Author: Robert Hyatt
Date: 07:01:10 08/27/00
Go up one level in this thread
On August 27, 2000 at 02:09:36, Peter McKenzie wrote:
>On August 26, 2000 at 23:43:34, Robert Hyatt wrote:
>
>>On August 26, 2000 at 23:06:10, Ed Schröder wrote:
>>
>>>On August 26, 2000 at 21:08:37, Robert Hyatt wrote:
>>>
>>>>On August 26, 2000 at 11:05:24, walter irvin wrote:
>>>>
>>>>>On August 26, 2000 at 09:21:15, Robert Hyatt wrote:
>>>>>
>>>>>>On August 26, 2000 at 09:16:50, Uri Blass wrote:
>>>>>>
>>>>>>>I tried this position from the game century3-crafty17.11
>>>>>>>
>>>>>>>[D]rnbqk2r/pp1p1ppp/4pn2/4P3/1b1N4/2N5/PPP2PPP/R1BQKB1R b KQkq - 0 1
>>>>>>>
>>>>>>>Crafty17.13 played 6...Qc7
>>>>>>>
>>>>>>>I gave my Crafty17.11 as engine for Hiarcs with 128 Mbyes hash time control of 4
>>>>>>>hours/60 moves
>>>>>>>(I guess that this time control is similiar to 2 hours/60 moves on the alpha)
>>>>>>>
>>>>>>>My Crafty17.11 changed its mind in the last second at depth 12 from 6..Qc7(0.15
>>>>>>>pawn advantage) to the better move 6...Nd5(0.16 pawns advantage).
>>>>>>>
>>>>>>>I am interested to know crafty17.13's opinion.
>>>>>>>Can crafty17.13 avoid 6...Qc7 at depth 12?
>>>>>>>
>>>>>>>Uri
>>>>>>
>>>>>>
>>>>>>It avoids it by depth=10. The problem was that the mode we were using forced it
>>>>>>to play Qc7 as it was a book move. Somehow we followed a very rarely played
>>>>>>line, but until I get the log files from Graham I can't tell exactly why. I
>>>>>>did notice a pretty significant CAP score that might have pulled it down that
>>>>>>line erroneously...
>>>>>
>>>>>what was the speed relitive x86 for the alpha you used .would it have been
>>>>>faster if you could have gotten similar hardware that deep junior had at
>>>>>dortmund ??what nps was you seeing on the alpha .
>>>>
>>>>
>>>>We were doing about 400K nps. My quad xeon does about 1M, for reference.
>>>>
>>>>Speed wasn't the issue here however, it was simply following a bad book line
>>>>until it was too late...
>>>
>>>But 6..Qc7? came not from the book but from the Crafty engine. In this
>>>game the Crafty book did not work.
>>>
>>>Ed
>>
>>
>>No... it came from the book. We were using "book random 0" which says to
>>search (for a short time, normally) all the book moves, and play the one with
>>the best score. Qc7 was in the book, but the score fails low pretty quickly.
>>Then, after resolving the fail low, it decides "hey, this is bad, I am not
>>going to play a book move at all." It then does a normal search, but it had
>>used too much time and the search wasn't very deep....
>
>Earlier you said that crafty rejects this move at depth = 10, so I guess we can
>assume it didn't complete 10 ply!? I find this pretty surprising because crafty
>is a fast searcher, and was running on decent hardware. When do you expect to
>get the logs? Will be interesting to figure out what happened.
>
The problem is that I can't predict exactly what the alpha saw. When I re-ran
this last night, I set the time control to 40/2hrs, with book random 0 on.
Crafty set a target time of 18 seconds. It searched the set of book moves,
found no problem with Qc7 (score steadily dropped iteration by iteration, but
didn't get to the -.5 threshold in 18 seconds) so it just played this move. I
don't know how long it thought when playing Rebel, but I assume it moved at the
18 second mark, most likely, with no fail lows or anything...
As far as where the London version would begin to notice Qc7 is bad, I don't
really know. I didn't use the same version for this test, as I have already
made a few changes since London.
>>
>>The book was actually working, but "book random 0" changes the way it looks,
>>and if you don't know, you could assume it is doing a normal search, unless
>>you see the line "searching only the following moves: {a b c d etc}
>>
>>I think Qc7 was the third most popular move in that very narrow (and bad) book
>>line...
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