function lorentz()
    dt = 0.01
    n = 2000000
    a = 10.
    b = 28.
    c = 8/3
    x = zeros(n)
    y = zeros(n)
    z = zeros(n)
    x[1] = 0
    y[1] = 1.
    z[1] = 1.05
    for i = 1:n-1
        x[i+1] = x[i] + dt * (- a * x[i] + a * y[i] )
        y[i+1] = y[i] + dt * (- x[i] * z[i] + b * x[i] - y[i] )
        z[i+1] = z[i] + dt * (x[i] * y[i] - c * z[i] )
    end
end
@time lorentz()