[R] about MCMC pack

[Mariagiulia Matteucci]

Hello,
I tryed to use the MCMC pack, particularly the function MCMCirtKd to
simulate the posterior distribution in a multidimensional IRT model.
The code I used is:

posterior1 <- MCMCirtKd(Y, dimensions=2,
item.constraints=list("V2"=list(3,0)),
   burnin = 1000, mcmc = 10000, thin=1, verbose = 1, seed = NA,
   alphabeta.start = NA, b0 = 0, B0=0, store.item = FALSE,
   store.ability=FALSE, drop.constant.items=TRUE)  


where Y is a matrix subjects x items (1500 x 32) of simulated response
sequences.

After running the program, if I ask for a plot or summary of the MCMC
object "posterior1", I obtain this message:


Error in as.matrix.mcmc(x) : the lenght of'dimnames' [2] doesn't
coincide with the array extension
More: Warning message:
the number of elements to replace is not a multiple of the lenght of
replacement


I cannot interpret this warning message, thank you for help or
suggestions!

Mariagiulia




Mariagiulia Matteucci
Dipartimento di Scienze Statistiche “Paolo Fortunati”
Università di Bologna
Via Belle Arti, 41 
40126 Bologna (ITALY)
e-mail: matteucci at stat.unibo.it
TEL: +39 051 272503
FAX: +39 051 232153