New algorithms for one-loop integrals

New algorithms are presented for evaluating the scalar one loop integrals for three- and four-point functions for arbitrary masses and external momenta. These formulations are useful both for analytic integration and for numerical evaluation in a computer program. The expressions are very compact and provide for an easy isolation of asymptotic behaviour and potential numerical problems. The tensor integrals have also been rewritten according to new algorithms, making it very easy to express amplitudes in terms of scalar loop integrals.