d6r3.frm

常用的数值算法的VB程序

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   4635
   ClientLeft      =   2655
   ClientTop       =   1950
   ClientWidth     =   6135
   LinkTopic       =   "Form1"
   ScaleHeight     =   4635
   ScaleWidth      =   6135
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   375
      Left            =   4440
      TabIndex        =   0
      Top             =   3840
      Width           =   1215
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
Private Sub Command1_Click()
    'PROGRAM D6R3
    'Driver for routine RAN2
    'Calculates pi statistically using volume of unit n-sphere
    PI = 3.1415926
    Dim IY(3), YPROB(3)
    IDUM& = -1
    For I = 1 To 3
        IY(I) = 0
    Next I
    Print Tab(13); "Volume of unit n-sphere, n=2,3,4"
    Print Tab(5); "# points     PI         (4/3)*PI     (1/2)*PI^2"
    For J = 1 To 15
        For K = 2 ^ (J - 1) To 2 ^ J
            x1 = RAN2(IDUM&)
            x2 = RAN2(IDUM&)
            x3 = RAN2(IDUM&)
            x4 = RAN2(IDUM&)
            If (FNC(x1, x2, 0#, 0#) < 1#) Then IY(1) = IY(1) + 1
            If (FNC(x1, x2, x3, 0#) < 1#) Then IY(2) = IY(2) + 1
            If (FNC(x1, x2, x3, x4) < 1#) Then IY(3) = IY(3) + 1
        Next K
        For I = 1 To 3
            YPROB(I) = 1# * (2 ^ (I + 1)) * IY(I) / (2 ^ J)
        Next I
        Print Tab(5); 2 ^ J;
        For M = 1 To 3
            Print Tab(15 + (M - 1) * 14); Format$(YPROB(M), "#.#####0");
        Next M
    Next J
    Print Tab(5); "actual"; Tab(15); Format$(PI, "#.#####0");
    Print Tab(29); Format$(4# * PI / 3#, "#.#####0");
    Print Tab(43); Format$(0.5 * (PI ^ 2), "#.#####0")
End Sub
Function FNC(x1, x2, x3, x4)
    FNC = Sqr(x1 ^ 2 + x2 ^ 2 + x3 ^ 2 + x4 ^ 2)
End Function
Static Function RAN2(IDUM&)
    M& = 714025: IA& = 1366: IC& = 150889: RM = 0.0000014005112
    Dim IR&(97)
    If IDUM& < 0 Or IFF = 0 Then
        IFF = 1
        IDUM& = (IC& - IDUM&) Mod M&
        For J = 1 To 97
            IDUM& = (IA& * IDUM& + IC&) Mod M&
            IR(J) = IDUM&
        Next J
        IDUM& = (IA& * IDUM& + IC&) Mod M&
        IY& = IDUM&
    End If
    J = 1 + Int((97 * IY&) / M&)
    If J > 97 Or J < 1 Then Print "Abnormal exit": Exit Function
    IY& = IR&(J)
    RAN2 = IY& * RM
    IDUM& = (IA& * IDUM& + IC&) Mod M&
    IR&(J) = IDUM&
End Function