There have been reports of Nengo not running after installation. This has been traced to a bug currently in Python 3.9-3.11. If you have this problem, please install in a Python 3.8 environment.
Here are steps in Anaconda CLI to reproduce the error:
conda update --all
conda create -n nengo_test
conda activate nengo_test
conda install pip
pip install nengo nengo-gui
nengo(nengo_test) PS C:\WINDOWS\system32> nengo
Traceback (most recent call last):
File “”, line 198, in run_module_as_main
File “”, line 88, in run_code
File "C:\Users\your_name\anaconda3\envs\nengo_test\Scripts\nengo.exe_main.py", line 4, in
File "C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui_init.py", line 1, in
from .gui import GUI, InteractiveGUI
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui\gui.py”, line 21, in
from nengo_gui.guibackend import GuiServer
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui\guibackend.py”, line 25, in
import nengo_gui.page
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui\page.py”, line 14, in
import nengo_gui.config
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui\config.py”, line 4, in
import nengo_gui.components
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui\components_init_.py”, line 10, in
from .sim_control import SimControl
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui\components\sim_control.py”, line 10, in
from nengo_gui.server import WebSocketFrame
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui\server.py”, line 31, in
from nengo_gui.vendor.cookies import Cookies
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui_vendor\cookies.py”, line 111, in
class Definitions(object):
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\site-packages\nengo_gui_vendor\cookies.py”, line 313, in Definitions
ATTR_RE = re.compile(ATTR)
^^^^^^^^^^^^^^^^
File "C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_init.py", line 227, in compile
return compile(pattern, flags)
^^^^^^^^^^^^^^^^^^^^^^^^
File "C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_init.py", line 294, in _compile
p = _compiler.compile(pattern, flags)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_compiler.py”, line 743, in compile
p = _parser.parse(p, flags)
^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_parser.py”, line 982, in parse
p = _parse_sub(source, state, flags & SRE_FLAG_VERBOSE, 0)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_parser.py”, line 457, in _parse_sub
itemsappend(_parse(source, state, verbose, nested + 1,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_parser.py”, line 865, in _parse
p = _parse_sub(source, state, sub_verbose, nested + 1)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_parser.py”, line 457, in _parse_sub
itemsappend(_parse(source, state, verbose, nested + 1,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_parser.py”, line 865, in _parse
p = _parse_sub(source, state, sub_verbose, nested + 1)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_parser.py”, line 457, in _parse_sub
itemsappend(_parse(source, state, verbose, nested + 1,
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File “C:\Users\your_name\anaconda3\envs\nengo_test\Lib\re_parser.py”, line 843, in _parse
raise source.error('global flags not at the start ’
re.error: global flags not at the start of the expression at position 399 (line 7, column 33)