AR.rar_AR_AR prediction_来水预测_河道

Private Function MRinv(N As Integer, mtxA() As Double) As Boolean '**************************************************************************************** ' 功能： 实现矩阵求逆的全选主元高斯－约当法 ' 参数： n - Integer型变量，矩阵的阶数 ' mtxA - Double型二维数组，体积为n x n。存放原矩阵A；返回时存放其逆矩阵A-1。 ' 返回值：Boolean型，失败为False，成功为True '**************************************************************************************** ReDim nIs(N) As Integer, nJs(N) As Integer Dim i As Integer, j As Integer, k As Integer Dim D As Double, p As Double ' 全选主元，消元 For k = 1 To N D = 0# For i = k To N For j = k To N p = Abs(mtxA(i, j)) If (p > D) Then D = p nIs(k) = i nJs(k) = j End If Next j Next i ' 求解失败 If (D + 1# = 1#) Then MRinv = False Exit Function End If If (nIs(k) <> k) Then For j = 1 To N p = mtxA(k, j) mtxA(k, j) = mtxA(nIs(k), j) mtxA(nIs(k), j) = p Next j End If If (nJs(k) <> k) Then For i = 1 To N p = mtxA(i, k) mtxA(i, k) = mtxA(i, nJs(k)) mtxA(i, nJs(k)) = p Next i End If mtxA(k, k) = 1# / mtxA(k, k) For j = 1 To N If (j <> k) Then mtxA(k, j) = mtxA(k, j) * mtxA(k, k) Next j For i = 1 To N If (i <> k) Then For j = 1 To N If (j <> k) Then mtxA(i, j) = mtxA(i, j) - mtxA(i, k) * mtxA(k, j) Next j End If Next i For i = 1 To N If (i <> k) Then mtxA(i, k) = -mtxA(i, k) * mtxA(k, k) Next i Next k ' 调整恢复行列次序 For k = N To 1 Step -1 If (nJs(k) <> k) Then For j = 1 To N p = mtxA(k, j) mtxA(k, j) = mtxA(nJs(k), j) mtxA(nJs(k), j) = p Next j End If If (nIs(k) <> k) Then For i = 1 To N p = mtxA(i, k) mtxA(i, k) = mtxA(i, nIs(k)) mtxA(i, nIs(k)) = p Next i End If Next k ' 求解成功 MRinv = True End Function