Author: Walter Faxon
Date: 17:20:30 03/03/06
Go up one level in this thread
On March 02, 2006 at 13:32:50, h.g.muller wrote: >(I must have hit a wrong key, somewhere, because suddenly the thing got posted >before it was finished...) > >With Kings the Queen's wing has only ~192M positions, and that is not asking too >much for computing a complete TB of this 9-men end-game. (Would perhaps take 3-5 >minutes, if you declare promoted positions without an enemy pawn on the 7th as >won.) This TB would reveal that the situation is always lost with 'swapped' >Kings, unless the black King is really much closer to the Pawns then the white >one. (Some specialized chess knowledge would reveal this too, of course.) > >For a specific position of the Kings (W:f5, B:f3) my minimalist engine would >find the promotion in 37 sec through ordinary search, where in essence it builds >the TB in its hash table. A specialized retrograde TB builder would be at least >10 times faster. > >A search for the play on the King's wing, probing this TB, would only have to be >extremely shallow to show that any forcing by black on this wing would lead to >forced clearing of this wing, and manouvre black in the lost position of the >TB... Building a TB on the fly is a neat trick but requiring so much time makes its use problematic. Perhaps another good trick would be to find a way to index an existing TB (or set of TBs) so that only a very small number of physical disk read operations would load the relevant TB subset, at the cost of a fraction of one second. Of course the TB would be optimized for this rather than to minimize the total space used. -W
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.