How to get seperate virial contributions

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1

Hi all, I am using jan 2009 version of LAMMPS for the simulations. I am pulling a periodic box of polymer in one direction with NPT ensemble for 100000 steps, I got a 6 components of stresses in log file. LAMMPS calculating the stresses by using virial formula with all components like pair,bond,angle,dihedral,improper so on,right. Now i want to get the stresses due to pair, stresses due to bond, stresses due to angle, so on separately. For this i have used commands like

compute peratomstress all stress/atom
compute globalstress all reduce sum c_peratomstress[1] c_peratomstress[2] c_peratomstress[3]
thermo_style custom c_globalstress[1] c_globalstress[2] c_globalstress[3]

But these are not matching with log file values pxx pyy pzz even after dividing with volume.
i want to know what is the problem ?

thanks,
grn

2

The compute pressure and compute stress/atom commands both
have additional arguments (pair, bond, etc) which allow you
to get components of the virial. You can define these
commands multiple times and output these quantities in
various ways.

Steve