Author: Ed Schröder
Date: 02:27:18 04/18/02
Go up one level in this thread
On April 17, 2002 at 17:45:03, Peter McKenzie wrote: >On April 17, 2002 at 16:53:30, Gian-Carlo Pascutto wrote: > >>On April 17, 2002 at 16:40:01, Dann Corbit wrote: >> >>>I don't see how it can completely remove the tactic from ever being seen unless >>>the implementation of null move is broken. >> >>If it has a zugzwang, you will _never_ see it if you don't check for it >>(verification search, double nullmove), or use another trick like force >>nullmoves away from the root (that is what Crafty does). >> >>You can always play the 'nullmove' no matter what depth, so you'll >>never realize the nullmove is no good. >> >>i.e. you make an illegal move that is not possible in the real game, and >>increasing search depth won't change this. > >Yes, you are correct. Some programs can never solve the following: > >[D]8/8/2p5/pkp3R1/7B/P7/2p3K1/8 w - - Rebel uses null-move since its latest version, no problem, just 8 seconds to see the draw. Maybe it is a matter of eval too, could be... Ed =================== 00:00:02.8 0,01 12 853807 Rxc5+ Kxc5 Bg5 Kd4 Kf3 Kd3 Bf4 c5 00:00:03.3 0,00 13 1771119 Rxc5+ Kxc5 Bg5 Kd4 Kf3 Kd3 Bf4 c5 00:00:05.6 -1,41 14 4456961 Rxc5+ Kxc5 Bg5 Kc4 Kf2 Kb3 Bc1 Ka2 00:00:08.7 0,00 14 7068951 a4+ Kb6 Bf2 c1Q Rxc5 Qxc5 Kh1 00:00:11.1 0,00 15 11124240 a4+ Kb6 Bf2 c1Q Rxc5 Qxc5 Kh1 00:00:18.6 0,00 16 20139015 a4+ Kb6 Bf2 c1Q Rxc5 Qxc5 Kh1 00:00:30.6 0,00 17 34891048 a4+ Kb6 Bf2 c1Q Rxc5 Qxc5 Kh1 00:00:53.2 0,00 18 64932256 a4+ Kb6 Bf2 c1Q Rxc5 Qxc5 Kh1 Revel XP (alpha), A1400, 60 Mb >http://homepages.caverock.net.nz/~peter/eg_test/pet013.htm > >> >>-- >>GCP
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