Optimization example error

[raunakvijayakar]

Hello,
I'm running into an error when I try to run the example code, "05. Optimize simulated evoked response parameters." I haven't modified the example, and the documentation version matches my hnn-core version. I've had no errors in running the other code examples.

Everything runs fine until I reach the optimization block:

from hnn_core.optimization import optimize_evoked
with MPIBackend(n_procs=n_procs):
    net_opt = optimize_evoked(net, tstop=tstop, n_trials=1,
                              target_dpl=exp_dpl, initial_dpl=initial_dpl,
                              scale_factor=scale_factor,
                              smooth_window_len=smooth_window_len)

The first iteration of optimization step one runs without issue, but the following error appears before the second iteration can begin:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
File [~/anaconda3/envs/hnn_core_env/lib/python3.11/site-packages/scipy/optimize/_differentiable_functions.py:141](https://file+.vscode-resource.vscode-cdn.net/Users/M298129/Desktop/Mayo/23%3A24/Q2/R2/hnn_core/~/anaconda3/envs/hnn_core_env/lib/python3.11/site-packages/scipy/optimize/_differentiable_functions.py:141), in ScalarFunction.__init__..fun_wrapped(x)
    140 try:
--> 141     fx = np.asarray(fx).item()
    142 except (TypeError, ValueError) as e:

ValueError: can only convert an array of size 1 to a Python scalar

As you can see, the line refers to _differentiable_functions.py from scipy.

System Information
hnn-core v0.3
Macbook Pro M2 (ventura 13.5.2)
python 3.11.4

I have also replicated the error on a Macbook Pro M1 and an iMac with intel procs.

Thank you.

[ntolley]

Thanks for pointing this out! I suspect this is due to one of our dependencies putting out an update since our last release of hnn-core Will do some digging and get back to you.

[rythorpe]

Which version are you using @raunakvijayakar? I suspect this is actually a bug fixed in #670.

[raunakvijayakar]

Hi @rythorpe, I was using hnn v0.3, now I've updated to v0.4.dev0 and optimization is working.
Thank you so much!

[rythorpe]

Great, let us know if anything else comes up! Note that our development branch also has a new Optimizer class to try out if you're ever in need of a more flexible API for optimizing different types of simulation metrics. The old version works just fine as well, but check out this tutorial if you're interested. :)

[raunakvijayakar]

Thanks for the headsup, the new version looks very useful.