  The prime candidate of LIGO/VIRGO sources of gravitational waves is the
spiral in of black holes and neutron stars in compact binaries. While the early
stages of the evolution of compact binaries is computable from post-Newtonian
calculations, prediction of their late stages requires large scale numerical
simulation. A fully covariant and strictly hyperbolic formulation for numerical
relativity is described, and illustrated in a one-dimensional computation of a
Gowdy-wave on the three-torus. This formulation allows foliations in full
generality, in particular it poses no restriction on the lapse function.
