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Subject: Re: Let's talk about fraud.

Author: Robert Hyatt

Date: 18:03:06 05/02/04

Go up one level in this thread


On May 02, 2004 at 19:36:13, Gian-Carlo Pascutto wrote:

>On May 02, 2004 at 18:49:38, Robert Hyatt wrote:
>
>>On May 02, 2004 at 18:23:44, Gian-Carlo Pascutto wrote:
>>
>>>On May 02, 2004 at 13:12:04, Robert Hyatt wrote:
>>>
>>>>He sent me an email trying to justify his poor performance.  He first claimed
>>>>that it was an artifact of null-move.  Testing disproved that.
>>>
>>>What testing?
>>>
>>>--
>>>GCP
>>
>>
>>The testing you and I both did.  It showed a minimal speedup difference if you
>>recall.  2.8 vs 3.1...  not _that_ significant...
>
>For 4 processors, it looks small (I don't happen to agree an 11% speed
>decrease is 'not significant' - I would be very happy which such a speedup).
>But it's not that easy to get that 0.3 back. The real problem is that
>scalability is reduced, and there are consequences at 8 or 16 cpus.

I don't see any at 8.  I don't personally have access to a 16-way box yet so I
can't say anything there.  But there is nothing that really makes null-move hurt
parallel search...


>
>As far as I'm concernced, the testing showed that Vincent was right and
>that recursive nullmove *does* change things. You were firmly claiming
>that it didn't matter a thing, before. So your recollection of whose
>claims were disproven is certainly a bit selective, to say the least.


No.  You have always had a selective memory when it comes to Vincent.  His claim
was that null-move made a _huge_ difference...  going from 2.8 to 3.1 is _not_ a
huge difference on 4 cpus.  It is a difference.  But it is within the noise
range for non-deterministic behavior anyway...

That was a red herring from the get-go...




>
>--
>GCP



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