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分享再次求助。。vb如何做二次曲线拟合和画图？求代码研究
功能要求是
输入5到6组实验数据（x，y）
要拟合成二次函数y=ax^2+bx+c的形式
算法最小二乘法最好
并能画出图形（坐标可变，不一定非要原点是0，0）
求高人出代码相助
感激不尽
输入5到6组实验数据（x，y）
要拟合成二次函数y=ax^2+bx+c的形式
算法最小二乘法最好
并能画出图形（坐标可变，不一定非要原点是0，0）
求高人出代码相助
感激不尽
...全文
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angrycoco 2015-04-21
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能给解析下这个代码吗，我要输入数据的应该做什么界面，对应哪个参数。。
Public Sub qxnh2() '最小二乘曲线拟合y=a+bx+cx^2
Dim b, c, m, n, a(1 To 10, 1 To 10) As Double
Dim i, j, k, d(10) As Double
'm = 14 '9 'm为数据个数
For i = 1 To 10 Step 1
d(i) = 0
Next i
For i = 1 To m Step 1
d(1) = d(1) + x(i)
a(1, 2) = d(1)
d(2) = d(2) + x(i) ^ 2
a(1, 3) = d(2)
d(3) = d(3) + y(i)
a(1, 4) = d(3)
d(4) = d(4) + x(i) ^ 3
a(2, 3) = d(4)
d(5) = d(5) + x(i) * y(i)
a(2, 4) = d(5)
d(6) = d(6) + x(i) ^ 4
a(3, 3) = d(6)
d(7) = d(7) + x(i) ^ 2 * y(i)
a(3, 4) = d(7)
Next i
a(1, 1) = m
a(2, 1) = a(1, 2)
a(2, 2) = a(1, 3)
a(3, 1) = a(1, 3)
a(3, 2) = a(2, 3)
n = 3 'n为行数
m = 4 'm为列数
For k = 1 To n - 1 Step 1
For i = k + 1 To n Step 1
For j = k + 1 To m Step 1
a(i, j) = a(i, j) - a(i, k) * a(k, j) / a(k, k)
Next j
Next i
Next k
z(n) = a(n, m) / a(n, n)
For k = n - 1 To 1 Step -1
z(k) = 0
For j = n To k + 1 Step -1
z(k) = z(k) + a(k, j) * z(j)
Next j
z(k) = (a(k, m) - z(k)) / a(k, k)
Next k
xs(1) = z(1): xs(2) = z(2): xs(3) = z(3): xs(4) = 0
End Sub[/quote]
这代码，不是学vb的人写的吧[/quote]
能实现功能吗。。。我需要输入的数据对应什么参数啊，出来的又是什么呢
zzyong00 2015-04-20
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能给解析下这个代码吗，我要输入数据的应该做什么界面，对应哪个参数。。
Public Sub qxnh2() '最小二乘曲线拟合y=a+bx+cx^2
Dim b, c, m, n, a(1 To 10, 1 To 10) As Double
Dim i, j, k, d(10) As Double
'm = 14 '9 'm为数据个数
For i = 1 To 10 Step 1
d(i) = 0
Next i
For i = 1 To m Step 1
d(1) = d(1) + x(i)
a(1, 2) = d(1)
d(2) = d(2) + x(i) ^ 2
a(1, 3) = d(2)
d(3) = d(3) + y(i)
a(1, 4) = d(3)
d(4) = d(4) + x(i) ^ 3
a(2, 3) = d(4)
d(5) = d(5) + x(i) * y(i)
a(2, 4) = d(5)
d(6) = d(6) + x(i) ^ 4
a(3, 3) = d(6)
d(7) = d(7) + x(i) ^ 2 * y(i)
a(3, 4) = d(7)
Next i
a(1, 1) = m
a(2, 1) = a(1, 2)
a(2, 2) = a(1, 3)
a(3, 1) = a(1, 3)
a(3, 2) = a(2, 3)
n = 3 'n为行数
m = 4 'm为列数
For k = 1 To n - 1 Step 1
For i = k + 1 To n Step 1
For j = k + 1 To m Step 1
a(i, j) = a(i, j) - a(i, k) * a(k, j) / a(k, k)
Next j
Next i
Next k
z(n) = a(n, m) / a(n, n)
For k = n - 1 To 1 Step -1
z(k) = 0
For j = n To k + 1 Step -1
z(k) = z(k) + a(k, j) * z(j)
Next j
z(k) = (a(k, m) - z(k)) / a(k, k)
Next k
xs(1) = z(1): xs(2) = z(2): xs(3) = z(3): xs(4) = 0
End Sub[/quote]
这代码，不是学vb的人写的吧
angrycoco 2015-04-20
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能给解析下这个代码吗，我要输入数据的应该做什么界面，对应哪个参数。。
Public Sub qxnh2() '最小二乘曲线拟合y=a+bx+cx^2
Dim b, c, m, n, a(1 To 10, 1 To 10) As Double
Dim i, j, k, d(10) As Double
'm = 14 '9 'm为数据个数
For i = 1 To 10 Step 1
d(i) = 0
Next i
For i = 1 To m Step 1
d(1) = d(1) + x(i)
a(1, 2) = d(1)
d(2) = d(2) + x(i) ^ 2
a(1, 3) = d(2)
d(3) = d(3) + y(i)
a(1, 4) = d(3)
d(4) = d(4) + x(i) ^ 3
a(2, 3) = d(4)
d(5) = d(5) + x(i) * y(i)
a(2, 4) = d(5)
d(6) = d(6) + x(i) ^ 4
a(3, 3) = d(6)
d(7) = d(7) + x(i) ^ 2 * y(i)
a(3, 4) = d(7)
Next i
a(1, 1) = m
a(2, 1) = a(1, 2)
a(2, 2) = a(1, 3)
a(3, 1) = a(1, 3)
a(3, 2) = a(2, 3)
n = 3 'n为行数
m = 4 'm为列数
For k = 1 To n - 1 Step 1
For i = k + 1 To n Step 1
For j = k + 1 To m Step 1
a(i, j) = a(i, j) - a(i, k) * a(k, j) / a(k, k)
Next j
Next i
Next k
z(n) = a(n, m) / a(n, n)
For k = n - 1 To 1 Step -1
z(k) = 0
For j = n To k + 1 Step -1
z(k) = z(k) + a(k, j) * z(j)
Next j
z(k) = (a(k, m) - z(k)) / a(k, k)
Next k
xs(1) = z(1): xs(2) = z(2): xs(3) = z(3): xs(4) = 0
End Sub
