ValueErrors and convergence failures in equilibrium #63
Description
In a database shared privately, equilibrium either fails with a ValueError: Invalid gradient_term or it fails to converge, depending on the passed conditions. One case of each is in the following comments. These use the latest pycalphad, ad385a0.
I have reproduced these results after removing magnetic parameters from the database. I also tried over a range of temperatures and compositions, all of which produced either a ValueError or convergence failure.