Author: Dann Corbit
Date: 12:43:03 07/07/05
Go up one level in this thread
On July 07, 2005 at 15:01:26, Dann Corbit wrote:
>On July 07, 2005 at 14:51:56, Gian-Carlo Pascutto wrote:
>
>>On July 07, 2005 at 14:37:19, Dann Corbit wrote:
>>
>>>On July 07, 2005 at 14:14:36, Gian-Carlo Pascutto wrote:
>>>
>>>>On July 07, 2005 at 13:56:04, Dann Corbit wrote:
>>>>
>>>>>On July 07, 2005 at 05:05:50, Gian-Carlo Pascutto wrote:
>>>>>
>>>>>>On July 05, 2005 at 14:37:46, Dann Corbit wrote:
>>>>>>
>>>>>>>The logfile does not consider the depth on-chip at the leaves. About 6 plies
>>>>>>>more. So consider it really to be 16-18 plies.
>>>>>>
>>>>>>This is quite simply completely wrong, and contradicts what Hsu and Campbell
>>>>>>published.
>>>>>>
>>>>>>http://sjeng.org/ftp/deepblue.pdf
>>>>>
>>>>>I read the paper. I was referring to this:
>>>>>"This typically results in 4- or 5-ply searches plus quiescence in middlegame
>>>>>positions and somewhat deeper searches in endgames."
>>>>>
>>>>>I did not see the contradiction. Can you please point it out ot me?
>>>>
>>>>The first number in the logs is the combined depth (excluding quiescence, but
>>>>nobody counts that). The nominal depth was around 12 ply for the combined
>>>>search, not 16-18.
>>>
>>>Then it represents the estimated maximum combined depth (last column of table
>>>2)?
>>
>>No, that's another matter. Maximum depth is rather meaningless.
>>
>>Look at Page 5, 1)b) for the statement that the nominal depth is 12 ply on
>>average. It's been a while since I read it but basically something like 12 (5)
>>meant 12 - 5 = 7 ply software, 5 ply hardware, and then extensions and quiescene
>>search.
>
>It makes me wonder why they got such excellent answers, then.
If they could average 100M NPS, then a 3 minute search (40/2 average) would give
18,000,000,000 {18 billion} nodes and 36 billion at 200 M (and I seem to recall
a theoretical peak NPS rate of 1 billion).
Since 6^12 = 2,176,782,336 [assuming a branching factor of 6 for pure
alpha-beta with no pruning whatsoever, no null move, and with 36 moves average
at each level] a 12 ply search should have taken only 21 seconds at 100 M NPS
and 10.5 seconds at 200M.
The math does not make sense to me.
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