功能:求Erdélyi函数值

格式:ErdelyiG(z)

说明:ErdelyiG(z)={DiGamma<算式解析\DiGamma>}(1/2+z/2)-{DiGamma<算式解析\DiGamma>}(z/2)

参考:{ErdelyiG Function<http://mathworld.wolfram.com/G-Function.html>}

例子:

ErdelyiG(10+6.5i)//回车
ans = 0.071733866241765 - 0.0488972297396743i