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Subject: Re: New version of TSCP (1.8)--opening book and hash keys

Author: Janos Keinrath

Date: 04:38:08 01/30/03

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On January 30, 2003 at 04:57:31, Tom Kerrigan wrote:

>A new version of TSCP is now available on my home page:
>
>http://home.attbi.com/~tckerrigan/
>
>A big change is the addition of an opening book. Many people have asked for this
>feature but until recently I couldn't think of a way to do it that was
>appropriately simple. The new version's opening book code is only 122 lines,
>about half of which are comments. The book that's included with the program
>(book.txt) has 385 opening lines. This feature should make TSCP much more fun
>for humans to play against and it should also make TSCP stronger in the
>tournaments that people run (I've heard of people "busting" TSCP).
>
>I also added hash keys to the program. I've said in the past that I would never
>do this, but TSCP's old repetition detection code was pretty hard to understand
>and I think it was a kinda buggy, too. So I was able to remove that and the new
>brain-dead-simple hash code is < 100 lines. (It does slow the program down by
>~10%, BTW.)

I look at the source code and found it you always calculate the full hash key
(with set_hash function) in makemove, but it not necessary.
If you only 'xor' the from and to square info, and handle the special cases
(capture,castle,promotion), it would be quicker.

>Another selling point for hash keys is that serious chess
>programmers will have to learn about hash keys at some point anyway so they
>might as well be in there. It also makes it a little easier for people to add
>hash tables to TSCP.
>
>Well, two pretty big changes to TSCP. I hope you like them. Let me know if you
>have any comments.
>
>-Tom

Janos



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