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Subject: Re: Disequilibrium schemes

Author: Tony Werten

Date: 02:34:29 10/23/03

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On October 23, 2003 at 04:43:31, Sergei S. Markoff wrote:

>Hello!
>
>>In case you forgot, the evaluation can just return 1 score
>
>Oh when I was such simply guy
>Than I was clean and brave :)
>
>>score it can't return 2 scores for either positional or tactical matters.
>
>The matter is not about the returning more than one score in search. The matter
>is to use eval disequilibrium in current node to make some descisions. It can
>affect search or evaluation itself.
>
>But, anyway, it's not impossible to use two scores. One example Centaur program
>which uses two evals - pessimistic and optimistic. It's allows to produce good
>cut-offs where optimistic eval < alpha or pessimistic > beta. I don't know
>detatil but it seems to be interesting concept.

Not really. It has been used for years, only most people use the term lazy eval.

Pessimistic score: simple eval-maximum positional score
Optimistic score : simple eval+maximum positional score

You can replace " simple eval" with "1/3 of the normal eval" or "fast part of
normal eval" etc.

Tony

>
>In my case I'm talking not about rebuilding whole search scheme but about more
>clever using of eval. to guide the search (basic SmarThink concept is to make
>search knowledge-based). But it's also about evaluation - what score must return
>eval in a case of losing one or two pawns vs lot positional advantage (king
>attack, passed score)?
>
>Best wishes,
>Sergei



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