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Subject: Re: Making book for Amy w/Dann's PGN files

Author: Pete Galati

Date: 01:27:59 03/22/00

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On March 22, 2000 at 03:54:22, Thorsten Greiner wrote:

>On March 21, 2000 at 12:54:16, Pete Galati wrote:
>
>>As it is now, and without adding Dann's pgn files yet, a 13.2mb pgn compiles a
>>20mb book with Amy, so I expect it to end up being on the large size before I'm
>>done, I'm hoping Amy doesn't have a limit.  Amy's a cool little program.
>
>Pete,
>
>Amy internally uses an open source but commercial grade database engine called
>Berkeley DB (see http://www.sleepycat.com). I am not aware of any size
>restrictions Berkeley DB has, other than those of the underlying operation
>system (many OSes limit file sizes to 2 GB).

I was nowhere near that big.

>
>To index the database Amy uses a 64 bit integer which is computed using the
>usual Zobrist hashing function. There is a very tiny chance that to
>non-identical positions hash to the same 64 bit integer, so that a bad opening
>move might be played. But I do not consider this to be relevant in real life.
>
>In the 0.7 version of Amy which I will release shortly the book size is
>decreased a little bit. Also you will have the option to 'flatten' (is this a
>good english word for what I mean) the opening book by removing positions which
>occur less than 'n' times. Even for n=1 I found that opening books reduce to
>1/10th of the original size.
>
>Hope you enjoy Amy
>
>	-Thorsten

Thanks Thorsten, I enjoy Amy allot, I've spent allot of time the last few days
playing with it and it's opening book.  I spent so much time putting my post
together (see above) that I didn't see the measage you had posted, so there's
some notes about the final book and a game I played.  Cool program.

Pete



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