Author: Odd Gunnar Malin
Date: 18:13:56 09/07/01
Go up one level in this thread
On September 07, 2001 at 15:51:29, Bruce Moreland wrote: >On September 07, 2001 at 03:50:03, Uri Blass wrote: > >>On September 07, 2001 at 02:14:17, Bruce Moreland wrote: >> >>>On September 06, 2001 at 13:58:00, Uri Blass wrote: >>> >>>>Do you assume that all programs use the same extensions? >>>> >>>>I can imagine that programs with more extensions can see it in less plies even >>>>with perfect move ordering. >>> >>>If you write a program that has a functional hash table, no null-move pruning, a >>>sensible eval, and so on, it will solve this problem in no time at between 18 >>>and 26 plies, which is approximately what Bob said. >>> >>>What is happening here is that Tiger is doing very badly. I am pretty good at >>>screwing up Fine 70. Assuming that Tiger's hashing system is not simply broken, >>>my bet is that he's doing null-move in some tricky way in the king + pawn ending >>>and/or he's doing some sort of reduced depth search that's eating his hash >>>table. >>> >>>It's hard to know what anyone would extend here. >> >>I can think of getting closer to the pawns with the king >>as something that encourage extensions in pawn endgames. >> >>I do not say to extend every move when the king gets closer to the pawns because >>it is too much but >>it is possible to think about extending 1/4 ply for every move that gets closer >>to the pawns so after 4 moves that reduce the distance to the pawns you extend 1 >>ply. > >It would be hard to figure out how to do that efficiently here, in any sense >that has any meaning here or elsewhere. It's a great problem, but it's also >just one big trick. I would venture that *nobody* is solving this faster with >extensions, and anyone who is solving it slower is either broken or trying to do >something tricky in the general endgame case, but which doesn't work here in a >position like this. > >This position is a classic "no tricks" position. There is another one like >this, too, where the key is Kh8, and you can find a fifty-move draw from the >root (100+ plies of search). > >bruce > Is it possible to first start with the 'eight square system'. In such positions where each king square has an opposite square for the other players king, Averbach suggest that if contructing of eight square is not possible then try the 'quadrat system', then tree ... two. I must admit that I have not thought in this path when it comes to evaluation with computer. Many of this 'gegenfeld' systems is nice for testing hash, here is one 'eigth square' problem: [D]7k/2p5/2p5/2P4p/3P1p1p/5P1P/8/K7 w - - 0 1 White wins 1.Kb1! Odd Gunnar
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.