NVE Ensemble

[FG-TUM]

Is your feature request related to a problem? Please describe. Currently, there is no intuitive way to set up an NVE ensemble. (See below how to do it currently)

Describe the solution you'd like

• [ ] In the input XML set ensemble to NVE and that is it.
• [ ] Thermostats that change the energy in the system should then either be disabled or the simulation should stop with an error about conflicting input.

~Describe alternatives you've considered~

Additional context

• 100% conservation of energy will not happen due to numerical imprecision.

• Currently (a2c2482) to set up an NVE ensemble configure your XML with the following:

  • Set ensemble to NVT
  • Choose thermostat type "TemperatureControl"
  • In the control tag of the thermostat, set start to an iteration number that will not be reached.

[HomesGH]

I am not sure if your proposed way works in all cases as there are still some explosion heuristics (and maybe other legacy thermostats) enabled which influence the velocity of the particles. I stumbled upon this when doing a simulation in the two phase region. Here is a quick and dirty plot of several quantities sampled over time. The "explosions" were detected at steps ~1100 and ~5100: You can see the jumps in velocity and total energy. The colors just indicate different sampling methods.