ISmExponentialSmoothing.TrendComponent

Syntax

TrendComponent: TrendType;

Description

The TrendComponent property determines trend line type (growth or decrease trend).

Comments

By default no trend is used.

Example

Sub Main;

Var

Method: SmExponentialSmoothing;

serie: Array Of Double;

status: Integer;

Params: IExponentialSmoothingParameters;

Seasonal: ISeasonal;

Sub Print(Data: Array Of Double);

Var

i: Integer;

CI: ICultureInfo;

Begin

CI := CultureInfo.Current;

Debug.WriteLine("---Begin---");

For i := 0 To Data.Length - 1 Do

If Double.IsNan(Data[i]) Then

Debug.WriteLine("---empty---");

Else

Debug.WriteLine(i.ToString + ", " + CI.FormatDoublePrec(Data[i], 4));

End If;

End For;

Debug.WriteLine("---End---");

End Sub Print;

Begin

Method := New SmExponentialSmoothing.Create;

serie := New Double[15];

serie[0] := 670.2000183;

serie[1] := 576.0680563;

serie[2] := 717.6484268;

serie[3] := 856.9105808;

serie[4] := 885.4609516;

serie[5] := 1011.846431;

serie[6] := 995.4496292;

serie[7] := 1064.74221;

serie[8] := 1033.324656;

serie[9] := 780.8584552;

serie[10] := 657.5033113;

serie[11] := 654.5472579;

serie[12] := 678.2380139;

serie[13] := 642.4128544;

serie[14] := 751.9611194;

Method.Serie.Value := serie;

Method.Forecast.LastPoint := 40;

Seasonal := Method.SeasonalComponent;

Seasonal.Mode := SeasonalityType.Additive;

Seasonal.Cycle := 4;

Method.TrendComponent := TrendType.Linear;

Params := Method.Parameters;

Params.Alpha := 0.15;

Params.Delta := 0.2;

Params.Gamma := 0.15;

status := Method.Execute;

If status <> 0 Then

Debug.WriteLine(Method.Errors);

Else

Debug.WriteLine("=== Modeling series ===");

Print(Method.Fitted);

End If;

End Sub Main;

After executing the example the console window displays the following results:

Module execution started

=== Modeling series ===

---Begin---

0, 727,5418

1, 670,3663

2, 649,9061

3, 735,5868

4, 755,8357

5, 725,4715

6, 803,2732

7, 933,1416

8, 972,9883

9, 973,9642

10, 968,1277

11, 1 005,2627

12, 942,7797

13, 826,7615

14, 777,2802

---End---

Module execution finished