Temporal Domain Parallelism : Does It Work ?

Time dependent partial di erential equations are often solved using algorithms which parallelize the solution process in the spatial domain. However, as the number of processors increases, the parallel e ciency is limited by the increasing communication/computation ratio. Recently, several researchers have proposed algorithms incorporating temporal domain parallelism in order to increase e ciency. In this paper we discuss a class of such algorithms and show that this approach is not normally useful.