Dear R-List, 

I apologize for not posting a reproducible example - the reason is that I
 actually do not succeed in reproducing my specific problem with 
generated data.

Let me still describe the problem: 

I want to impute missing data using the "pan" package. 

a) It works, when I use a fraction of my data (e.g. 200 out of 44000 cases)
b) It works, when I generate a dataset of equal size as the original 
based on my empirical means and covs using "mvrnorm" package.
c) It works, when I use "norm" instead of "pan" (though I used the 
stand-alone package - I do not know whether it makes a difference)

BUT R CRASHES without log after about 30 minutes whenever I try imputation on my original dataset using "pan".

This is the code I used:

library(pan)

level2<-DF$l2.id                                                      #specify my level 2 ID in my dataframe (DF)

subj<-match(level2,unique(level2))                            #number the level 2 units from 1:n

y<-as.matrix(DF[-1])                                               
#specify the variables to be used for imputation  
                                                   

pred <- matrix( rep( 1 , nrow(y) ) , ncol= 1)               #specify predictor matrix
xcol <- 1                                                               #col with fixed effect in pred
zcol <- 1                                                               #col with random effect in pred  

prior <- list( a=ncol(y),                                           #non-informative prior
                     Binv= diag( rep(1,ncol(y) ) ) ,
                     c= ncol(y) * length(zcol) ,
                     Dinv= diag( rep(1 ,ncol(y)*length(zcol) ) ) 
                      ) 

                      
imput1 <-  pan(y,subj,pred,xcol,zcol,prior,seed= 13579 ,iter= 1000) #run first imputation

...after 30 minutes: CRASH (R ends automatically, Rgui is closed without log)


Is there a way to identify the source of such a problem? Or any idea what could be the problem?

Thank you in advance.

Best wishes

Alain
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