  UKQCD's dynamical fermion project uses the Generalised Hybrid Monte-Carlo
(GHMC) algorithm to generate QCD gauge configurations for a non-perturbatively
O(a) improved Wilson action with two degenerate sea-quark flavours. We describe
our implementation of the algorithm on the Cray-T3E, concentrating on issues
arising from code verification and performance optimisation, such as parameter
tuning, reversibility, the effect of precision, the choice of matrix inverter
and the behaviour of different molecular dynamics integration schemes.
