# Support **URL:** https://brian.discourse.group/c/support/5.md [Latest](https://brian.discourse.group/latest.md) · [Categories](https://brian.discourse.group/categories.md) · [Tags](https://brian.discourse.group/tags.md) --- ## [About the Support category](https://brian.discourse.group/t/about-the-support-category/13)
**Author:** [@dan](https://brian.discourse.group/u/dan)\ **Replies:** 0\ **Last updated:** [13 August 2020 14:06 UTC](https://brian.discourse.group/t/about-the-support-category/13 "2020-08-13T14:06:13Z")
This category is for asking questions of the community and developers when something isn’t working right. Before you post here, please create a minimal script that reproduces the problem. It is unlikely anyone will read… --- ## [ValueError: Equations of type 'parameter' cannot have a flag 'linked', only the following flags are allowed: \['constant', 'shared'\]](https://brian.discourse.group/t/valueerror-equations-of-type-parameter-cannot-have-a-flag-linked-only-the-following-flags-are-allowed-constant-shared/1373)
**Author:** [@paulbrodersen](https://brian.discourse.group/u/paulbrodersen)\ **Replies:** 8\ **Last updated:** [7 September 2026 12:42 UTC](https://brian.discourse.group/t/valueerror-equations-of-type-parameter-cannot-have-a-flag-linked-only-the-following-flags-are-allowed-constant-shared/1373 "2026-09-07T12:42:46Z")
Description of problem I am trying to implement the homeostatic inhibitory STDP rule used in Zenke (2015) in Brian2. The rule uses a symmetric STDP kernel that is modulated in size and sign by a global factor G, which c… --- ## [NeuronGroup Class can i use rk4 like this](https://brian.discourse.group/t/neurongroup-class-can-i-use-rk4-like-this/1564)
**Author:** [@KotsiosKotsiou](https://brian.discourse.group/u/KotsiosKotsiou)\ **Replies:** 1\ **Last updated:** [16 July 2026 15:15 UTC](https://brian.discourse.group/t/neurongroup-class-can-i-use-rk4-like-this/1564 "2026-07-16T15:15:26Z")
Description of problem Minimal code to reproduce problem can i use the class with rk4 like this P = NeuronGroup(1, model=eqs, threshold=‘v\>-20\*mV’,refractory=3\*ms, method=rk4) --- ## [Memory error insufficient disc space](https://brian.discourse.group/t/memory-error-insufficient-disc-space/1471)
**Author:** [@MitchG\_HunterCollege](https://brian.discourse.group/u/MitchG_HunterCollege)\ **Replies:** 8\ **Last updated:** [6 June 2026 14:40 UTC](https://brian.discourse.group/t/memory-error-insufficient-disc-space/1471 "2026-06-06T14:40:04Z")
I am using a PC laptop with ~200 GB free space for running network simulations, and I am encountering a memory limitation problem. The model of 2000 PYR neurons and 20 PVN neurons will successfully run for 5 seconds wit… --- ## [Should a computer with faster processor execute simulation faster?](https://brian.discourse.group/t/should-a-computer-with-faster-processor-execute-simulation-faster/1531)
**Author:** [@MitchG\_HunterCollege](https://brian.discourse.group/u/MitchG_HunterCollege)\ **Replies:** 1\ **Last updated:** [23 February 2026 16:36 UTC](https://brian.discourse.group/t/should-a-computer-with-faster-processor-execute-simulation-faster/1531 "2026-02-23T16:36:43Z")
12-second simulation of my neural network on my HP laptop with 1.7GHz processor had taken ~28min to execute. Thinking that a “faster” computer would perform better, I have tried buying another HP laptop with purported 5… --- ## [Implemented of Wacongne et al. 2012 with using Brian2, wanna contrubute to the Brian documentation](https://brian.discourse.group/t/implemented-of-wacongne-et-al-2012-with-using-brian2-wanna-contrubute-to-the-brian-documentation/1526)
