A simple Barnes-Hut simulation of n-body gravity, written in Rust and exposed as a Python library via pyo3. Uses a multipole expansion up to the quadrupole moment. Supports evaluation of both potentials and accelerations.
Download the right wheel from Releases for your platform (for example, if you have Python 3.11 on 64-bit Windows, you want the cp311-none-win_amd64 one) and install it with pip install path_to_the_wheel.whl. Alternatively, see Building on building a wheel from source.
Compile with maturin build --release, then install the resulting wheel via pip install.
from fastgravity import GravitySystem
import numpy as np
# generate a random arrangement of masses:
n = 20
pts = np.random.random((n, 2))
pts[:,0]/=10
masses = np.random.normal(1, 0.2, n)
# create the simulation object:
tree = GravitySystem(pts, masses)
# grid to evaluate things at:
from_x, to_x, nx = -1.1, 1.1, 300
from_y, to_y, ny = -1.1, 1.1, 300
x = np.linspace(from_x, to_x, nx)
y = np.linspace(from_y, to_y, ny)
grid = np.stack(np.meshgrid(x,y, indexing="ij"), axis=2).reshape(-1, 2)
# evaluate potentials:
potentials = np.array(tree.evaluate_potential(grid)).reshape((len(x),) * 2)
# evaluate accelerations:
fields = np.stack(tree.evaluate_gravity(grid)).reshape((nx, ny, 2))- Stub file for types
- Parallelization?
- Higher moments?