2d_Ising.jl

2d_Ising.jl

using Pkg
Pkg.add("Plots")
Pkg.add("ProgressMeter")

previous_GKSwstype = get(ENV, "GKSwstype", "")
ENV["GKSwstype"] = "100"

using Plots, ProgressMeter, Random, Printf
N(i, m) = ifelse(i == 1, m, i-1)
P(i, m) = ifelse(i == m, m, i+1)
function ising2d!(s, skip, prob, rng)
    (m, n) = size(s)
    for _ in 1:skip, j in 1:n, i in 1:m
        sij = s[i,j]
        k = sij * (s[N(i, m), j] + s[P(i, m), j] + s[i, N(j, n)] + s[i, P(j, n)])
        s[i, j] = ifelse(rand(rng) < prob[k+5], -sij, sij)
    end
end
n, skip, L = 200, 1, 500
β = log(1 + √2)/2
prob = ((exp(-2β*k) for k in -4:4)...,);
rng = Random.default_rng();
s = rand(rng, Int8[-1,1], n, n);
prog = Progress(L, 0);
anim = @animate for t in 0:L
    heatmap(s; size=(240, 260), colorbar=false, frame=false, axis=false, ticks=false)
    title!("$(n)×$(n) × $(skip) skip × $(@sprintf("%3d", t))"; titlefontsize=11)
    ising2d!(s, skip, prob, rng)
    next!(prog)
end
gif(anim, "2d_Ising.gif")

For the setting ENV["GKSwstype"] = 100 or ENV["GKSwstype"] = "null", see https://discourse.julialang.org/t/deactivate-plot-display-to-avoid-need-for-x-server/19359/2