VB写的最小二乘法曲线拟合

《VB写的最小二乘法曲线拟合》由会员分享，可在线阅读，更多相关《VB写的最小二乘法曲线拟合（8页珍藏版）》请在装配图网上搜索。

1、Option ExplicitDim x() As Double, y() As DoubleDim 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 DoubleDim xiaoA() As DoubleDim Xmin As Double, Xmax As DoubleDim Ymin As Double, Ymax As DoubleDim X0pos As Double, Y0pos As DoubleDim xmaxpos As Double, ym

2、axpos As DoubleDim xstep As Double, ystep As DoubleDim xl As Double, yl As DoubleDim xbc As Double, ybc As DoubleDim bc As DoubleDim Xh As DoublePrivate Sub HuaZuoBiao(x() As Double, y() As Double)ReDim xpos(I) As DoubleReDim ypos(I) As DoubleReDim x(I), y(I)X0pos = Width * 0.25 坐标原点最左点Y0pos = Heigh

3、t * 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 = vbBlueLine (Width * 0.1, Y0pos)-(Width * 0.9, Y0pos) 画 X 坐标轴 ,从左 10% ，到右的 90%处Line

4、(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 * 0.9CurrentY = Y0pos + 100Print X 在横线上画 X 轴标志在横线上画 X 轴箭头标志CurrentX = Width * 0.9CurrentY = Y0posLine (CurrentX - 200, CurrentY - 50)-(CurrentX, CurrentY)Line (CurrentX, CurrentY)-(Cur

5、rentX - 200, CurrentY + 50)CurrentX = X0pos - 500CurrentY = 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 = X0posCurrentY = Height * 0.1Line (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C

6、urrentY = 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 - YminIf xl 0.01 Then xbc = 0.001ElseIf xl = 0.1 Then xbc = 0.01ElseIf xl = 2 Thenxbc = 0.1ElseIf xl = 20 Then xbc = 1ElseIf xl = 120 Then xbc = 10ElseIf xl = 1000 Then xbc = 100ElseIf xl = 10

7、000 Then xbc = 1000Elsexbc = 10000End IfIf yl 0.01 Then ybc = 0.001ElseIf yl = 0.1 Then ybc = 0.01ElseIf yl = 2 Then ybc = 0.1ElseIf yl = 20 Then ybc = 1ElseIf yl = 120 Thenybc = 10ElseIf yl = 1000 Thenybc = 100ElseIf yl = 10000 Then ybc = 1000Elseybc = 10000End IfFor bc = Xmin To Xmax Step xbcIf bc

8、 = Xmax Then x(j) = bc X 轴上的相对坐标值xpos(j) = X0pos + (x(j) - Xmin) * xstepLine (xpos(j), Y0pos)-(xpos(j), ymaxpos), vbRed 画垂直于 X 轴的刻度线，只画了ElseEnd IfFont.Size = 10 指定X轴，Y轴坐标刻度值的字体大小CurrentX = xpos(j) - 200 取当前X轴上的相对坐标值CurrentY = Y0pos + 100 此为X轴下方100绝对坐标处Print x(j)在X轴下方100绝对坐标处对应显示 X轴相对坐标刻度值Next bcFor

9、bc = Ymin To Ymax Step ybcIf bc = Ymax Theny(j) = bc X 轴上的相对坐标值ypos(j) = Y0pos + (y(j) - Ymin) * ystepLine (X0pos, ypos(j)-(xmaxpos, ypos(j), vbRed 画垂直于 X 轴的刻度线，只画了ElseEnd IfFont.Size = 10 指定X轴，Y轴坐标刻度值的字体大小CurrentX = X0pos - 500 取当前 X轴上的相对坐标值100 个绝对尺寸100 个绝对尺寸CurrentY = ypos(j) - 100 此为X轴下方100绝对坐标处P

10、rint y(j)在X轴下方100绝对坐标处对应显示X轴相对坐标刻度值Next bcEnd SubPrivate Sub ZuoDian(x() As Double, y() As Double)ReDim xpos(I) As DoubleReDim ypos(I) As DoubleFor I = 0 To Nxpos(I) = X0pos + (x(I) - Xmin) * xstepypos(I) = Y0pos + (y(I) - Ymin) * ystepIf y(I) = Ymax ThenDrawWidth = 4PSet (xpos(I), ypos(I), vbRedEls

11、eEnd IfNext IDrawWidth = 1End SubPrivate Sub HuaQuXian(xiaoA() As Double)ReDim xpos(I) As DoubleReDim ypos(I) As DoubleDim Ysum As Double, Ii As DoubleFor Ii = Xmin To Xmax Step 1 / (Xmax - Xmin)Ysum = 0For j = 1 To MYsum = Ysum + xiaoA(j) * Ii A (j - 1)Next jxpos(I) = X0pos + (Ii - Xmin) * xstepypo

