GPU-accelerated N-Body particle simulator with visualizer
### A GPU-accelerated N-body particle simulator and animator
Create complex particle simulations the easy way: a high-level package for designing and simulating large-scale particle interactions. Let nBody do the hard work for you!
Easy to use – and fast – nBody can simulate:
- Gravitational acceleration
- Coulomb interactions
- Particle collisions
nBody is highly optimized:
- GPU acceleration available via [`cupy`](https://cupy.chainer.org “cuPY”)
- CPU multiprocessing with [`numpy`](https://numpy.org/ “NumPy”)
- Energy conservation via the velocity-verlet algorithm
Animated [`matplotlib`](https://matplotlib.org/ “Matplotlib”) visualizations included for 2-D simulations. 3-D animations are also supported through the use of [`vpython`](https://vpython.org/ “VPython”).
Using `numpy` arrays, you will need:
- An initial position array `x` with shape `(N,p)`
- N is the number of particles
- p is the number of dimensions
- An initial velocity array `v` with shape `(N,p)`
- An array of masses `m```with shape ```(N,)`
- An array of charges `q` with shape `(N,)`
- An array of radii `r` with shape `(N,)`
A possible configuration is as follows:
import numpy as np x = np.random.normal(0, 10, (N,p)) # Positions v = np.random.normal(0, 2, (N,p)) # Velocities m = np.random.normal(8, 1, (N, )) # Masses q = np.random.normal(0, 1E-6, (N, )) # Charges r = np.random.normal(1, 0.1, (N, )) # Radii
m[m < 0] = np.abs(m[m < 0]) m[m == 0] = 1E-3
Next, pass these arrays in the given order to the `spheres` function, so as to create a new instance `S` of class `System` with the above conditions.
from nbody import * S = spheres(x, v, m, q, r)
After selecting a simulation runtime `T` and (optional) time-step `dt`, use the `solve` method to calculate the particles’ trajectories.
If the system is 2-D such that `p == 2`, an animation can be created and saved to file; here, the filename `quick_start` is chosen, and will produce a file `animations/quick_start.mp4`.
If the system is 3-D such that `p == 3`, animations can be created but not saved to file – simply omit the string argument shown above, and no warnings will be raised.
Once the `solve` method has been called, it is also possible to save the `System` instance to file; in this case, the data will be saved to a directory `saved/quick_start`.
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