[R] NaN Log-lik value in EM algorithm (fitting Gamma mixture model)

[Aanchal Sharma]

Hi,

I am trying to fit Gamma mixture model to my data (residual values obtained
after fitting Generalized linear Model) using gammamixEM. It is part of the
script which does it for multiple datasets in loop. The code is running
fine for some datasets but it terminates for some giving following error:

" iteration = 1  log-lik diff = NaN  log-lik = NaN
Error in while (diff > epsilon && iter < maxit) { :
  missing value where TRUE/FALSE needed"

Seems like EM is not able to calculate log-lik value (NaN) at the first
iteration itself. any idea why that can happen?
It works fine for the other genes in the loop. Tried looking for difference
in the inputs, but could not come up with anything striking.

Regards
Anchal



-- 
Anchal Sharma, PhD
Postdoctoral Fellow
195, Little Albany street,
Cancer Institute of New Jersey
Rutgers University
NJ-08901

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