Issue 1:
Firstly, I installed Xcode command line developer tools. Then, I installed numpy via pip3. When I try to run python code, I give an error. In previous version (macOS Mojave) everything was okay.

Reproducing code example:

import numpy as np

Error message:

Python(3853,0x112ed8e00) malloc: can't allocate region

:*** mach_vm_map(size=18446744072247156736, flags: 100) failed (error code=3)

Python(3853,0x112ed8e00) malloc: *** set a breakpoint in malloc_error_break to debug

init_dgelsd failed init

Traceback (most recent call last):

File "", line 1, in

File "/Users/martin/Library/Python/3.8/lib/python/site-packages/numpy/init.py", line 286, in

raise RuntimeError(msg)

RuntimeError: Polyfit sanity test emitted a warning, most likely due to using a buggy Accelerate backend. If you compiled yourself, see site.cfg.example for information. Otherwise report this to the vendor that provided NumPy.

RankWarning: Polyfit may be poorly conditioned

NumPy/Python version information:

Numpy: 1.19.4

Python: 3.8.2

Issue 2:
Reproducing code example:

Install Pandas with PIP after a clean install of macOS Big Sur and Python3.9 via Homebrew.

pip install pandas
pip3 install pandas
pip3 install pandas --no-build-isolation --no-cache-dir
sudo pip3 install pandas --no-cache-dir

These are the only packages actually installed:

Package Version
---------- -------
pip 20.2.4
setuptools 50.3.2
wheel 0.35.1

Error message:

Getting requirements to build wheel ... error
ERROR: Command errored out with exit status 1:
command: /usr/local/opt/python@3.9/bin/python3.9 /usr/local/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/tmpzr3sthd6
cwd: /private/var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/pip-install-pvlaq6iq/pandas
Complete output (23 lines):
init_dgelsd failed init
Traceback (most recent call last):
File "/usr/local/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py", line 280, in <module>
main()
File "/usr/local/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py", line 263, in main
json_out['return_val'] = hook(**hook_input['kwargs'])
File "/usr/local/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py", line 114, in get_requires_for_build_wheel
return hook(config_settings)
File "/private/var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/pip-build-env-ly4c8n5_/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 149, in get_requires_for_build_wheel
return self._get_build_requires(
File "/private/var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/pip-build-env-ly4c8n5_/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 130, in _get_build_requires
self.run_setup()
File "/private/var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/pip-build-env-ly4c8n5_/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 253, in run_setup
super(_BuildMetaLegacyBackend,
File "/private/var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/pip-build-env-ly4c8n5_/overlay/lib/python3.9/site-packages/setuptools/build_meta.py", line 145, in run_setup
exec(compile(code, __file__, 'exec'), locals())
File "setup.py", line 488, in <module>
import numpy as np
File "/private/var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/pip-build-env-ly4c8n5_/overlay/lib/python3.9/site-packages/numpy/__init__.py", line 286, in <module>
raise RuntimeError(msg)
RuntimeError: Polyfit sanity test emitted a warning, most likely due to using a buggy Accelerate backend. If you compiled yourself, see site.cfg.example for information. Otherwise report this to the vendor that provided NumPy.
RankWarning: Polyfit may be poorly conditioned

----------------------------------------
ERROR: Command errored out with exit status 1: /usr/local/opt/python@3.9/bin/python3.9 /usr/local/lib/python3.9/site-packages/pip/_vendor/pep517/_in_process.py get_requires_for_build_wheel /var/folders/zv/0q58rjv549bd4qjdqlrwlvl40000gn/T/tmpzr3sthd6 Check the logs for full command output.

NumPy/Python version information:

I have also installed NumPy first (numpy 1.19.4) still getting the same error.

I have opened the following issues and in both of them they said that it's a Numpy error: Pandas#37880 and Pip#9138