Author: Vincent Diepeveen
Date: 06:32:39 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 - - I'm always using nullmove except pawn endgames (so that's with zero pieces for both sides). Of course i have double nullmove. To eliminate EGTBs from playing a role i also turned those off: 00:00 0 0 14329 (430) 7 0.033 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5-c1 00:00 0 0 31867 (519) 8 0.016 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5-c1 a 5-a4 00:00 0 0 74442 (705) 9 0.069 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5-c1 a 5-a4 Kf3-e4 00:01 0 0 152194 (741) 10 0.064 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5-c1 a5-a4 Kf3-e4 c6-c5 00:02 0 0 272268 (833) 11 0.103 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5-c1 c6-c5 Kf3-e4 c5-c4 Ke4-d4 00:03 0 0 475101 (1128) 12 0.045 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5-c 1 c6-c5 Kf3-e4 c5-c4 Ke4-d5 c4-c3 00:06 0 0 887541 (36900) 13 0.053 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5- c1 c6-c5 Kf3-e4 c5-c4 Ke4-d5 c4-c3 Kd5-e6 00:10 0 0 1644353 (52965) 14 0.031 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5 -c1 c6-c5 Kf3-e4 c5-c4 Ke4-d5 c4-c3 Kd5-e6 a5-a4 00:18 0 0 3029757 (58913) 15 0.031 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 Bg5 -c1 c6-c5 Kf3-e4 c5-c4 Ke4-d5 c4-c3 Kd5-e6 a5-a4 Ke6-d6 00:32 0 0 5430916 (103995) 16 -1.566 Rg5xc5 Kb5xc5 Bh4-g5 Kc5-c4 Kg2-f3 Kc4-b3 K f3-e4 Kb3-b2 Ke4-d4 a5-a4 Bg5-f4 Kb2-b1 Kd4-c3 c2-c1Q Bf4xc1 Kb1xc1 Kc3-b4 ++ a3-a4 00:52 0 0 9017580 (270984) 16 0.000 a3-a4 Kb5-b6 Bh4-f2 c2-c1Q Rg5xc5 Qc1xc5 Kg2 -h1 Qc5xf2 01:17 0 0 13468821 (277288) 17 0.000 a3-a4 Kb5-b6 Bh4-f2 c2-c1Q Rg5xc5 Qc1xc5 Kg 2-h1 Qc5xf2 So i find this WITH double nullmove. How can one *ever* miss such a combination with double nullmove? Of course i agree that if there are a big number of zugzwangs in a line, that the extra depth needed might be big. But this is a peanut to find for DIEP. >http://homepages.caverock.net.nz/~peter/eg_test/pet013.htm > >> >>-- >>GCP
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.