scipy.fftpack.cc_diff

scipy.fftpack.cc_diff(x, a, b, period=None, _cache={})

Return (a,b)-cosh/cosh pseudo-derivative of a periodic sequence.

If x_j and y_j are Fourier coefficients of periodic functions x and y, respectively, then:

y_j = cosh(j*a*2*pi/period)/cosh(j*b*2*pi/period) * x_j

Parameters :

x : array_like

The array to take the pseudo-derivative from.

a,b : float

Defines the parameters of the sinh/sinh pseudo-differential operator.

period : float, optional

The period of the sequence x. Default is 2*pi.

Returns :

cc_diff : ndarray

Pseudo-derivative of periodic sequence x.

Notes

cc_diff(cc_diff(x,a,b),b,a) == x