From: Roger Pack <rogerpack2005@...>
Date: 2007-08-24T06:56:06+09:00
Subject: Re: Probability distributions library in Ruby

From wikipedia : algorithm for generating pseudo poissons:

def poisson(lambda)

 # init
 l = Math.exp(-lambda)
 k = 0
 p = 1
 while p >= l
   k += 1
   u = rand
   p = p *u
 end
 return k -1
end

only returns ints, but hey, they center around lambda
gl.
-Roger

maw wrote:
> Libra wrote:
>> Libra
> R is great! maybe too great for your requirements
> rb-gsl is easy
> 
> for example this will print you a nice gauss-shape graph
> from rb-gsl-1.8.3/samples/histogram/gauss.rb
>> 
>> sigma, mean, height, = h.fit_gaussian
>> 
>> x = GSL::Vector.linspace(-MAX, MAX, 100)
>> y = height*Ran::gaussian_pdf(x-mean, sigma)
>> GSL::graph(h, [x, y], "-T X -C -g 3")
> 
> NICE!
> 
> cauchy exponential power poisson etc. also available
> ruby - making maths easy

-- 
Posted via http://www.ruby-forum.com/.