compute temp/profile with fix npt

Dear Sirs,

while simulating a Couette flow, I am encountering an issue in using the compute “temp/profile” to subtract from the computed temperature the imposed velocity in a NPT run (fix npt). As previously reported by others for NVT simulations (), after the first step I receive a segmentation fault error. This problem is not encountered in purely serial jobs or substituting NPT with NVT fix.This suggests that the bug (if any) might be something concerning the parallel implementation and the change in boxsize due to the pressure control. Moreover, the compute itself is working properly; only when specifying “fix_modify” to “fix npt” the job crashes. I am using the version “LAMMPS (9 Nov 2011)”. This is the part of the input script generating the error: compute newtemp flow temp/profile 1 0 0 y 10 fix 1 flow npt temp 0.8 0.8 1.0 tchain 4 iso 1.0 1.0 10.0 pchain 4 fix_modify 1 temp newtemp I thank you in advance for your response, Best Regards Alberto

Can you post a (simple) complete input script (with data
file if needed) that shows the crash? I don't recall
the earlier email or if we looked at this, and that script
is quite complex.


Please find attached a modified version of one of LAMMPS example files that shows the crash.
As you will notice, serial execution does not crash, while parallel does.


in.flow.couette (1.07 KB)