# define unit set and class of atomic model units metal atom_style atomic # periodic boundary conditions along all three dimensions boundary p p p # create a supercell with cubic lattice (fcc, bcc, sc, or diamond) # using 10*10*10 conventional (orthogonal) unit cells lattice bcc 2.86649995297 region simbox block 0 10 0 10 0 10 units lattice create_box 1 simbox create_atoms 1 box # specify which KIM Model to use, letting LAMMPS compute the virial/pressure pair_style kim LAMMPSvirial EAM_Dynamo_Ackland_Bacon_Fe__MO_142799717516_004 pair_coeff * * Fe mass 1 55.845 # create initial velocities consistent with the chosen temperature velocity all create 293.15 17 mom yes rot yes # set the time step (in picoseconds) timestep 0.001 # set NPT ensemble for all atoms fix ensemble all npt temp 293.15 293.15 0.1 iso 0.0 0.0 1 # compute the time averages of pressure, temperature, and volume, respectively # ignore the first 5000 timesteps variable myTemp equal temp variable myPress equal press variable myVol equal vol fix avgmyTemp all ave/time 5 20 100 v_myTemp ave running start 5000 fix avgmyPress all ave/time 5 20 100 v_myPress ave running start 5000 fix avgmyVol all ave/time 5 20 100 v_myVol ave running start 5000 variable T equal f_avgmyTemp # cannot use f_avgmyTemp directly in `if' statement variable P equal f_avgmyPress variable V equal f_avgmyVol # set error bounds for temperature and pressure variable T_low equal "293.15 - 0.2" variable T_up equal "293.15 + 0.2" variable P_low equal "0.0 - 0.2" variable P_up equal "0.0 + 0.2" # print to logfile every 1000 timesteps thermo 1000 # Run a simulation for at most 2000*1000 timesteps. At each 1000th time step, check # whether the temperature and volume have converged. If yes, break. label top variable a loop 2000 run 1000 if "${T}>${T_low} && ${T}<${T_up} && ${P}>${P_low} && ${P}<${P_up}" then "jump SELF break" print "flag: Temp = ${T}, Press = ${P}" next a jump SELF top label break # Write final averaged volume to file if temperature and volume have converged; otherwise wirte a # flag to indicate non-convergence. variable myStep equal step if "${myStep} < 2000000" then "print '${V}' file output/vol_T293.15.out" & else "print 'not_converged' file output/vol_T293.15.out" print "ALL DONE"