Re: computer-go: 5 x 5 perfect play

["Ran Xiao" <ranxiao@xxxxxxxxxxxx>]

Consider symmetric, possible board configuration should be around (3^25)/8.
Thus, log2((3^25)/8)=36.6 bits. Total storage required is (2^36.6)/8 bytes
=1.3e10, 13 Gig harddisk.

Weimin

----- Original Message -----
From: "Tristan Cazenave" <cazenave@xxxxxxxxxxxxxxxxx>
To: <computer-go@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, October 15, 2002 4:23 PM
Subject: Re: computer-go: 5 x 5 perfect play



Hi,

3^25 = 847 288 609 443 positions for the index, one bit per position
gives (3^25)/8 = 105 911 076 181 octets. Therefore 100 Go is enough if
you only have one bit per position. One bit per position is enough if
you assume you know the score at the end which should be around 25 for
Black (depending on rules). So solving 5x5 Go with retrograde analysis
on a current PC looks doable from a memory point of view. I suspect the
program will be bound by the I/O on the disk.

I am interested in understanding why you use 2^25 instead of 3^25.