Running a Simulation

This is a quick guide to running your first custom simulation. After completing the installation and correcting any FFMpeg issues, try running with the default settings

from simulation.pm import SimPM
SimPM('default.mp4')

This will run a simulation with 100 particles on a 30^3 grid for 1000 frames, and save the video to the file ‘default.mp4’.

Next, try running the same code with the correlation function and power spectrum plotting enabled,

SimPM('default_ps.mp4', show_ps=True)

Now, all that’s left is to experiment! Remember that the time complexity scales with number of particles N and number of grid points G as O(N + G log[G]), so pushing N to high values of N ~ 4000 can still be completed in reasonable times. For example, you might try

SimPM('highn.mp4', n_particles=4000)
SimPM('longtime.mp4', n_particles=100, n_frames=3000)
SimPM('finergrid.mp4', n_particles=1000, n_grid=50, n_frames=500)

Using BasicSim with these higher number of particles results in structure formation in the simulation, which is detectable in the power spectrum and correlation functions.

Another parameter that can be changed is the gravity factor. This scales the strength of gravity, and modifying it will change structure formation.

# For gravity twice as strong
SimPM('stronggrav.mp4', n_particles=4000, gravity_factor=2)