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Subject: Re: late move reductions

Author: Gerd Isenberg

Date: 23:23:21 03/02/06

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On March 02, 2006 at 03:40:36, Volker Böhm wrote:

>Hi Bob,
>
>for Spike I discovered the following:
>
>Statistically most fail highs occures at the first three moves. The fourth move
>has again some fail highs, all others have very little fail highs.
>
>History based reduction gains at max. 20 Elo compared to a simple move ordering
>based reduction (allways reduce after move 3). The move ordering is based on
>history thus this is again some sort of history based pruning.
>
>Typically Spike plays better if more is reduced, I hardly found any
>"less-reducing" rule that is better. Thus the test you are doing will show
>little success for Spike as it will quickly drops beyond the "allways reduce"
>level.
>
>In consequence the calculation of the history reduction threshold is very easy
>in spike. Every time a move fails high it gets one point and every time a move
>does not fail high (but a later move does) it is reduced by one point (there is
>some depth related factor). Below zero: reduce; above zero: don´t reduce.
>Surprisingly the value of a move does not grow too much and gets relative
>stable.
>
>Greetings Volker

So it seems that you already succesfully implemented Bob's idea with a 50%
threshold.

Thanks,
Gerd



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