Running Dedalus with MPI on a MacBook Pro with M2 chip (Sequoia)

[Caroline T.]

To add to my previous post and be more specific: I've followed the installation instructions from the dedalus website for Silicon mac.  Running the code serially works, but I get the following message:

<frozen importlib._bootstrap>:488: RuntimeWarning: mpi4py.MPI.Session size changed, may indicate binary incompatibility. Expected 32 from C header, got 40 from PyObject

and the code doesn't work with mpiexec

Best,

Caroline Terquem

[Miguel Beneitez]

Hi Caroline,

I checked with a fresh installation on my macbook M1 pro yesterday and it worked fine. I've had issues with very new versions of Python, so I set it to python 3.10 in the installation script. 

This gives me: 6562 passed, 16 skipped, 143 xfailed, 18 xpassed in 84.06s (0:01:24) on the tests, but I'm able to essentially run all my codes in serial and in parallel. 

Also you can find the list of packages in my environment below in case that helps.

Cheers,

Miguel

Package           Version
----------------- -----------
cached-property   1.5.2
contourpy         1.3.2
coverage          7.9.2
cycler            0.12.1
Cython            3.1.2
dedalus           3.0.3
docopt            0.6.2
exceptiongroup    1.3.0
filelock          3.18.0
fonttools         4.58.5
fsspec            2025.5.1
h5py              3.14.0
iniconfig         2.1.0
Jinja2            3.1.6
kiwisolver        1.4.8
MarkupSafe        3.0.2
matplotlib        3.10.3
mpi4py            4.1.0
mpmath            1.3.0
munkres           1.1.4
networkx          3.4.2
numexpr           2.11.0
numpy             2.2.6
packaging         25.0
pandas            2.3.1
pillow            11.3.0
pip               25.1.1
pluggy            1.6.0
py                1.11.0
py-cpuinfo        9.0.0
Pygments          2.19.2
pyparsing         3.2.3
pytest            8.4.1
pytest-benchmark  5.1.0
pytest-cov        6.2.1
pytest-parallel   0.1.1
python-dateutil   2.9.0.post0
pytz              2025.2
scipy             1.15.2
setuptools        80.9.0
six               1.17.0
sympy             1.14.0
tblib             3.1.0
tomli             2.2.1
torch             2.7.0
tornado           6.5.1
typing_extensions 4.14.1
tzdata            2025.2
unicodedata2      16.0.0
wheel             0.45.1
xarray            2025.6.1

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[Caroline T.]

Thank you very much Miguel, downgrading python did the trick!  Thank you for giving the list of packages, that's really helpful!  

With best wishes,

Caroline