kissfft-tools 131+git20201106.cc862cb-2 (s390x binary) in ubuntu hirsute

 There are many great fft libraries already around. Kiss FFT is not trying to be
 better than any of them. It only attempts to be a reasonably efficient,
 moderately useful FFT that can use fixed or floating data types and can be
 incorporated into someone's C program in a few minutes with trivial licensing.
 .
 This package installs CLI tools by kissfft.