A local greedy algorithm and higher order extensions for global numerical continuation of analytically varying subspaces

We present a family of numerical implementations of Kato’s ODE propagating global bases of analytically varying invariant subspaces, of which the first-order version is a surprising simple “greedy algorithm” that is both stable and easy to program and the second-order version a relaxation of a first-order scheme of Brin and Zumbrun. The method has application to numerical Evans function computations used to assess stability of traveling-wave solutions of time-evolutionary PDE.