# After using DynamicalSystems, I don't have "lyapunovx"

**URL:** https://discourse.julialang.org/t/after-using-dynamicalsystems-i-dont-have-lyapunovx/99533
**Category:** New to Julia
**Tags:** package, dynamical-systems
**Created:** [May 28, 2023, 11:07pm UTC](https://discourse.julialang.org/t/after-using-dynamicalsystems-i-dont-have-lyapunovx/99533 "2023-05-28T23:07:08Z")
**Posts on this page:** 3
**Page:** 1

<div class="post-metadata">

### Author: ![axelwang](https://avatars.discourse-cdn.com/v4/letter/a/6a8cbe/32.png) [@axelwang](https://discourse.julialang.org/u/axelwang)
#### Post date: [May 28, 2023, 11:07pm UTC](https://discourse.julialang.org/t/after-using-dynamicalsystems-i-dont-have-lyapunovx/99533/1 "2023-05-28T23:07:08Z")

</div>

Hey, I just set up my Julia environment (1.9.0) and installed some packages. I tried

```julia
using DynamicalSystems
lorenz = ContinuousDynamicalSystem(lorenz_rule, u₀, p₀)
lyapunovs(lorenz,50)

```

and get the error:

```julia
UndefVarError: `lyapunovs` not defined

Stacktrace:
 [1] top-level scope
   @ In[37]:1

```

However, I have access to `lyapunov` for the maximal Lyapunov Exponent.  
I have `"DynamicalSystems" => v"3.0.0"`.

This seems very strange to me. Can anyone offer some help? Thanks!

---

<div class="post-metadata">

### Author: ![empet](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/empet/32/221303_2.png) [@empet](https://discourse.julialang.org/u/empet)
#### Post date: [May 29, 2023, 5:58am UTC](https://discourse.julialang.org/t/after-using-dynamicalsystems-i-dont-have-lyapunovx/99533/2 "2023-05-29T05:58:47Z")

</div>

`lyapunovs` was the function defined in older versions of DynamicalSystems.jl. If you have installed the version 3.0.0, then call it as `lyapunovspectrum`:

```julia
function lorenz_rule(u, p, t)
    σ = p[1]; ρ = p[2]; β = p[3]
    du1 = σ*(u[2]-u[1])
    du2 = u[1]*(ρ-u[3]) - u[2]
    du3 = u[1]*u[2] - β*u[3]
    return SVector{3}(du1, du2, du3)
end

lrz = CoupledODEs(lorenz_rule, [0,10.0,1.0], [10, 32, 8/3])
lp = lyapunovspectrum(lrz, 10000; Δt = 0.1)

```

---

<div class="post-metadata">

### Author: ![axelwang](https://avatars.discourse-cdn.com/v4/letter/a/6a8cbe/32.png) [@axelwang](https://discourse.julialang.org/u/axelwang)
#### Post date: [May 29, 2023, 9:40pm UTC](https://discourse.julialang.org/t/after-using-dynamicalsystems-i-dont-have-lyapunovx/99533/3 "2023-05-29T21:40:16Z")

</div>

I see. Thank you so much!