Exact chiral symmetry for domain wall fermions with finite L-s

We show how the standard domain wall action can be simply modified to allow arbitrarily exact chiral symmetry at finite fifth dimensional extent L-s. We note that the method can be used for both quenched and dynamical calcula tions. We test the method using smooth and thermalized gauge field configur ations. We also make comparisons of the performance (cost) of the domain wa ll operator for spectroscopy compared to other methods such as the overlap- Dirac operator and find both methods are comparable in cost.