Scale masses for PIMD

[tbraeckevelt]

To perform thermodynamic integration between the classical and quantum partition functions, mulitple path integral molecular dynamics simulations should be performed for which the masses of the atoms are different than their standard mass.

Would it be possible to give an optional scale_masses argument to psiflow.sampling.sample() so that these PIMD simulations can be performed?

[svandenhaute]

Yes, very good suggestion. This is a TODO for 4.1

[tbraeckevelt]

Because the masses indicate a different kind of PI state, it makes more sense to use masses as an argument for Walker and instead use nbeads as an argument for sample (because the number of beads is a quantity that defines how this PI state is sampled, i.e., this number needs to be high enough that the state is properly sampled).