The check is done after the init:
I thought this was a good idea, to check if there were some vectors
instantiated before running any simulation, to avoid running a
simulation and not having even one vector recorded.
Of course, if you have created the vectors via hoc, or via python, not
using the neuronvisio data structure that check is not a good one.
We could delete the check and leave it to the user to remember to
create the vectors!
>> - How can the user tell which variables are available, other than 'v'?
This is a tricky one. this is more a NEURON question than a
Usually a variable can be recorded if it has been added to the section
(usually if it is written by a mod file!)
I think the best way is to head off to NEURON forum and check over there.
I didn't find a nice method to check what is available. If you manage
to find one, please let me know :)