[OS X TeX] Typesetting linear algebra (matrices, etc)

[Rafael Hernandez Heredero]

Dear all,

I am planning to write some linear algebra class notes. Latex does  
have a limited built-in matrix and vector typesetting capabilities.
For example, it is desirable to typeset matrices with equal spaced  
columns, regardless of the sign of the entries (right aligned). One can
achieve that writing:

	\setlength{\arraycolsep}{3mm}
	$$
	\left(
	\begin{array}{rrrrr}
	\llap{$-$}1 & 0 & 0 & 0 & \llap{$-$}3 \\
	0 & 0 & 0 & 0 & 0 \\
	0 & 0 & \llap{$-$}1 & 0 & 0 \\
	0 & 0 & 0 & 0 & 1 \\
	2 & 0 & 0 & 1 & 0
	\end{array} \right)
	$$

I think this is a good format for a teaching document, but quite  
cumbersome to write  if you plan to write several hundreds of  
different matrices.  And one also eventually want to annotate columns,  
box them, etc.

Do you know of packages or tricks developed / used by people  
confronted before with such task ? (there must be many). Googling
does not help me much ...

Thanks a lot !

Rafael