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Release Candidate 3.10-rc1
by Dennis Terhorst 05 May '26

05 May '26

Dear users and developers, in preparation for the NEST 3.10 release, the pre-release version NEST 3.10-rc1 <https://github.com/nest/nest-simulator/releases/tag/v3.10_rc1> is now available for testing. This long-awaited release changes the inner structure by removing the legacy simulation language interface (SLI) layer and promoting PyNEST as primary user interface. People already using NEST via Python will benefit from the cleaner function calls, /without any changes necessary to their code/. Depending on the model setup, instantiation of large models may be noticeably faster. Additionally to the traditional install methods, the new version will be available in an unoptimized, non-MPI version via "pip install nest-simulator" once the release is complete. Due to a quirk in the process the pre-release version however is currently not installable with the usual "--pre" flag. If you want to test the pre-release version use `pip install nest-simulator==3.10rc1` as a workaround for now (we "yanked" the rc-version from PyPI). Note that pre-releases are not fully tested and will be removed after the actual release is complete, so don't base your work on it. Let us know about your experience! We'd be happy to hear where we can improve, and even happier to hear if you're happy. If everything goes well, we're looking forward to the full release in the coming days and will announce it accordingly. Best, Dennis https://github.com/nest/nest-simulator/releases/tag/v3.10_rc1 -- Dipl.-Phys. Dennis Terhorst Coordinator Software Development Institute for Advanced Simulation (IAS-6) Computational and Systems Neuroscience & JARA-Institute Brain Structure-Function Relationships (INM-10) Institute of Neuroscience and Medicine Jülich Research Center, Member of the Helmholz Association 52425 Jülich, Germany http://www.csn.fz-juelich.de/ --------------------------------------------------------------------------------------------- Forschungszentrum Jülich GmbH 52425 Jülich Sitz der Gesellschaft: Jülich Eingetragen im Handelsregister des Amtsgerichts Düren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Stefan Müller Geschäftsführung: Prof. Dr. Astrid Lambrecht (Vorsitzende), Dr. Stephanie Bauer (stellvertretende Vorsitzende), Prof. Dr. Ir. Pieter Jansens, Prof. Dr. Laurens Kuipers ---------------------------------------------------------------------------------------------

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NEST is now part of SPEC CPU 2026
by Hans Ekkehard Plesser 05 May '26

05 May '26

Dear NEST Users and Developers, Today is an exciting day in the history of NEST: The NEST Simulator is now part of the SPEC CPU 2026 industry benchmark. You can find the list of benchmarks here https://www.spec.org/cpu2026/docs/overview.html#Q13, where NEST is included with two cases (single and multithreaded). SPECrate®2026 Floating Point: nest.767_r SPECspeed®2026 Floating Point: nest.867_s For more on SPEC CPU 2026, see Madhav, M., Lee, A., Mejia, A., Moore, B., Soppadandi, C., Cambly, C., Müllner, C., Bowers, D., Reiner, D., Bakhvalov, D., Zhao, D., Voth, D., Xue, F., Silber-Chaussumier, F., Bucek, J., Southern, J., Liu, J., Himer, J., Henning, J., … Todorovski, Z. (2026). SPEC CPU: The Next Generation (Version 1). arXiv. https://doi.org/10.48550/ARXIV.2605.01575 The two-year process of getting NEST ready for SPEC CPU 2026 is documented in the now closed issue https://github.com/nest/nest-simulator/issues/3217. I consider the inclusion of the NEST Simulator in the SPEC CPU 2026 industry benchmark a tremendous validation of over 30 years of focused work on quality research software engineering and would like to thank all who have contributed to NEST code for making this success possible. I'd also like to thank Mahesh Madhav from Ampere Computing for promoting NEST as a SPEC CPU test case and for the excellent collaboration in getting NEST ready for the benchmark. All the best! Hans Ekkehard -- Prof. Dr. Hans Ekkehard Plesser Research Committee Chair, Faculty of Science and Technology Department of Data Science Faculty of Science and Technology Norwegian University of Life Sciences PO Box 5003, 1432 Aas, Norway Phone +47 6723 1560 Email hans.ekkehard.plesser(a)nmbu.no<mailto:hans.ekkehard.plesser@nmbu.no> Home http://arken.nmbu.no/~plesser

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Open NEST Developer Video Conference Monday May 4, at 11:30 CEST (UTC+0200)
by Dennis Terhorst 04 May '26

