NPT Ensemble

LAMMPS LAMMPS Beginners
1

Dear Sir,
If I want to maintain the pressure of system 1 atm, then which one is the correct code, (A) or (B) :
Basically, my doubt is whether Pstart should be zero or 1 ?
(A) fix 1 all npt temp 300 300 50 iso 0 1 1000

(B) fix 1 all npt temp 300 300 50 iso 1 1 1000

2

For the system sizes available to MD simulations and the corresponding pressure fluctuations, there is no significant difference between these two options.

3

Thanks, Sir