Error using pde.Equati​onModel/so​lveStation​aryNonline​ar (line 104) Stepsize too small.

I am solving this system of PDEs with diritchlet boundry conditions and It does not converge, and gives me this error.

Error using pde.EquationModel/solveStationaryNonlinear (line 104)
Stepsize too small.

Do you know how can I solve it.

Answer 1

[Alan Weiss]

Are you giving nonzero initial conditions for the solution? It looks like your equations might be singular where the solution gradient is zero, so your initial conditions should avoid those areas.

Just a guess,

Alan Weiss

MATLAB mathematical toolbox documentation

[Kaveh Gharibi]

Actually the initial conditions are non zero but my PDE c coefficients have a denumerator that can be close to zero and I added a small number 10^-12 to avoid singularity.

[Kaveh Gharibi]

The problem is it doesn't converge. The residual doesn't go to 0.0001. It is around 0.1.

[Kaveh Gharibi]

I found out that I made a mistake in finding the coefficients. you need to be careful when converting everything to divergence form.