|
1 |
1 |
1 |
6 |
|
2 |
-1 |
3 |
5 |
|
4 |
2 |
-3 |
3 |
假设SHEET1中，A1：D3(上面的示例数据) 的数据代表一个 三元一次方程组：
x1+x2+x3=6
2x1-x2+3x3=5
4x1+2x2-3x3=3
求x1,x2,x3
Function Determinant(ByRef factor) As Single
Dim i As Long, j As Long, k As Long, row As Long, order As Long
Dim r As Long, c As Long, Pivot As Single, Pivot2 As Single, temp() As Single
Determinant = 1
Dim m
m = factor
row = UBound(m, 1)
If Not UBound(m, 2) = row + 1 Then MsgBox "无解或不定解！": Exit Function
ReDim temp(1 To row)
For i = 1 To row
Pivot = 0
For j = i To row
For k = i To row
If Abs(m(k, j)) > Pivot Then
Pivot = Abs(m(k, j))
r = k: c = j
End If
Next k
Next j
If Pivot = 0 Then Determinant = 0: Exit Function
If r <> i Then
order = order + 1
For j = 1 To row
temp(j) = m(i, j)
m(i, j) = m(r, j)
m(r, j) = temp(j)
Next j
End If
If c <> i Then
order = order + 1
For j = 1 To row
temp(j) = m(j, i)
m(j, i) = m(j, c)
m(j, c) = temp(j)
Next j
End If
Pivot = m(i, i)
Determinant = Determinant * Pivot
For j = i + 1 To row
Pivot2 = m(j, i)
If Pivot2 <> 0 Then
For k = 1 To row
m(j, k) = m(j, k) - m(i, k) * Pivot2 / Pivot
Next
End If
Next
Next
Determinant = Determinant * (-1) ^ order
End Function
Sub getresult(ByVal r As Range, Optional ByRef answer As String)
Dim row As Integer, i As Integer, D0 As Single
Dim m
Dim factor
Dim result() As String
factor = r
row = UBound(factor, 1)
ReDim result(1 To row)
D0 = Determinant(factor)
If D0 = 0 Then MsgBox "无解！": Exit Sub
For i = 1 To row
m = factor
For j = 1 To row
m(j, i) = factor(j, row + 1)
Next
result(i) = "X" & i & "= " & Format(Determinant(m) / D0, "0.00") ' Di/D0
Next
answer = Join(result, vbCrLf)
End Sub
Sub solver()
Dim answer As String
getresult [a1:d3], answer
MsgBox answer, 0, "答案"
End Sub |