04 May '26

Dear NEST Users & Developers! I would like to invite you to our next fortnightly Open NEST Developer Video Conference today *Monday May 4, at 11:30 CEST (UTC+0200).* As usual, in the Project team round, a contact person of each team will give a short statement summarizing ongoing and planned work in the team and highlight cross-cutting points that need discussion among the teams. The remainder of the meeting we would go into a more in-depth discussion of topics that came up on the mailing list or that are suggested by the teams. Feel free to join the meeting also if it’s just to bring your own quick questions for direct discussion in the in-depth section. Agenda * Welcome * Review of NEST User Mailing List * Project team round * In-depth discussion The agenda for this meeting is also available online, see https://github.com/nest/nest-simulator/wiki/2026-05-04-Open-NEST-Developer-… <https://github.com/nest/nest-simulator/wiki/2026-05-04-Open-NEST-Developer-…> Looking forward to seeing you soon! Cheers, Dennis Terhorst Log-in information We use a virtual conference room provided by DFN <https://www.dfn.de/en/> (Deutsches Forschungsnetz). You can use the web client to connect. We however encourage everyone to use a headset for better audio quality or even a proper video conferencing system (see below) or software when available. Web client * Visit https://conf.dfn.de/webapp/conference/97938800 <https://conf.dfn.de/webapp/conference/97938800> * Enter your name and allow your browser to use camera and microphone * The conference does not need a PIN to join, just click join and you’re in. In case you see a dfnconf logo and the phrase “Auf den Meetingveranstalter warten”, just be patient, the meeting host needs to join first (a voice will tell you). VC system/software How to log in with a video conferencing system, depends on you VC system or software. * Using the H.323 protocol (eg Polycom): |vc.dfn.net##97938800| or |194.95.240.2##97938800| * Using the SIP protocol:97938800@vc.dfn.de <mailto:97938800@vc.dfn.de> * By telephone: |+49-30-200-97938800| For those who do not have a video conference system or suitable software, Polycom provides a pretty good free app for iOS and Android, so you can join from your tablet (Polycom RealPresence Mobile, available from AppStore/PlayStore). Note that firewalls may interfere with videoconferencing in various and sometimes confusing ways. For more technical information on logging in from various VC systems, please see http://vcc.zih.tu-dresden.de/index.php?linkid=1.1.3.4 <http://vcc.zih.tu-dresden.de/index.php?linkid=1.1.3.4> -- Dipl.-Phys. Dennis Terhorst Coordinator Software Development Institute for Advanced Simulation (IAS-6) Computational and Systems Neuroscience & JARA-Institute Brain Structure-Function Relationships (INM-10) Institute of Neuroscience and Medicine Jülich Research Center, Member of the Helmholz Association 52425 Jülich, Germany http://www.csn.fz-juelich.de/ --------------------------------------------------------------------------------------------- Forschungszentrum Jülich GmbH 52425 Jülich Sitz der Gesellschaft: Jülich Eingetragen im Handelsregister des Amtsgerichts Düren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Stefan Müller Geschäftsführung: Prof. Dr. Astrid Lambrecht (Vorsitzende), Dr. Stephanie Bauer (stellvertretende Vorsitzende), Prof. Dr. Ir. Pieter Jansens, Prof. Dr. Laurens Kuipers ---------------------------------------------------------------------------------------------

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NEST Conference 2026: Abstract submission deadline on Sunday 3 May
by Hans Ekkehard Plesser 30 Apr '26

30 Apr '26

Dear NEST Users! Just a quick reminder that the deadline for submitting your abstract to the NEST Conference 2026 is this Sunday, 3 May. Please submit your abstract on the conference website https://www.nest-initiative.org/conference. Best, Hans Ekkehard -- Prof. Dr. Hans Ekkehard Plesser Research Committee Chair, Faculty of Science and Technology Department of Data Science Faculty of Science and Technology Norwegian University of Life Sciences PO Box 5003, 1432 Aas, Norway Phone +47 6723 1560 Email hans.ekkehard.plesser(a)nmbu.no<mailto:hans.ekkehard.plesser@nmbu.no> Home http://arken.nmbu.no/~plesser

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Hackathon at the University of Sussex, UK, 22-25 June 2026
by Johanna Senk 27 Apr '26

