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Subject: Re: Whither Null Move?

Author: Miguel A. Ballicora

Date: 09:03:10 08/22/01

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On August 22, 2001 at 10:44:42, Antonio Dieguez wrote:

>On August 21, 2001 at 11:48:23, Georg v. Zimmermann wrote:
>
>>On August 20, 2001 at 12:02:11, Antonio Dieguez wrote:
>>
>>>On August 20, 2001 at 01:03:30, Georg v. Zimmermann wrote:
>>>
>>>...
>>>>nullscore = -search(-beta, -beta+1, depth-3, 1);
>>>>
>>>>=> he is using R=2
>>>>
>>>>Georg
>>>
>>>oops am I missing something?
>>>The search here recieved a "depth", and here the nullmove call the search with
>>>depth-3 so three plies less will be played right? I 'm not understanding what
>>>that depth variable means or what a r=3 or r=2 means for you all?
>>>
>>>thx.
>>
>>R is the Null Move Depth Reduction. For the normal search you reduce the
>>remaining depth by one ply the deeper you go into the tree.
>>So for the Nullmove
>>
>>nullscore = -search(-beta, -beta+1, depth -R -1, 1);
>>
>>Therefore his extra reduction is 2.
>>
>>Georg
>
>wow...... thanks..... amazing :)
>
>I suspected that before only by a post of Vincent before, that said something
>like if there is 5 plies remaining, with r=3, only one ply will be played by the
>other side. That's true anyway. A little ambiguous for me :)
>
>so I'm using r=2. Thanks for the info :)
>I do have tried r=3, it didn't look better.
>
>thanx again. doh.
>
>Anyway the REAL reduction is 3 there. I don't get the sense of the oficial
>definition.

At the beginning I understood the reduction like you Antonio!
The official definition takes into account that nullmove is like a real
move, so the reduction would be 2. Well, that is my interpretation that could
be wrong again :-)

Saludos,
Miguel




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