[R] poLCA package inquiry

[KDT]

Dear R-users!
I am using the poLCA package to find latent classes in a dataset with binary
outcomes. Several hundreds of persons can engage hundreds of items. Assume
100 items being engaged by 500 persons, the resulting dataframe is as shown
below (5 persons).

item1  item2  item3  item4  item5  . . . . . . .  item97  item98  item99 
item100
   1           0           1           0           1        . . . . . . .      
1            1              0              1
   1           0           1           0           0        . . . . . . .      
1            0              0              1
   0           1           0           0           0        . . . . . . .      
0            1              1              0
   1           0           1           0           1        . . . . . . .      
1            1              0              1
   0           0           1           1           1        . . . . . . .      
0            0              0              1

If the number of items (columns) are less than 63, everything works well.
But for items (columns)  is above 63, I get an Error message  saying "*Error
in model.matrix.default(formula, mframe) :  model frame and formula mismatch
in model.matrix()*" . I can not figure out why this happens. Could someone
explain me why this happens or how to overcome it? 

Assume the dataframe is called DATA, the macro I am arunning is as follows:

DATA.int=DATA+1  # poLCA can only analyze 1,2,...
f<-as.formula(paste("cbind(", paste(colnames(DATA.int), collapse = ","),
")~1")) #all items are dependent variables
fit<-list() #collect fits
Kmax=5 #maximum nr of classes
bic=rep(0,Kmax) #vector of BIC values
ll=rep(0,Kmax) #vector of loglikelihood values
for (j in 1:Kmax){ #fits for #classes=1,2,...,Kmax
  cat(j,"\n") #print current analysis number
  fit[[j]]<-poLCA(f,DATA.int,nclass=j,nrep=20,verbose=FALSE) #20 random
starts
  bic[j]<-fit[[j]]$bic #collect BICs
  ll[j] <- fit[[j]]$llik #collect logliks
}

Thanks in Advance
Kadengye Trevor

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