This is part of https://coderefinery.github.io/research-software-engineering/.

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• Python (tested with Python 3.12)

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The code is written to accept command-line arguments to specify the number of planets and the number of time steps.

We first generate starting data:

$ python generate-data.py --num-planets 10 --output-file initial.csv

The generated file (initial.csv) could look like this:

px,py,pz,vx,vy,vz,mass
-46.88,-42.51,88.33,-0.86,-0.18,0.55,6.70
-5.29,17.09,-96.13,0.66,0.45,-0.17,3.51
83.53,-92.83,-68.77,-0.26,-0.48,0.24,6.84
-36.31,25.48,64.16,0.85,0.75,-0.56,1.53
-68.38,-17.21,-97.07,0.60,0.26,0.69,6.63
-48.37,-48.74,3.92,-0.92,-0.33,-0.93,8.60
40.53,-75.50,44.18,-0.62,-0.31,-0.53,8.04
-27.21,10.78,-78.82,-0.09,-0.55,-0.03,5.35
88.42,-74.95,-45.85,0.81,0.68,0.56,5.36
39.09,53.12,-59.54,-0.54,0.56,0.07,8.98

Then we can simulate their motion (in this case for 20 steps):

$ python simulate.py --num-steps 20 \
                     --input-file initial.csv \
                     --output-file final.csv

The --output-file (final.csv) is again a CSV file (comma-separated values) and contains the final positions of all planets.

It is possible to run on multiple cores and to animate the result. Here is an example with 100 planets:

$ python generate-data.py --num-planets 100 --output-file initial.csv

$ python simulate.py --num-steps 50 \
                     --input-file initial.csv \
                     --output-file final.csv \
                     --trajectories-file trajectories.npz \
                     --num-cores 8

$ python animate.py --initial-file initial.csv \
                    --trajectories-file trajectories.npz \
                    --output-file animation.mp4

• Tutorials covering key functionality
• Reference documentation (e.g. API) covering all functionality

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