[R] Function to compute the multinomial beta function?

[Robert A LaBudde]

At 05:10 PM 7/5/2010, Gregory Gentlemen wrote:
>Dear R-users,
>
>Is there an R function to compute the multinomial beta function? 
>That is, the normalizing constant that arises in a Dirichlet 
>distribution. For example, with three parameters the beta function 
>is Beta(n1,n2,n2) = Gamma(n1)*Gamma(n2)*Gamma(n3)/Gamma(n1+n2+n3)

 > beta3<- function (n1, n2, n3) 
exp(lgamma(n1)+lgamma(n2)+lgamma(n3)-lgamma(n1+n2+n3))
 > beta3(5,3,8)
[1] 1.850002e-07

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Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: ral at lcfltd.com
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