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Subject: Re: Perft(4) and Perft(5) for Gothic Chess

Author: Uri Blass

Date: 23:52:56 01/07/04

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On January 08, 2004 at 01:36:30, Ed Trice wrote:

>Something happened during ply 5 of the iteration. I am not sure if I am doing
>the perft properly since it required a great deal of unraveling of the move
>generator. I also was spawning large text files, writing every move to disk as a
>double check.
>
>The first four plies have been computed. I got "0 moves" for black after Ah3  j5
>  Ae6 which is an Archbishop checking black with no mate or stalemate.The full
>program handles this with no problem, so again, it must be something I whacked
>doing perft.
>
>total 1-ply positions = 28
>total 2-ply positions = 784
>total 3-ply positions = 25,112
>total 4-ply positions = 828,560
>
>An error occurred counting the positions
>at ply 5 for: Ah3  j5   Ae6
>
>0 black replies
>checkmate: no
>stalemate: no
>black pieces: yes
>
>total 5-ply positions > 29,393,835

perft 5 is the number of legal games of 5 plies.
perft 5 is not the total 5-ply positions.

The total 5-ply positions is smaller because you may get the same position in
different order of move.

perft 1 and perft 2 are the number of 1 ply position and 2 ply position
respectively because in that case you cannot get the same position by different
order of moves.

Uri



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