st: Heckprob and Maximum likelihood algorithm

[Rachel <academicgirl@gmail.com>]

Does Heckprob supply the maximum likelihood estimator with the
appropriate gradient and Hessian, or does Stata compute them
numerically?  I looked at the ado file but, as a casual Stata user,
could not determine which is the case.

Thanks,
Rachel
*
*   For searches and help try:
*   http://www.stata.com/support/faqs/res/findit.html
*   http://www.stata.com/support/statalist/faq
*   http://www.ats.ucla.edu/stat/stata/