d12r3.txt

VB常用数值算法集2

Private Sub Command1_Click()
    'PROGRAM D12R3
    'Driver for routine REALFT
    EPS = 0.001
    NP = 32
    NPP2 = NP + 2
    Width1 = 50#
    PI = 3.14159
    Dim DATA(34), SIZE1(32)
    N = NP / 2
    Print Tab(5); "Period of sinusoid in channels (2-";
    Print Format$(NP, "##"); "; or 0 to stop)"
    PER = 5
    If PER <= 0# Then Exit Sub
    For I = 1 To NP
        DATA(I) = Cos(2# * PI * (I - 1) / PER)
    Next I
    Call REALFT(DATA(), N, 1)
    BIG = -10000000000#
    For I = 1 To N
        SIZE1(I) = Sqr(DATA(2 * I - 1) ^ 2 + DATA(2 * I) ^ 2)
        If I = 1 Then SIZE1(I) = DATA(I)
        If SIZE1(I) > BIG Then BIG = SIZE1(I)
    Next I
    SCAL1 = Width1 / BIG
    For I = 1 To N
        NLIM = SCAL1 * SIZE1(I) + EPS
        Form1.Print Tab(5); Format$(I, "##");
        For J = 1 To NLIM + 1
            Print "*";
        Next J
    Next I
    Call REALFT(DATA(), N, -1)
    BIG = -10000000000#
    SMALL = 10000000000#
    For I = 1 To NP
        If DATA(I) < SMALL Then SMALL = DATA(I)
        If DATA(I) > BIG Then BIG = DATA(I)
    Next I
    SCAL1 = Width1 / (BIG - SMALL)
    For I = 1 To NP
        NLIM = Int(SCAL1 * (DATA(I) - SMALL) + EPS)
        Print Tab(5); Format$(I, "##");
        For J = 1 To NLIM + 1
            Print "*";
        Next J
    Next I
End Sub