IModelling.DLog

Syntax

DLog(Input: ITimeSeries): Variant;

Parameters

Input. Variable.

Description

The DLog method calculates increment of the logarithm of variable points in comparison with the previous period.

Comments

Increment of the logarithm of variable points is calculated by the formula: (ln(x[t]/X[t-N]).

Example

Executing the example requires that the repository contains a modeling container with the MS identifier. This container includes a model with the MODEL_D identifier that is calculated using the determinate equation method and contains at least one input variable.

Add links to the Metabase and Ms system assemblies.

Sub UserProc;
Var
    Mb: IMetabase;
    ModelSpace, ModelObj: IMetabaseObject;
    Transf: IMsFormulaTransform;
    Formula: IMsFormula;
    Model: IMsModel;
    Determ: IMsDeterministicTransform;
    TransVar: IMsFormulaTransformVariable;
    Slice: IMsFormulaTransformSlice;
    TermInfo: IMsFormulaTermInfo;
    Expr: IExpression;
Begin
    Mb := MetabaseClass.Active;
    ModelSpace := Mb.ItemById("MS").Bind;
    ModelObj := Mb.ItemByIdNamespace("MODEL_D", ModelSpace.Key).Edit;
    Model := ModelObj As IMsModel;
    Transf := Model.Transform;
    Formula := Transf.FormulaItem(0);
    Determ := Formula.Method As IMsDeterministicTransform;
    TransVar := Transf.Inputs.Item(0);
    Slice := TransVar.Slices.Item(0);
    TermInfo := Transf.CreateTermInfo;
    TermInfo.Slice := Slice;
    Expr := Determ.Expression;
    Expr.References := "Ms";
    Expr.AsString := "DLog(" + TermInfo.TermInnerText + ")";
    If Expr.Valid
    Then ModelObj.Save;
    Else Debug.WriteLine("Model is not saved: error in formula");
End If;
End Sub UserProc;

After executing the example the model will calculate increment of the logarithm of the first input variable points in comparison with the previous period.

Example of Use in Expressions

Expression 1:

DLog({Brazil|BCA})

Result: increment of Brazil|BCA factor observations logarithm is calculated to the previous period.

Use: it can be used in formulas of cross functional expression editor in any platform tool where it is available.

Expression 2:

DLog(X1)

Result: increment of X1 factor points logarithm is calculated to the previous period.

Use: it can be used in model formulas of modeling container.