def mex_hat(x, sigma):
    r"""Mexican hat

    This method implements a Mexican hat (or Ricker) wavelet.

    Parameters
    ----------
    x : float
        Input data point
    sigma : float
        Standard deviation (filter scale)

    Returns
    -------
    float Mexican hat filtered data point

    Examples
    --------
    >>> from modopt.signal.filter import mex_hat
    >>> mex_hat(2, 1)
    -0.35213905225713371

    """

    x = check_float(x)
    sigma = check_float(sigma)

    xs = (x / sigma) ** 2
    val = 2 * (3 * sigma) ** -0.5 * np.pi ** -0.25

    return val * (1 - xs) * np.exp(-0.5 * xs)
def mex_hat ( x , sigma ) : x = check_float ( x ) sigma = check_float ( sigma ) xs = ( x / sigma ) ** 2 val = 2 * ( 3 * sigma ) ** - 0.5 * np . pi ** - 0.25 return val * ( 1 - xs ) * np . exp ( - 0.5 * xs )
r"""Mexican hat

    This method implements a Mexican hat (or Ricker) wavelet.

    Parameters
    ----------
    x : float
        Input data point
    sigma : float
        Standard deviation (filter scale)

    Returns
    -------
    float Mexican hat filtered data point

    Examples
    --------
    >>> from modopt.signal.filter import mex_hat
    >>> mex_hat(2, 1)
    -0.35213905225713371