ImportError: symbol not found in flat namespace '___kmpc_barrier'

[1cosmologist]

CCL installed in conda environment. The package cannot be called successfully.

Error message:

----> 1 import pyccl as ccl

File ~/opt/anaconda3/envs/uEnv/lib/python3.10/site-packages/pyccl/__init__.py:17
     14 del environ, path
     16 # SWIG-generated
---> 17 from . import ccllib as lib
     19 # monkey patch for isitgr and fast-pt if Numpy>=1.24
     20 from packaging.version import parse

File ~/opt/anaconda3/envs/uEnv/lib/python3.10/site-packages/pyccl/ccllib.py:16
     14 # Import the low-level C/C++ module
     15 if __package__ or "." in __name__:
---> 16     from . import _ccllib
     17 else:
     18     import _ccllib

ImportError: dlopen(/Users/shamik/opt/anaconda3/envs/uEnv/lib/python3.10/site-packages/pyccl/_ccllib.so, 0x0002): symbol not found in flat namespace '___kmpc_barrier'

Note: Installation on arm64 M1 Macbook with clang 14.0.6, python 3.10.9

[tilmantroester]

To clarify, ccl was installed using conda? Is openmp installed in the conda env?

[1cosmologist]

Yes, ccl was installed with conda (arm64) distribution. I find llvm-openmp installed in my conda environment.

[alexander-mead]

I see this too! I just tried to install ccl globally from the cloned repository using:

pip install -e .

and I see:

Physics/CCL> python3 -c 'import pyccl'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/Mead/Physics/CCL/pyccl/__init__.py", line 17, in <module>
    from . import ccllib as lib
  File "/Users/Mead/Physics/CCL/pyccl/ccllib.py", line 19, in <module>
    from . import _ccllib
ImportError: dlopen(/Users/Mead/Physics/CCL/pyccl/_ccllib.so, 0x0002): symbol not found in flat namespace '___kmpc_barrier'

This is pyccl-2.6.1 on a Mac with macOS 13.1, Python 3.10.9 and clang 14.0.0. I get a similar error if I install via pip install pyccl, and whether or not I install in an environment. If I do brew install libomp I see that I have the latest version 15.0.7.

[tilmantroester]

I unfortunately can't reproduce this. I tried a fresh conda environment and both the conda and pip versions (pypi and locally) work for me. Tested on macOS 12.6.2, python 3.10 and 3.11, conda clang 14.0.6.

[alexander-mead]

Hmm... could it be anything to do with an Xcode installation, or lack there of? At the moment I only have the command line tools installed, to save space.

[tilmantroester]

That shouldn't matter I think. And especially not in a conda environment with it's own compilers.

[damonge]

@1cosmologist were you able to solve this?

[1cosmologist]

I tried a few combinations of build environments on my mac to try and solve this issue, but unlitmately did not succeed.

[hsinfan1996]

I know unsuccessfully linked OpenMP can lead to this error. Maybe try disabling OpenMP when installing ccl from source. Not sure if there is a more proper way to do this, but to disable OpenMP, I will just comment out line 66 of CMakeLists.txt.

[elisachisari]

Any updates on this?