As far as I'm aware these two things aren't possible with Arraymancer at the moment. But using normal a seq[T] there's ways to do both:
For interpolation: * numericalnim by @hugogranstrom: [https://github.com/HugoGranstrom/numericalnim#natural-cubic-splines](https://github.com/HugoGranstrom/numericalnim#natural-cubic-splines) * to an extent seqmath by @jlp765 (and me to an extent, but not on interpolation): [https://github.com/Vindaar/seqmath/blob/master/src/seqmath/smath.nim#L639](https://github.com/Vindaar/seqmath/blob/master/src/seqmath/smath.nim#L639) and below And for FFT the only way I'm aware of at the moment is via the C library kiss FFT: [https://github.com/m13253/nim-kissfft](https://github.com/m13253/nim-kissfft) I wrote down a couple of notes (mainly for myself and @kaushalmodi) about using kiss FFT from Nim a couple of days ago: [https://gist.github.com/Vindaar/fc158afbc75627260aed90264398e473](https://gist.github.com/Vindaar/fc158afbc75627260aed90264398e473)
