Re: Random spherical troubles

*To*: mathgroup at smc.vnet.net*Subject*: [mg25312] Re: [mg25170] Random spherical troubles*From*: Yossi Lonke <jrl16 at po.cwru.edu>*Date*: Tue, 19 Sep 2000 03:45:41 -0400 (EDT)*Organization*: Dept. Mathematics, CWRU*References*: <8pmmhc$r6a@smc.vnet.net> <8psh4a$a8v@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

Hello, Take a look at http://mathworld.wolfram.com/SpherePointPicking.html where you'll find the answer to your question. Yossi Lonke Geoffrey Steeves wrote: > 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 > ------------------------------------------------------------------------------- -- ************************************************* Dr. Yossi Lonke Mathematics Department Case Western Reserve University 10900 Euclid Avenue Cleveland, Ohio 44106 216 368-5423 http://www.cwru.edu/artsci/math/lonke/home.html *************************************************