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Subject: Re: Delta Pruning

Author: Tord Romstad

Date: 01:29:35 08/11/04

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On August 10, 2004 at 23:41:46, Stuart Cracraft wrote:

>This repy from Bob Hyatt to Alessandro 5 years ago
>seems the best explanation so far. Anything to add
>anyone? Implementation gotchas?
>
>Mine is (roughly) and untested until the ovenright run:
>
>  quiesce
>  :
>  baseval = eval();
>  :
>  while next capture move available
>    if (value_of_captured_piece + (2*maxpositionalscoresofar) + baseval
>           < alpha)
>       continue;
>    else
>       makemove
>       see or mvv/pva, etc.
>       decide whether to search further
>       unmakemove
>    fi
>  endloop
>  :
>  :

"Delta pruning" was a new name to me.  The above looks exactly like what
is usually called futility pruning.  The pseudo code above looks OK, but
there is one simple improvement:  In addition to the value of the
captured piece, you also add the change in piece square table score.

Tord



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