What is the mean of the "Total"?

[Piney]

Hi,everyone. I would like to ask a simple question.
This is an extract of the OUTCAR file for an Ni calculation


FORCE on cell =-STRESS in cart. coord. units (eV/reduce length):
Direction X Y Z XY YZ ZX
-------------------------------------------------------------------------------------
Alpha Z 92.00 92.00 92.00
Ewald -129.83 -129.83 -129.83 0.00 0.00 0.00
............
Kinetic 77.37 80.17 76.93 1.43 -1.34 -1.14
-------------------------------------------------------------------------------------
Total 0.01 0.01 0.01 0.00 0.00 0.00
in kB 0.75 0.75 0.75 0.00 0.00 0.00
external pressure = 0.75kB Pullay stress = 0.00 kB

firstly, I don´t really understand the mean of the "Total" . Is it the total forces ? secondly,when total <>0.00 and external pressure <>0.00, is the result of calculation reliable?


Thank you very much!

[admin]

1) "total" denotes the total stress.
2) yes, of course, the external pressure may be either negative or positive, leading to a compression or expansion of the cell in the next relaxation step.