功能: 计算Heumann Lambda函数
格式: HeumannLambda(p, k)
p : 数值或者矩阵变量
k : 数值或者矩阵变量,此参数范围(-1,1)

说明:
1、函数定义如下
$$
\begin{aligned}
\mathbf{HeumannLambda}(p, k) &= \dfrac{2}{\pi}\sqrt{w}\sin(p)\int_0^{\pi/2}\dfrac{1+k_c^2\tan^2(t)}{(1+w\tan^2(t))\sqrt{\cos^2(t)+k_c^2\sin(t)}}dt
\\
\\
w&=1+k^2\tan^2(p)
\end{aligned}
$$
参考:
[1] Bulirsch R. An extension of the Bartky-transformation to incomplete elliptic integrals of the third kind[J]. Numerische Mathematik, 1969, 13(3): 266-284.
[2] Carlson B C. Numerical computation of real or complex elliptic integrals[J]. Numerical Algorithms, 1995, 10(1): 13-26.
[3] NIST handbook of mathematical functions hardback and CD-ROM[M]. Cambridge university press, 2010.

例子:
a = HeumannLambda(0.1,0.2)//执行得到如下结果
a =
[ 0.09882756888840 ]