Compute ti


I would like to calculate free energy change of my LJ system using
compute ti command.

I couldnt figure out what i should have put to the variables defines
in the documentation page.
    pair style args = v_name1 v_name2
                 v_name1 = variable with name1 that is energy scale
factor and function of lambda
                 v_name2 = variable with name2 that is derivative of
v_name1 with respect to lambda

the part of the code related is here..

pair_coeff 1 3 lj/cut 0.8 0.75

variable scale1 equal ramp(0.8,0.0)
variable lj equal v_scale1
variable dlj equal 0.8/50000
fix Eps all adapt 100 pair lj/cut epsilon 1 3 v_scale1
compute Thermoint all ti lj/cut v_lj v_dlj
fix FreeEng all ave/time 100 10 1000 c_Thermoint ave one file 0FreeEng.profile

thermo_style custom step c_Thermoint
thermo_modify norm no
run 50000

I'll let Sai respond to this Q ...