Dear all,
I am trying to calculate the center of mass of the molecules present in my system during the lammps run and want to output the same to a file at some interval of time. I am using
compute com/molecule command to do that and then accessing them through variable assignment. Finally I am trying to print them to a file using fix print command. But an error occurs while doing so. The error is “ERROR: Compute used in variable between runs is not current”. I have tried to use running 0 step before accessing the compute through the
variables. Still the same problem. Below is the script I am using. Any comments will be highly appreciated.
units real
atom_style full
boundary p p p
pair_style lj/class2/coul/cut 13.3 13.3
pair_modify mix sixthpower
dielectric 1.0
special_bonds lj 0.0 0.0 1.0 coul 0.0 0.0 1.0
bond_style class2
angle_style class2
dihedral_style class2
read_data molecule.data
group MOVING molecule > 1
timestep 1.0 #femto seconds
velocity MOVING create 300 2309483 mom yes rot yes dist gaussian
fix NVE MOVING nve
fix TEMPRESCALE MOVING temp/rescale 1 300 300 0.0 1.0
compute TEMP_C4 MOVING temp
thermo 10
thermo_style custom step c_TEMP_C4 press vol ke pe etotal ecoul
thermo_modify flush yes
compute COM_C4 MOVING com/molecule
run 0
variable comx equal c_COM_C4[1][1]
variable comy equal c_COM_C4[1][2]
variable comz equal c_COM_C4[1][3]
fix comvalues MOVING print 10 {comx} {comy} ${comz} com.dat
run 2000
kind regards
bhaskar