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Subject: Re: Null move R=3

Author: Bruce Moreland

Date: 12:16:17 08/08/01

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On August 08, 2001 at 14:59:04, Andrew Williams wrote:

>On August 07, 2001 at 16:03:34, Bruce Moreland wrote:
>
>>I've often heard people state that null move with R=3 is better than with R=2,
>>but I have never ever ever gotten a test result that indicates this.
>>
>>I've tried everything.  I've tried it throughout the tree, I've tried it near
>>the root, and I've tried it near the tips.
>>
>>My measurement standard is ECM positions solved, which *always* goes down.
>>
>>What are other people doing that I'm not doing, or are people testing in some
>>other way, if so is their way better or worse?
>>
>>I would test Crafty both ways (it's currently doing R=3 some places), but my
>>machines will be busy until after the WMCCC.
>>
>>bruce
>
>I do something similar to Ernst Heinz's approach with R=3 in some places and
>R=2 in others. At the time I implemented it, I ran some test-sets and found
>it marginally better, but nothing spectacular.
>
>I've just run a 200-game match between my standard version and an R=2 version.
>This test has 100 starting positions and the two versions plays white and black
>sides of each position. The result was:
>
>	standard 101.5		nullR=2 99.5

That's 201, but either way it would have been hard to come up with results that
would differentiate between them less, but I'm sure you know that.

>
>The games were 2 1 with no pondering. Average depths (for what they're worth):
>
>	standard 10.26,		nullR=2 10.22

The Ernst paper claims a greater improvement with more depth than you could
achieve in a 2 1.  There's probably a lot of endgame depth distorting these
numbers.  He's talking about 12 middlegame plies.

bruce


>
>Cheers
>
>Andrew



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