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Subject: Re: An improvement to null move search

Author: Uri Blass

Date: 05:35:58 04/07/04

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On April 07, 2004 at 07:14:36, Tord Romstad wrote:

>On April 07, 2004 at 05:11:44, José Carlos wrote:
>
>>  You share your ideas, and that's great. Keep doing so please.
>
>I will, whenever I think I have something interesting to share.
>
>I'll now make an attempt to give a simple explanation of the more general
>idea I mentioned:
>
>Like most programmers, I don't do a null move search at all nodes, but only
>at nodes where I am reasonably sure of a fail high.

I doubt if it is like most programmers.

Movei does today null move at all nodes except pawn endgames.
In endgames I also do verified null move pruning.


  I regard the null move
>search as a technique to prune moves which does not even threaten to bring
>the score up to alpha.
>
>At the node directly following the null move, the side to move should try
>to prove that the move played before the null move contained some important
>threat.  Therefore, it makes sense to search some moves more deeply than
>others after the null move.  Moves which were made possible by the previous
>move should be searched deeply, and also moves which attack squares and
>pieces which were also attacked by the previous move.  Other moves, which
>have no logical connection to the move played before the null move, could
>be searched with reduced depth.
>
>It would clearly take a lot of thought and experimentation to make something
>like this work well, but I think the idea might have some potential.
>
>> Even if you make
>>a mistake, you:
>>  -get feedback and avoid useless developing+testing
>>  -give something interesting to think about
>
>Yes, but in this case my mistake was so obvious that I was just wasting
>everybody's time and bandwidth.

I do not think so.
Your mistake may help people to think about better ideas.
>
>>  Congratulations on your success with Gothmog. Really impressive how your
>>"stupid" ideas are working on your program. I wish I was so "stupid" as you.
>
>Thanks, but it seems to me that Averno is around the same strength.  :-)
>
>Tord

Not to me

based on wbec averno is only in the 3th division when gothmog is in the second
division and has 2.5-1.5 against knightdreamer and 2-2 against the baron
when these programs are expected to fight for promotion places.

Uri



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