27 Apr '26

Dear NEST Users, We are organising an *application-oriented hackathon* in the week after the NEST Conference 2026. This in-person event will take place at the *University of Sussex in Brighton, UK, on the 22-25 June*. Your are welcome to bring your ideas for new NEST features and get started implementing them with the help of experienced NEST developers. For more information and *registration*, you may visit: https://events.hifis.net/event/3366 Please note that while participation is free of charge, costs for travelling, accommodation, food/drinks, etc. are *at your own expense.* If you have any questions, please don't hesitate to contact me ( J.Senk(a)sussex.ac.uk ). Best regards, Johanna Senk -- Dr. Johanna Senk Institute for Advanced Simulation (IAS-6) Computational and Systems Neuroscience Jülich Research Centre, Juelich, Germany --------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------- Forschungszentrum Jülich GmbH 52425 Jülich Sitz der Gesellschaft: Jülich Eingetragen im Handelsregister des Amtsgerichts Düren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Stefan Müller Geschäftsführung: Prof. Dr. Astrid Lambrecht (Vorsitzende), Karsten Beneke (stellv. Vorsitzender), Dr. Ir. Pieter Jansens --------------------------------------------------------------------------------------------- --------------------------------------------------------------------------------------------- The Forschungszentrum Jülich is currently switching to a new certificate provider for digitally signing emails. During this changeover, the DFN Community PKI certificate used to sign this email may be displayed as invalid.

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NESTML example of neuromodulated STDP synapse
by Han-Jia Jiang 24 Apr '26

24 Apr '26

Dear all, My colleague and I were trying to run a NESTML example, the neuromodulated STDP synapse, as specified here <https://github.com/nest/nestml/blob/main/models/synapses/neuromodulated_std…>. We encountered some problems. First we made some workarounds in order to avoid some errors associated with NESTML. We changed *emit_spike(w)* to *emit_spike()* in the synapse model to avoid the following error: * [15,neuromodulated_stdp_synapse_nestml, ERROR, [33:4;34:4]]: emit_spike() function was called, but with different parameter types than the output port was defined with! Then we added *d ms = 1 ms* and *"delay_variable": {"neuromodulated_stdp_synapse": "d"}* to avoid another set of error: * [29,neuromodulated_stdp_synapse_nestml__with_iaf_psc_delta_neuron_nestml, ERROR]: Delay variable is not specified for synapse model. * [29,neuromodulated_stdp_synapse_nestml__with_iaf_psc_delta_neuron_nestml, ERROR]: Delay variable 'd' not found in synapse. Finally, we failed during the make stage and could not overcome. I attach the code (adapted from the tutorial <https://nestml.readthedocs.io/en/latest/tutorials/stdp_dopa_synapse/stdp_do…>; neuron model as in here <https://github.com/nest/nestml/blob/main/models/neurons/iaf_psc_delta_neuro…>), as well as the error messages (two files because we tried NEST 3.8 and 3.9 respectively) from the make stage. Could you provide any advice on how to solve this? Thank you in advance for your help! Best regards, Han-Jia Jiang

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Open NEST Developer Video Conference Monday April 20, at 11:30 CEST (UTC+0200)
by Dennis Terhorst 20 Apr '26

20 Apr '26

Dear NEST Users & Developers! I would like to invite you to our next fortnightly Open NEST Developer Video Conference today *Monday April 20, at 11:30 CEST (UTC+0200).* As usual, in the Project team round, a contact person of each team will give a short statement summarizing ongoing and planned work in the team and highlight cross-cutting points that need discussion among the teams. The remainder of the meeting we would go into a more in-depth discussion of topics that came up on the mailing list or that are suggested by the teams. Feel free to join the meeting also if it’s just to bring your own quick questions for direct discussion in the in-depth section. Agenda * Welcome * Review of NEST User Mailing List * Project team round * In-depth discussion o NEST 3.10 release status The agenda for this meeting is also available online, see https://github.com/nest/nest-simulator/wiki/2026-04-20-Open-NEST-Developer-… <https://github.com/nest/nest-simulator/wiki/2026-04-20-Open-NEST-Developer-…> Looking forward to seeing you soon! Cheers, Dennis Terhorst Log-in information We use a virtual conference room provided by DFN <https://www.dfn.de/en/> (Deutsches Forschungsnetz). You can use the web client to connect. We however encourage everyone to use a headset for better audio quality or even a proper video conferencing system (see below) or software when available. Web client * Visit https://conf.dfn.de/webapp/conference/97938800 <https://conf.dfn.de/webapp/conference/97938800> * Enter your name and allow your browser to use camera and microphone * The conference does not need a PIN to join, just click join and you’re in. In case you see a dfnconf logo and the phrase “Auf den Meetingveranstalter warten”, just be patient, the meeting host needs to join first (a voice will tell you). VC system/software How to log in with a video conferencing system, depends on you VC system or software. * Using the H.323 protocol (eg Polycom): |vc.dfn.net##97938800| or |194.95.240.2##97938800| * Using the SIP protocol:97938800@vc.dfn.de <mailto:97938800@vc.dfn.de> * By telephone: |+49-30-200-97938800| For those who do not have a video conference system or suitable software, Polycom provides a pretty good free app for iOS and Android, so you can join from your tablet (Polycom RealPresence Mobile, available from AppStore/PlayStore). Note that firewalls may interfere with videoconferencing in various and sometimes confusing ways. For more technical information on logging in from various VC systems, please see http://vcc.zih.tu-dresden.de/index.php?linkid=1.1.3.4 <http://vcc.zih.tu-dresden.de/index.php?linkid=1.1.3.4> -- Dipl.-Phys. Dennis Terhorst Coordinator Software Development Institute for Advanced Simulation (IAS-6) Computational and Systems Neuroscience & JARA-Institute Brain Structure-Function Relationships (INM-10) Institute of Neuroscience and Medicine Jülich Research Center, Member of the Helmholz Association 52425 Jülich, Germany http://www.csn.fz-juelich.de/ --------------------------------------------------------------------------------------------- Forschungszentrum Jülich GmbH 52425 Jülich Sitz der Gesellschaft: Jülich Eingetragen im Handelsregister des Amtsgerichts Düren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Stefan Müller Geschäftsführung: Prof. Dr. Astrid Lambrecht (Vorsitzende), Dr. Stephanie Bauer (stellvertretende Vorsitzende), Prof. Dr. Ir. Pieter Jansens, Prof. Dr. Laurens Kuipers ---------------------------------------------------------------------------------------------

