# Where can I find documentation for instream()
**URL:** https://discourse.julialang.org/t/where-can-i-find-documentation-for-instream/83355
**Category:** Modelling & Simulations
**Tags:** modelingtoolkit
**Created:** [June 26, 2022, 12:18pm UTC](https://discourse.julialang.org/t/where-can-i-find-documentation-for-instream/83355 "2022-06-26T12:18:53Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@dodoplus](https://discourse.julialang.org/u/dodoplus)
#### Post date: [June 26, 2022, 12:18pm UTC](https://discourse.julialang.org/t/where-can-i-find-documentation-for-instream/83355/1 "2022-06-26T12:18:53Z")
It seems that MTK has an `instream()` operator.
I think this is inspired by Modelica’s similarly named operator.
Are there any examples using `instream()`? I could only find a single test using it (in state\_selection.jl).
Thanks,
DD
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### Author:  [@ohmsweetohm1](https://discourse.julialang.org/u/ohmsweetohm1)
#### Post date: [June 26, 2022, 2:08pm UTC](https://discourse.julialang.org/t/where-can-i-find-documentation-for-instream/83355/2 "2022-06-26T14:08:46Z")
Not really an example
>
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### Author:  [@dodoplus](https://discourse.julialang.org/u/dodoplus)
#### Post date: [June 26, 2022, 2:29pm UTC](https://discourse.julialang.org/t/where-can-i-find-documentation-for-instream/83355/3 "2022-06-26T14:29:07Z")
Yeah - that’s the one I found. Not very illuminating.
I more-or-less understand Modelica `inStream`. However, there they also have an `actualStream` operator which is missing here. I _think_ `actualStream` can be implemented via `ifelse`, so I’m not sure we need it.
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### Author:  [@dodoplus](https://discourse.julialang.org/u/dodoplus)
#### Post date: [June 26, 2022, 2:30pm UTC](https://discourse.julialang.org/t/where-can-i-find-documentation-for-instream/83355/4 "2022-06-26T14:30:36Z")
PS:
[https://github.com/SciML/ModelingToolkit.jl/issues/1666](https://github.com/SciML/ModelingToolkit.jl/issues/1666)