**Author:** [@cagataydisli](https://brian.discourse.group/u/cagataydisli)\ **Replies:** 0\ **Last updated:** [7 February 2026 19:35 UTC](https://brian.discourse.group/t/implemented-of-wacongne-et-al-2012-with-using-brian2-wanna-contrubute-to-the-brian-documentation/1526 "2026-02-07T19:35:05Z")
Hi, We have implemented Wacongne et al. (2012) paper with using Brian2. We thought we could contribute to the brian2 documentation by adding this to the examples/from\_papers section. We have allready made pull-request … --- ## [Non-standalone restoring states from saved states of standalone mode](https://brian.discourse.group/t/non-standalone-restoring-states-from-saved-states-of-standalone-mode/1523)
**Author:** [@Shreshthallbestno1](https://brian.discourse.group/u/Shreshthallbestno1)\ **Replies:** 4\ **Last updated:** [2 February 2026 23:27 UTC](https://brian.discourse.group/t/non-standalone-restoring-states-from-saved-states-of-standalone-mode/1523 "2026-02-02T23:27:29Z")
Description of problem One cannot use store() or restore() in the standalone modes. I want to restore the saved states from standalone mode in a cython initiation of network, for quick runs/ testing and not necessarily l… --- ## [Trouble Making Synapse with AMPA and NMDA receptors](https://brian.discourse.group/t/trouble-making-synapse-with-ampa-and-nmda-receptors/1520)
**Author:** [@MitchG\_HunterCollege](https://brian.discourse.group/u/MitchG_HunterCollege)\ **Replies:** 2\ **Last updated:** [13 January 2026 15:35 UTC](https://brian.discourse.group/t/trouble-making-synapse-with-ampa-and-nmda-receptors/1520 "2026-01-13T15:35:31Z")
Description of problem I am working with coding for an excitatory AMPAR-like synapses (see AMPA synapse and target neuron eqs below). It works fine. I also generated an excitatory NMDAR-like synapses (see NMDA synapse … --- ## [Long compiling time for a complex network](https://brian.discourse.group/t/long-compiling-time-for-a-complex-network/1516)
**Author:** [@sivanni](https://brian.discourse.group/u/sivanni)\ **Replies:** 2\ **Last updated:** [11 December 2025 19:54 UTC](https://brian.discourse.group/t/long-compiling-time-for-a-complex-network/1516 "2025-12-11T19:54:29Z")
First, cordial thanks for updating the brian2cuda to use latest brian2! Description of problem We are going after plasticity in multi-object network, and were hit apparently by brian2cuda slow compiling time. This issue… --- ## [Change the input and update weigths between runs](https://brian.discourse.group/t/change-the-input-and-update-weigths-between-runs/1509)
**Author:** [@dmytr0](https://brian.discourse.group/u/dmytr0)\ **Replies:** 11\ **Last updated:** [27 November 2025 14:44 UTC](https://brian.discourse.group/t/change-the-input-and-update-weigths-between-runs/1509 "2025-11-27T14:44:14Z")
Description of problem I created spiking neural network and i have train dataLoader from which i want to take input for my network. Also after run i wnat to update weights offline and run next example with updated weight… --- ## [Saving and restoring in cpp\_standalone with multiple runs](https://brian.discourse.group/t/saving-and-restoring-in-cpp-standalone-with-multiple-runs/1506)
**Author:** [@ccluri](https://brian.discourse.group/u/ccluri)\ **Replies:** 3\ **Last updated:** [19 November 2025 18:26 UTC](https://brian.discourse.group/t/saving-and-restoring-in-cpp-standalone-with-multiple-runs/1506 "2025-11-19T18:26:21Z")
Description of problem Thank you for Brian2 and for your support. I have to store and restore my simulations starting from 10k seconds. The C++ code is substantially faster for me, and I would like to use it instead of … --- ## [Project compilation failed (error code: 2)](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507)
