Réf. : Re: [computer-go] Testing move generation and tree traversal

["jEF NEUF" <bocquet.jean-francois@xxxxxxx>]

 Hello,
Don has said :
"2.  I don't see captures as really getting much excercise with this test,"

as a consequence, the case were the first white point is 1-1 and is captured
does not count.
the number of points where the first white stone could have been played
becomes 78.

If captures were taken into account, you would be right.

regards 

-------Message original-------
 
De : computer-go
Date : 01/13/05 14:49:45
A : computer-go
Sujet : Re: [computer-go] Testing move generation and tree traversal
 
In message <BAY21-F15EB80BA08DF0CC93B83E5FE8A0@xxxxxxxxxxxxxxxxx>, Peter McKenzie
<peter_mckenzie@xxxxxxxxxxxxxxxxx> writes
>Hi All,
>
>In computer chess there is a thing called perft
>(http://homepages.caverock.net.nz/~peter/perft.htm) for testing the
>move generation and tree traversal functionality of a chess program.
>
>Has anyone done this in Go?
>
>I've been working on a Go program and would like to verify that my core
>code is working OK. It does incremental updating of chains etc so
>there is a fair chance of bugs :-)
>
>According to my program, for 9x9 Go, there are:
>
>81 ways of playing a 1ply game,
>6,480 ways of playing a 2ply game,
>511,920 ways of playing a 3ply game,
 
I agree so far
 
>39,929,136 ways of playing a 4ply game,
 
The obvious, and wrong, number to give here is 81*80*79*78 = 39,929,760.
This has to be reduced by the cases where White can't play on a 1-1
point because there are black stones on both the adjacent 1-2 points.
How many such cases are there? I make it 4 (the number of corners where
it can happen) * 2 (the number of orders the two black stones could have
been played in) * 79 (the number of points where the first white stone
could have been played) = 632. This leaves 39,929,128. Your number is
eight more than this.
 
Nick
 
>3,074,496,080 ways of playing a 5 ply game.
>
>Oh, that is excluding passing at all nodes. Maybe its a bad idea to
>exclude pass moves? But I thought it would make things simpler and it
>meant I didn't have to think about what to do after 2 consecutive passes.
>
>Similarly for 5x5 Go there are 2,411,088,112 ways of playing a 7ply game.
>
>Is anyone able to verify those numbers?
>
>cheers,
>Peter McKenzie
--
Nick Wedd nick@xxxxxxxxxxxxxxxxx
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