using?System;
using?System.Collections.Generic;
using?System.Text;
using?System.Data;

namespace?鐵路運量預測及改擴建輔助程序
{
????class?Forecast
????{
????????//data有二列，第一列表示x值，第二列表示y值
????????
????????//一元線性回歸分析預測返回相關系數
????????public?static?double?LinearRegression（double[]?dataout?double?Aout?double?B）
????????{
????????????double[]?derivedData?=?new?double[data.GetLength（0）?+?1?data.GetLength（1）?+?3];
????????????for?（int?i?=?0;?i?????????????{
????????????????derivedData[i?0]?=?data[i?0];???//X
????????????????derivedData[i?1]?=?data[i?1];???//Y
????????????????derivedData[i?2]?=?data[i?0]?*?data[i?1];??//XY
????????????????derivedData[i?3]?=?data[i?0]?*?data[i?0];??//XX
????????????????derivedData[i?4]?=?data[i?1]?*?data[i?1];??//YY
????????????????derivedData[derivedData.GetLength（0）?-?1?0]?+=?derivedData[i?0];?//X的累加
????????????????derivedData[derivedData.GetLength（0）?-?1?1]?+=?derivedData[i?1];?//Y的累加
????????????????derivedData[derivedData.GetLength（0）?-?1?2]?+=?derivedData[i?2];?//XY的累加
????????????????derivedData[derivedData.GetLength（0）?-?1?3]?+=?derivedData[i?3];?//XX的累加
????????????????derivedData[derivedData.GetLength（0）?-?1?4]?+=?derivedData[i?4];?//YY的累加
????????????}

????????????double?xba?=?derivedData[derivedData.GetLength（0）?-?1?0]?/?data.GetLength（0）;
????????????double?yba?=?derivedData[derivedData.GetLength（0）?-?1?1]?/?data.GetLength（0）;
????????????double?Lxx?=?derivedData[derivedData.GetLength（0）?-?1?3]?-?Math.Pow（derivedData[derivedData.GetLength（0）?-?1?0]?2）?/?data.GetLength（0）;
????????????double?Lyy?=?derivedData[derivedData.GetLength（0）?-?1?4]?-?Math.Pow（derivedData[derivedData.GetLength（0）?-?1?1]?2）?/?data.GetLength（0）;
????????????double?Lxy?=?derivedData[derivedData.GetLength（0）?-?1?2]?-?derivedData[derivedData.GetLength（0）?-?1?0]?*?derivedData[derivedData.GetLength（0）?-?1?1]?/?data.GetLength（0）;
????????????double?b?=?Lxy?/?Lxx;
????????????double?a?=?yba?-?b?*?xba;
????????????A?=?a;
????????????B?=?b;
????????????return?Lxy?/?Math.Sqrt（Lxx?*?Lyy）;
????????}
????????public?static?double?LinearRegression（double[]?data?double?x?out?double?r）
????????{
????????????double?a;
????????????double?b;
????????????r?=?LinearRegression（data?out?a?out?b）;
????????????return?a?+?b?*?x;
????????}
????????//冪回歸分析預測
????????public?static?double?PowerRegression（double[]?data?out?double?A?out?double?B）
????????{
????????????double[]?derivedData?=?（double[]）data.Clone（）;
????????????for?（int?i?=?0;?i?????????????{
????????????????for?（int?j?=?0;?j?????????????????{
????????????????????derivedData[i?j]?=?Math.Log（derivedData[i?j]）;
????????????????}
????????????}
????????????double?a;
????????????double?b;
????????????double?r;
????????????r?=?LinearRegression（derivedData?out?a?out?b）;
????????????A?=?Math.Exp（a）;
????????????B?=?b;
?