PARI/GP is a widely used Computer Algebra System designed for fast computations in number theory, but also contains a large number of other useful functions to compute with mathematical entities such as matrices, power series, algebraic or p-adic numbers, etc., and a lot of transcendental functions. PARI is also available as a C library to allow for faster computations.

**Citation:**

@preamble{"\usepackage{url}"} @manual{PARI, title = "{PARI/GP, version {\tt 2.1.5}}", note = "\url{http://pari.math.u-bordeaux.fr/}", address = {Bordeaux}, year = 2003 } % no author mentioned: using "The PARI group" was not too informative ]