# Tema10 - 10.14 Option Explicit Sub LUDTest Dim n As Integer...

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Unformatted text preview: 10.14 Option Explicit Sub LUDTest() Dim n As Integer, er As Integer, i As Integer, j As Integer Dim a(3, 3) As Single, b(3) As Single, x(3) As Single Dim tol As Single n = 3 a(1, 1) = 3: a(1, 2) = -0.1: a(1, 3) = -0.2 a(2, 1) = 0.1: a(2, 2) = 7: a(2, 3) = -0.3 a(3, 1) = 0.3: a(3, 2) = -0.2: a(3, 3) = 10 b(1) = 7.85: b(2) = -19.3: b(3) = 71.4 tol = 0.000001 Call LUD(a(), b(), n, x(), tol, er) 'output results to worksheet Sheets("Sheet1").Select Range("a3").Select For i = 1 To n ActiveCell.Value = x(i) ActiveCell.Offset(1, 0).Select Next i Range("a3").Select End Sub Sub LUD(a, b, n, x, tol, er) Dim i As Integer, j As Integer Dim o(3) As Single, s(3) As Single Call Decompose(a, n, tol, o(), s(), er) If er = 0 Then Call Substitute(a, o(), n, b, x) Else MsgBox "ill-conditioned system" End End If End Sub Sub Decompose(a, n, tol, o, s, er) Dim i As Integer, j As Integer, k As Integer Dim factor As Single For i = 1 To n o(i) = i s(i) = Abs(a(i, 1)) For j = 2 To n If Abs(a(i, j)) > s(i) Then s(i) = Abs(a(i, j)) Next j Next i For k = 1 To n - 1 Call Pivot(a, o, s, n, k) If Abs(a(o(k), k) / s(o(k))) < tol Then er = -1 Exit For End If For i = k + 1 To n factor = a(o(i), k) / a(o(k), k) a(o(i), k) = factor For j = k + 1 To n a(o(i), j) = a(o(i), j) - factor * a(o(k), j) Next j Next i Next k If (Abs(a(o(k), k) / s(o(k))) < tol) Then er = -1 End Sub Sub Pivot(a, o, s, n, k) Dim ii As Integer, p As Integer Dim big As Single, dummy As Single p = k big = Abs(a(o(k), k) / s(o(k))) For ii = k + 1 To n dummy = Abs(a(o(ii), k) / s(o(ii))) If dummy > big Then big = dummy...
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Tema10 - 10.14 Option Explicit Sub LUDTest Dim n As Integer...

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