[R] Is there a way to not use an explicit loop?

Juancarlos Laguardia brassman785 at gmail.com
Wed Sep 17 20:56:36 CEST 2008


I have a problem in where i generate m independent draws from a  
binomial distribution,
say

draw1 = rbinom( m , size.a, prob.a )


then I need to use each draw to generate a beta distribution.  So,  
like using a beta prior, binomial likelihood, and obtain beta  
posterior, m many times.  I have not found out a way to vectorize  
draws from a beta distribution, so I have an explicit for loop within  
my code



for( i in 1: m ) {

beta.post = rbeta( 10000, draw1[i] + prior.constant  ,  prior.constant  
+ size.a  - draw1[i] )

beta.post.mean[i] = mean(beta.post)
beta.post.median[i] = median(beta.post)

etc.. for other info

}

Is there a way to vectorize draws from an beta distribution?

UC Slug



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