. > >Here is a simple idea(this idea can be improved but the point is that even this >idea can do their program better) > >Before searching if there is a threat to depth x>12 do a small search to depth >((x-10)/2) and get an exact score of the position when it is white to move and >when it is black to move. > >If you see that the exact scores suggest a big zugzwang do not use null move >pruning. But is a 1-2 ply search usually enough to detect zugzwangs? And what if this verification is wrong? Often the initial plies return very different scores from the deeper ones, so you may turn off nullmove when you shouldn't have. You may end up being over cautious, I think that can be just as bad as being careless. It is a question of tuning of course. >The only reason that I did not use that kind of idea(with smaller number than >10) in movei is that I found that it cause movei to search more nodes in other >branches of the tree so I guess that I should be careful to define a special >search function that does not change history tables,killer moves or hash tables >in order to use that idea in a productive way. That sounds a bit odd, nodes searched should help in the history matrix, and the hash tables (if you have the right replacement strategy) shouldn't be affected either I think, on the contrary. -S. >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.