[R] mclust: modelName="E" vs modelName="V"

[Christian Hennig]

This normally happens if the algorithm gets caught in a solution where one 
of the components has variance converging to zero.

One way of dealing with this is the use of a prior that penalises too 
small variances. This works through the prior argument of Mclust (the 
defaultPrior should do the trick but I currently don't have the time to 
figure out again how to do this precisely; I have done it before with 
success).

Another option is to have a look at the flexmix package.

Best regards,
Christian

On Sun, 4 Sep 2011, Nico902 wrote:

> Hi,
>
> I'm trying to use the library mclust for gaussian mixture on a numeric
> vector. The function Mclust(data,G=3) is working fine but the fitting is not
> optimal and is using modelNames="E". When I'm trying
> Mclust(data,G=3,modelName="V") I have the following message:
>
> Error in if (Sumry$G > 1) ans[c(orderedNames, "z")] else ans[orderedNames] :
>  argument is of length zero
> In addition: Warning message:
> In pickBIC(object[as.character(G), modelNames, drop = FALSE], k = 3) :
>  none of the selected models could be fitted
>
>
> Using variable variance would fit my data better, any idea how to do it?
>
> Thanks a lot.
>
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*** --- ***
Christian Hennig
University College London, Department of Statistical Science
Gower St., London WC1E 6BT, phone +44 207 679 1698
chrish at stats.ucl.ac.uk, www.homepages.ucl.ac.uk/~ucakche