Binary package “libfftw3-3” in ubuntu focal

Library for computing Fast Fourier Transforms

 The FFTW library computes Fast Fourier Transforms (FFT) in one or more
 dimensions. It is extremely fast.
 This package is a transitional package depending on the packages containing
 the single and double precision libraries.
 .
 To get the static library and the header files, you need to install
 libfftw3-dev. For documentation, see libfftw3-doc.