Hello Abderrahim El Khou,

You do not really have to run the tutorial notebooks through jupyter, you can just use jupyter as a viewer for the information and follow along using the video recording.

If you do not have Jupyter installed then github's online viewer also works. e.g.:

https://github.com/EinsteinToolkit/jupyter-et/blob/master/tutorial-server/no...

you can see the content that goes into the individual files in the cells that start with %writefile and the remainder of that cell is the content written to the file.

SimpleWave.m is an example on how to use Kranc to generate a thorn. If you intent to use Kranc then it is a good first example to start with.

Many more complex thorns are generated using Kranc eg the WeylScal4 thorn, the mclachlan thorns and the EinsteinExact thorns.

If you would rather write a thorn using C/C++ or Fortran then Yosef's lecture on how to create a heat equation / wave equation may be your best starting point.

Or you can use one of the very old examples of how to implement a wave equation, like the attached one. There's not video recording of it though.

Yours, Roland

[CAUTION: Non-UBC Email]

I found one problem here, i don't work with Juypter so the language is confusing me a little bit so i start following the example that you give me at the first "the SimpleWave.m" my question here is it necessarily to take the same process for any create of other thorns or the is just for the simple wave, if no what is the solution please. Thank you a lot sir.

On Tue, Jan 27, 2026 at 8:36 PM Roland Haas rhaas@mail.ubc.ca wrote:

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Hello Abderrahim El Khou,

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if it possible i want a tutorial how to write my own thorn if it is thank you a lot

Kranc has an example (the SimpleWave.m one) in:

http://kranccode.org/documentation.html

though note that it uses the `Bin/kranc` wrapper so that all required Mathematica packages are being found.

There are a number of recorded tutorials on how to write a new thorn that you can find in:

https://www.youtube.com/playlist?list=PLRxi-yB7cTGc6_RtPA8g3qm2XOGfmvkoH

for example:

https://youtu.be/PcuPhODh34o?si=tAaM54bRT584N7Qo

There's also the CreatingANewThorn-*.ipyb notebooks in:

https://github.com/EinsteinToolkit/jupyter-et/tree/master/tutorial-server/no...

which are actually used in the recording above.

Yours, Roland

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Yours, Roland