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Subject: Re: History based pruning question

Author: Robert Hyatt

Date: 12:38:06 08/26/05

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On August 26, 2005 at 15:27:51, Alvaro Jose Povoa Cardoso wrote:

>>My first thought is that the number of "fail lows" is irrelevant.  What you
>>really want to avoid is a reduction on a move that might fail high.  Any move
>>will fail low in some situations, but you want to handle the "typical" case
>>correctly and not reduce if there is a reasonable chance the reduction will hide
>>something.
>
>So, you are saying history based pruning is not a safe thing to do?
>Or are you saying I should use tipical history values instead of counters?
>
>Alvaro

I don't know how safe it is.  Bruce Moreland and I played with this idea back
around 1996 or so, but we were not paying any attention to the actual moves
themselves (for example, never reducing a checking move perhaps) so that what we
fooled around with never worked very well in actual games.

I'm not sure what I would use, should I try to play with this again.  In fact, I
have it on my "to do list" since such ideas (futility) have been used in Crafty
with good results already, and this is just another variation on that sort of
theme...



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