mne.fit_dipole throwing AssertionError: (blank) when n_jobs=-1

mjcourte commented 2 years ago

Describe the bug

When setting n_jobs=-1 as an argument of mne.fit_dipole(), a blank AssertionError is thrown. Reading up the trace, one can see there is an assert n_jobs > 0 within mne/surface.py. Elsewhere in MNE-Py, setting n_jobs=-1 is valid and selects maximum available workers, and the docs for fit_dipole state this. Setting n_jobs=16 runs successfully, where 16 is the maximum workers on my system, and the number of workers when using -1 in the steps prior to dipole fitting.

Steps to reproduce

Run:

dip = mne.fit_dipole(..., n_jobs=-1)

Expected results

The dipole fit to complete using maximum workers.

Actual results

(snip)
~\anaconda3\envs\mne\lib\site-packages\mne\surface.py in _points_outside_surface(rr, surf, n_jobs, verbose)
    561     rr = np.atleast_2d(rr)
    562     assert rr.shape[1] == 3
--> 563     assert n_jobs > 0
    564     parallel, p_fun, _ = parallel_func(_get_solids, n_jobs)
    565     tot_angles = parallel(p_fun(surf['rr'][tris], rr)

AssertionError:

Additional information

Output from `mne.sys_info()`

Platform: Windows-10-10.0.22000-SP0 Python: 3.9.9 | packaged by conda-forge | (main, Dec 20 2021, 02:36:06) [MSC v.1929 64 bit (AMD64)] Executable: C:\Users\Matt\anaconda3\envs\mne\python.exe CPU: Intel64 Family 6 Model 167 Stepping 1, GenuineIntel: 16 cores Memory: 63.8 GB mne: 0.24.1 numpy: 1.22.0 {blas=NO_ATLAS_INFO, lapack=lapack} scipy: 1.7.3 matplotlib: 3.5.1 {backend=module://matplotlib_inline.backend_inline} sklearn: 1.0.2 numba: 0.53.1 nibabel: 3.2.1 nilearn: 0.8.1 dipy: 1.4.1 cupy: Not found pandas: 1.3.5 mayavi: 4.7.2 pyvista: 0.33.2 {OpenGL 4.5.0 NVIDIA 496.49 via NVIDIA GeForce GTX 1070/PCIe/SSE2} pyvistaqt: 0.6.0 ipyvtklink: Not found vtk: 9.0.3 PyQt5: 5.12.3 ipympl: Not found mne_qt_browser: 0.1.7 pooch: v1.5.2 C:\Users\Matt\anaconda3\envs\mne\lib\site-packages\mne\utils\check.py:728: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead. if LooseVersion(version) >= LooseVersion('5.10'): C:\Users\Matt\anaconda3\envs\mne\lib\site-packages\mne\utils\check.py:728: DeprecationWarning: distutils Version classes are deprecated. Use packaging.version instead. if LooseVersion(version) >= LooseVersion('5.10'):