Dear Nest users,

I’ve been trying to disconnect a population of neurons that is recurrently connected to itself. This works for a simple connection rule, like conn_spec=‘all_to_all’, but it fails for a more complex rule, like, conn_spec={'rule': 'pairwise_bernoulli', 'p': 1.0, 'allow_autapses': False}. When connecting two different populations to each other, disconnecting works with this rule. However, when connecting to the same population, the output of nest.GetConnections states that there are no connections, and calling nest.Disconnect() results in an error:

nest.lib.hl_api_exceptions.NESTErrors.The connection does not exist: The connection does not exist in SLI function Disconnect_g_g_D_D: Deletion of connection is not possible.

I’ve added a minimal example reproducing the issue in the attachment, Nest version is 3.8.0-post0.dev0.

Btw, I’ve gotten this issue in a network model that was developed for Nest 3.5, so it seemed to work in that version.

Best regards, Willem

---------------------- Dr. Willem Wybo, group leader Peter Grünberg Institute 15 - Neuromorphic Software Ecosystems Forschungszentrum Jülich www.fz-juelich.de/pgi/PGI-15 ———————————

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