How much time should the demo_quick_sr example take? Unit tests not finishing as well.

[riobanerjee]

Hi,
Thanks for making this package public, I think this could be very helpful in my work.
I have followed the installation instructions and installed it with no hitches, but when I try to run the unit tests or demo_quick_sr examples (both notebook and terminal), it keeps running for more than 3-4 hours without any result. I am running on an M1 Pro chip.
Output from unit test so far:
/Users/riobanerjee/Codes/PhySO/physo/physym/program.py:20: UserWarning: Can not import display packages. warnings.warn("Can not import display packages.") ....

Output from demo_quick_sr.ipynb so far:
`/Users/riobanerjee/Codes/PhySO/physo/physym/program.py:20: UserWarning: Can not import display packages.
warnings.warn("Can not import display packages.")
Parallel mode is not available because physo is being ran from a notebook on a system returning multiprocessing.get_start_method() = 'spawn' (typically MACs/Windows). Run physo from the terminal to use parallel mode.
Parallel mode is not available because physo is being ran from a notebook on a system returning multiprocessing.get_start_method() = 'spawn' (typically MACs/Windows). Run physo from the terminal to use parallel mode.

default get_start_method : spawn
Running from notebook : True
Is CUDA available : False
Total nb. of CPUs : 8
Recommended config {'parallel_mode': False, 'n_cpus': 8}
Parallel mode is not available because physo is being ran from a notebook on a system returning multiprocessing.get_start_method() = 'spawn' (typically MACs/Windows). Run physo from the terminal to use parallel mode.
Parallel mode is not available because physo is being ran from a notebook on a system returning multiprocessing.get_start_method() = 'spawn' (typically MACs/Windows). Run physo from the terminal to use parallel mode.

default get_start_method : spawn
Running from notebook : True
Is CUDA available : False
Total nb. of CPUs : 8
Recommended config {'parallel_mode': False, 'n_cpus': 8}
Parallel mode is not available because physo is being ran from a notebook on a system returning multiprocessing.get_start_method() = 'spawn' (typically MACs/Windows). Run physo from the terminal to use parallel mode.
Parallel mode is not available because physo is being ran from a notebook on a system returning multiprocessing.get_start_method() = 'spawn' (typically MACs/Windows). Run physo from the terminal to use parallel mode.
`