I want to make clear about how FreeFEM deal with the variable coefficient while assembling.
Here is an example:
$$ a(u, v) = \int c \nabla u \cdot \nabla v $$
where c = \cos (x) is a given function.
Is there an explicit step to interpolate c to a high order FE function first?
Or it is to apply numerical integral directly, namely c is evaluated at the quadrature points?