EXPFIT4 — a FORTRAN program for the numerical solution of systems of nonlinear second-order initial-value problems

Abstract In this paper we present a FORTRAN program which solves the initial-value problem associated with nonstiff system of the form y″ = ƒ(x,y). The program is based on a family of exponential-fitted four-step methods. The presented code is particularly suited to solve second-order initial-value problems arising from physics. Title of program: EXPFIT4 Catalogue Id: ADEZ_v1_0 Nature of problem All physical problems which lend themselves to a description by a non- stiff system of linear and/or nonlinear differential equations of second order, such as pendulum problems, anharmonic oscillator problems, Lagrange problems, celestial mechanics problems, etc. Versions of this program held in the CPC repository in Mendeley Data ADEZ_v1_0; EXPFIT4; 10.1016/S0010-4655(96)00146-4 This program has been imported from the CPC Program Library held at Queen's University Belfast (1969-2019)