We examine the problem of solving hyperbolic initial boundary value problems in several space dimensions on parallel computers using domain decomposition. Imposing continuity conditions across an inter-domain boundary in several space dimensions is in general not well posed. If however the boundary moves faster than the fastest wave associated with the hyperbolic equation then the problem becomes well posed. We minimize a function which is the sum of squares of the L2 norm of the residuals in the partial differential equation, initial and boundary conditions and a penalty term which is the...