Thanks all for the replies. I am not sure I quite get the 20x21+2 idea but I will take a look back in the archives. Does anyone remember roughly when it was posted to the list?
Thanks again, Carter. --- On Mon, 7/13/09, Peter Drake <dr...@lclark.edu> wrote: > From: Peter Drake <dr...@lclark.edu> > Subject: Re: [computer-go] Basic question concerning the edges of the board > To: "computer-go" <computer-go@computer-go.org> > Date: Monday, July 13, 2009, 9:08 AM > As in LibEGO, if you define the > off-board points to be both black AND white, finding > captures requires fewer branches. > Peter Drakehttp://www.lclark.edu/~drake/ > > > On Jul 13, 2009, at 8:48 AM, David Fotland > wrote: > I use one dimensional arrays for speed (to > avoid a multiply by 21). > > Old Many Faces code uses arrays of 363 (361 points, pass, > and null-point). > The smallest possible arrays were required to run under 500 > KB total memory. > I avoided edge checks by having a set of small offset > arrays (with 2, 3, or > 4 offsets), chosen by the board. > > My MCTS code uses single dimension arrays with size > suggested by Mark Boon, > from Goliath, 20 * 21 + 2. This is enough to have > points off the edge on > all sides and diagonals. > > David > > -----Original Message----- > From: > computer-go-boun...@computer-go.org [mailto:computer-go- > boun...@computer-go.org] > On Behalf Of Carter Cheng > Sent: Monday, July 13, > 2009 8:36 AM > To: computer-go@computer-go.org > Subject: [computer-go] > Basic question concerning the edges of the board > > > Hi, > > I have again been > considering trying my hand at implementing a simple go > program. The question > I have pertains to checking for the edge of the > board > in capture situations and so on. > For a modern CPU (given what limited > information I have on > this) the extra branches might result in pipeline > stalls if I am > constantly checking if values are in range. Is it best to > extend the size of the > board to say 21x21 to somehow avoid these sorts of > checks? Or are the > relative cost of these branches negligible in the > scheme > of things? > > Thanks in advance, > > Carter. > > > > _______________________________________________ > 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/ > > > -----Inline Attachment Follows----- > > _______________________________________________ > 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/
