macos-latest passes with warnings

[purva-thakre]

Noticed the following 66 warnings in a macos-latest workflow run.

https://github.com/unitaryfund/mitiq/actions/runs/9006365923/job/24743744344#step:6:4149

I don't think this is fixable on our end. Created this issue to look up the source of the error later.

[purva-thakre]

From what I could find, this appears to be an issue with ARM macos devices. numpy relies on BLAS and LAPACK libraries. There's a bug in OpenBLAS LAPACK. numpy/numpy#22025 (comment)

Qiskit/qiskit#10248 (comment)

I don't have access to a mac and I don't really know a lot about the differences between macos devices on ARM and Intel architectures. For this reason, I can't tell if this is something we should keep track of or will get fixed when the linked numpy issue is closed.

Feel free to close this issue.

[cosenal]

I can reproduce it on my M2 Pro.

(mitiqenv) ➜  mitiq git:(main) ✗ py.test -r w mitiq/benchmarks/tests/test_mirror_qv_circuits.py
================================================================================================ test session starts =================================================================================================
platform darwin -- Python 3.11.8, pytest-8.0.0, pluggy-1.4.0
rootdir: /Users/cosenal/Coding/unitaryfund/mitiq
configfile: pyproject.toml
plugins: cov-5.0.0, anyio-4.3.0, xdist-3.0.2, dash-2.16.1
collected 17 items

mitiq/benchmarks/tests/test_mirror_qv_circuits.py .................                                                                                                                                            [100%]

================================================================================================== warnings summary ==================================================================================================
mitiq/benchmarks/tests/test_mirror_qv_circuits.py: 18 warnings
  /opt/miniconda3/envs/mitiqenv/lib/python3.11/site-packages/numpy/linalg/linalg.py:2180: RuntimeWarning: divide by zero encountered in det
    r = _umath_linalg.det(a, signature=signature)

mitiq/benchmarks/tests/test_mirror_qv_circuits.py: 18 warnings
  /opt/miniconda3/envs/mitiqenv/lib/python3.11/site-packages/numpy/linalg/linalg.py:2180: RuntimeWarning: invalid value encountered in det
    r = _umath_linalg.det(a, signature=signature)

Environment info

(mitiqenv) ➜  mitiq git:(main) ✗ pip list | grep numpy
numpy                           1.26.4
(mitiqenv) ➜  mitiq git:(main) ✗ python -c "import numpy, threadpoolctl, pprint; \
pprint.pprint(threadpoolctl.threadpool_info())"

[{'architecture': 'armv8',
  'filepath': '/opt/miniconda3/envs/mitiqenv/lib/python3.11/site-packages/numpy/.dylibs/libopenblas64_.0.dylib',
  'internal_api': 'openblas',
  'num_threads': 12,
  'prefix': 'libopenblas',
  'threading_layer': 'pthreads',
  'user_api': 'blas',
  'version': '0.3.23.dev'}]

I propose we keep this open as a reminder to update the dependency whenever the upstream numpy/openblas issue is resolved.