**pendulum_elastic_ode_test**,
an Octave code which
calls pendulum_elastic_ode(), which
sets up the ordinary differential equations (ODE) that represent
the behavior of a nonlinear elastic pendulum, with gravitational
force G, spring constant K, unstretched length L, and mass M.

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

pendulum_elastic_ode, an Octave code which sets up the ordinary differential equations (ODE) that represent the behavior of a nonlinear elastic pendulum, with gravitational force G, spring constant K, unstretched length L, and mass M.

- pendulum_elastic_ode_test.m, calls all the tests.
- pendulum_elastic_ode_test.sh, runs all the tests.
- pendulum_elastic_ode_test.txt, the output file.

- midpoint.m, a midpoint ODE solver.
- pendulum_elastic_midpoint_energy.png, a plot of the energy of the nonlinear pendulum behavior over time.
- pendulum_elastic_midpoint_theta.png, a plot of the angular deflection over time.
- pendulum_elastic_midpoint_theta_phase.png, the theta phase plot.
- pendulum_elastic_midpoint_nu.png, a plot of the strain over time.
- pendulum_elastic_midpoint_nu_phase.png, the theta phase plot.

- pendulum_elastic_ode23_energy.png, a plot of the energy of the nonlinear pendulum behavior over time.
- pendulum_elastic_ode23_theta.png, a plot of the angular deflection over time.
- pendulum_elastic_ode23_theta_phase.png, the theta phase plot.
- pendulum_elastic_ode23_nu.png, a plot of the strain over time.
- pendulum_elastic_ode23_nu_phase.png, the theta phase plot.