d1r9.txt

VB常用数值算法集2

Private Sub Command1_Click()
    'program D1R9
    'Driver program for routine SPARSE
    N = 20
    Dim B(20), X(20), BCMP(20)
    '输入已知的方程组的右端向量B
    For I = 1 To N
        X(I) = 0#
        B(I) = 1#
    Next I
    B(1) = 3#
    B(N) = -1#
    '利用下列子程序ASUB输入已知的方程组的系数矩阵
    Call SPARSE(B(), N, X(), RSQ)
    Print
    Print Tab(5); "Sum - squared residual:", RSQ
    Print
    Print Tab(5); "计算出的方程组的解"
    For I = 1 To 4
        For J = I * 5 - 4 To I * 5
            Print Tab((J - (I - 1) * 5) * 9); Format$(X(J), "#.####E+00");
        Next J
        Print
    Next I
    '将计算出的方程组的解乘以系数矩阵，以验证计算结果正确
    Call ASUB(X(), BCMP())
    Print
    Print Tab(5); "计算出的方程组的解乘以系数矩阵的结果"
    Print
    Print Tab(7); "解乘以系数矩阵"; Tab(25); "方程组的右端向量"
    For I = 1 To N
        Print Tab(13); Format$(BCMP(I), "##.##"); Tab(32); Format$(B(I), "##.##")
    Next I
End Sub
Sub ASUB(XIN(), XOUT())
    N = 20
    XOUT(1) = XIN(1) + 2# * XIN(2)
    XOUT(N) = -2# * XIN(N - 1) + XIN(N)
    For I = 2 To N - 1
        XOUT(I) = -2# * XIN(I - 1) + XIN(I) + 2# * XIN(I + 1)
    Next I
End Sub
Sub ATSUB(XIN(), XOUT())
    N = 20
    XOUT(1) = XIN(1) - 2# * XIN(2)
    XOUT(N) = 2# * XIN(N - 1) + XIN(N)
    For I = 2 To N - 1
        XOUT(I) = 2# * XIN(I - 1) + XIN(I) - 2# * XIN(I + 1)
    Next I
End Sub