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Subject: Re: Beginner's guide?

Author: Don Dailey

Date: 20:23:31 05/14/98

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On May 14, 1998 at 18:41:22, Brian McKinley wrote:

>
>On May 14, 1998 at 17:10:37, Don Dailey wrote:
>
>>On May 14, 1998 at 05:32:13, frank phillips wrote:
>>
>>>Can anyone point me in the direction of explanations of the techniques
>>>used in chess programming.   Having learnt a bit of C this year and with
>>>the help of articles found on the Net about search algorithms managed to
>>>write crude connect4 and othello programs,  I would now appreciate some
>>>pointers to simple but thorough and complete explanations of  bitboards
>>>and hashtables.  Several articles I have found partially explain these
>>>topics but usually assume that the reader has more knowledge than I do,
>>>perhaps because they assume a basic programming background which I do
>>>not have.  The source code to Crafty (thanks Bob) is well documented but
>>>beyond me at the moment.  On a specific issue, I would be grateful for
>>>an explanation of how to get a pv out of the (alpha/beta negamax)
>>>search.  Everything I have tried so far based on storing the best move
>>>in an array pv[depth] has failed, so I seem to be missing a fundamental
>>>point - or am just plain stupid :-/
>>
>>Frank,
>>
>>Another idea that some use is to "walk the hash table" if you have one.
>>Each hash table entry has a best move associated with it so you simply
>>walk through them.   I don't like this method as well but it's easier
>>to implement and has the advantage of not slowing down the program.
>>PV's take a small toll on the search speed.
>>
>>- Don
>
>I take it you do this once at the end of the search. ?

You do it every time you report a score change.  You just keep making
moves as you find them in the table and then unmake them all in
sequence.

- Don



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