d1r2.txt

VB常用数值算法集2

Private Sub Command1_Click()
    'program D1R2
    'Driver program for routine LUBKSB,LUDCMP
    N = 3
    Dim A(3, 3), B(3), A1(3, 3), INDX(3), X(3)
    '输入已知的方程组的系数矩阵
    A(1, 1) = 1#: A(1, 2) = 2#: A(1, 3) = 3#
    A(2, 1) = 2#: A(2, 2) = 2#: A(2, 3) = 3#
    A(3, 1) = 3#: A(3, 2) = 3#: A(3, 3) = 3#
    '输入已知的方程组的右端向量
    B(1) = 1#
    B(2) = 2#
    B(3) = 3#
    Print
    Print Tab(5); "已知的方程组的右端向量"
    Print Tab(14); Format$(B(1), "##.##")
    Print Tab(14); Format$(B(2), "##.##")
    Print Tab(14); Format$(B(3), "##.##")
    For I = 1 To N
        For J = 1 To N
            A1(I, J) = A(I, J)
        Next J
    Next I
    Call LUDCMP(A1(), N, INDX(), P)
    For L = 1 To N
        X(L) = B(L)
    Next L
    Call LUBKSB(A1(), N, INDX(), X())
    Print
    Print Tab(5); "计算出的方程组的解"
    Print Tab(14); Format$(X(1), "#.####E+00")
    Print Tab(14); Format$(X(2), "#.####E+00")
    Print Tab(14); Format$(X(3), "#.####E+00")
    '将计算出的B乘以系数矩阵，以验证计算结果正确
    For L = 1 To N
        B(L) = 0#
        For J = 1 To N
            B(L) = B(L) + A(L, J) * X(J)
        Next J
    Next L
    Print
    Print Tab(5); "计算出的解乘以系数矩阵的结果"
    Print Tab(14); Format$(B(1), "##.##")
    Print Tab(14); Format$(B(2), "##.##")
    Print Tab(14); Format$(B(3), "##.##")
End Sub