Struct nbody_barnes_hut::barnes_hut_3d::OctTree

pub struct OctTree { /* fields omitted */ }

Implementations

impl OctTree

pub fn new(particles: &[&Particle3D], theta: f64) -> Self

Constructs a tree from an array of particles. Also takes in theta, which - roughly speaking - describes how accurate the simulation should be. For more information, check here.

"Whether a node is or isn't sufficiently far away from a body, depends on the quotient s / d, where s is the width of the region represented by the internal node, and d is the distance between the body and the node's center of mass. The node is sufficiently far away when this ratio is smaller than a threshold value θ. The parameter θ determines the accuracy of the simulation; larger values of θ increase the speed of the simulation but decreases its accuracy. If θ = 0, no internal node is treated as a single body and the algorithm degenerates to a direct-sum algorithm."

A value of 0.5 is quite common.

pub fn update_theta(&mut self, theta: f64)

pub fn calc_forces_on_particle<T: Copy, F: Fn(f64, f64, Vector3D, T) -> Vector3D + Copy>(
    &self,
    particle_position: Vector3D,
    other_attributes: T,
    calc: F
) -> Vector3D

Calculates the force on a particle.

Takes in the position of the particle, any attributes you wish to pass in, and a closure

The closure will need to take in the distance squared, the mass, the distance vector, and the other attributes which you passed in. It will need to return a force (or acceleration) vector Please note that the distance vector is not normalized! It is your responsibility to do this.