bench_fftw.nim

import complex, math, benchy, fftw3

proc benchFFT(name: string, size: int) =
  GC_fullCollect()
  var
    input = newSeq[Complex64](size)

  timeit name & " - " & $size:
    var output = newSeq[Complex64](size)

    let bufIn = cast[ptr UncheckedArray[Complex64]](addr(input[0]))
    let bufOut = cast[ptr UncheckedArray[Complex64]](addr(output[0]))
    let plan = fftw_plan_dft_1d(cint size, bufIn, bufOut, FFTW_FORWARD, FFTW_ESTIMATE)
    fftw_execute(plan)

for size in [64, 128, 256, 512, 1024, 2048, 4096, 16384, 65536]:
  benchFFT("pow2", size)

for size in [5, 17, 149, 151, 251, 1009, 2017, 2879, 32767, 65521, 65537, 746483, 746497]:
  benchFFT "prime", size

for size in [211^2, 401^2]:
  benchFFT "prime-power", size

for size in [24576, 20736]:
  benchFFT "mult-of-power-of-2", size

for size in [30270]:
  benchFFT "small-comp-large-prime", size

for size in [18, 360, 44100, 48000, 46656, 100000]:
  benchFFT "small-comp", size