**ozone_ode_test**,
an Octave code which
calls ozone_ode(), which
defines a stiff system of four ordinary differential equations (ODE) that
simulate the daily variation in atmospheric ozone concentration.

This problem apparently was too difficult for the Octave versions of ode23() or ode45(), or for my version of midpoint(). Instead, I had to switch to the lsode() solver, which in turn uses a nonstandard arrangement for the arguments.

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

ozone_ode, an Octave code which defines a stiff system of four ordinary differential equations (ODE) that simulate the daily variation in atmospheric ozone concentration.

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

- ozone_lsode.m, uses lsode() to solve the ODE.
- ozone_lsode_y1.png, displays y1.
- ozone_lsode_y2.png, displays y2.
- ozone_lsode_y3.png, displays y3.
- ozone_lsode_y4.png, displays y4.
- ozone_lsode_conservation.png, displays the conservation quantity.