CPM{P,N}CPM{P,N} methods extended for the solution of coupled channel Schrödinger equations

The successful CPM{P,N}{P,N} methods for the one-dimensional time-independent Schrödinger problem are generalized to the coupled channel case. The derivation of the formulae is discussed and a Maple program code is included which allows to determine the analytic expressions of the perturbation corrections needed to construct methods of different orders. Some numerical illustrations are given showing the accuracy, the robustness and the CPU-time gain of the proposed algorithms over the sixth order LILIX method which was presented in [L.Gr. Ixaru, LILIX—A package for the solution of the coupled channel Schrödinger equation, Comput. Phys. Comm. 147 (2002) 834–852].