Maybe add another smarter runtime method called model that will go through the model types and return the one that is there

Closing in

Also a method to give more helpful error methods for EOS-specific methods

Everything seems pretty promising aside from the mutant, which requires additional thought. How can we store the mutant in AllowedModels

Very fast in C++ (less than a microsecond for 4 outputs in the Jacobian), but 10 microseconds in Python for 2. Need to find a way to make it closer to original speed. Perhaps pass in a buffer to be populated.  That should allow the copy to be avoided. It must be the Eigen arrays that are so slow.

See #21

It avoids a quiet copies throughout the interface

Add conversion routines for ideal-gas Helmholtz terms from CoolProp format

Yet another forceeval

Switch TP VLE solver to Powell's dogleg method. Might be just a little bit more reliable, but hard to tell.

Add routine for TP flash for binary mixture, to solve for molar concentrations (and therefore mole fractions)