# Diffeq\_rd not found

**URL:** <https://discourse.julialang.org/t/diffeq-rd-not-found/91310>\
**Category:** General Usage\
**Created:** [December 6, 2022, 3:29pm UTC](https://discourse.julialang.org/t/diffeq-rd-not-found/91310 "2022-12-06T15:29:08Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![erlebach](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/erlebach/32/12973_2.png) [@erlebach](https://discourse.julialang.org/u/erlebach)\
**Post date:** [December 6, 2022, 3:29pm UTC](https://discourse.julialang.org/t/diffeq-rd-not-found/91310/1 "2022-12-06T15:29:08Z")

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@ChrisRackauckas

Hi Chris,

When using

```julia
  [aae7a2af] DiffEqFlux v1.52.0
  [0c46a032] DifferentialEquations v7.6.0

```

I get an error: `diffeq_rd not found`, when running code found at URL: [model-zoo/ode.jl at da4156b4a9fb0d5907dcb6e21d0e78c72b6122e0 · FluxML/model-zoo · GitHub](https://github.com/FluxML/model-zoo/blob/da4156b4a9fb0d5907dcb6e21d0e78c72b6122e0/other/diffeq/ode.jl)

The function was probably deprecated. What is the proper use now?  
(the function `param` is also not found`)

Thanks for any insights!

```
Gordon

```

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<div class="post-metadata">

**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 6, 2022, 3:41pm UTC](https://discourse.julialang.org/t/diffeq-rd-not-found/91310/2 "2022-12-06T15:41:33Z")

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Just use `solve`. Nothing special is required. The official version of that example is:

[https://docs.sciml.ai/SciMLSensitivity/stable/ode\_fitting/optimization\_ode/](https://docs.sciml.ai/SciMLSensitivity/stable/ode_fitting/optimization_ode/)

BTW, I thought I removed these examples from the model zoo years ago ([Remove from the model-zoo and point README to tutorials by ChrisRackauckas · Pull Request #237 · FluxML/model-zoo · GitHub](https://github.com/FluxML/model-zoo/pull/237)). How did you find that old version? Is there some blog post with an old link?

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**Author:** ![erlebach](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/erlebach/32/12973_2.png) [@erlebach](https://discourse.julialang.org/u/erlebach)\
**Post date:** [December 6, 2022, 4:46pm UTC](https://discourse.julialang.org/t/diffeq-rd-not-found/91310/3 "2022-12-06T16:46:53Z")

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> [@erlebach](#):
>
> [model-zoo/ode.j](https://github.com/FluxML/model-zoo/blob/da4156b4a9fb0d5907dcb6e21d0e78c72b6122e0/other/diffeq/ode.jl)

Thank you, @ChrisRackauckas! I did go to a more recent site shortly after sending out the message. I do not recall how I got to the site, but almost for sure, it via a google search. Removing content is notoriously difficult. You also do not know whether somebody copied the page or not to some other site.

Cheers!

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<div class="post-metadata">

**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 6, 2022, 4:49pm UTC](https://discourse.julialang.org/t/diffeq-rd-not-found/91310/4 "2022-12-06T16:49:21Z")

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Well hopefully this Q&A will now show up in the Google search after someone finds that old code. Cheers!