最小二乘法Visual basic

Public puba(20) As Double
Public Sub Iapcir(x() As Double, _
y() As Double, _
ByVal n As Integer, _
ByRef a() As Double, _
ByVal m As Integer, _
ByRef rdblAverageX As Double, _
ByRef dt() As Double)

Dim I As Integer, J As Integer, K As Integer
Dim Z As Double, p As Double, C As Double, G As Double, Q As Double, D1 As Double, D2 As Double
Dim S(19) As Double, t(19) As Double, B(19) As Double

For I = 0 To m - 1
a(I) = 0
Next I

If m > n Then m = n
If m > 20 Then m = 20

Z = 0#

For I = 0 To n - 1
rdblAverageX = rdblAverageX + x(I)
Z = Z + x(I) / (1# * n)
Next I
rdblAverageX = rdblAverageX / n

B(0) = 1#

D1 = 1# * n
p = 0#
C = 0#

For I = 0 To n - 1
p = p + (x(I) - Z)
C = C + y(I)
Next I

C = C / D1
p = p / D1
a(0) = C * B(0)

If m > 1 Then
t(1) = 1#
t(0) = (-1) * p
D2 = 0#
C = 0#
G = 0#
For I = 0 To n - 1
Q = x(I) - Z - p
D2 = D2 + Q * Q
C = C + y(I) * Q
G = G + (x(I) - Z) * Q * Q
Next I

C = C / D2
p = G / D2
Q = D2 / D1
D1 = D2