# Function to compute the multinomial beta function?

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## Function to compute the multinomial beta function?

 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) Thanks in advance for any assisstance. Regards, Greg         [[alternative HTML version deleted]] ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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## Re: Function to compute the multinomial beta function?

 How about this? mbeta <- function(...) {     exp(sum(lgamma(c(...)))-lgamma(sum(c(...)))) }   > gamma(5)*gamma(6)*gamma(7)/gamma(18) [1] 5.829838e-09 > mbeta(5,6,7) [1] 5.829838e-09 On Mon, 2010-07-05 at 17:10 -0400, 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) > > Thanks in advance for any assisstance. > > Regards, > Greg > > > > [[alternative HTML version deleted]] > > ______________________________________________ > [hidden email] mailing list > https://stat.ethz.ch/mailman/listinfo/r-help> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html> and provide commented, minimal, self-contained, reproducible code. -- Matthew S. Shotwell Graduate Student Division of Biostatistics and Epidemiology Medical University of South Carolina http://biostatmatt.com______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.
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## Re: Function to compute the multinomial beta function?

 In reply to this post by Gregory Gentlemen 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 ================================================================ Robert A. LaBudde, PhD, PAS, Dpl. ACAFS  e-mail: [hidden email] Least Cost Formulations, Ltd.            URL: http://lcfltd.com/824 Timberlake Drive                     Tel: 757-467-0954 Virginia Beach, VA 23464-3239            Fax: 757-467-2947 "Vere scire est per causas scire" ______________________________________________ [hidden email] mailing list https://stat.ethz.ch/mailman/listinfo/r-helpPLEASE do read the posting guide http://www.R-project.org/posting-guide.htmland provide commented, minimal, self-contained, reproducible code.