Describe the bug
If eps_r is shape (N,) then the fields solved are shape (N,1)

Either:

• disallow 1-D eps_r arrays
  Or:
• keep track of eps_r shape and reshape the fields to match.

Any help in developing the following essential unit operations would be greatly appreciated:

• Compressor
• Turbine
• Fenske-Gilliland-Underwood shortcut column (added 3/22/2020)
• Rigorous heat exchanger for heat integration (added 6/6/2020)
• Multi-component distillation models (preferably MESH equation based)
• Kinetic fermentation models
• ~Centrifuge modeled by liquid-liquid equi

Currently, values for the llh, gradient, the computed trajectories of states and observables, or the sensitivities are checked in unit tests.
Unfortunately, some bugs, such as incorrect Jacobians or switched minus signs in the Newton solver, will not necessarily affect those quantities. However, they will substantially impact solver performance, by causing way too many steps to be taken. Hence, w