Author: Robert Hyatt
Date: 07:05:17 08/27/00
Go up one level in this thread
On August 27, 2000 at 00:28:08, Ed Schröder 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....
>>
>>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...
>
>This is what I remember from our game: 1.e4 by Rebel and Crafty immediately
>replied with 1..c5 from the book. Then 2.Nf3 and then Crafty started to
>think shortly (5-10 seconds) and the second Crafty move was played. This
>behaviour (5-10 secons for the move) continued till move 5 or 6 and then
>Crafty started to use the normal 2-4 minutes for its moves. 6..Qc7 came
>at the last moment after a 2-4 minutes search. After 6..Qc7 Rebel was also
>out of book.
>
>I don't know that much about Crafty but everybody was saying Crafty was
>out of book after move 1. Also Graham said the above Crafty behavior was
>the same in game 1 (implied Crafty playing without book in game-1).
>
>Hope this gives you sufficient information to make up your mind what
>really went wrong with the book.
>
>Ed
That sounds like what I would expect here... If the score for Qc7 dropped
enough, it will refuse to play it as a book move and do a search. I had not
factored in the problem with a fail low at the end of the book search, which
could use over 1/2 of the total time allocated to this move. But I will cover
this hole quickly, of course. :)
Qc7 was played several thousand times, however, which makes it surprising it
isn't in your book.
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