Function zoom::particle::gravitate_radius_squared

pub fn gravitate_radius_squared<V, D, T1: ?Sized, T2: ?Sized>(lhs: &T1, rhs: &T2, radius_squared: D, magnitude: D) where T1: PhysicsParticle<V, D>, T2: PhysicsParticle<V, D>, V: Vector<D>, D: Float

This is the same as the radius function, but the sum of the radii squared is passed separately to avoid overhead.