Author: leonid
Date: 08:25:30 02/17/01
Go up one level in this thread
On February 17, 2001 at 10:56:14, Uri Blass wrote: >On February 17, 2001 at 08:10:24, leonid wrote: > >>Hi! >> >>If you like to solve the mate that is apperently easy but still contain some >>challenge then try the next one: >> >>[D]R3Nnrk/1Q3bqq/3QnQ1r/1Q4bn/4Q1qN/2Q2nQ1/Q2BB3/1Q1K3R w - - >> >>Please, indicate your result. >> >>I hope that your brute force search will be more successful that mine. Mine went >>this way: >> >>LLchess mate solver. AMD 400Mhz. No hash. >> >>3 moves - 1.4 sec. >>4 moves - 20.7 sec. >>5 moves - 8 min. 23 sec. >> >>My chances to solve by brute force, after those numbers, looke not very bright. >>Even solution by selective took 25 sec. I hope your program will do better. >> >>Initial number of white moves is 152. >> >>Thanks, >>Leonid. > >1)Junior found mate in 8 by 1.Qxh7+(Did you find a shorter mate?) No. I found mate in 9 moves. Expect that maybe somebody will look this position by brute force and will reach much shorter mate. It could be that other program will have better branching factor and huge hash to succeed. >2)How do you decide if a problem is easy or hard? When initial move is checking, given position is "easy" to solve. When intial one, or few moves after initial, are not checking moves then few programs will reach mate at high speed. This position from one side is very simple and easy (initial move is checking one and number of checking moves are few) from other side time for solution for my program was considerable. 25 sec. Usually, 9 moves (easy position) search will take split of one second or few seconds only. >I think that deciding only by the distance to mate if the problem is easy or >hard is wrong. When mate is not in a place "usual" to go for finding it, then it is "difficult" mate. This is where very often only brute force search do the work and work is time consuming. >There are longer mates that are more easy to find and Crafty could find mate in >16 in few seconds in a different position when it needs more time to find a mate >in this position. Probably other position had less that 152 initial moves. Leonid. >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.