On Fri, Aug 1, 2008 at 11:52 PM, Michael Rogers <m.rogers at cs.ucl.ac.uk> wrote: > Daniel Cheng wrote: >> in a circular space, we can get infinite number of "average" by changing >> point of reference. --- choose the point of reference with the smallest >> standard deviation. > > From an infinite number of alternatives? Sounds like it might take a > while. ;-) I think we can get away with just trying each location as the > reference point, but that's still O(n^2) running time.
That's what I have in mind. It is not as large as you think as we don't have to calculate every single data point -- just take a good random sample of it should do. > How about this: the average of two locations is the location midway > along the shortest line between them. So to estimate the average of a > set of locations, choose two locations at random from the set and > replace them with their average, and repeat until there's only one > location in the set. > > It's alchemy but at least it runs in linear time. :-) > > Cheers, > Michael > _______________________________________________ > Devl mailing list > Devl at freenetproject.org > http://emu.freenetproject.org/cgi-bin/mailman/listinfo/devl >