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Subject: Re: An MTD(f) question about NULL MOVE searching

Author: Tord Romstad

Date: 12:18:13 07/16/04

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On July 16, 2004 at 14:52:35, Vasik Rajlich wrote:

>On July 16, 2004 at 13:49:41, Tord Romstad wrote:
>>The idea is not mine; I learnt it from Andrew.  At the beginning of each
>>iteration, I assume that the score will end up within a window of +- 2 pawns
>>centered around the result of the previous iteration.  I use this window
>>as a basis for pruning decisions.  When it turns out that the score is
>>likely to end up outside the window, I clear the hash table and restart
>>the iteration with most speculative pruning tricks disabled.
>Aha, thanks. Although that seems very wide ...

Depends on what kind of pruning you use it for.  In fact, I was simplifying
a bit when I wrote my previous post.  I don't have a single such window,
but several concentric windows centered around the last root score.  The
biggest windows are used for the most risky pruning tricks.


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