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Subject: Re: question about futility pruning and positional evaluation

Author: Robert Hyatt

Date: 16:51:28 12/07/00

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On December 07, 2000 at 18:39:34, Ernst A. Heinz wrote:

>>>But the effects you describe, Bob, are rather due to the
>>>hash-table usage than to the pruning. They might also
>>>occur if you just change your move ordering.
>>
>>Correct.  However, the question he asked was could futility pruning affect
>>the score at the root.  The answer is yes, because of the transposition table
>>problem...
>
>No, the question asked ran as follows:
>
>"Can sombody explain me why futility pruning tends to give
> slight positional differences?"
>
>My answer to this still stands.


So does mine.   My 'question' was simply a paraphrased version of his.  With
the same answer.

>
>However, you have pointed out a fine detail about the
>idiosyncracies of transposition tables -- namely, *their*
>usage *does* indeed tend to result in differences whenever
>you change *anything* in the sequence and number of nodes
>visited!
>
>Specifically, the use of transposition tables actually
>also tends to lead to differences between alpha-beta and
>normal minimax searches.
>
>=Ernst=

Absolutely...



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