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Subject: Re: OK, where do I find the alpha-beta for Dummies documentation.

Author: blass uri

Date: 07:31:38 08/04/00

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On August 04, 2000 at 08:38:27, Larry Griffiths wrote:

>I see that my moves have dropped from 1.6 million to 800,000 moves per second
>after adding what appears to be a simple alpha-beta algorithm.  Is there an
>explanation of the alpha-beta alorithm that a 3 year old could understand :)
>
>LOL
>
>Larry.

The main idea of the alpha beta is to prune illogical lines.


Suppose you use only material evaluation in the starting position

If you find that the score of 1.e4 is 0 for white
and the score of 1.d4 e5 is +1 for white then you are not interested in the
exact score of 1.d4 d5

If the score of 1.d4 d5 is lower than 0 for white then e4 is better than d4 and
you can stop analyzing d4 and e4 is the main line.

If the score of 1.d4 d5 is more than +1 for white then e5 is better than d5 and
you can stop analyzing 1.d4 d5 because d5 is not logical.

You are interested in the exact score of d4 d5 only if it is between 0 and 1 so
if it is less than 0 you will get the same move like in the case it is 0 and
if it is more than 1 you will get the same move like in the case it is 1.
This is the reason to have 2 numbers alpha and beta.

I do not think that a 3 years old can understand it but I hope that you can.

Uri



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