def max_amplitude(pathways):
    """Return the maximum of pathway prefactors
    
    
    Parameters
    ----------
    
    pathways : list
        List of Liouville pathways
        
        
    Returns
    -------
    
    pmax : float
        Maximum prefactor of the pathways
        
    rec : int
        position of the pathway with the maximum prefactor
    
    """
    pmax = 0.0
    k = 0
    rec = -1
    for pway in pathways:
        if pway.pref > pmax:
            rec = k
            pmax = pway.pref
        k += 1
    return pmax, rec