**Author:** [@danielmk](https://brian.discourse.group/u/danielmk)\ **Replies:** 4\ **Last updated:** [16 November 2025 02:57 UTC](https://brian.discourse.group/t/project-compilation-failed-error-code-2/1507 "2025-11-16T02:57:14Z")
Description of problem My cpp\_standalone compilation capabilities broke. Not sure what I did to break it. Maybe it was the Windows11 update? I get the error RuntimeError: Project compilation failed (error code: 2), consi… --- ## [Default test " brian2cuda.example\_run()" throws error after installation?](https://brian.discourse.group/t/default-test-brian2cuda-example-run-throws-error-after-installation/1504)
**Author:** [@alexyz](https://brian.discourse.group/u/alexyz)\ **Replies:** 2\ **Last updated:** [3 November 2025 10:15 UTC](https://brian.discourse.group/t/default-test-brian2cuda-example-run-throws-error-after-installation/1504 "2025-11-03T10:15:23Z")
Description of problem I’m trying to install Brian2CUDA as mentioned in Installation — Brian2CUDA 1.0.0 documentation , but the default installation throws an error on my Ubuntu WSL on Windows 11, and I can’t get even a … --- ## [Is there a way to update (summed) variables only on events?](https://brian.discourse.group/t/is-there-a-way-to-update-summed-variables-only-on-events/1503)
**Author:** [@kjohnsen](https://brian.discourse.group/u/kjohnsen)\ **Replies:** 2\ **Last updated:** [31 October 2025 11:45 UTC](https://brian.discourse.group/t/is-there-a-way-to-update-summed-variables-only-on-events/1503 "2025-10-31T11:45:13Z")
I have expensive summed variable code running on synapses that I only need at spike time. I’ve tried leaving the variable undefined in model and updating it in pre, but I get \`ValueError: Equations of type 'parameter' c… --- ## [Easy way to sum over all values in a group?](https://brian.discourse.group/t/easy-way-to-sum-over-all-values-in-a-group/1502)
**Author:** [@kjohnsen](https://brian.discourse.group/u/kjohnsen)\ **Replies:** 1\ **Last updated:** [29 October 2025 10:48 UTC](https://brian.discourse.group/t/easy-way-to-sum-over-all-values-in-a-group/1502 "2025-10-29T10:48:49Z")
Description of problem I have a complex weight tuning procedure that does linear algebra on the weight matrix, which is a pain to implement with pure Brian since I need to introduce a new set of synapses for every matrix… --- ## [Can we go beyond store/restore to more easily reuse the network?](https://brian.discourse.group/t/can-we-go-beyond-store-restore-to-more-easily-reuse-the-network/1374)
**Author:** [@kjohnsen](https://brian.discourse.group/u/kjohnsen)\ **Replies:** 11\ **Last updated:** [28 October 2025 11:59 UTC](https://brian.discourse.group/t/can-we-go-beyond-store-restore-to-more-easily-reuse-the-network/1374 "2025-10-28T11:59:09Z")
Description of problem I want to save the entire network (setup and states) to reuse across interpreter sessions. I wish I could pickle/dill the whole thing, but this runs into problems with weakref and generated code. I… --- ## [Multiple calls to (stateful) user defined functions](https://brian.discourse.group/t/multiple-calls-to-stateful-user-defined-functions/406)
**Author:** [@schmitts](https://brian.discourse.group/u/schmitts)\ **Replies:** 5\ **Last updated:** [24 October 2025 14:19 UTC](https://brian.discourse.group/t/multiple-calls-to-stateful-user-defined-functions/406 "2025-10-24T14:19:47Z")
Hi! I have the following #!/usr/bin/env python3 from brian2 import \* @check\_units(x=1, result=1) def heaviside(x): return (x \> 0).astype(int) neuron = NeuronGroup(1, "dv/dt = -v/(1\*ms) : 1", method='euler') ssg … --- ## [AttributeError on VSCode, Mac](https://brian.discourse.group/t/attributeerror-on-vscode-mac/1498)
**Author:** [@lpiovano](https://brian.discourse.group/u/lpiovano)\ **Replies:** 5\ **Last updated:** [16 October 2025 13:08 UTC](https://brian.discourse.group/t/attributeerror-on-vscode-mac/1498 "2025-10-16T13:08:46Z")
Description of problem I was trying to model a simple group of 3 neurons with a sinusoidal input current, based on the example from the brian2 documentation. I’m using Visual Studio Code (version 1.91.1) on a Mac (Sonoma… --- ## [Anomalies with Time Segmentation](https://brian.discourse.group/t/anomalies-with-time-segmentation/1497)
