Hi,
I just added a new nonlinear solver for the steady command: it is a trust-region solver, available under solve_algo=4 (it replaces the old value of that option, which was a Newton without the correction for singular Jacobian; I had added that variant a long time ago, and it was neither really useful nor theoretically grounded).
The implementation of the solver is essentially the fsolve.m from Octave, that I have adapted for MATLAB compatibility and that I have also slightly simplified.
I am wondering whether we may want to use this new solver as the default, since trust-region algorithms are nowadays considered to be the state of the art for solving systems of nonlinear equations. Said otherwise, should we modify the default to be solve_algo=4 instead of solve_algo=2 ?
Since I have not thoroughly tested the new solver, a first step would probably to test it on various relevant examples.
Best,