1)   Matrix TCL 2.11
This is a C++ template class library to perform matrix calculations with ease and efficiency in your programs. It supports most of the matrix calculations that you may need to do in your C++ programs. Full source code is included with the package.

 2)   RF21 0.91
Graphing scientific calculator with ample support for user defined functions and libraries. Numeric features include derivation, integration, Monte Carlo simulations, Runge Kutta, matrix inversion, nonlinear equation systems, function minimizer.