Author: William Bryant
Date: 08:26:45 09/11/99
Go up one level in this thread
On September 11, 1999 at 00:19:40, Robert Hyatt wrote: >That seems to be backward. If score > beta, the _current move_ you just >searched failed high. That move should be stored in the hash table to try it >first the next time you search this position. The problem we are discussing >is the _other_ case.. the one where you search all movs and still end up >with best == alpha, which means all moves were bad... Alright, on re-rereading, let me try this again. You completed a ply and found no new alpha (failed-low). alpha is already greater than a constant MateScore (Mate - some constant). You store this in the hash table as follows. if (alpha>MateScore) store the value as MateScore and the flag as hash_Lower to show that this is the lowest value this position could have. Because you failed low, there is not best move. if (alpha<-MateScore) storethis normally, with the flag hash_Upper to show that this is the highest value this position could have. Again, because you failed low, there is no best move. Closer? William wbryant@ix.netcom.com
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.