Kit deleted the posting by Shihe Fan to which
my posting was the reply. Shihe's posting was clearly
about Stata. Despite the name of the thread, Shihe
made a comment picking up something Bobby Gutierrez
said (about -xtmixed-, a Stata command).
The story with Mata is indeed different and something
like tracing I presume to be a matter Mata masters
and mistresses will have on their amenda. In fact, it is
surely a priority for MataCorp.
Indeed, I did not repeat the posting by Mr Fan, but Mr Fan's concern
was that the error reporting was 'not specific' -- that is, errors
thrown by Mata (which generated the original posting) were not linked
to a line in the Mata source code. That is indeed true, and the error
trace provided by Stata for Mata errors is 'not specific', as I
mentioned---unlike the specificity that would arise from a program
written in C or Fortran, for instance. "set trace" is not very useful
when ado-files invoke Mata functions. In Robby's response, xtmixed (a
Stata command implemented as an ado-file) calls Mata functions, but
if an error occurs within the Mata function, little information is
available.
