Add multi-state neuron models

[jasperalbers]

This PR proposes to add multi-state neuron models used for studying infection dynamics as described in [1]. Building on the implementation of the binary neuron, these models can be in either of three states: S, I or R.
In particular, three new neuron models are added:

• the SIS neuron that can only be in states S or I where transitions from I to S are allowed
• the SIR neuron that can be in all three states S, I or R where transitions from R to S are forbidden
• the SIRS neuron that can be in all three states S, I or R where transitions from R back to S are allowed
  Their implementation closely follows the example set by the binary neuron.

If these models are deemed interesting enough to be added to the NEST simulator, we (@jasperalbers and @ClaudiaMer) would also add the corresponding documentation and tests. Here, we would be grateful for a pointer to a minimal example of what is required for both documentation and tests if that exists.

[1] https://arxiv.org/abs/2312.14851

[jessica-mitchell]

Hi @jasperalbers @ClaudiaMer thanks for your contribution!

In terms of documentation:

• any new model should include a a userdoc segment in the header file (section starts with BeginUserDocs and ends with EndUserDocs). See an example here.
  Note that the section headings need to stay the same, and you should add a list of 'keywords' on the first line as you'll see in other model files. These are used to index the models.
• To build and preview HTML output of documentation locally see here.
• We also usually want a PyNEST example script that explains how the new model is used.

Note that we use reStructured text markup

Please don't hesitate to ask if you have further questions :)

[jasperalbers]

Thanks for the information regarding the documentation! Before we start to work on this we would like to get confirmation on whether these models will be integrated into NEST or not, just to avoid unnecessary work in case they are deemed as not useful.

[jessica-mitchell]

Thanks for the information regarding the documentation! Before we start to work on this we would like to get confirmation on whether these models will be integrated into NEST or not, just to avoid unnecessary work in case they are deemed as not useful.

Makes sense, I would suggest that the quickest way would be to join the open NEST developer meeting on Monday @ 1130 and we can add it to the agenda :)

[jasperalbers]

We decided in this week's meeting that the models should be added to NEST. I will mark this PR as a draft until we supply the necessary tests and documentation, at which point it will be ready for review.

[github-actions]

Pull request automatically marked stale!