d4r9.frm

数据拟合源程序

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "Form1"
   ClientHeight    =   4335
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   6315
   LinkTopic       =   "Form1"
   ScaleHeight     =   4335
   ScaleWidth      =   6315
   StartUpPosition =   3  '窗口缺省
   Begin VB.CommandButton Command1 
      Caption         =   "Command1"
      Height          =   375
      Left            =   4200
      TabIndex        =   0
      Top             =   3600
      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 D4R9
    'Driver for routine GCF
    Open "f:\vb学习\VB常用数值算法集\DATA\FNCVAL.DAT" For Input As #1
    Do
      Line Input #1, Text$
    Loop While Text$ <> "Incomplete Gamma Function"
    Line Input #1, NVAL$
    NVAL = Val(NVAL$)
    Print Text$
    Print
    Print "     A         X        Actual    GCF(A,X)   GAMMLN(A)     GLN"
    For I = 1 To NVAL
        Line Input #1, DUM$
        A = Val(Mid(DUM$, 1, 6))
        X = Val(Mid(DUM$, 7, 16))
        Value = Val(Mid(DUM$, 23))
        If X >= A + 1 Then
            Call GCF(GAMMCF, A, X, GLN)
            Print Tab(4); Format$(A, "#0.00");
            Print Tab(12); Format$(X, "#0.####00");
            Print Tab(24); Format$(1 - Value, "0.000000");
            Print Tab(35); Format$(GAMMCF, "0.000000");
            Print Tab(47); Format$(GAMMLN(A), "##.000000");
            Print Tab(59); Format$(GLN, "##.000000")
        End If
    Next I
    Close #1
End Sub
   Sub GCF(GAMMCF, A, X, GLN)
      ITMAX = 100
      EPS = 0.0000003
      GLN = GAMMLN(A)
      GOLD = 0#
      A0 = 1#
      A1 = X
      B0 = 0#
      B1 = 1#
      FAC = 1#
      For N = 1 To ITMAX
          AN = N
          ANA = AN - A
          A0 = (A1 + A0 * ANA) * FAC
          B0 = (B1 + B0 * ANA) * FAC
          ANF = AN * FAC
          A1 = X * A0 + ANF * A1
          B1 = X * B0 + ANF * B1
          If A1 <> 0# Then
              FAC = 1# / A1
              G = B1 * FAC
              If Abs((G - GOLD) / G) < EPS Then GoTo 1
              GOLD = G
          End If
      Next N
      Print "A too large, ITMAX too small"
1     GAMMCF = Exp(-X + A * Log(X) - GLN) * G
   End Sub
   Function GAMMLN(XX)
      Dim COF(6)
      COF(1) = 76.18009173
      COF(2) = -86.50532033
      COF(3) = 24.01409822
      COF(4) = -1.231739516
      COF(5) = 0.00120858003
      COF(6) = -0.00000536382
      STP = 2.50662827465
      HALF = 0.5
      ONE = 1#
      FPF = 5.5
      X = XX - ONE
      TMP = X + FPF
      TMP = (X + HALF) * Log(TMP) - TMP
      SER = ONE
      For J = 1 To 6
          X = X + ONE
          SER = SER + COF(J) / X
    Next J
      GAMMLN = TMP + Log(STP * SER)
   End Function