[R-sig-ME] Parameter-expanded priors with MCMCglmm

[Jarrod Hadfield]

Hi,

You need alpha.mu = rep(0,7) too. Also, note that to obtain marginal  
priors on each variance that are scaled F(1,1) you need to have nu=7.   
What effect this has on the covariances, correlations etc I'm not  
sure. I haven't come across any work looking at the prior properties  
of multi-parameter expansion.

Cheers,

Jarrod


Quoting W Robert Long <longrob604 at gmail.com> on Sun, 07 Oct 2012  
11:35:12 +0100:

> I would be grateful if anyone can advise me on how to use parameter  
> expanded priors in the following context.
>
> With random=~idh(1+year):hospital I initially had:
>
> prior3b <- list(R = list(V = 1, fix = 1), G=list(G1=list(V=diag(7), nu=1)))
>
> which worked OK, but I would like to use parameter expanded prior. I  
> have tried this:
>
> prior3a <- list(R = list(V = 1, fix = 1), G = list(G1 =  
> list(V=diag(7), nu = 1, alpha.mu = 0, alpha.V = diag(25^2,7,7)))
>
> But this gives the error:
> alpha.V is the wrong dimension for some prior$G/prior$R elements
>
> Thanks
> Robert Long
> PhD Student
> University of Leeds
>
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>



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