st: ml plot and flat regions

[Katia Bobulova <katia.bobulova@googlemail.com>]

Dear All,

I am estimating parameters with a maximum likelihood.
I did ml plot for each parameter estimated and the graph shows the
maximumum at the value founded.

However, when I change my likelihood combining two separate
likelihoods, I cannot find the maximum.
The ml plot command shows that one of the parameters that I want to
estimate is flat.

How can I overcome this issue in order to reach the convergence?
I tried with search, imposing restricted value, but it doesn't work.

Thank you very much for your help.
Katia
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