label atomi variable atomi loop 1 $(atoms) variable vx equal $(vx[v_atomi]) variable vy equal $(vy[v_atomi]) variable vz equal $(vz[v_atomi]) print "DEBUG ${timestep}: Velocity BEFORE for atom ${atomi} is ${vx} ${vy} ${vz}" variable fx equal v_fx_${atomi} variable fy equal v_fy_${atomi} variable fz equal v_fz_${atomi} print "DEBUG ${timestep}: Force for atom ${atomi} is ${fx} ${fy} ${fz}" variable vx equal $(v_vx+v_fx*0.5*v_dt) # mass = 1 variable vy equal $(v_vy+v_fy*0.5*v_dt) # mass = 1 variable vz equal $(v_vz+v_fz*0.5*v_dt) # mass = 1 print "DEBUG ${timestep}: Velocity AFTER for atom ${atomi} is ${vx} ${vy} ${vz}" group atomi id ${atomi} velocity atomi set ${vx} ${vy} ${vz} units box group atomi delete next atomi jump half_kick.in atomi