# Question with DiffEqBiological

**URL:** <https://discourse.julialang.org/t/question-with-diffeqbiological/30119>\
**Category:** General Usage\
**Tags:** question\
**Created:** [October 21, 2019, 2:08am UTC](https://discourse.julialang.org/t/question-with-diffeqbiological/30119 "2019-10-21T02:08:14Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![David\_Wang](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/david_wang/32/10913_2.png) [@David\_Wang](https://discourse.julialang.org/u/David_Wang)\
**Post date:** [October 21, 2019, 2:08am UTC](https://discourse.julialang.org/t/question-with-diffeqbiological/30119/1 "2019-10-21T02:08:14Z")

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Hi all,

I have been running into a problem with the DiffEqBiological package. The following code always returns “ERROR: LoadError: Base.Meta.ParseError(”+1")":

rn = @reaction\_network begin  
1.0, 0 → M  
end

whereas the following code works fine:  
rn = @reaction\_network begin  
1.0, 0 → M  
1.0, M → 0  
end

Does anyone happen to know the cause of the error?

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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:** [October 21, 2019, 4:12am UTC](https://discourse.julialang.org/t/question-with-diffeqbiological/30119/2 "2019-10-21T04:12:27Z")

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That’s 🤷‍♂️ . Please open an issue.

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**Author:** ![isaacsas](https://avatars.discourse-cdn.com/v4/letter/i/f6c823/32.png) [@isaacsas](https://discourse.julialang.org/u/isaacsas)\
**Post date:** [October 21, 2019, 12:04pm UTC](https://discourse.julialang.org/t/question-with-diffeqbiological/30119/3 "2019-10-21T12:04:57Z")

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> [@David\_Wang](#):
>
> rn = @reaction\_network begin  
> 1.0, 0 → M  
> end

This works fine for me on the latest release. Have you tried updating?

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**Author:** ![David\_Wang](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/david_wang/32/10913_2.png) [@David\_Wang](https://discourse.julialang.org/u/David_Wang)\
**Post date:** [October 21, 2019, 1:01pm UTC](https://discourse.julialang.org/t/question-with-diffeqbiological/30119/4 "2019-10-21T13:01:51Z")

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Thanks @isaacsas. I tried Pkg.update(“DifferentialEquations”) and Pkg.update(“DiffEqBiological”) , which does not update the package. Finally, I tried Pkg.update(), which updates all the packages and solves the problem.

This is exciting, but why does “Pkg.update(“DifferentialEquations”)” not work?

@ChrisRackauckas I will open an issue about updating packages.

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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:** [October 21, 2019, 1:07pm UTC](https://discourse.julialang.org/t/question-with-diffeqbiological/30119/5 "2019-10-21T13:07:09Z")

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It’s probably because you had a dependency that needed updating as well. That shouldn’t get an issue.

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<div class="post-metadata">

**Author:** ![David\_Wang](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/david_wang/32/10913_2.png) [@David\_Wang](https://discourse.julialang.org/u/David_Wang)\
**Post date:** [October 21, 2019, 1:11pm UTC](https://discourse.julialang.org/t/question-with-diffeqbiological/30119/6 "2019-10-21T13:11:40Z")

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Thanks @ChrisRackauckas. Is there any chance Julia could update the dependencies during the update of an individual package?

I have already created an issue… If I do not hear anything, I will close the issue.  
[https://github.com/JuliaLang/julia/issues/33618](https://github.com/JuliaLang/julia/issues/33618)