fd_predator_prey_test

fd_predator_prey_test, a C code which calls fd_predator_prey() to apply the finite difference method to estimate solutions of a pair of ordinary differential equations that model the behavior of a pair of predator and prey populations.

Licensing:

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

Related Data and Programs:

fd_predator_prey, a C code which applies the finite difference method (FDM) to a predator-prey system with time dependence and no spatial variation.

Source Code:

• fd_predator_prey_test.sh, runs all the tests.
• fd_predator_prey_test.txt, the output file.

The program writes out a file of the solution data. The data can be plotted by MATLAB, for instance, using commands like this:

        trf = load ( 'trf_10000.txt' );
        plot ( trf(:,1), trf(:,2), 'g-', trf(:,1), trf(:,3), 'r-' )

        title ( 'A Predator Prey System' );
        xlabel ( 'Time' );
        ylabel ( 'Population' );
      

TRF_100 uses 100 timesteps, which are not enough.

• trf_100.txt, the data.
• trf_100.png, a plot.

TRF_1000 uses 1000 timesteps; the solution does not explode, and seems to show periodicity, except that it is clearly growing.

• trf_1000.txt, a table of the prey and predator values using 1000 steps.
• trf_1000.png, a plot.

TRF_10000 uses 10000 timesteps. The cyclic nature of the solution is clear.

• trf_10000.txt, a table of the prey and predator values using 10000 steps.
• trf_10000.png, a plot.