[sfepy] question about non-linear solver

Dear all,

I have some questions about the internal behaviour of Sfepy that I hope you can answer me.

• What is it the convergence criterion of the non-linear Newton solver?
• When modelling a Nearly incompressible Mooney-Rivlin hyperelastic material, like the example shown here: http://sfepy.org/doc-devel/examples/large_deformation/hyperelastic.html, how the nearly-incompressibility constraint is stabilised?

Thank you very much in advance.