[R-sig-ME] problem of convergence of simulated data

[Ben Bolker]

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On 06/27/2011 10:10 AM, Jim Maas wrote:
> I've faced the same problem with fitting models before.  I'm simulating
> different permutations of data sets, starting off with the baseline that
> has almost no variance at all, hence it is difficult for the algorithm
> to converge.  Having said that, the estimates will be more than adequate
> if I could relax the convergence criteria even a little.  Is there a way
> to do such with the lme procedure?
> 
> Thanks for any suggestions.
> 
> J
> 
> 
> Error in lme.formula(nmalor ~ 0 + nmatr1 + nmatr3, ~1 | trtpair, data =
> fednmadat,  :
>   nlminb problem, convergence error code = 1
>   message = singular convergence (7)
> 


  You could play with the "tolerance" and "msTol" parameters (see
?lmeControl), although I don't know if that will actually help.
Alternately, try try() if you're willing to filter out failures.

  Ben Bolker
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