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

[W Robert Long]

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