Dear all users,

Always, Thank you for your kind answers.

Due to the complex letter to understand, I was sorry for that, and now I send the simpler one.

When I performed the NEMD calculation for thermal conductivity calculation for silicon (2x2x2nm^3) ,

I faced a problem that showed me the phrase "ERROR: Fix in variable not computed at compatible time (../variable.cpp:1640)"

I followed the example "in.mp" file in example/KAPPA folder and changed the values a little bit. But it stopped at equilibration2 step or calculation step.

I posted my input script and let me know where is the problem...

Always, Thank you for your kindness.

From. Soon-sung

P.S input script

## sample LAMMPS input script for thermal conductivity by Muller-Plathe method via fix thermal_conductivity

## setup problem

variable T equal 298.13

variable dt equal 0.001 #0.001=1fs

units metal

atom_style atomic

boundary p p s

read_data atoms.dat

velocity all create T 1004 sum no dist gaussian rot yes mom yes
pair\_style tersoff
pair\_coeff \* \* SiHGe\.tersoff Si\(D\)
minimize 1\.0e\-8 1\.0e\-12 1000 10000
timestep {dt}

## 1st equilibration run

fix NVT all nvt temp $T $T 500

thermo 1000000

run 3000000

velocity all scale $T

unfix NVT

## 2nd equilibration run

reset_timestep 0

thermo 2000000

compute ke all ke/atom

variable temp atom c_ke

fix NVT all nve

compute layers all chunk/atom bin/1d z 0.5 0.25 units reduced

fix 2 all ave/chunk 2 500000 1000000 layers v_temp file profile.mp

fix 3 all thermal/conductivity 100 z 4 swap 1

variable Tdiff equal f_2[11][3]-f_2[1][3]

thermo_style custom step temp epair etotal f_3 v_Tdiff

run 4000000

## thermal conductivity calculation

## reset fix thermal/conductivity to zero energy accumulation

thermo 1000000

fix 3 all thermal/conductivity 100 z 4

fix ave all ave/time 2 500000 1000000 v_Tdiff ave running

thermo_style custom step temp epair etotal f_3 v_Tdiff f_ave

run 2000000