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Subject: Re: nullmove and tactics

Author: Anthony Cozzie

Date: 15:10:13 03/25/04

Go up one level in this thread


On March 25, 2004 at 16:32:09, Robert Hyatt wrote:

>On March 25, 2004 at 14:28:09, Anthony Cozzie wrote:
>
>>On March 25, 2004 at 13:35:03, Dann Corbit wrote:
>>
>>>On March 25, 2004 at 10:02:57, Anthony Cozzie wrote:
>>>
>>>>On March 23, 2004 at 18:18:51, Uri Blass wrote:
>>>>
>>>>>On March 23, 2004 at 17:28:17, martin fierz wrote:
>>>>>
>>>>>>On March 23, 2004 at 17:13:46, Aivaras Juzvikas wrote:
>>>>>>
>>>>>>>On March 23, 2004 at 16:40:46, Renze Steenhuisen wrote:
>>>>>>>
>>>>>>>>On March 23, 2004 at 16:38:28, Aivaras Juzvikas wrote:
>>>>>>>>
>>>>>>>>>forgot to mention, i dont try null move on 0 ply
>>>>>>>>
>>>>>>>>Than what's your test set?
>>>>>>>
>>>>>>>test set?i just let two versions of my engine play each other a couple of 15 0
>>>>>>>games, the result is either a draw or a win for the one w/o null move, even tho
>>>>>>>it searches deeper as i already mentioned
>>>>>>
>>>>>>"a couple" meaning...?
>>>>>>
>>>>>>if it's two games, forget it. if it's 10 games, forget it too. start believing
>>>>>>it when it's 100 games...
>>>>>
>>>>>I think that if you do not get improvement with null move based on 10 games then
>>>>>there is good chance that you have a bug in the implementation.
>>>>>
>>>>>Uri
>>>>
>>>>I have to agree with Uri here.  If your program plays weaker with null move
>>>>after 10 games, you screwed something up.
>>>>
>>>>Null move is simply _that big_.
>>>>
>>>>Getting 2 extra plys should show up long before 100 games . . .
>>>
>>>I have to disagree with you.  You can implement null move incorrectly and still
>>>score better in ten games.  The reason I say that is because I have seen it.
>>
>>Please do not put words in my mouth. I said "If A then B", which you corrupted
>>to "If !A then !B".
>>
>>I stand by my statement: If you implement null move correctly, it _will_ win a
>>10 game match.  2 ply -> 100 elo -> dominance.  Someone can do the math here on
>>confidence regions, but I'm very sure the version with null move has a 95%
>>chance or better to win.
>>
>>anthony
>

>Null-move is better, but it is _not_ 200 elo better.  Try it.  Both Bruce and I
>played some of these matches (null on vs null off).  It is more like 50-60 Elo
>improvement.

I said 100.  200 would indeed be a little much :)  But even 60 elo is a pretty
clear difference; you would definitely notice that in a 10 game match.

>And it _definitely_ isn't "2 plies".  There is a great difference
>in accuracy between 12 plies no null and 12 plies with null...  You go 2 plies
>deeper, but you don't outplay the no-null opponent like it would outplay itself
>with a 2 ply handicap...

I do checks in q-search which mitigates this problem somewhat.

anthony



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