d2r1.txt

常用的数值算法的VB程序

Private Sub Command1_Click()
    'PROGRAM D2R1
    'Driver for routine POLINT
    N = 9    '输入插值节点个数
    PI = 3.1415926
    Dim XA(10), YA(10)
    Print Tab(5); "Generation of interpolation tables"
    Print Tab(5); " ... sin(x)    0<x<PI"
    Print Tab(5); " ... exp(x)     0<x<1"
    Print Tab(5); "How many entries go in these tables?(Note: N<10)"
    Print Tab(5); N
    For NFUNC = 1 To 2
        If NFUNC = 1 Then
            Print Tab(5); "sine function from 0 to PI"
            For I = 1 To N
                XA(I) = I * PI / N
                YA(I) = Sin(XA(I))
            Next I
        ElseIf NFUNC = 2 Then
            Print Tab(5); "exponential function from 0 to 1"
            For I = 1 To N
                XA(I) = I * 1# / N
                YA(I) = Exp(XA(I))
            Next I
        Else
            Exit Sub
        End If
        Print Tab(5); "     x           f(x)       interpolated        error"
        For I = 1 To 10
            If NFUNC = 1 Then
                X = (-0.05 + I / 10#) * PI
                F = Sin(X)
            ElseIf NFUNC = 2 Then
                X = (-0.05 + I / 10#)
                F = Exp(X)
            End If
            Call POLINT(XA(), YA(), N, X, Y, DY)
            Print Tab(5); Format$(X, "0.##0000");
            Print Tab(20); Format$(F, "0.####00");
            Print Tab(35); Format$(Y, "0.####00");
            Print Tab(50); Format$(DY, ".##00E+00")
        Next I
    Next NFUNC
End Sub