I will include functions from PDL::FFTW ...

PDL::FFTW only works with an outdated version of the FFTW library. If someone intelligent (that's my escape clause) likes to rewrite PDL::FFTW so that it works with the latest version of the FFTW library, that would be a most welcome improvement to PDL. (This has been on the PDL 'todo' list for quite some time.)

Btw, ++ to you, lin0 for what you've provided in this thread.

Cheers,
Rob