pure c implementation of FFT and a concurrent version.(parallel_dft.c)
Not fully testedm but have a glance:
test N=seq_len=4096*4
vanilla_dft: 3.734s
fft_v1: 3.968s
matlab: 3.018s
> emmm, sth wrong?
- fix stack overflow
- accelerate the programme
not a good chice...