### Navigation

- index
- modules |
- modules |
- next |
- previous |
- SciPy v0.12 Reference Guide (DRAFT) »
- Signal processing (`scipy.signal`) »

# scipy.signal.lfiltic

`scipy.signal.``lfiltic`(b, a, y, x=None)

  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

  `lfilter`

### Navigation

- index
- modules |
- modules |
- next |
- previous |
- SciPy v0.12 Reference Guide (DRAFT) »
- Signal processing (`scipy.signal`) »