Fails to compile on Apple silicon

[jneen]

Maybe I'm doing something wrong, I'm happy to try some debugging steps.

I have fftw3 installed via brew install fftw. The directory /opt/homebrew/lib contains:

libfftw3.3.dylib@
libfftw3.a@
libfftw3.dylib@
libfftw3_mpi.3.dylib@
libfftw3_mpi.a@
libfftw3_mpi.dylib@
libfftw3_omp.3.dylib@
libfftw3_omp.a@
libfftw3_omp.dylib@
libfftw3_threads.3.dylib@
libfftw3_threads.a@
libfftw3_threads.dylib@
libfftw3f.3.dylib@
libfftw3f.a@
libfftw3f.dylib@
libfftw3f_mpi.3.dylib@
libfftw3f_mpi.a@
libfftw3f_mpi.dylib@
libfftw3f_omp.3.dylib@
libfftw3f_omp.a@
libfftw3f_omp.dylib@
libfftw3f_threads.3.dylib@
libfftw3f_threads.a@
libfftw3f_threads.dylib@
libfftw3l.3.dylib@
libfftw3l.a@
libfftw3l.dylib@
libfftw3l_mpi.3.dylib@
libfftw3l_mpi.a@
libfftw3l_mpi.dylib@
libfftw3l_omp.3.dylib@
libfftw3l_omp.a@
libfftw3l_omp.dylib@
libfftw3l_threads.3.dylib@
libfftw3l_threads.a@
libfftw3l_threads.dylib@

Unfortunately, gem install numo-fftw fails with the following error:

checking for fftw3.h... yes
checking for -lfftw3... no
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers.  Check the mkmf.log file for more details.  You may
need configuration options.

Full logs here:
mkmf.log
gem_make.out

I also tried manually symlinking fftw3* to libfftw3*, but that didn't seem to help. What's odd is that the mkmf.log reports /opt/homebrew/lib as being on DYLD_LIBRARY_PATH.

Happy to help with debugging, or even submitting a fix once we figure out what's wrong!

[jac241]

I was able to install from command line with gem install numo-fftw -- --with-fftw-include=/opt/homebrew/include --with-fftw-lib=/opt/homebrew/lib

[OriPekelman]

In the mileage may vary area.. I had to do something like: gem install numo-fftw -- --with-fftw-include=/usr/local/Cellar/fftw/3.3.10_1/include --with-fftw-lib=/usr/local/Cellar/fftw/3.3.10_1/lib