Is it possible to modify the Intel MKL Fast Poisson Solver for the problem of type:
Δ .[K(u). Δ(u) ] = f
where Δ is the gradient symbol (I didn't find the reverse triangle in the special characters). K(u) is a positive differentiable function dependent on the position. Check the equation here:
The difference between the above equation and the demonstrated Poisson eqn. at MKL Poisson solver page is the term K(u).