N-Body Dynamics Simulator

SIMULATES THE DYNAMICS OF N MASSIVE BODIES UNDER THE GRAVITATIONAL FORCE MASSES ARE SIMULATED AS POINT MASSES AND PROPAGATED FORWARD IN TIME VIA KICK-DRIFT-KICK DISCRETE TIME PROPAGATION (SEE n_body.simulate() BELOW)

AUTHOR: KYLE MORGENSTEIN ([email protected])

See www.kylemorgenstein.com for more

DATE: 11/28/2020

USAGE DOCUMENTATION

this example generates the movie file listed in the repository under "n_body_trials/*" using: G = 1 view_lim = 5 save = 100 run_time = 100

set initial conditions

init_conds = np.array([ [100,0,0,0,0,0,0], [1,0,-3,0,3,4,0], [1,0,3,0,-3,-4,0], [1,-3,0,0,0,-4,0], [1,3,0,0,0,4,0] ])

set experiment runtime

run_time = 10 [seconds]

initialize simulation class

sim = n_body(init_conds,run_time)

run simulation

sim.simulate()

plot the results

sets framerate for saved simulation - set to 0 to playback only

save = 100

automatically adjusts view to keep all masses in view

autoscroll = False

better to just generate the video and watch it at full speed

replay = False

scales view to [-view_lim, view_lim]

view_lim = 20

sim.plot(save,autoscroll,replay,view_lim)

saved simulations take up ~2-20 MB depedning on run_time generating the simulated video will take ~1-15 minutes depending on the length of simulation and your hardware

WAIT UNTIL THE CODE FINISHES RUNNING COMPLETLY BEFORE TRYING TO OPEN THE VIDEO FILE

OTHER HELPFUL USAGE TIPS

if you don'y care about selecting parameters, the entire simulation can be run inline as

n = 3

sim = n_body(3).run()

or

randomly generates 2-5 masses

sim = n_body().run()

The parameters you should focus on changing are:

• initial_conds - be creative with your initial conditions!

• self.G - strength of gravity

• self.S - damping on collisions

• run_time - simulation length

• scale - scales maximum radius of uniform random distribution for random poisition generation

• save - frames per second of simulation output video

• view_lim - axes ranges for visualization

DEV NOTES:

• visualizations are mapped from X-Y-Z space to the X-Y plane for visualization

• visualizations are shown in the Center-of-Mass (COM) frame

• everything should work but I wrote this in three days so pls don't roast me on Twitter for my hacky code thx <3

• lmk if something is broken though, thx!!!

• have fun :)