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Subject: Re: Null move R=3

Author: Andrew Williams

Date: 12:29:16 08/08/01

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On August 08, 2001 at 15:16:17, Bruce Moreland wrote:

>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.
>

Oops. Yes it was 100.5 - 99.5  As you say, no discernible difference.

>>
>>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

Hmmm.. Not sure if I've got time for a decent match at that sort of TC.


Cheers

Andrew



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