A class which allows for developers to implement numbers much larger than previously allowed by built in data types in C++. (currently supports up to 1000 decimal places)
Template based math library for C++. Also has algorithms that compute the Smith and the Smith-McMillan form for matrices of polynomials or rational functions respectively.
A compact cross platform C++ matrix operations class library for Windows, Mac OS X and Linux. It provides over a hundred different matrix operations and interfaces to BLAS and LAPACK. [Commercial]