RANDGAMMA RANDGAMMA Generate Gamma-Distributed Random Variable

Usage

Generates random variables with a gamma distribution.  The general
syntax for its use is

   y = randgamma(a,r),

where a and r are vectors describing the parameters of the
gamma distribution.  Roughly speaking, if a is the mean time between
changes of a Poisson random process, and we wait for the r change,
the resulting wait time is Gamma distributed with parameters a 
and r.