Author: Tim Foden
Date: 23:53:59 04/22/02
Go up one level in this thread
On April 22, 2002 at 15:22:39, Will Singleton wrote: >On April 22, 2002 at 02:29:40, Tim Foden wrote: > >>On April 21, 2002 at 19:29:39, Will Singleton wrote: >> >>>All, >>> >>>[D]5nk1/2R3p1/r4p2/4P3/p2R2N1/7P/1r4P1/7K b - - 0 42 >>> >>>The question is, my prog wants to play a3, and doesn't see the forced repetition >>>until ply 9. I've just thrown away my old buggy rep code, and replaced it with >>>a dedicated hash table. The new stuff seems to be debugged and working (maybe), >>>but there must be a trick to getting this position earlier. An extension, >>>perhaps? >> >>Green Light sees this at 5 ply. The line it gives is: >>42... a3 43. Nxf6+ gxf6 44. Rg4+ Kh8 45. Rh4+ Kg8 46. Rg4+ >> >>The only extension used here is a check extension x 4, which gets it to the >>required 9 ply. The other trick, of course, is that GL considers it a draw if >>the position occurs twice in the current search. >> > >Ok, found a bug having to do with null move. Always nice to kill bugs. It sure is. It's sometimes alarming to find them and realise how long they have been there. :) I'm fairly sure there's one in GL that I've been trying to track down for months... just try Fine 70. :) > 2 90 0.02 339 10140 Ne6 Rc8 Kf7 > 3 63 0.02 913 27360 Ne6 Rc8 Kh7 Rd7 > 3 69 0.02 1183 35460 Rb1 Kh2 Ne6 Rc8 Kf7 > 4 42 0.04 3208 48120 Rb1 Kh2 Ne6 Rc8 Kh7 Rd7 > 5 14 0.12 18176 90840 Rb1 Kh2 Pxe5 Nxe5 a3 Rd8 > 5 102 0.24 40963 102360 a3 Rd1 a2 Rc1 Nh7 Pxf6 Nxf6 > 6 0 0.49 91554 112080 a3 Nxf6 Pxf6 Rg4 Kh8 Rh4 Kg8 Rg4 > 6 67 1.06 126419 114900 Rb1 Kh2 a3 Pxf6 a2 Rxg7 Kh8 Rd8 Rxf6 > 7 54 1.44 203988 117660 Rb1 Kh2 Pxe5 Nxe5 a3 Rg4 Ne6 Rd7 > 7 90 2.25 289403 119700 Pxe5 Nxe5 a3 Rg4 g6 > 8 111 3.30 432827 123660 Pxe5 Nxe5 a3 Rd1 a2 Rc1 Re2 Nc4 Rf6 > > >btw, gl chess looks real strong now. Thanks. I'm currently trying quite hard to make GL stronger. But as you know, many of the things you try turnout to have the opposite effect. >I'd like to see that algorithm info you The algorithm info describes some the things I needed to know when I was first developing GL. e.g. It has some hints on hash tables (you need to store items for both black-to-move and white-to-move, etc.) It also describes in a general way how an old version of GL works. I put it on a web page so that others may be able to benefit from it. It is very out of date now, and I don't think it says anything new. >mention on your web site, perhaps it's in the download? The download includes a file called changes.txt, which hash a list of the changes made in each realeased version. Cheers, Tim.
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