def ifft(x, y, n):
from numpy import empty
w = empty(4 * n + 15)
y[:] = x[:]
zffti(n, w)
zfftb(n, x, w)
def fft(x, y, n):
from numpy import empty
w = empty(4 * n + 15)
y[:] = x[:]
zffti(n, w)
zfftf(n, y, w)