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From: Eric Sosman <esosman@ieee-dot-org.invalid>
Newsgroups: comp.lang.java.programmer
Subject: Re: RandomDirichlet?
Date: Tue, 01 Nov 2011 07:50:01 -0400
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On 11/1/2011 5:09 AM, Giovanni Azua wrote:
> Hello,
>
> I need to generate random TPCH workloads but I don't want a Uniform
> distribution where Q1, RF1, RF2 would be equally probable i.e. using new
> Random().nextInt(..)
>
> I instead would like to draw samples from a Dirichlet distribution which
> would give a very skewed PD depending on the input alphas (which specify how
> skewed I want the PD to be). The Matlab code would be exactly:
>
> function r = dirichlet_sample(a,n)
> p = length(a);
> r = gamrnd(repmat(a,n,1),1,n,p);
> r = r ./ repmat(sum(r,2),1,p);
> End
>
> But there is no "gamrnd" RandomGamma in Java nor RandomDirichlet. Before I
> spend time writing this, can anyone advice for a low-footprint library
> implementing those functions?

     Google finds ~114,000 hits for "gamma distribution java".

     As an aside, Google finds ~396,000 hits for "dirichlet
distribution java".

     Finally, Google finds ~111,000,000 hits for "people who
never heard of google".  I'm not sure just what that means ...

-- 
Eric Sosman
esosman@ieee-dot-org.invalid