[lammps-users] Default pressure value

LAMMPS LAMMPS Mailing List Mirror
1

I found this on the lammps website

“Thermodynamic output, which can be setup via the thermo_style command, often includes pressure values. As explained on the page for the thermo_style command, the default pressure is setup by the thermo command itself. It is NOT the pressure associated with any barostatting fix you have defined or with any compute you have defined that calculates a pressure. The doc pages for the barostatting fixes explain the ID of the pressure compute they create. Thus if you want to view these pressures, you need to specify them explicitly via the thermo_style custom command. Or you can use the thermo_modify command to re-define what pressure compute is used for default thermodynamic output.”

So, if i am using fix npt, the pressure value in the output file with keyword press is not the one which the fix npt gives or what it is.?

2

Unless you have done something unusual, the pressure that fix npt is calculating is probably the same
as what thermodynamic output is calculation and outputting. If you want to check, then
add a keyword to your thermo_style command that also outputs the value for the compute that
fix npt creates. If you read the doc page for fix npt, it tells you what the ID of that compute is.
That’s what the paragraph above is saying.

Steve