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From: Giovanni Azua <bravegag@hotmail.com>
Newsgroups: comp.lang.java.programmer
Subject: RandomDirichlet?
Date: Tue, 01 Nov 2011 10:09:32 +0100
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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?

TIA,
Best regards,
Giovanni