Author: Uri Blass
Date: 07:34:17 08/27/00
Go up one level in this thread
On August 27, 2000 at 10:05:17, Robert Hyatt wrote:
>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.
Rebel does not need Qc7 in the book for the following reasons:
1)it is a bad move.
2)It is no problem for Rebel to win the game with white after Qc7 with no book.
If the book (or at least the part of the book that includes this line) is done
manually and not generated automatically from human-human games it is logical to
decide not to include this line in the book.
It is also logical not to include the line if you assume slow automatic
generating of the book that means that every move is analyzed before you put it
in the book.
In this case analysis can show that Qc7 is not good and not put the move in the
book(it is a waste of space to put replies to bad moves in the book when the
computer can find the right contradiction to the moves at tournament time
control).
Uri
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