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Subject: Re: An improvement to null move search

Author: Tord Romstad

Date: 04:14:36 04/07/04

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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 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.

>  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




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