cannot increase the number of iterations in lme call over 146

Hi Antonio,

Look at the error message: "function evaluation limit reached without
convergence" you increased the number of iterations, but the objective
function reached its limit for max evaluations prior to convergance.
The 'brute force' approach would be to use the msMaxEval argument of
lmeControl to up that, but I would suggest carefully scrutinizing your
data and model prior before blindly asking the optimizer to run
longer.

Have you graphed your data?  What sort of variables are time and
maternal_educ?  If you send us data, we can show you some examples of
how you might graph and examine your data.  Also, do you really want a
random interaction?

Finally, in model formulae, * behaves specially, so x * z expands to:
x + z + x:z, thus a simplified writing of your model (not really
important and if the other way is clearer to you, by all means use it,
but you can save a few keystrokes; also note I show the msMaxEval
argument):

model.c2 <- lme(log(child_mortality) ~  time * log(maternal_educ),
  control = lmeControl(msMaxIter = 200, msMaxEval = 500 msVerbose = TRUE),
  merged1, random = ~ log(maternal_educ) * time | country.x,
  na.action = na.omit, method = "ML")

Cheers,

Josh

On Tue, Jan 3, 2012 at 5:52 PM, Antonio P. Ramos

cannot increase the number of iterations in lme call over 146

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