Function greens_function_3d 

pub fn greens_function_3d(r: f64, k: f64) -> Complex64

3D Helmholtz Green’s function G = exp(ikr)/(4πr)

Arguments

• r - Distance |x - y|
• k - Wave number

Returns

Complex value exp(ikr)/(4πr)

Example

use math_wave::special::helmholtz::greens_function_3d;

let g = greens_function_3d(1.0, 2.0);
// |G| = 1/(4.0 * std::f64::consts::PI) for any k
assert!((g.norm() - 1.0/(4.0 * std::f64::consts::PI)).abs() < 1e-10);