# Adding a new function to the PowerModelsAnnex

**URL:** <https://discourse.julialang.org/t/adding-a-new-function-to-the-powermodelsannex/43634>\
**Category:** Optimization (Mathematical)\
**Created:** [July 24, 2020, 8:21pm UTC](https://discourse.julialang.org/t/adding-a-new-function-to-the-powermodelsannex/43634 "2020-07-24T20:21:08Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![ccoffrin](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ccoffrin/32/400_2.png) [@ccoffrin](https://discourse.julialang.org/u/ccoffrin)\
**Post date:** [July 25, 2020, 1:06am UTC](https://discourse.julialang.org/t/adding-a-new-function-to-the-powermodelsannex/43634/2 "2020-07-25T01:06:09Z")

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This seems like a repeat of a question in,

> [@SDP relaxation in PowerModelsAneex](https://discourse.julialang.org/t/sdp-relaxation-in-powermodelsaneex/41898/6):
>
> Hi Dr Coffrin, Thanks for the response. I is the eye matrix, defined in LinearAlgebra package, that you have directly used in your SDP code in PowerModels. You have used LinearAlgebra package in your code. But When I added that package to PowerModelsAnnex I got the above error. My problem is how I can use the LinearAlgebra library in the power model annex. I will definitely look at the Julia package development documents. All the best, Rasoul

I think the core point here is that a lot changed about how package development works between Julia v0.6 and Julia v1.0. You might start by reviewing those changes. For example,

> **[My New Workflow with Julia 1.0](https://erik-engheim.medium.com/my-new-workflow-with-julia-1-0-99711103d97c)**
>
> A practical guide to how you can work with Julia in a practical and effective manner.

[http://abelsiqueira.github.io/blog/package-development-on-julia-10/](http://abelsiqueira.github.io/blog/package-development-on-julia-10/)

It’s fairly similar to how it use to work, just make sure that you are working out of the “dev” directory and that your active environment is setup to use that version of the code.

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