# Detect convergence in a simulation using the relative change in
# moments. This demonstrates the "history" option.
# ---------------------------------------------------------------------

# create pure copper system
units metal
lattice fcc 3.75
region box block 0 6 0 6 0 6
create_box 2 box

timestep 0.002
create_atoms 1 box

pair_style eam/alloy
pair_coeff * * AlCu.eam.alloy Cu Al

# Initialize to a high temperature, then cool in npt ensemble
velocity all create 1000.0 6567345
fix 1 all npt temp 300.0 300.0 $(500*dt) iso 0.0 0.0 $(100*dt)

# compute mean and stddev over the preceding 5000 steps, every 20 steps
variable toteng equal "etotal"
fix 2 all ave/moments 10 500 200 v_toteng mean stddev history 5

# Convergence criterion: stddev is smaller than threshold and was previously larger
# This avoids issues with system oscillations in the order of the averaging window
# that would otherwise lead to "nodes" in the stddev.
variable conv equal "(f_2[2] < 2.0) && (f_2[2][1] < f_2[2][5])"
fix 3 all halt 100 v_conv == 1

thermo_style custom step temp press etotal f_2[*][1] f_2[*][5] v_conv

thermo 100
run 10000