lfiltic#

scipy.signal.lfiltic(b,a,y,x=None)[source]#

Construct initial conditions for lfilter given input and output vectors.

Given a linear filter (b, a) and initial conditions on the outputyand the inputx, return the initial conditions on the state vector ziwhich is used bylfilter to generate the output given the input.

Parameters:

barray_like

Linear filter term.

aarray_like

Linear filter term.

yarray_like

Initial conditions.

IfN=len(a)-1, theny={y[-1],y[-2],...,y[-N]}.

Ify is too short, it is padded with zeros.

xarray_like, optional

Initial conditions.

IfM=len(b)-1, thenx={x[-1],x[-2],...,x[-M]}.

Ifx is not given, its initial conditions are assumed zero.

Ifx is too short, it is padded with zeros.

Returns:

zindarray

The state vectorzi={z_0[-1],z_1[-1],...,z_K-1[-1]},whereK=max(M,N).

See also

lfilter,lfilter_zi