**Author:** [@MitchG\_HunterCollege](https://brian.discourse.group/u/MitchG_HunterCollege)\ **Replies:** 4\ **Last updated:** [24 September 2025 15:21 UTC](https://brian.discourse.group/t/anomalies-with-time-segmentation/1497 "2025-09-24T15:21:48Z")
I am encountering a very surprising problem. I am providing a current stimulus to network neurons for total of 4 sec. If I input current by specifying net.run(4000\*ms), I get a different simulation outcome than if I inp… --- ## [Error encountered with object named ‘readout\_layer\_subexpression\_update’ when running network (with functions in different scripts)](https://brian.discourse.group/t/error-encountered-with-object-named-readout-layer-subexpression-update-when-running-network-with-functions-in-different-scripts/1496)
**Author:** [@MisterOrbit](https://brian.discourse.group/u/MisterOrbit)\ **Replies:** 5\ **Last updated:** [24 September 2025 07:59 UTC](https://brian.discourse.group/t/error-encountered-with-object-named-readout-layer-subexpression-update-when-running-network-with-functions-in-different-scripts/1496 "2025-09-24T07:59:53Z")
Description of problem I am running a custom brian2 network inside a genetic algorithm. It works when everything is in the same python script, but after refactoring to be across multiple modular scripts that import funct… --- ## [Resetting spike and rate monitors in C++ standalone mode](https://brian.discourse.group/t/resetting-spike-and-rate-monitors-in-c-standalone-mode/1495)
**Author:** [@flmuk](https://brian.discourse.group/u/flmuk)\ **Replies:** 1\ **Last updated:** [18 September 2025 15:46 UTC](https://brian.discourse.group/t/resetting-spike-and-rate-monitors-in-c-standalone-mode/1495 "2025-09-18T15:46:00Z")
Description of problem I am trying to find a fast way to find an optimal parameter setting to see when the neurons from my CA3 network have the highest spatial information. Therefore, I run the network once before the o… --- ## [Namespace Issues with PoissonGroup](https://brian.discourse.group/t/namespace-issues-with-poissongroup/1484)
**Author:** [@flmuk](https://brian.discourse.group/u/flmuk)\ **Replies:** 3\ **Last updated:** [16 September 2025 14:38 UTC](https://brian.discourse.group/t/namespace-issues-with-poissongroup/1484 "2025-09-16T14:38:34Z")
Problem I’m encountering a persistent KeyError when trying to use a state variable from one NeuronGroup to dynamically modulate the rates of a PoissonGroup. I’ve tried providing the necessary objects in the namespace bot… --- ## [Duplicate variable error in Synapses with unique names and cache cleared (Brian2.9.0 / Python 3.13)](https://brian.discourse.group/t/duplicate-variable-error-in-synapses-with-unique-names-and-cache-cleared-brian2-9-0-python-3-13/1490)
**Author:** [@Peace](https://brian.discourse.group/u/Peace)\ **Replies:** 2\ **Last updated:** [13 September 2025 01:54 UTC](https://brian.discourse.group/t/duplicate-variable-error-in-synapses-with-unique-names-and-cache-cleared-brian2-9-0-python-3-13/1490 "2025-09-13T01:54:54Z")
I’m experiencing persistent “Duplicate definition of variable ‘elig\_syn’” errors in Brian2 Synapses, even after renaming all variables to unique names, clearing all caches, and restarting in fresh terminals. System Info… --- ## [Spike detection in multicompartment models](https://brian.discourse.group/t/spike-detection-in-multicompartment-models/1488)
**Author:** [@lucasbinder](https://brian.discourse.group/u/lucasbinder)\ **Replies:** 0\ **Last updated:** [11 September 2025 17:30 UTC](https://brian.discourse.group/t/spike-detection-in-multicompartment-models/1488 "2025-09-11T17:30:54Z")
Description of problem I’m trying to create a model that includes spatialneuron objects with STDP. My current implementation is using spike detection at the soma, however the spike events don’t show up in any other compa… --- ## [LSM on spiking nuerons](https://brian.discourse.group/t/lsm-on-spiking-nuerons/1487)
