[Bugfix] Segmentation fault for darts[all] on macOS arm64

[daidahao]

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• Mentioned all issues that this PR fixes or addresses.
• Summarized the updates of this PR under Summary.
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Fixes #.

Summary

torch (latest, 2.11) bundled libomp is not compatible with lightgbm (latest, 4.6.0) on macOS arm64, causing segmentation faults:

from darts.models import LightGBMModel
from darts.utils.timeseries_generation import linear_timeseries

series = linear_timeseries(length=100)
model = LightGBMModel(12).fit(series)

Related Issue:

• [python-package] SegFault on MacOS when pytorch is installed lightgbm-org/LightGBM#6595

Until it is fixed on either side, I suggest capping the torch version to 2.10.

Other Information

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.69%. Comparing base (ac01d25) to head (f22de6a).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #3050      +/-   ##
==========================================
- Coverage   95.75%   95.69%   -0.07%     
==========================================
  Files         158      158              
  Lines       17229    17229              
==========================================
- Hits        16498    16487      -11     
- Misses        731      742      +11     

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[dennisbader]

Thanks @daidahao. I'm not sure how quickly (I would assume it's LightGBM) resolves this issue. For me (also mac user), setting the env variable to the brew installed libomp resolved this issue:

# Only add libomp to DYLD_LIBRARY_PATH if Homebrew and libomp are installed
if command -v brew &>/dev/null; then
    _libomp="$(brew --prefix libomp 2>/dev/null)/lib"
    [ -d "$_libomp" ] && export DYLD_LIBRARY_PATH="${_libomp}${DYLD_LIBRARY_PATH:+:$DYLD_LIBRARY_PATH}"
    unset _libomp
fi

[daidahao]

@dennisbader

Thank you for the suggestion and I can confirm it fixes the problem for me!

Would it be helpful to include it in INSTALL.md or pin the solution to Issues so users could find it easily? I think it affects new fresh install of darts[all] on macOS, even when torch models are not imported (see snippet above).