IV. Практическая часть

4.1. Графическое решение модели канальной подсистемы управления базами данных.

Листинг:

unit Unit1;

 

interface

 

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, StdCtrls, ExtCtrls, TeeProcs, TeEngine, Chart, Series;

 

type

TForm1 = class(TForm)

Chart1: TChart;

Series1: TLineSeries;

Series2: TLineSeries;

Series3: TLineSeries;

Series4: TLineSeries;

Series5: TLineSeries;

Panel1: TPanel;

D_L: TRadioButton;

D_n: TRadioButton;

Lambda: TLabeledEdit;

D_m: TRadioButton;

Mu: TLabeledEdit;

_n: TLabeledEdit;

Button1: TButton;

Series1a: TLineSeries;

Series2a: TLineSeries;

Series3a: TLineSeries;

Series4a: TLineSeries;

Series5a: TLineSeries;

Procedure Draw_n_Lmbd_fix(ASeries:TChartSeries;BSeries:TChartSeries;Lambda:real);

Procedure Draw_mu_Lmbd_fix(ASeries:TChartSeries;BSeries:TChartSeries;Lambda:real);

Procedure Draw_Lmbd_n_fix(ASeries:TChartSeries;BSeries:TChartSeries;N:integer);

procedure Button1Click(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

 

var

Form1: TForm1;

 

implementation

 

{$R *.dfm}

function fact(n:integer):real;

var i:integer;

Rez:real;

begin

Rez:=1;

if n>=2 then

for i:=2 to n do

Rez:=Rez*i;

fact:=Rez;

end;

 

function Erlang(Lambda:real;Mu:real;N:integer):real;

var j:integer;

Rez:real;

begin

Rez:=0;

for j:=0 to N do

Rez:=Rez + exp(j*ln(Lambda/Mu))/ fact(j);

Erlang:= exp(N*ln(Lambda/Mu))/ fact(N)/Rez;

end;

 

Procedure TForm1.Draw_n_Lmbd_fix(ASeries:TChartSeries;BSeries:TChartSeries;Lambda:real);

Var t:Longint;

P,M:real;

Begin

ASeries.Clear;

BSeries.Clear;

M:=StrToFloat(Mu.Text);

for t:=1 to StrToInt(_n.Text) do

Begin

P:=1-Erlang(Lambda,M,t);

ASeries.AddXY(t,P,'');

BSeries.AddXY(t,Lambda*P/M/t,'');

end;

End;

 

Procedure TForm1.Draw_mu_Lmbd_fix(ASeries:TChartSeries;BSeries:TChartSeries;Lambda:real);

Var t,n:Longint;

M,P:real;

 

Begin

ASeries.Clear;

BSeries.Clear;

n:=StrToInt(_n.Text);

for t:=0 to 30 do

Begin

M:=StrToFloat(Mu.Text)/30*t+0.0001;

P:=1-Erlang(Lambda,M,n);

ASeries.AddXY(M,P,'');

BSeries.AddXY(M,Lambda*P/M/n,'');

end;

End;

 

Procedure TForm1.Draw_Lmbd_n_fix(ASeries:TChartSeries;BSeries:TChartSeries;N:integer);

Var t:Longint;

L,M,P:real;

Begin

M:=StrToFloat(Mu.Text);

ASeries.Clear;

BSeries.Clear;

for t:=0 to 30 do

Begin

L:=StrToFloat(Lambda.Text)/30*t+0.0001;

P:=1-Erlang(L,M,N);

ASeries.AddXY(L,P,'');

BSeries.AddXY(L,L*P/M/N,'');

end;

End;

 

 

procedure TForm1.Button1Click(Sender: TObject);

var i:Extended;

j:real;

begin

if (_n.Text<>'') and (Mu.Text<>'') and (StrToFloat(Mu.Text)<>0) and (Lambda.Text<>'') then

if D_n.Checked=True then begin

Draw_n_Lmbd_fix(Series1,Series1a,0.1); Series1.Title:='Lm=0.1 Pо/КЗ';

Draw_n_Lmbd_fix(Series2,Series2a,0.25); Series2.Title:='Lm=0.25 Pо/КЗ';

Draw_n_Lmbd_fix(Series3,Series3a,0.5); Series3.Title:='Lm=0.5 Pо/КЗ';

Draw_n_Lmbd_fix(Series4,Series4a,1); Series4.Title:='Lm=1 Pо/КЗ';

Draw_n_Lmbd_fix(Series5,Series5a,5); Series5.Title:='Lm=5 Pо/КЗ';

Chart1.BottomAxis.Title.Caption:='число каналов';

Chart1.BottomAxis.Increment:=1;

_n.Enabled:=True;

Mu.Enabled:=True;

Lambda.Enabled:=False;

end

else if D_m.Checked=True then begin

Draw_mu_Lmbd_fix(Series1,Series1a,0.1); Series1.Title:='Lm=0.1 Pо/КЗ';

Draw_mu_Lmbd_fix(Series2,Series2a,0.25); Series2.Title:='Lm=0.25 Pо/КЗ';

Draw_mu_Lmbd_fix(Series3,Series3a,0.5); Series3.Title:='Lm=0.5 Pо/КЗ';

Draw_mu_Lmbd_fix(Series4,Series4a,1); Series4.Title:='Lm=1 Pо/КЗ';

Draw_mu_Lmbd_fix(Series5,Series5a,5); Series5.Title:='Lm=5 Pо/КЗ';

Chart1.BottomAxis.Title.Caption:='время обслуживания';

Chart1.BottomAxis.Increment:=0.1;

_n.Enabled:=True;

Mu.Enabled:=True;

Lambda.Enabled:=False;

end

else begin

Draw_Lmbd_n_fix(Series1,Series1a,2); Series1.Title:='N=2 Pо/КЗ';

Draw_Lmbd_n_fix(Series2,Series2a,5); Series2.Title:='N=5 Pо/КЗ';

Draw_Lmbd_n_fix(Series3,Series3a,10); Series3.Title:='N=10 Pо/КЗ';

Draw_Lmbd_n_fix(Series4,Series4a,20); Series4.Title:='N=20 Pо/КЗ';

Draw_Lmbd_n_fix(Series5,Series5a,50); Series5.Title:='N=50 Pо/КЗ';

Chart1.BottomAxis.Title.Caption:='плотность поступления заявок';

Chart1.BottomAxis.Increment:=0.1;

_n.Enabled:=False;

Mu.Enabled:=True;

Lambda.Enabled:=True;

end;

 

end;

 

end.

 

Тест программы:

Рис. 4.1