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Subject: Re: How do hash tables help move ordering? (Fail Low)?

Author: Robert Hyatt

Date: 17:59:55 09/20/98

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On September 20, 1998 at 19:49:57, Roberto Waldteufel wrote:

>
>On September 20, 1998 at 17:49:17, Inmann Werner wrote:
>
>>On September 20, 1998 at 17:30:31, Robert Hyatt wrote:
>>
>>>On September 20, 1998 at 14:21:15, John Coffey wrote:
>>>
>>>>I think that the subject says it all.
>>>>
>>>>John Coffey
>>>
>>>
>>>Yes.  You store the best move when you store a position, assuming you
>>>have a best move (you don't if you searched all moves and failed low,
>>>of course.)  You should try this move first each time you encounter this
>>>position...
>>
>>Whats the thing with the fail low?
>>Why can I not use the Hash table for move ordering in this case?
>>(I do now!)
>>
>>Werner
>
>Hi Werner,
>
>When a fail low occurs, there is no guarantee that any of the moves that were
>searched are worth as much as the respective scores they produced (they can't be
>worth more, but could be worth less, maybe a lot less). Thus the move with the
>best score is not necessarily the best move....
>
>Best wishes,
>Roberto


problem is, you don't even get "real scores" of any kind... only an indication
that the score is <= alpha, whatever alpha is...



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