On Nov 27, 2007 1:58 PM, Stuart A. Yeates <[EMAIL PROTECTED]> wrote: > Could you give us a quick reference for exactly _which_ Euler numbers > you're using? Wikipedia has three separate ones and the MathWorld site > a similiar number.
I cannot speak for Don, but in the work on solving Go I calculated the zeros-joined Euler number from independent bitmaps for Black and White with the border set to zero. IIRC half-joined and ones-joined performed worse (in the sense that the tree got bigger). An interesting alternative may be to combine colours so that the quad-counts directly use all the local information (that way, e.g., the diagonal miai-connection can be distinguished from one where the opponent is interfering). Back in 2002 I did not use this because the binary version has a smaller lookup table. The ICGA article contains a bit less information than my thesis. E.g., an explanation of the Euler numbers can be found on page 28 of the thesis. Here's a link: http://erikvanderwerf.tengen.nl/publications.html Erik > On 26/11/2007, Don Dailey <[EMAIL PROTECTED]> wrote: > > > > After reading the paper on solving go on small boards, I am curious > > about the use of euler numbers as a simple evaluation element. > > > > I implemented a little euler number test program and it works correctly > > from a sample of about 50 positions of various types. I'm using the > > fast version where you scan 2 lines at a time with a lookup table. > > > > However, it calculates holes inside of groups and this does not detect > > eyes or "holes" on the edges of the board. It's not clear how to deal > > with this. > > > > I'm experimenting with a version that wraps a border around the whole > > board so that even the empty position looks like a 1 group with one big > > hole. This causes a lot of silly anomalies - for instance if you > > surround a big chunk of safe opponent stones it looks like a big > > hole. If you own half the board and the opponent owns the other > > half, his half contributes favorably to your euler number (it looks > > like a big hole of yours.) > > > > Of course I realize that this is just a quick and dirty calculation but > > I was curious about any tricks that others use to deal with it. > > > > - Don > > > > _______________________________________________ > > computer-go mailing list > > computer-go@computer-go.org > > http://www.computer-go.org/mailman/listinfo/computer-go/ > > > _______________________________________________ > computer-go mailing list > computer-go@computer-go.org > http://www.computer-go.org/mailman/listinfo/computer-go/ > _______________________________________________ computer-go mailing list computer-go@computer-go.org http://www.computer-go.org/mailman/listinfo/computer-go/
