Dear all!

The problem reported below is finally gone due to the merge of

Happy model copying ;-)

On 09.05.22 01:35, Barna Zajzon wrote:

Hi Jochen,

the changes in the PR do solve the problem, thanks so much! Not sure whether the response should've gone the the whole mailing list, so just replying to you.


On 5/4/22 2:13 PM, Jochen Martin Eppler wrote:

Dear Barna,

sorry, this somehow slipped our attention for way too long.

Can you please check if the code in solves the problem for you?


On 19.02.22 01:32, Barna Zajzon wrote:

Dear all,

I'm encountering the following error

    python: /home/zbarni/software/packages/nest/znest/nestkernel/model_manager.h:296: nest::Model* nest::ModelManager::get_node_model(nest::index) const: Assertion `m < node_models_.size()' failed.

when using the following code:

nest.SetKernelStatus({'total_num_virtual_procs': 16, 'local_num_threads': 16})

for i in range(16):
    nest.CopyModel('MyNeuron', f'MyNeuron_{i}')

neurons = nest.Create('MyNeuron_0', 2)
nest.Connect(neurons, neurons)

The script uses a neuron model that I wrote in C++ and is loaded without errors. The error is thrown upon nest.Connect(), and goes away if I create the neurons using `MyNeuron` and not `MyNeuron_x` (copied) or if the #vp and #threads is 1. I've used the model with NEST 2.20.0 without problems, but I'd like to port the code to the latest version. Maybe I'm just missing something new functionality/API related to CopyModel and multiprocessing - have there been any critical changes in the model requirements?

Any help would be greatly appreciated.


Barna Zajzon
PhD Candidate 

Computation in Neural Circuits Group
Institute of Neuroscience and Medicine (INM-6)
Institute for Advanced Simulation (IAS-6)
JARA Institute Brain Structure-Function Relationships (INM-10)
Jülich Research Centre and JARA
52425 Jülich, Germany
Dr. Jochen Martin Eppler
Phone: +49(2461)61-96653
Simulation Laboratory Neuroscience
Jülich Supercomputing Centre
Institute for Advanced Simulation

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