configure: WARNING: FFTW3F library not found. The slower FFTPACK library will be used instead

Question

I'm compiling octave on my LFS - Linux from scratch - system.

While configuring octave, I receive a warning:

configure: WARNING: FFTW3F library not found. The slower FFTPACK library will be used instead.

I compiled and installed FFTW 3.3.4, and then reconfigured octave, however I still receive the following messages:

checking fftw3.h usability... yes

checking fftw3.h presence... yes

checking for fftw3.h... yes

checking for fftw_plan_dft_1d in -lfftw3... yes

checking for fftw3.h... (cached) yes

checking for fftwf_plan_dft_1d in -lfftw3f... no

configure: WARNING: FFTW3F library not found. The slower FFTPACK library will be used instead.

I notice that FFTW 3.3.4 installs libfftw3.so but NOT libfftw3f.so, that's why even after installing FFTW 3.3.4, octave cannot find FFTW3F library. Now, I wonder how I can install libfftw3f.so.

Hallucinate

Answer 1

It looks like you have the double precision FFTW libraries (libfftw3) but not the single precision versions (libfftw3f). Build it again with:

./configure --enable-float --enable-sse && make install

(assuming we're talking x86 here).

This should then install the libfftw3f libraries next to the existing libfftw3 libs.

Auld

These options are not correct for 5.2.0, From my experience, both fftw double precision and single precision are needed in order to get that build feature going. – Pauly

Really helpful answer. – Hove

Yes, very helpful, thank you. Do you know where can I find documentation explaining the difference between libfftw3 and libfftw3f? I am not able to find it – Whydah

@Chachni: it’s all in the FFTW manual, e.g. here. – Auld