# NetworkDynamics.jl Kuramoto oscillators tutorial example: definition sum\_coupling!()

**URL:** <https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129>\
**Category:** General Usage\
**Tags:** question, package\
**Created:** [May 14, 2021, 7:42am UTC](https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129 "2021-05-14T07:42:20Z")\
**Posts on this page:** 6\
**Page:** 1

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**Author:** ![ziolai](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ziolai/32/23422_2.png) [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Post date:** [May 14, 2021, 7:42am UTC](https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129/1 "2021-05-14T07:42:20Z")

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How is the function sum\_couling!() on the page [https://pik-icon.github.io/NetworkDynamics.jl/dev/heterogeneous\_system/](https://pik-icon.github.io/NetworkDynamics.jl/dev/heterogeneous_system/) defined?

Thx! Domenico.

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**Author:** ![ziolai](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ziolai/32/23422_2.png) [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Post date:** [May 20, 2021, 7:17am UTC](https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129/2 "2021-05-20T07:17:56Z")

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Any ideas?

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**Author:** ![zekeriya.sari](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/zekeriya.sari/32/13695_2.png) [@zekeriya.sari](https://discourse.julialang.org/u/zekeriya.sari)\
**Post date:** [May 20, 2021, 7:48am UTC](https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129/3 "2021-05-20T07:48:37Z")

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> <https://github.com/PIK-ICoNe/NetworkDynamics.jl/blob/81afc50d17d67398612e75363bb8d101778cb56c/src/Utilities.jl#L162-L165>

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**Author:** ![ziolai](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ziolai/32/23422_2.png) [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Post date:** [May 20, 2021, 7:51am UTC](https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129/4 "2021-05-20T07:51:20Z")

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Thank you!

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**Author:** ![nilshg](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/nilshg/32/2283_2.png) [@nilshg](https://discourse.julialang.org/u/nilshg)\
**Post date:** [May 20, 2021, 7:52am UTC](https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129/5 "2021-05-20T07:52:12Z")

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Here’s how you find out:

```julia
julia> using NetworkDynamics, OrdinaryDiffEq, LightGraphs # as I don't know which package it is from!

julia> methods(sum_coupling!)
# 1 method for generic function "sum_coupling!":
[1] sum_coupling!(e_sum, dst_edges) in NetworkDynamics.Utilities at ...\.julia\packages\NetworkDynamics\r6g0k\src\Utilities.jl:166

```

which points to the definition here:

> <https://github.com/PIK-ICoNe/NetworkDynamics.jl/blob/main/src/Utilities.jl#L166>

For these purposes, `@which` and `@edit` are also useful, although they require an actual function call with arguments to work out which method is called. In this case that’s easy as the function only has one method which is untyped, so you can call it with any arguments:

```julia
julia> @which sum_coupling!(rand(10), rand(10))
sum_coupling!(e_sum, dst_edges) in NetworkDynamics.Utilities at C:\Users\ngudat\.julia\packages\NetworkDynamics\r6g0k\src\Utilities.jl:166

```

and

```julia
julia> @edit sum_coupling!(rand(10), rand(10))
sum_coupling!(e_sum, dst_edges) in NetworkDynamics.Utilities at C:\Users\ngudat\.julia\packages\NetworkDynamics\r6g0k\src\Utilities.jl:166

```

should take you straight to the definition on your local machine in a text editor of your choice.

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**Author:** ![ziolai](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/ziolai/32/23422_2.png) [@ziolai](https://discourse.julialang.org/u/ziolai)\
**Post date:** [May 20, 2021, 7:54am UTC](https://discourse.julialang.org/t/networkdynamics-jl-kuramoto-oscillators-tutorial-example-definition-sum-coupling/61129/6 "2021-05-20T07:54:06Z")

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Right! Thx.