Defines convection-diffusion-reaction problems
Returns a linearization for the Bratu problem -Delta u +e^u =0.
Generates a convection-diffusion-reaction model problem. Defaults are identity diffusion, right-hand-side equal 1, and Dirichlet zero boundary conditions. Ordinary function are converted into coefficient functions depending on a global coordinate. The first argument can be either a domain or an integer n which is interpreted as the n-dimensional unit cube.
Returns the Newton linearization -Delta u + F'(u) u = F'(u) u - F(u) for the nonlinear problem -Delta u +F(u) =0.
Scalar isotropic diffusion as an ellsys coefficient. value is the diffusion strength, compressed-p designates the storage form.