scipy.fftpack.diff¶
- scipy.fftpack.diff(x, order=1, period=None, _cache={})[source]¶
Return k-th derivative (or integral) of a periodic sequence x.
If x_j and y_j are Fourier coefficients of periodic functions x and y, respectively, then:
y_j = pow(sqrt(-1)*j*2*pi/period, order) * x_j y_0 = 0 if order is not 0.
Parameters: x : array_like
Input array.
order : int, optional
The order of differentiation. Default order is 1. If order is negative, then integration is carried out under the assumption that x_0 == 0.
period : float, optional
The assumed period of the sequence. Default is 2*pi.
Notes
If sum(x, axis=0) = 0 then diff(diff(x, k), -k) == x (within numerical accuracy).
For odd order and even len(x), the Nyquist mode is taken zero.