Eikonal equation

Your variatonal form is not correct, as you are missing a sqrt.

Solving the unsmoothed version of the eikonal equations are notoriously difficult. Usually, one smooths the equation by adding a Laplace operator.
See:

and
https://fenicsproject.org/qa/1446/distance-to-boundary/

Me and collaborators are working on a new mixed method/variational form for solving the Eikonal equation. I will post it here once we have a preprint out.