diff_bulk.py 文件源码

def Cn(l):
    alpha = acosh(l/r)
    s = 0.
    for n in range(1, 100):
        n = float(n)
        K = n*(n+1)/(2*n-1)/(2*n+3)
        s += K*((2*sinh((2*n+1)*alpha)+(2*n+1)*sinh(2*alpha))/(4*(sinh((n+.5)*alpha))**2-(2*n+1)**2*(sinh(alpha))**2) - 1)
    return 1./((4./3.)*sinh(alpha)*s)