Author: Georg v. Zimmermann
Date: 04:37:26 03/05/03
Go up one level in this thread
On March 04, 2003 at 07:12:21, Sune Fischer wrote: >On March 04, 2003 at 05:45:53, Georg v. Zimmermann wrote: > >>>While on the subject, how does one detect singular moves? >>> >>>-S. >> >>Shallower search for all possible moves on that node (Overhead). If all but 1 >>move fall under a certain thereshold, that 1 is singular. >> >>Georg > >I just don't see how that works with alpha-beta. Is it a low-level minimax? > >-S. Why not ? Maybe I am missing smth. After you get the best move or fail high at a node you search all other moves with a lower depth and a window at beta- margin (like 1.2 pawns). If none of those searches fail high, they are all worse than the found move => you research the best move with depth+singular_extension. The only situation where this fails is when you failed high on (i.e.) the 2nd best move and during the depth-reduced search find the "real best move", which of course fails high. Now you skip the singular extension even if the real best move was actually singular, because it is much better than the first best move found. But that case can be ignored since in such a situation the side to move is already doing so well (2 ways to fail high, 1 of them even much better) it is probably not a relevant node. Georg
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.