Re: Random spherical troubles

*To*: mathgroup at smc.vnet.net*Subject*: [mg25230] Re: [mg25170] Random spherical troubles*From*: Geoffrey Steeves <gsteeves at gpu.srv.ualberta.ca>*Date*: Fri, 15 Sep 2000 02:22:00 -0400 (EDT)*Organization*: University of Alberta*References*: <8pmmhc$r6a@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I just happened upon this post, but I think I have a similar question. In studying whether a sequence of numbers is random, one can construct what is called a Noise Sphere(http://mathworld.wolfram.com/NoiseSphere.html). When I tried this out, I got a non-uniform distibution of points concentrated along the verticle axis (phi ~= 0) of the sphere. Initially I thought that this was an artifact of my pseudo-random number generator, but I later tried this out with "real" random numbers and got the same distribution. Looking at the mapping(as it is shown on the web page): theta = 2 * Pi * Random[] phi = Pi * Random[] r = Sqrt[Random[]] I thought that the problem was with the distribution in phi. Is this a mistake in the map? Or am I misunderstanding the what a Noise spehere is supposed to be? Thanks for the help! -- _______________________________________________________________________________ Geoff Steeves // University of Alberta Physics // http://www.ualberta.ca/~gsteeves -------------------------------------------------------------------------------