The PARI system is a package which is capable of doing formal computations on
recursive types at high speed.

It is possible to use PARI in two different ways:

1) as a library, which can be called from any upper-level language
application (for instance written in C, C++, Pascal or Fortran);

2) as a sophisticated programmable calculator, named GP, which contains
most of the standard control instructions of a standard language
like C.

This is the alpha quality version that development is in the way.
Algorithm, improvement of implementation are done.
Because improvement of performance was big, ports was made as -devel in
particular.

WWW: http://pari.math.u-bordeaux.fr/