对数回归方程 LogarithmRegress.cs

　　方程模型为 Y=a*LnX+b

public override double[] buildFormula()

得到系数数组，存放顺序与模型系数相反，即该数组中系数的值依次是b,a。

public override double forecast(double x)

预测函数，根据模型得到预测结果。

public override double computeR2()

计算相关系数（决定系数），系数越接近1，数据越满足该模型。

-Logarithmic regression equation LogarithmRegress.cs equation model for Y = a* LnX+ Bpublic override double [] buildFormula () get coefficient array, the storage order and model coefficients contrary, that is, the array is followed by the value of coefficient b, a. public override double forecast (double x) prediction function, according to the results of model prediction. public override double computeR2 () calculated the correlation coefficient (determination coefficient), coefficient of the closer one, the data satisfy the model more.