# [lammps-users] about compute heat/flux command

1. Is compute heat/flux command only used for NVE ensemble?

2. variable J equal c_flux[1]/vol:
Is the “vol” always the total volumn of the box?

3. Is the following simulation system can use “compute myStress all stress/atom virial” for the entire box?
compute myKE all ke/atom
compute myPE all pe/atom
compute myStress all stress/atom virial
compute flux all heat/flux myKE myPE myStress

┌────┐
│ NVT │ 3 T_low=constant
├────┤
│ NVE │ 2
├────┤
│ NVT │ 1 T_High=constant
└────┘
The ensembles for group 1, 2 and 3 are NVT, NVE and NVT respectively.
The temperature for group 1 and 3 are constant.

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1. Is compute heat/flux command only used for NVE ensemble?
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If you thermostat you are adding/subtracting energy, so that doesn’t make sense
with what compute heat/flux is doing.

2. variable J equal c_flux[1]/vol:
Is the “vol” always the total volumn of the box
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it is in that formula - you can use whatever formula you like

3. Is the following simulation system can use “compute myStress all stress/atom virial” for the entire box?
compute myKE all ke/atom
compute myPE all pe/atom
compute myStress all stress/atom virial
compute flux all heat/flux myKE myPE myStress

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I don’t understand this question. If you use group all, then
you’re computing quanties for all atoms in the box.