Module « scipy.signal »

Fonction qspline1d_eval - module scipy.signal

Signature de la fonction qspline1d_eval

def qspline1d_eval(cj, newx, dx=1.0, x0=0) 

Description

qspline1d_eval.__doc__

Evaluate a quadratic spline at the new set of points.

    Parameters
    ----------
    cj : ndarray
        Quadratic spline coefficients
    newx : ndarray
        New set of points.
    dx : float, optional
        Old sample-spacing, the default value is 1.0.
    x0 : int, optional
        Old origin, the default value is 0.

    Returns
    -------
    res : ndarray
        Evaluated a quadratic spline points.

    See Also
    --------
    qspline1d : Compute quadratic spline coefficients for rank-1 array.

    Notes
    -----
    `dx` is the old sample-spacing while `x0` was the old origin. In
    other-words the old-sample points (knot-points) for which the `cj`
    represent spline coefficients were at equally-spaced points of::

      oldx = x0 + j*dx  j=0...N-1, with N=len(cj)

    Edges are handled using mirror-symmetric boundary conditions.

    Examples
    --------
    We can filter a signal to reduce and smooth out high-frequency noise with
    a quadratic spline:

    >>> import matplotlib.pyplot as plt
    >>> from scipy.signal import qspline1d, qspline1d_eval
    >>> rng = np.random.default_rng()
    >>> sig = np.repeat([0., 1., 0.], 100)
    >>> sig += rng.standard_normal(len(sig))*0.05  # add noise
    >>> time = np.linspace(0, len(sig))
    >>> filtered = qspline1d_eval(qspline1d(sig), time)
    >>> plt.plot(sig, label="signal")
    >>> plt.plot(time, filtered, label="filtered")
    >>> plt.legend()
    >>> plt.show()