fftw_threads symbols

[colinjcotter]

I get an import error when executing: from mpi4py_fft.fftw import fftw_xfftn

In [1]: from mpi4py_fft.fftw import fftw_xfftn

ImportError Traceback (most recent call last)
in
----> 1 from mpi4py_fft.fftw import fftw_xfftn

ImportError: dlopen(/Users/colincotter/firedrake-fftw2/lib/python3.8/site-packages/mpi4py_fft/fftw/fftw_xfftn.cpython-38-darwin.so, 2): Symbol not found: _fftw_cleanup_threads
Referenced from: /Users/colincotter/firedrake-fftw2/lib/python3.8/site-packages/mpi4py_fft/fftw/fftw_xfftn.cpython-38-darwin.so
Expected in: flat namespace
in /Users/colincotter/firedrake-fftw2/lib/python3.8/site-packages/mpi4py_fft/fftw/fftw_xfftn.cpython-38-darwin.so

I have built fftw with --enable-threads --enable-shared (I'm asking PETSc to build it because I need to ensure that I'm using the right mpi library). libfftw3_threads can be found in the PETSc lib and I am adding the PETSc lib and include directories to FFTW_INCLUDE_DIR and FFTW_LIBRARY_DIR. How can I get mpi4py_fft to pick up these symbols?

[mikaem]

Hi Colin,
Not sure I can be of much help. Do you install mpi4py_fft from source? And you actually find the FFTW libraries during setup, but there are missing symbols? We do make use of both FFTW_INCLUDE_DIR and FFTW_LIBRARY_DIR in the setup.

[colinjcotter]

Yes, PETSc installs mpi4py_fft from source. It finds the FFTW libraries during setup, but trying to use mpi4py_fft then reports that stuff is missing.

…

________________________________ From: Mikael Mortensen ***@***.***> Sent: 30 September 2021 14:37 To: mpi4py/mpi4py-fft ***@***.***> Cc: Cotter, Colin J ***@***.***>; Author ***@***.***> Subject: Re: [mpi4py/mpi4py-fft] fftw_threads symbols (#13) Hi Colin, Not sure I can be of much help. Do you install mpi4py_fft from source? And you actually find the FFTW libraries during setup, but there are missing symbols? We do make use of both FFTW_INCLUDE_DIR and FFTW_LIBRARY_DIR in the setup. — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#13 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/ABOSV4WGG4FJI2UB4GTEO3TUERRYTANCNFSM5FB7K5YA>. Triage notifications on the go with GitHub Mobile for iOS<https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android<https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>.

[colinjcotter]

OK, so I discovered that this issue only arises if I pip install mpi4py-fft from pypi and not if I clone the git repository and pip install from there.