Givaro is a C++ library for arithmetic and algebraic computations.  Its main
features are implementations of the basic arithmetic of many mathematical
entities: prime fields, extension fields, finite fields, finite rings,
polynomials, algebraic numbers, arbitrary precision integers and rationals
(via C++ wrappers over gmp). It also provides data structures and templated
classes for the manipulation of basic algebraic objects, such as vectors,
matrices (dense, sparse, and structured), univariate polynomials, and recursive
multivariate polynomials.

WWW: http://ljk.imag.fr/CASYS/LOGICIELS/givaro/