My goal is to solve lorenz equations and plot them as it shows in the figure. I have two different initial conditions [x0, 1, 0] and x0= 0 then x0 =1* 10^-5 the two values of rho are ρ= 14 and ρ=28. I wrote this code in julia but I’m getting errors says “Got exception outside of a @test UndefVarError: u not defined lorenz_solver(x₀::Float64, ρ::Int64)” any idea on how to solve this issue.

```
using DifferentialEquations
using Plots
using LaTeXStrings
function lorenz!(t,p,u,du)
x, y ,z = u
sigma, ρ, beta = p
du[1] = sigma*(u[2]-u[1])
du[2] = u[1]*(ρ-u[3]) - u[2]
du[3] = u[1]*u[2] - beta*u[3]
end
function lorenz_solver(x₀, ρ)
u[0] = [x₀, 1, 0]
tspan = (0.0, 100.0)
p = [10, ρ, 8/3]
x₀, ρ = params
prob = ODEProblem(lorenz!, u0, tspan, params)
sol = solve(prob)
return sol
#return the ODESolution
end
function lorenz_plot()
params = [0, 14]
sol1 = solve(prob)
params = [1 * 10^-5 , 14]
sol2 = solve(prob)
p1 = plot(t, [sol1 sol2], ylabel=L"x1, x2", title="ρ = 14")
p2 = plot(abs(sol1 - sol2), xlabel=L"t", ylabel=L"|x1 - x2|")
p3 = plot(sol1, vars = (1,2,3), xlabel=L"x1", ylabel=L"z1")
params = [0, 28]
sol3= solve(prob)
params = [1 * 10^-5, 28]
sol4 = solve(prob)
p4 = plot(t, [sol3 sol4], title="ρ = 28")
p5 = plot(abs(sol3 - sol4), xlabel=L"t")
p6 = plot(sol3, vars = (1,2,3), xlabel=L"x1")
link=:all
plot(p1, p2, p3, p4, p5, p6, layout(3, 2))
#return the final plot
end
export lorenz_solver, lorenz_plot
end
```