**Author:** [@dmytr0](https://brian.discourse.group/u/dmytr0)\ **Replies:** 0\ **Last updated:** [11 September 2025 13:50 UTC](https://brian.discourse.group/t/lsm-on-spiking-nuerons/1487 "2025-09-11T13:50:17Z")
Description of problem Hi Brian2 community. I have a problem building liquid state mashine with LIF neurons. Could you please assist me with correct formulas or other changes to my code to make it work? I have 1 neuron … --- ## [Cannot import brain2modelfitting](https://brian.discourse.group/t/cannot-import-brain2modelfitting/1485)
**Author:** [@OttDes](https://brian.discourse.group/u/OttDes)\ **Replies:** 3\ **Last updated:** [9 September 2025 16:29 UTC](https://brian.discourse.group/t/cannot-import-brain2modelfitting/1485 "2025-09-09T16:29:34Z")
Description of problem: I am trying to import brian2modelfitting but get and error related to importing NaN Minimal code to reproduce problem: I install brian2modelfitting: with pip install brian2modelfitting and then … --- ## [A way to save the brain2 objects for later use + single neuron average FR](https://brian.discourse.group/t/a-way-to-save-the-brain2-objects-for-later-use-single-neuron-average-fr/1481)
**Author:** [@Jeevan\_codes8580](https://brian.discourse.group/u/Jeevan_codes8580)\ **Replies:** 3\ **Last updated:** [2 September 2025 12:29 UTC](https://brian.discourse.group/t/a-way-to-save-the-brain2-objects-for-later-use-single-neuron-average-fr/1481 "2025-09-02T12:29:57Z")
Description of problem I have a simulation which takes a while to run. Even after parallelisation. Now I was wondering if there is a way to save the array exactly as to be saved in data and import and use later. What is… --- ## [Error while running parallel standalone simulation in Brian2?](https://brian.discourse.group/t/error-while-running-parallel-standalone-simulation-in-brian2/1482)
**Author:** [@Jeevan\_codes8580](https://brian.discourse.group/u/Jeevan_codes8580)\ **Replies:** 4\ **Last updated:** [1 September 2025 15:48 UTC](https://brian.discourse.group/t/error-while-running-parallel-standalone-simulation-in-brian2/1482 "2025-09-01T15:48:08Z")
Description of problem I have a simulation that runs fine without the cpp\_standalone parallelization. However, if I do that with parallelization described here, it throws error. What am I doing wrong ? … --- ## [How to deal with a differential equation that has integral expressions of other variables](https://brian.discourse.group/t/how-to-deal-with-a-differential-equation-that-has-integral-expressions-of-other-variables/1473)
**Author:** [@czx](https://brian.discourse.group/u/czx)\ **Replies:** 3\ **Last updated:** [7 August 2025 08:49 UTC](https://brian.discourse.group/t/how-to-deal-with-a-differential-equation-that-has-integral-expressions-of-other-variables/1473 "2025-08-07T08:49:08Z")
Description of problem Hello everyone. I try to introduce a probability distribution to my model, and the model has integral terms just like: Where ωD is the variable that has a probability density function f(ωD), an… --- ## [Pinsky Rinzel - spiking problem](https://brian.discourse.group/t/pinsky-rinzel-spiking-problem/1477)
**Author:** [@imlittledove](https://brian.discourse.group/u/imlittledove)\ **Replies:** 7\ **Last updated:** [2 August 2025 11:06 UTC](https://brian.discourse.group/t/pinsky-rinzel-spiking-problem/1477 "2025-08-02T11:06:34Z")
Description of problem Hello everyone! I’m trying to build a single neuron model with the Pinsky Rinzel model of 1994. Even though I’m producing graphs i cannot seem to produce spikes. I’m really hoping someone can ident… [Next page](https://brian.discourse.group/c/support/5.md?page=1)