Source: wikibot/eikonal-equation
= Eikonal equation
{wiki=Eikonal_equation}
The Eikonal equation is a fundamental equation in the field of geometric optics and wave propagation. It is typically expressed in the form: \\\[ |\\nabla u(x)| = n(x) \\\] where \\( u(x) \\) is the wavefront (or phase) function, \\( \\nabla u \\) denotes the gradient of this function, and \\( n(x) \\) represents the refractive index at point \\( x \\) in space.