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NEST Conference 2026 — Abstract Submission Deadline extended to 3 May
by Hans Ekkehard Plesser 10 Apr '26

10 Apr '26

Dear all, The abstract submission deadline for the NEST Conference 2026 has been extended to Sunday, 3 May. We are inviting contributions to the conference, including talks, "posters" and workshops on specific topics. Do not miss out on contributing to this exciting event! The NEST Conference provides an opportunity for the NEST Community to meet, exchange success stories, swap advice, learn about current developments in and around NEST spiking network simulation and its application. Take the opportunity to advance your skills in using NEST at our hands-on workshops! This year's conference will again take place as a virtual conference on Tuesday/Wednesday 16/17 June 2026. We are delighted to welcome * Marja-Leena Linne, Tampere University * Maxime Carriere and Fynn Dobler, Freie Universität Berlin * Agnes Korcsak-Gorzo, Forschungszentrum Jülich * Pablo Martínez Cañada, University of Granada as keynote speakers at the conference. For more information on how to submit your contribution, register and participate, please visit the conference website: https://nest-simulator.org/conference We are looking forward to seeing you all in June! Hans Ekkehard Plesser and the conference organizing committee -- Prof. Dr. Hans Ekkehard Plesser Research Committee Chair, Faculty of Science and Technology Department of Data Science Faculty of Science and Technology Norwegian University of Life Sciences PO Box 5003, 1432 Aas, Norway Phone +47 6723 1560 Email hans.ekkehard.plesser(a)nmbu.no<mailto:hans.ekkehard.plesser@nmbu.no> Home http://arken.nmbu.no/~plesser

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Test
by Jochen Martin Eppler 30 Mar '26

30 Mar '26

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Changes in main branch: Now using std::variant<> instead of boost::any in Dictionary
by Hans Ekkehard Plesser 27 Mar '26

27 Mar '26

Dear NEST Users and Developers! Last night, we made another "under the hood" change to NEST, replacing boost::any with std::variant<> as the flexible data type for entries in the dictionaries that we use to move data between Python and the NEST Kernel (thanks to Jan for the implementation and Agnes and Catherine for reviewing!). If you are a user, this should not affect you at all. If you are writing your own model code in C++, you may need to make small adjustments in case you pass unsigned integers. You can find the details here: https://nest-simulator.readthedocs.io/en/main/whats_new/v3.10/index.html#wh… If you are a core developer, you may want to take a look at the doxygen documentation in libnestutil/dictionary.h for implementation details. Note that we recently changed the default on our ReadTheDocs page: You will land at "stable", which now is always the latest release, currently NEST 3.9. To see the documentation for the most recent code in the main branch, you need to explicitly select "main". Best, Hans Ekkehard -- Prof. Dr. Hans Ekkehard Plesser Research Committee Chair, Faculty of Science and Technology Department of Data Science Faculty of Science and Technology Norwegian University of Life Sciences PO Box 5003, 1432 Aas, Norway Phone +47 6723 1560 Email hans.ekkehard.plesser(a)nmbu.no<mailto:hans.ekkehard.plesser@nmbu.no> Home http://arken.nmbu.no/~plesser

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