d16r2.txt

VB常用数值算法集2

Private Sub Command1_Click()
    'PROGRAM D16R2
    'Driver for routine ADI
    JMAX = 11
    PI = 3.1415926
    Dim A(11, 11), B(11, 11), C(11, 11), D(11, 11)
    Dim E(11, 11), F(11, 11), G(11, 11), U(11, 11)
    For I = 1 To JMAX
        For J = 1 To JMAX
            A(I, J) = -1#
            B(I, J) = 2#
            C(I, J) = -1#
            D(I, J) = -1#
            E(I, J) = 2#
            F(I, J) = -1#
            G(I, J) = 0#
            U(I, J) = 0#
        Next J
    Next I
    Mid1 = JMAX / 2 + 1
    G(Mid1, Mid1) = 2#
    ALPHA = 2# * (1# - Cos(PI / JMAX))
    BETA = 2# * (1# - Cos((JMAX - 1) * PI / JMAX))
    ALIM = Log(4# * JMAX / PI)
    K = 0
    Do
        K = K + 1
    Loop While 2 ^ K < ALIM
    EPS = 0.0001
    Call ADI(A(), B(), C(), D(), E(), F(), G(), U(), JMAX, K, ALPHA, BETA, EPS)
    Print
    Print Tab(5); "ADI Solution:"
    Print
    For I = 1 To JMAX
        For J = 1 To JMAX
            Print Tab(5 + (J - 1) * 8); Format$(U(I, J), "#.#0");
        Next J
    Next I
    Print Tab(5)
    Print Tab(5); "Test that sulotion satisfies Difference Eqns:"
    Print
    For I = 2 To JMAX - 1
        For J = 2 To JMAX - 1
            AAA = -4# * U(I, J) + U(I + 1, J)
            G(I, J) = AAA + U(I - 1, J) + U(I, J - 1) + U(I, J + 1)
        Next J
        For J = 2 To JMAX - 1
            Print Tab(5 + (J - 2) * 8); Format$(G(I, J), "#.#0");
        Next J
    Next I
End Sub