Units of g_k in the code

[bas-rustenburg]

The titration state weight is assumed to be in units of molar energy: https://github.com/choderalab/protons/blob/master/protons/driver.py#L515

If you store the numbers obtained directly from calibration, this would give you beta^2 * g_k. I overlooked this when setting up the abl-imatinib calculations. https://github.com/choderalab/protons/blob/master/protons/driver.py#L1836

Maybe we want to make sure that beta is appropriately removed from the results spat out by the calibration, so that the current API works when you store the same numbers in the ffxml file.

Or, we could adjust the code to only takes a unitless reference energy for each state (beta * gK being the standard), to avoid any confusion with unit conversion.

[jchodera]

Or, we could adjust the code to only takes a unitless reference energy for each state (beta * gK being the standard), to avoid any confusion with unit conversion.

We only ever want to store g_k and energies as unitless quantities to avoid exactly the issues you are seeing.