Author: Odd Gunnar Malin
Date: 19:08:27 09/07/01
Go up one level in this thread
On September 07, 2001 at 18:04:17, Peter McKenzie wrote: >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). > >I want that position, do you have it handy? > >> I don't have his position but I have another 'quadrat position' like the Fine 70 with a not so obvious first move, well it is Kb1 but that must be a coincidence :) [D]2k5/2p2p2/2p1p3/2P1PpP1/1p1P1p2/1P3P2/1K3P2/8 w - - 0 1 White wins. 1.Kb1! Odd Gunnar
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