" HHna is not a MECHANISM "

[CleoHuhuihan]

Hi I am a new one to NEURON. I just completed my installation of NEURON these days.

However, when I tried to follow the tutorial lectures on Youtube:
open demo -> click "release"

and an error message came out:
oc>C:\nrn\bin\nrniv.exe: HHna is not a MECHANISM
in release.hoc near line 13
{insert HHna insert HHk insert cachan insert cadifpmp }
^
xopen("$(NRNDEMO)...")
demo(4)

It seems that somebody in the lecture met the same problem and he had been told to reinstall NEURON. Therefore, I did the same thing. But just after a reinstallation, the problem still did not get solved.

I will appreciate it if someone can tell me what is going on and what should I do.
Thank you!

[ted]

Are you using Windows 11? If not, what operating system are you using?

[CleoHuhuihan]

Yes it is windows 11.

[ted]

Installing NEURON should have created a folder on your desktop that has a name that starts with NEURON. Double click on that folder. Inside the folder is an icon with the label "bash". Double click on that. That should open a bash terminal. The prompt will look something like
bash-5.2$

At the prompt, execute the command
neurondemo
If that succeeds, the mod files in C:\nrn\demo\release will be compiled, and after that completes, you will see a NEURON Main Menu toolbar plus a bunch of panels with various buttons.

If it fails, you'll get the "HHna is not a mechanism" error message. Press ^D to exit NEURON. Then at the bash prompt enter this command
cd c:/nrn/demo/release
and then execute
nrnivmodl
That should compile the mod files in c:/nrn/demo/release

Next execute the commands
cd ..
nrniv demo.hoc
and you should now see the NEURON Main Menu toolbar plus a bunch of panels with buttons.

[CleoHuhuihan]

That works. Thank you!!!

[ted]

You're welcome. It works, but it should be much, much easier. It will take a while to figure out how to deal with Win 11.