I have a non-linear form of the Poisson equation where the "diffusion"
coefficient depends on the derivatives of the state variable (see image).
There are no Dirichlet-type boundary conditions (i.e. no ebcs) so I really need to specify a good initial guess at the solution.
My questions are:
it doesn't seem like initial guesses can be directly passed to the nls.newton solver as an argument (though they are an argument of the subroutine __call__). 2) In what form should the initial guess vector/array be written? Can a function be passed? Do numerical values have be be specified at the mesh nodes?
Thanks for any help on this matter.