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Subject: Re: Schröder's new web page

Author: Ricardo Gibert

Date: 08:57:45 12/28/02

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On December 28, 2002 at 11:18:58, Alessandro Damiani wrote:

>On December 28, 2002 at 10:10:53, Ricardo Gibert wrote:
>
>>It seems Ed Schröder has added a bit more to his web page:
>>
>>http://members.home.nl/matador/chess840.htm#SEARCH
>>
>>I have the feeling that ES will be getting a lot of thank yous for quite awhile
>>for his fine contributions to computer chess.
>>
>>Thanks again!
>
>It seems to me that there are two typos in the following code:
>
>{
>   if (remaining_depth > 2
>      && king_not_in_check
>      && move_is_no_capture
>      && move_is_not_giving_a_check) then
>       { if (ALPHA < SCORE + MARGIN) reduce depth with 1 }
>}
>
>1) king_not_in_check <=> move_is_not_giving_a_check

I interpret "king_not_in_check && move_is_no_capture &&
move_is_not_giving_a_check" as My king is not in check and I can't capture any
of his material and I can't check his king, so it looks fine to me.

>2) instead of
>
>       ALPHA < SCORE + MARGIN

You have a SCORE below ALPHA and you want to know if it is far enough below
ALPHA to warrant a reduction, so you add MARGIN to it to see if it is still
below ALPHA. If it is, you reduce. This looks fine to me too.

>
>   it should be
>
>       ALPHA > SCORE + MARGIN
>
>   since this is equivalent to
>
>       SCORE < ALPHA - MARGIN
>
>
>Ed?
>
>Alessandro



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