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Subject: Re: Evaluate Hashtab and Lazy evaluate

Author: Mikael Bäckman

Date: 03:58:02 10/30/04

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On October 29, 2004 at 09:48:31, Peter Fendrich wrote:

>How do you guys deal with this?
>
>In addition to the ordinary hash table, I have an evaluate hash table with only
>absolute values (no upper and lower flags) and a lazy evaluate that just quits
>evaluating when the score exceeds alpha-Magin or beta+Margin.
>I don't store lazy evaluate values in the evaluate hashtab - they are not
>complete. As I see it there are a few options:
>
>1. Don't use lazy evaluate
>2. Include upper, lower and inside flags in the evaluate hashtab as well
>3. Don't use a specialised evlaute hashtab. Instead use the ordinary one.
>
>How do you deal with this? Personally I don't like number 3.
>
>/Peter

I do much the same thing you described.

I evaluate only in quiescence search, and only store the full evaluation into
the evalutation hash. I use lazy eval and probe the hashtable if lazy eval
fails.

In middlegames I typically get an 5-10% speed improvement, in endgames the
improvement is slighty larger.

/Mikael



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