**kepler_ode_test**,
an Octave code which
calls kepler_ode(), which
defines and solves an ordinary differential equation (ODE) which models
a Kepler two-body gravitational problem.

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

kepler_ode, an Octave code which defines an ordinary differential equation (ODE) which models a Kepler two-body gravitational problem.

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

- euler.m, solves an ODE using the Euler method.
- kepler_euler.m, used euler() to solve the Kepler problem.
- kepler_euler_plot.png, a plot of t versus p1, p2, q1, q2.
- kepler_euler_phase.png, a phase plane plot of p1 versus p2.
- kepler_euler_h1.png, conservation of energy.
- kepler_euler_h2.png, conservation of angular momentum.

- midpoint_fixed.m, solves an ODE using the midpoint method.
- kepler_midpoint.m, used midpoint_fixed() to solve the Kepler problem.
- kepler_midpoint_plot.png, a plot of t versus p1, p2, q1, q2.
- kepler_midpoint_phase.png, a phase plane plot of p1 versus p2.
- kepler_midpoint_h1.png, conservation of energy.
- kepler_midpoint_h2.png, conservation of angular momentum.

- kepler_ode45.m, used ode45() to solve the Kepler problem.
- kepler_ode45_plot.png, a plot of t versus p1, p2, q1, q2.
- kepler_ode45_phase.png, a phase plane plot of p1 versus p2.
- kepler_ode45_h1.png, conservation of energy.
- kepler_ode45_h2.png, conservation of angular momentum.