crefl_utils.py 文件源码

def csalbr(tau):
    # Previously 3 functions csalbr fintexp1, fintexp3
    a = [-.57721566, 0.99999193, -0.24991055, 0.05519968, -0.00976004,
         0.00107857]
    #xx = a[0] + a[1] * tau + a[2] * tau**2 + a[3] * tau**3 + a[4] * tau**4 + a[5] * tau**5
    #xx = np.polyval(a[::-1], tau)

    # xx = a[0]
    # xftau = 1.0
    # for i in xrange(5):
    #     xftau = xftau*tau
    #     xx = xx + a[i] * xftau
    fintexp1 = np.polyval(a[::-1], tau) - np.log(tau)
    fintexp3 = (np.exp(-tau) * (1.0 - tau) + tau**2 * fintexp1) / 2.0

    return (3.0 * tau - fintexp3 *
            (4.0 + 2.0 * tau) + 2.0 * np.exp(-tau)) / (4.0 + 3.0 * tau)

# From crefl.1.7.1