2025 05 19 Open NEST Developer Video Conference

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Agenda

1. Welcome
2. Review of NEST User Mailing List
3. Project team round
4. In-depth discussion
   • pip install nest[server,docs]
   • List ring-buffer (Charl)

Mailing list

• https://nest-simulator.org/mailinglist

Project team round

Here we discuss topics that need broader attention, for example questions that came up but are outside a single project's scope, larger planned changes/PRs that affect all teams or pending work that is blocked by external factors.

Go to the Project boards.

In-depth discussion

List ring-buffer

• list of ring-buffers (vector of vectors)

• inhibitory vs. excitatory spikes in different ports, or coming into the same port (then routed via sign of the weight)

• using weight on same port causes an issue: buffering needed between event handling on incoming spikes and integration, but single input port cannot handle positive and negative inputs in one float value (inhibitory and excitatory time constants may be different, etc.).

• separate handling of inhibitory and excitatory events keeps linear time invariance

• currently differentiation is done in neuron models' handle() function, so models can decide if they need one or two buffers.

• in NESTML split between positive/negative weights is done during update not during handle

  → ⚠️ breaks symmetry between nestml-generated models and hand-written for use in network models for requiring additional port specification: nest.Connect(…, {"receptor_type": …})

• differentiate between splitting to two buffers and the if statement, and the read-out from the buffer.

→ Need to have a mechanism to distinguish between update and handle phase.

• definition of order between events incoming from different threads?
• compatibility on the API level with broader models comes with a performance hit.