Author: Bruce Moreland
Date: 12:51:29 09/07/01
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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 > >Uri
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