Alcides Fonseca

40.197958, -8.408312

ImportError in numpy caused by missing libgfortran

Today I got the following error when executing regular numpy code in my homebrew Python3.9 installation.

ImportError: dlopen(/usr/local/lib/python3.9/site-packages/scipy/linalg/, 0x0002): Library not loaded: /usr/local/opt/gcc/lib/gcc/10/libgfortran.5.dylib Referenced from: /usr/local/lib/python3.9/site-packages/scipy/linalg/ Reason: tried: '/usr/local/opt/gcc/lib/gcc/10/libgfortran.5.dylib' (no such file), '/usr/local/lib/libgfortran.5.dylib' (no such file), '/usr/lib/libgfortran.5.dylib' (no such file)

The issue was that I had gcc 11 installed (you can check via brew info gcc), but homebrew-installed bumpy expected gcc 10 to be installed.

Reinstalling numpy from bottle or from source didn’t work.

The workaround:

brew install gcc@10
sudo ln -s /usr/local/opt/gcc@10/lib/gcc/10/libgfortran.dylib /usr/local/lib/libgfortran.5.dylib  
sudo ln -s /usr/local/opt/gcc@10/lib/gcc/10/libquadmath.0.dylib /usr/local/lib/libquadmath.0.dylib