flopscope.accounting.hfft_cost
flopscope.accounting.hfft_cost(n_out)[flopscope source]
Weighted FLOP cost of a Hermitian FFT.
Parameters
- n_out:int
Argument forwarded to the analytical fft.hfft cost formula.
Returns
- :int
Weighted public cost estimate, floored to match runtime accounting.
Notes
This helper multiplies the analytical FLOP count by the active weight from flopscope._weights and then applies int(...) so public estimates match budget deductions.
hfft(a, n) == irfft(conj(a), n): real-output c2r transform (Van Loan 1992 §1.4). Exploits conjugate symmetry, roughly halving the work vs a full complex FFT.