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Subject: Re: Junior-Crafty hardware user experiment - 17th game

Author: Peter Berger

Date: 02:26:59 12/19/03

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On December 19, 2003 at 00:16:03, Robert Hyatt wrote:

>On December 18, 2003 at 18:32:21, Peter Berger wrote:
>
>>To call Crafty's
>>book wide is really wrong - I will try to reach you the last time with this
>>message, aware that I am _most_ probably not the first one to come up with this
>>anyway. To answer your second question: given 1. e4 e5, Crafy being white: what
>>is the probability that it will play 2. Bc4 against a computer?
>
>
>10% of the time:
>
>  move     played    %  score    learn     CAP     sortv   P%  P
>   Nf3!    152593   81   0.11     0.27  -655.36   14041.0  90  Y
>   Bc4!      6913    3   0.07     0.00  -655.36   12046.3  10  Y
>
>that 3% you are quoting is the "percent of the time this was played
>in all the games in enormous.pgn, after 1. e4 e5.  Bc4 was played 3%
>of the time.  Crafty plays it about once out of every 10 games.
>
>However, once you are past that point, the book is _wide open_.  So
>I don't understand your usage of the term "narrow".  IE from here on
>in the game the program can choose from _any_ variation in the Bishop's
>opening that it wants...
>

You are correct with the 10% number for 2. Bc4, I get the same number here. I
looked at the wrong column of the table.

Why did I call Crafty's book narrow? One example: if 1. e4 e5 2. Nf3 Nc6 is
played Crafty as black will _always_ play only the following line against a
computer: 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O Be7 6. Re1 b5 7. Bb3
O-O 8. c3 d6 9. h3 Bb7 - there are several similar lines , but I am sure you are
aware of this anyway.

Or are you? I just had a look at Crafty's most recent games on ICC:

CSMath(C)-Crafty    1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6
glories(C)-Crafty   1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 d6
StrongBad(C)-Crafty 1. d4 Nf6 2. c4 g6

These lines would not be possible with the bookc.bin provided for download.
Yesterday I had a short conversation with another WB engine author who said that
testing against Crafty is mostly useless as it's only a booklearner test - so I
am not alone with this observation.

>I don't believe we ever discussed how it should be set up.

I won't start quoting ;). But it is true that it is a user experiment done by me
just as I see fit, although I set up Crafty as closely as possible to your
recommendations for an experiment like this.

Peter



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