scipy.fftpack.
cs_diff#
- scipy.fftpack.cs_diff(x, a, b, period=None, _cache=<_thread._local object>)[source]#
- Return (a,b)-cosh/sinh pseudo-derivative of a periodic sequence. - If - x_jand- y_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.