Author: Robert Hyatt
Date: 09:17:47 04/17/00
Go up one level in this thread
On April 17, 2000 at 10:42:33, William Bryant wrote: >On April 16, 2000 at 09:53:15, Robert Hyatt wrote: > > >>Crafty stops at the right point, _unless_ given a sd=N command. It uses the >>rule of "search to 2*N=1" when it finds a mate in N, just to be sure there >>isn't a shorter mate. In the position you gave, it stopped after 4 plies >>as that is the minimum depth it will normally search to, regardless of the >>mate found... >> > >I'm not sure I understand you rule to exit a search with a mate score. > >Do you search to 2 times the depth of the mate, ie 4 ply for a mate in 2? > >William >wbryant@ix.netcom.com For crafty, it requires 2*N-1 plies to find the shortest mate in N. IE to find a mate in 2, I stop after 3 plies. Since the last move must be a check, and since I extend on checks in the basic search, the check at depth 3 extends 1 ply where I find that the opponent is mated. I often find mates in 10 with a 5 ply search or so, but I rarely find the _shortest_ mate unless I go to the above depth. Many mate compositions have _every_ move but the last move as a non-checking move, to make them hard to find.
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.