GROMACS version: 2020.1

GROMACS modification: No

I am trying to understand the calculation of viscosity using combinations of different ensembles and different methods.

For non equilibrium MD calculation using periodic perturbation of external shear, which is the best ensemble that can be used? My values appear similar for NVT and NPT but vary significantly with NVE ensemble. I am assuming that NVE gives the best results because of no influence of thermostat and barostat and all of the change in energy due to the applied shear is captured in calculation of viscosity. Is my reasoning appropriate? Can someone direct me to a research paper with the right way of calculating viscosity using Non equilibrium MD?

Finally, which is the best way to calculate viscosity optimising computational time and accuracy of results?