def Lennard_Jones(r, params, lam):
    """
    Computes the Lennard-Jones potential with epsilon and sigma parameters

    Parameters
    ----------

    eps: float
        Epsilon parameter used for LJ equation
    sig: float
        Sigma parameter used for LJ equation
    grid.ri: ndarray
        In the context of rism, ri corresponds to grid points upon which
        RISM equations are solved
    lam: float
        Lambda parameter to switch on potential

    Returns
    -------
    result: float
        The result of the LJ computation
    """
    eps, sig = params
    return 4.0 * eps * ((sig / r) ** 12 - (sig / r) ** 6) * lam