Incorporation of matter into characteristic numerical relativity - art. no. 024005

A code that implements Einstein's equations in the characteristic formulati on in 3D has been developed and thoroughly tested for the vacuum case. Here , we describe how to incorporate matter, in the form of a perfect fluid, in to the code. The extended code has been written and validated in a number o f cases where shocks do not form. It is stable and capable of contributing towards an understanding of a number of problems in black hole astrophysics . [S0556-2821(99)00614-1].