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Subject: Re: Move ordering - How do I know if I have played this move already?

Author: Bruce Moreland

Date: 14:43:44 04/06/99

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On April 06, 1999 at 17:39:23, Steve Maughan wrote:

>Hi Folks!
>In my progam I have been playing around with move ordering.  If possible I would
>like to play certain moves (e.g. Hash move, killer move) before I call the
>general MoveGeneration routine.  Hopefully this will save time as the hash move
>etc will often cause a cutoff.  However, in the common case were these do not
>create a cutoff I will still need to generate all the other possible moves.  My
>question is - what is the best method for keeping track of moves played or
>testing whether or not a move has already been played?
>Do people;
>a) iterate through all moves generate?
>b) iterate through special moves such as hash?
>c) create a 64 bit integer for each piece, with each bit representing a 'to'
>square.  If the 'OR' gives a new number then it is a new move.
>d) Generate all the moves in the first place and give a high weight to special
>moves as desired?
>e) Use some form of hash table?
>I am favouring 'c' at the moment but am not sure if there isn't an easier way.
>All ideas and help appreciated.
>Steve Maughan

Another idea, which may very well be bad, would be to ignore the whole problem
and simply search some moves twice.


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