# DifferentialEquations.jl OrwenZen5 not defined

**URL:** <https://discourse.julialang.org/t/differentialequations-jl-orwenzen5-not-defined/8041>\
**Category:** General Usage\
**Tags:** question, diffeq\
**Created:** [December 28, 2017, 4:05pm UTC](https://discourse.julialang.org/t/differentialequations-jl-orwenzen5-not-defined/8041 "2017-12-28T16:05:43Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Ajoo](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@Ajoo](https://discourse.julialang.org/u/Ajoo)\
**Post date:** [December 28, 2017, 4:05pm UTC](https://discourse.julialang.org/t/differentialequations-jl-orwenzen5-not-defined/8041/1 "2017-12-28T16:05:43Z")

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Hi. I recently started using Julia. I’m currently trying to simulate a Mackey-Glass chaotic time-series with DifferentialEquations.jl.

The package documentation advises the use of a solver OrwenZen5() for solving delay differential equations. But trying to use this I find that neither OrwenZen5 nor OrwenZen3 are defined. I am able to use other solvers with the MethodOfSteps such as those recommended for standard ODEs. I don’t know if these solvers were removed but the documentation wasn’t updated or what happened…

PS: I have little experience with delay differential equations, I was simply trying to reproduce a paper that used this time-series as a benchmark for some estimation algorithms. As such I would greatly appreciate any tips you might have on what the most appropriate solver is.

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**Author:** ![ChrisRackauckas](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/chrisrackauckas/32/77_2.png) [@ChrisRackauckas](https://discourse.julialang.org/u/ChrisRackauckas)\
**Post date:** [December 28, 2017, 4:20pm UTC](https://discourse.julialang.org/t/differentialequations-jl-orwenzen5-not-defined/8041/2 "2017-12-28T16:20:51Z")

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Can you post your `Pkg.status("DifferentialEquations"); Pkg.status("OrdinaryDiffEq")`? My guess is you’re on an old version, and this will tell me what version you have.

> [@Ajoo](#):
>
> The package documentation advises the use of a solver OrwenZen5() for solving delay differential equations.

It used to, but that’s no longer true. I would suggest `Tsit5()` or `Vern6()` depending on the tolerance you need. Of course, we should get you an up to date version first though.

> [@Ajoo](#):
>
> I’m currently trying to simulate a Mackey-Glass chaotic time-series with DifferentialEquations.jl.

BTW, this equation is one of the ones we use to benchmark the solvers.

[http://nbviewer.jupyter.org/github/JuliaDiffEq/DiffEqBenchmarks.jl/blob/master/DDE/Mackey%20and%20Glass.ipynb](http://nbviewer.jupyter.org/github/JuliaDiffEq/DiffEqBenchmarks.jl/blob/master/DDE/Mackey%20and%20Glass.ipynb)

and it’s defined here:

[https://github.com/JuliaDiffEq/DiffEqProblemLibrary.jl/blob/master/src/dde\_premade\_problems.jl#L363-L373](https://github.com/JuliaDiffEq/DiffEqProblemLibrary.jl/blob/master/src/dde_premade_problems.jl#L363-L373)

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<div class="post-metadata">

**Author:** ![Ajoo](https://avatars.discourse-cdn.com/v4/letter/a/ebca7d/32.png) [@Ajoo](https://discourse.julialang.org/u/Ajoo)\
**Post date:** [December 28, 2017, 5:44pm UTC](https://discourse.julialang.org/t/differentialequations-jl-orwenzen5-not-defined/8041/3 "2017-12-28T17:44:39Z")

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Wow, thanks for the prompt response.

I went back to the documentation at [http://docs.juliadiffeq.org/latest/tutorials/dde\_example.html](http://docs.juliadiffeq.org/latest/tutorials/dde_example.html) at it does recommend Tsit5 or Vern6 now 😛 I dunno if it was changed in the meanwhile or maybe I was looking at a cached version…

I had already tried using Tsit5 before and it worked great, I was just worried about whether that integrator wasn’t the most appropriate.

Looking at the notebook helped me figure out the problem though. It is OwrenZen5 and not OrwenZen5. I think I might have copied it wrong from the tutorial.

Thanks a lot for your help 🙂