12、s(I) = Y0pos + (Ysum - Ymin) * ystep DrawWidth = 2If Ii = Xmin Thenxpos(0) = X0pos + (Ii - Xmin) * xstepypos(0) = Y0pos + (Ysum - Ymin) * ystep PSet (xpos(0), ypos(0)ElseEnd IfIf Ysum = Ymax ThenDrawWidth = 2Line -(xpos(I), ypos(I), vbBlueElseEnd IfNext IiDrawWidth = 1End SubPrivate Sub JieFangCheng

13、(A() As Double, B() As Double, x() As Double) Dim nn As Double nn = UBound(B)Dim TempA As Double, L As Double, K As Double, Kk As DoubleDim Ii As Double, ChuShu As Double, Sum As DoubleFor I = 1 To nnL = 0: Kk = 0For j = I To nnIf A(j, I) = 0 Then L = L + 1Next jFor j = I To nn - LIf A(j, I) = 0 The

14、nKk = Kk + 1For K = I To nnTempA = A(j, K)A(j, K) = A(nn - Kk + 1, K)A(nn - Kk + 1, K) = TempANext KTempA = B(j): B(j) = B(nn - Kk + 1): B(nn - Kk + 1) = TempA End IfNext jFor Ii = I To nn - L ChuShu = A(Ii, I)For j = I To nnA(Ii, j) = A(Ii, j) / ChuShuNext jB(Ii) = B(Ii) / ChuShuNext IiFor Ii = I +

15、 1 To nn - LFor j = I To nnA(Ii, j) = A(Ii, j) - A(I, j)Next jB(Ii) = B(Ii) - B(I)Next IiNext IFor I = 1 To nnFor j = 1 To I - 1A(I, j) = 0Next jNext I x(nn) = B(nn) / A(nn, nn)For I = nn - 1 To 1 Step -1Sum = 0For j = I + 1 To nnSum = Sum + A(I, j) * x(j)Next jx(I) = (B(I) - Sum) / A(I, I) Next IEn

16、d SubPrivate Sub Command1_Click()ClsXmin = 0 InputBox( 请输入 x 坐标下限值 , x 坐标下限值 , 0) Ymin = 0 InputBox( 请输入 y 坐标下限值 , y 坐标下限值 , 0) Xmax = 10 InputBox( 请输入 x 坐标上限值 , x 坐标上限值度 , 10) Ymax = 10 InputBox( 请输入 y 坐标上限值 , y 坐标上限值度 , 10) N = 20For I = 0 To NReDim Preserve x(I)ReDim Preserve y(I)Next ICall HuaZu

17、oBiao(x, y)End SubPrivate Sub Command2_Click()For I = 0 To Nx(I) = Xmin + I * (Xmax - Xmin) / N InputBox( 请输入 X 坐标测量值 , X 坐标值 , 0) y(I) = Sin(x(I) + 5 InputBox( 请输入 Y 坐标测量值 , Y 坐标值 , 0) Next ICall ZuoDian(x, y)End SubPrivate Sub Command3_Click()M = 20 InputBox( 请输入拟合曲线次数 M, 拟合曲线 , 3)Erase B: Erase x

18、iaoA: Erase A 必不可少 *ReDim B(M): ReDim xiaoA(1 To M)形成方程组的各元素A(1, 1) = NFor I = 1 To NB(1) = B(1) + y(I)Next IFor j = 2 To MFor I = 1 To NA(1, j) = A(1, j) + x(l)八(j - 1)Next INext jFor l = 2 To MFor j = 1 To MFor Xh = 1 To NA(l, j) = A(l, j) + x(Xh)人(I + j - 2)lf j = 1 ThenB(l) = B(l) + x(Xh) A (I -

19、 1) * y(Xh)End lfNext XhNext jNext lCall JieFangCheng(A, B, xiaoA)ForeColor = vbBlackPSet (0, 0)For I = 1 To MPrint Tab(6); a; I - 1; Tab(12); =; xiaoA(I);Next IDim Str As String: Str = y=For I = 1 To M写方程If I M ThenStr = Str & xiaoA(l) & 吩& I - 1 & +ElseStr = Str & xiaoA(I) & 吩& I - 1End IfNext IPr

20、int vbCrLf; 曲线方程 :; vbCrLf & StrCall HuaQuXian(xiaoA)End SubPrivate Sub Command4_Click()EndEnd SubPrivate Sub Form_Load()Width = Screen.Width * 1 取屏幕宽度的一半 Height = Screen.Height * 0.5 取屏幕高度的一半Height = Screen.Width * 1 取屏幕宽度的一半Left = (Screen.Width - Width) / 2 使窗体居屏幕中心 Top = (Screen.Height - Height) / 2 使窗体居屏幕中心End Sub