Question regarding compute heat/flux

Hi, All

I was using the compute heat/flux commands on different groups within an equilibrium bulk crystalline system(with periodic boundary conditions)

here is the commands that I used, where “surface” + “ inner” group equals group “all”

compute innerKE inner ke/atom
compute innerPE inner pe/atom
compute innerStress inner stress/atom NULL virial
compute innerflux inner heat/flux innerKE innerPE innerStress

compute surfaceKE surface ke/atom
compute surfacePE surface pe/atom
compute surfaceStress surface stress/atom NULL virial
compute surfaceflux surface heat/flux surfaceKE surfacePE surfaceStress

compute allKE all ke/atom
compute allPE all pe/atom
compute allStress all stress/atom NULL virial
compute allflux all heat/flux allKE allPE allStress

Then I outputted c_innerflux, c_surfaceflux, c_allflux to files and it turns out that c_innerflux, c_surfaceflux is much larger than c_allflux, and the first two autocorrelation functions don’t decay, just oscillate.

I was expecting c_innerflux + c_surfaceflux = c_allflux but it is not the case here. Has anyone encountered similar issue before? or am I doing anything wrong?


Maybe Reese has an idea.