**rk4_test**
a FORTRAN90 code which
calls rk4(), which
implements a simple Runge-Kutta solver for an initial value problem.

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

rk4, a FORTRAN90 code which applies the fourth order Runge-Kutta (RK) algorithm to estimate the solution of an ordinary differential equation (ODE).

- rk4_test.f90, a sample calling program.
- rk4_test.sh, runs all the tests.
- rk4_test.txt, the output file.

- predator_commands.txt, gnuplot commands.
- predator_data.txt, data for gnuplot.
- predator.png, phase plot image.