This subroutine is in the file PGmorematrixmacros.pl -- you can see the source code at http://cvs.webwork.rochester.edu/viewcvs.cgi/pg/macros/PGmorematrixmacros.pl?rev=1.18&content-type=text/vnd.viewcvs-markup
In general you can view the source code of any of the pg files at
There is a good deal of documentation on the PG language, but it is
not comprehensive and some of the newer features are not documented
except in the code. A good place to start looking is from the links in the PGeditor which you use to edit problems with.
In addition to direct access to the code base above you can get access to the pod documentation at
There is a complete list of all macros at
and there is an old, but still useful first attempt at
detailed manpages for each subroutine at:
Incidentally, all of the discussion on the old discussion forum site has been transferred to the new one and can be searched using the moodle search feature appearing on most pages. We are continuing to transfer information from the old site to this one and eventually we'll close the old site down -- ancient Windows PC it runs on has earned it's retirement. :-)
Hope this helps.