Advanced Usage with Command-line Options

Apart from the configuration files listed in Overview of the Configuration Files, the behaviour of the Dynamics program can be changed using command line options. We list all possible options with examples here.

Random initial conditions and parameter values

If we want the simulations to start with a random initial value of x, we can issue the following command from the dynamics directory:

python3 run.py --random_ic x

Random values for initial conditions of multiple variables can be given by separating them with a semicolon. For instance, if in the previous example, we want to have random initial conditions for x and y, we can run:

python3 run.py --random_ic x;y

Similar to the initial conditions, if we want to run a simulation with random values of parameters a abd b, we can do so using:

python3 run.py --random_params a;b

Computing local eigenvalues

Dynamics can also compute local eigenvalues for all simulated trajectories. This helps us identify the stable and unstable portions of periodic quasi-periodic and chaotic attractors in addition to the fixed point attractors. To do this, we use the --eigen option:

python3 run.py --eigen

This creates a new file (named eigenvalues.csv by default) which stores the local eigenvalues of the trajectory at each time step.

Changing the output filenames

The output files for the timeseries and the eigenvalues are named timeseries.csv and eigenvalues.csv by default. These filenames can be changed using the --outfile and the --evfile options as shown below:

python3 run.py --outfile out.csv
python3 run.py --evfile ev.csv

Combining the options

All the options described above can be combined in any order and combination. For example:

python3 run.py --eigen --random_ic x;y

randomises the initial values for x and y and also computes the eigenvalues.