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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.

Community
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Megidd
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1 Answers1

16

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.

Paul R
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  • 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. – Doron Behar Feb 11 '20 at 14:10
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    Really helpful answer. – frankliuao May 03 '20 at 20:58
  • 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 – Chachni Mar 30 '21 at 20:30
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    @Chachni: it’s all in the FFTW manual, e.g. [here](http://www.fftw.org/fftw3_doc/Precision.html#Precision). – Paul R Mar 30 '21 at 20:40