d3r9.txt

VB常用数值算法集 内含有解线性代数方程组

Private Sub Command1_Click()
    'PROGRAM D3R9
    'Driver for routine GAULEG
    NPOINT = 10
    X1 = 0#
    X2 = 1#
    X3 = 10#
    Dim X(10), W(10)
    Call GAULEG(X1, X2, X(), W(), NPOINT)
    Print
    Print Tab(5); "#           X(I)        W(I)"
    For I = 1 To NPOINT
        Print Tab(5); Format$(I, "##");
        Print Tab(14); Format$(X(I), "0.######");
        Print Tab(27); Format$(W(I), "0.######")
    Next I
    'Demonstrate the use of GAULEG for an integral
    Call GAULEG(X1, X3, X(), W(), NPOINT)
    XX = 0#
    For I = 1 To NPOINT
        XX = XX + W(I) * FUNC(X(I))
    Next I
    Print
    Print Tab(5); "Integral from GAULEG: "; Format$(XX, "0.######")
    Print Tab(5); "Actual value: ";
    Print Tab(20); Format$((1# - (1# + X3) * Exp(-X3)), "0.######")
End Sub
Function FUNC(X)
    FUNC = X * Exp(-X)
End Function