Hi Lorenzo, Just a quick thought, the uniform probability density on a unit sphere is 1 / (4pi), what about binning those random points according to their directions and do a chi-square test?
Regards, Guo On Sun, Oct 7, 2012 at 2:16 AM, <cbe...@tajo.ucsd.edu> wrote: > "Lorenzo Isella" <lorenzo.ise...@gmail.com> writes: > > > Dear All, > > I implemented an algorithm for (uniform) random rotations. > > In order to test it, I can apply it to a unit vector (0,0,1) in > > Cartesian coordinates. > > The result is supposed to be a set of random, uniformly distributed, > > points on a sphere (not the point of the algorithm, but a way to test > > it). > > This is what the points look like when I plot them, but other then > > eyeballing them, can anyone suggest a test to ensure that I am really > > generating uniform random points on a sphere? > > There is a substantial literature on this topic and more than one > (metaphorical?) direction you could follow. > > I suggest you Google 'directional statistics' and start reading. > > Visit http://www.rseek.org and enter 'directional statistics' in > the search box and click on the search button to see if there is > something in R to meet your needs. > > A post to r-sig-geo might get more helpful responses once you can focus > the question a bit more. > > > HTH, > > Chuck > > > Many thanks > > > > Lorenzo > > > > -- > Charles C. Berry Dept of Family/Preventive > Medicine > cberry at ucsd edu UC San Diego > http://famprevmed.ucsd.edu/faculty/cberry/ La Jolla, San Diego 92093-0901 > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
