title: Matrix classes in c++
body: <p>I'm doing some linear algebra math, and was looking for some really lightweight and simple to use matrix class that could handle different dimensions: 2x2, 2x1, 3x1 and 1x2 basically.
  I presume such class could be implemented with templates and using some specialization in some cases, for performance.
  Anybody know of any simple implementation available for use? I don't want "bloated" implementations, as I'll running this in an embedded environment where memory is constrained.</p>
  
  <p>Thanks</p>