Dear Petia!
My approach is the same as Andrew's but nevertheless it takes time to connect a complex network having multiple layers and feedback/feedforward connectivity even though I have prepared and saved all parameters in advance, esspecially if I want to have sparse connectivity.
Of course it takes time to re-instantiate a network completely to do repeated experiments on pristine networks, but so would saving and loading. In fact, all our attempts to implement this functionality showed that it actually often takes *more* time to restore a network from disk than it would to just re-running the script that created it. The main reason for this is that memory and processors are lightning fast compared to disks.
The other reason for not having any checkpointing functionality and removing ResetNetwork in NEST 3 is that is just crazy complicated to get this right. There are spike buffers in neurons and inside the NEST kernel, modified default values, random number generator states, internal flags indicating simulation phases, possibly open files, and so on and so forth. Because it is almost impossible to implement this in a way that is both complete and correct, we rather not provide it.
I was also wandering is it possible to have sparse connectivity matrix W to be used in the following manner: connect(pop1, pop2, "all_to_all", W). Now I am generating full matrix with numerous zero elements but if I want to have dynamic synapses, initial zero weights might result in non-zero one after some time.
You have to create all connections from the start if you want them to exhibit dynamic weight changes during the simulation. The only exception to this rule is structural plasticity: https://www.fz-juelich.de/ias/jsc/EN/Expertise/SimLab/slns/research/structur...
Best regards, Jochen!
On Wednesday, November 27, 2019, 4:42:32 PM GMT+2, Simon Brodeur simon.brodeur@usherbrooke.ca wrote:
Hi Andrew,
Is it because the network takes a long time to build? Are you working with very large networks that need to be spread on multiple machines?
I am personally building networks with complex topologies, where creating the synaptic connections requires a lot of time since I do random sampling with constraint satisfaction directly in Python. I also need to compute per-synapse approximations of axonal delays, dendritic tree attenuations and much more. I do build the network once and have written some Python code that allow to pickle the necessary information (e.g. parameters of the neuron models, synaptic weights) to instantiate faster the network in NEST when I want to perform simulations. But that is just a custom solution, not general to any network.
Cordially, Simon
On Tue, 2019-11-26 at 12:39 +0100, alehr wrote:
Dear NEST developer,
I am wondering if my inquiry from November 11th has been looked at.
Thanks, Andrew Lehr
On Mon, Nov 11, 2019 at 1:52 PM alehr <alehr@mun.ca mailto:alehr@mun.ca> wrote:
Dear NEST developer,
I would like to initialize a network with neurons and connections and then run many simulations with it. It would be great if I could build the network one time and then deepcopy (or something similar) for each simulation. Is something like this possible?
Thanks, Andrew Lehr
NEST Users mailing list --users@nest-simulator.org mailto:users@nest-simulator.org To unsubscribe send an email tousers-leave@nest-simulator.org mailto:users-leave@nest-simulator.org
--
*Simon Brodeur* /Étudiant au doctorat/ Université de Sherbrooke Département génie électrique et génie informatique Laboratoire NECOTIS, C1-3036 Tél. : (819) 821-8000 poste 62187 Courriel: Simon.Brodeur@USherbrooke.ca mailto:Simon.Brodeur@USherbrooke.ca
NEST Users mailing list -- users@nest-simulator.org mailto:users@nest-simulator.org To unsubscribe send an email to users-leave@nest-simulator.org mailto:users-leave@nest-simulator.org
NEST Users mailing list -- users@nest-simulator.org To unsubscribe send an email to users-leave@nest-simulator.org
-- Dr. Jochen Martin Eppler Phone: +49(2461)61-96653 ---------------------------------- Simulation Laboratory Neuroscience Jülich Supercomputing Centre Institute for Advanced Simulation
------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------ Forschungszentrum Juelich GmbH 52425 Juelich Sitz der Gesellschaft: Juelich Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 Vorsitzender des Aufsichtsrats: MinDir Volker Rieke Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender), Karsten Beneke (stellv. Vorsitzender), Prof. Dr.-Ing. Harald Bolt, Prof. Dr. Sebastian M. Schmidt ------------------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------------------