scipy.fftpack.cs_diff#
- scipy.fftpack.cs_diff(x, a, b, period=None, _cache={})[source]#
Return (a,b)-cosh/sinh pseudo-derivative of a periodic sequence.
If
x_jandy_jare Fourier coefficients of periodic functions x and y, respectively, then:y_j = -sqrt(-1)*cosh(j*a*2*pi/period)/sinh(j*b*2*pi/period) * x_j y_0 = 0
- Parameters
- xarray_like
The array to take the pseudo-derivative from.
- a, bfloat
Defines the parameters of the cosh/sinh pseudo-differential operator.
- periodfloat, optional
The period of the sequence. Default period is
2*pi.
- Returns
- cs_diffndarray
Pseudo-derivative of periodic sequence x.
Notes
For even len(x), the Nyquist mode of x is taken as zero.