python-nbody

N-body simulator in Python

Simulates gravity between celestial bodies. Uses pygame.

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Command-line arguments

python3 python-nbody.py <WIDTH (optional)> <HEIGHT (optional)> <GRAVITATIONAL CONSTANT (optional)> <TRAIL QUALITY (optional)>

WIDTH - optional (default: 1920) - width of the simulator window

HEIGHT - optional (default: 1080) - height of the simulator window

GRAVITATIONAL CONSTANT - optional (default: 1) - sets the value of G—how strong the gravity is between objects

TRAIL QUALITY - optional (default: 10000) - the number of coordinates that will be saved in each object's trail

The formulae

for body in bodies:
    if body.index != self.index:
        dist_x = abs(body.x - self.x)
        dist_y = abs(body.y - self.y)
        dist = math.sqrt(dist_x ** 2 + dist_y ** 2)

        force = G * (body.mass * self.mass / dist ** 2)

        if not self.stationary:
            self.xvel += (body.x - self.x) / dist * force
            self.yvel += (body.y - self.y) / dist * force

        if not body.stationary:
            body.xvel += (self.x - body.x) / dist * force
            body.yvel += (self.y - body.y) / dist * force