st: nonlinear MLE estimate:results always come back to its initial value

[Lizzy Zhang <lizzy1230@gmail.com>]

Hi,

As I am doing an estimate of coefficients in a nonlinear model using
MLE, no matter what initial values I set, the results always come back
to its initial value. Is it more likely that there is something wrong
with my model, or with my code?
Thanks.

Lizzy
*
*   For searches and help try:
*   http://www.stata.com/help.cgi?search
*   http://www.stata.com/support/faqs/resources/statalist-faq/
*   http://www.ats.ucla.edu/stat/stata/