scipy.signal.lfiltic¶
- scipy.signal.lfiltic(b, a, y, x=None)[source]¶
Construct initial conditions for lfilter.
Given a linear filter (b, a) and initial conditions on the output y and the input x, return the inital conditions on the state vector zi which is used by lfilter to generate the output given the input.
Parameters : b : array_like
Linear filter term.
a : array_like
Linear filter term.
y : array_like
Initial conditions.
If N=len(a) - 1, then y = {y[-1], y[-2], ..., y[-N]}.
If y is too short, it is padded with zeros.
x : array_like, optional
Initial conditions.
If M=len(b) - 1, then x = {x[-1], x[-2], ..., x[-M]}.
If x is not given, its initial conditions are assumed zero.
If x is too short, it is padded with zeros.
Returns : zi : ndarray
The state vector zi. zi = {z_0[-1], z_1[-1], ..., z_K-1[-1]}, where K = max(M,N).
See also