def integral_scale(u, t, tau1=0.0, tau2=1.0):
    """Calculate the integral scale of a time series by integrating up to
    the first zero crossing.
    """
    tau, rho = autocorr_coeff(u, t, tau1, tau2)
    zero_cross_ind = np.where(np.diff(np.sign(rho)))[0][0]
    int_scale = np.trapz(rho[:zero_cross_ind], tau[:zero_cross_ind])
    return int_scale
def integral_scale ( u , t , tau1 = 0.0 , tau2 = 1.0 ) : tau , rho = autocorr_coeff ( u , t , tau1 , tau2 ) zero_cross_ind = np . where ( np . diff ( np . sign ( rho ) ) ) [ 0 ] [ 0 ] int_scale = np . trapz ( rho [ : zero_cross_ind ] , tau [ : zero_cross_ind ] ) return int_scale
Calculate the integral scale of a time series by integrating up to
    the first zero crossing.