功能: 计算神经网络LLine激活函数

格式: netFunByLLine(x)

x : 为矩阵变量或者数值

说明:
1. 函数执行成功返回和x同纬度的矩阵变量

2. 本函数主要计算的原理如下
$$\mathbf{netFunByLLine}(x_i) = \dfrac{x_i}{2}(1 + \dfrac{x_i}{1 + |x_i|})$$

例子:
x =
[-0.73290256607947   -1.95092696112158    0.21744714338213    2.19789781453921
 -4.72275318588258    1.99957438581603    2.94959032789319   -4.31942455462153
 -6.10488919615973   -1.19050327068684   -6.38943656901337    2.98098757280083
 -2.76742173278119   -4.81647247463300   -3.72662812435377   -4.00467786914887 ]
y = netFunByLLine(x)//回车得到如下结果
y =
[-0.21146675538071   -0.33056171617004    0.12814259140870    1.85425052778938
 -0.41262946631466    1.66626470107020    2.57618573614828   -0.40600487047690
 -0.42962592572587   -0.27174195232165   -0.43233584247861    2.60658454864073
 -0.36728324157357   -0.41403724470791   -0.39421634475033   -0.40009346993495 ]