  The ALPHA algorithm to evaluate the exact, tree-level matrix elements is
reviewed in the context of multi-parton processes in QCD. The algorithm is
suited for the authomatic calculation of tree-level scattering amplitudes and
allows for straightforward inclusion of mass effects. It's CPU cost grows like
K^n (K constant, n number of external particles) as opposed to the factorial
growth of Feynman graphs. I also discuss the summation over colour
configurations which is designed to allow the construction of parton-level
event generators suitable to interfacing with a parton-shower evolution
including the effects of colour-coherence. Explicit results for the total rates
and differential distributions of processes with 8 final-state partons are
given.
