A while back I tried taking a jab at converting some matrix calculus rules
into maxima, but I'm not very good with Lisp. However, Paul Horsfall has
been kind enough to point out the following source to me (
http://zulko.wordpress.com/2012/04/15/symbolic-matrix-differentiation-with-sympy/).
I'm much better with Python and have found this to be incredibly useful.
I thought I would share Paul's findings with the general community. Thanks
Paul!