VB写的最小二乘法曲线拟合.doc

Option Explicit Dim x() As Double, y() As Double Dim A(20, 20) As Double, M As Double, B() As Double 最多取20次的拟合 Dim N As Double, I As Double, j As Double Dim xiaoA() As Double Dim Xmin As Double, Xmax As Double Dim Ymin As Double, Ymax As Double Dim X0pos As Double, Y0pos As Double Dim xmaxpos As Double, ymaxpos As Double Dim xstep As Double, ystep As Double Dim xl As Double, yl As Double Dim xbc As Double, ybc As Double Dim bc As Double Dim Xh As Double Private Sub HuaZuoBiao(x() As Double, y() As Double) ReDim xpos(I) As Double ReDim ypos(I) As Double ReDim x(I), y(I) X0pos = Width * 0.25 坐标原点最左点 Y0pos = Height * 0.75 坐标原点最低点 xmaxpos = Width * 0.85 坐标最右点 ymaxpos = Height * 0.15 坐标最高点 xstep = (xmaxpos - X0pos) / (Xmax - Xmin) 对应X轴上单位长度代表的屏幕宽度值 ystep = (ymaxpos - Y0pos) / (Ymax - Ymin) 对应Y轴上单位长度代表的屏幕高度值 在屏幕上画直角坐标系 ForeColor = vbBlue Line (Width * 0.1, Y0pos)-(Width * 0.9, Y0pos) 画X坐标轴,从左10%，到右的90%处 Line (X0pos, Height * 0.1)-(X0pos, Height * 0.9) 画y坐标轴,从上10%，到下的90%处 Font.Size = 20 指定X轴，Y轴标志的字体大小 CurrentX = Width * 0.9 CurrentY = Y0pos + 100 Print X 在横线上画X轴标志 在横线上画X轴箭头标志 CurrentX = Width * 0.9 CurrentY = Y0pos Line (CurrentX - 200, CurrentY - 50)-(CurrentX, CurrentY) Line (CurrentX, CurrentY)-(CurrentX - 200, CurrentY + 50) CurrentX = X0pos - 500 CurrentY = Height * 0.1 Print y 在纵线上画Y轴标志 在纵线上画Y轴箭头标志 CurrentX = X0pos CurrentY = Height * 0.1 Line (CurrentX - 50, CurrentY + 200)-(CurrentX, CurrentY) Line (CurrentX, CurrentY)-(CurrentX + 50, CurrentY + 200) CurrentX = X0pos + 200 此为Y轴左边500绝对坐标处 CurrentY = Y0pos + 400 取当前Y轴上的相对坐标值 Print f=f(x) 在Y轴左边500绝对坐标处对应显示Y轴相对坐标刻度值 xl = Xmax - Xmin yl = Ymax - Ymin If xl 0.01 Then xbc = 0.001 ElseIf xl = 0.1 Then xbc = 0.01 ElseIf xl = 2 Then xbc = 0.1 ElseIf xl = 20 Then xbc = 1 ElseIf xl = 120 Then xbc = 10 ElseIf xl = 1000 Then xbc = 100 ElseIf xl = 10000 Then xbc = 1000 Else xbc = 10000 End If If yl 0.01 Then ybc = 0.001 ElseIf yl = 0.1 Then ybc = 0.01 ElseIf yl = 2 Then ybc = 0.1 E