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Subject: Re: Fine 70 same 7 engines

Author: Peter McKenzie

Date: 15:04:17 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).

I want that position, do you have it handy?

>
>bruce
>
>>
>>Uri



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