  We present a C++ library for the numerical evaluation of one-loop virtual
corrections to multi-jet production in massless QCD. The pure gluon primitive
amplitudes are evaluated using NGluon. A generalized unitarity reduction
algorithm is used to construct arbitrary multiplicity fermion-gluon primitive
amplitudes. From these basic building blocks the one-loop contribution to the
squared matrix element, summed over colour and helicities, is calculated. No
approximation in colour is performed. While the primitive amplitudes are given
for arbitrary multiplicities we provide the squared matrix elements only for up
to 7 external partons allowing the evaluation of the five jet cross section at
next-to-leading order accuracy. The library has been recently successfully
applied to four jet production at next-to-leading order in QCD.
