IModelling.PchX

Syntax

PchX(Input: ITimeSeries; [Lag: Integer = 1]): Variant;

Parameters

Input. Variable.

Lag. The parameter sets a shift (lag) of variable points in a time period.

Description

The PchX method calculates the rate of change of variable points in comparison with the specified period.

Comments

The Lag parameter can take only positive values; optional parameter; the default value is 1 - the previous period.

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 by the determinate equation method and contains at least one input variable.

Add links to the Metabase and Ms system assemblies.

Sub UserNvl;
Var
    Mb: IMetabase;
    ModelSpace, ModelObj: IMetabaseObject;
    Transf: IMsFormulaTransform;
    Formula: IMsFormula;
    Model: IMsModel;
    Determ: IMsDeterministicTransform;
    TransVar: IMsFormulaTransformVariable;
    Slice: IMsFormulaTransformSlice;
    TermInfo: IMsFormulaTermInfo;
    Expr: IExpression;
Begin
    // Get repository
    Mb := MetabaseClass.Active;
    // Get modeling container
    ModelSpace := Mb.ItemById("MS").Bind;
    // Get model
    ModelObj := Mb.ItemByIdNamespace("MODEL_D", ModelSpace.Key).Edit;
    Model := ModelObj As IMsModel;
    // Get model calculation parameters
    Transf := Model.Transform;
    Formula := Transf.FormulaItem(0);
    Determ := Formula.Method As IMsDeterministicTransform;
    // Get the first input variable
    TransVar := Transf.Inputs.Item(0);
    Slice := TransVar.Slices.Item(0);
    TermInfo := Transf.CreateTermInfo;
    TermInfo.Slice := Slice;
    // Set mode of passing variable into calculation
    TermInfo.Type := MsFormulaTermType.Pointwise;
    // Get model calculation expression
    Expr := Determ.Expression;
    Expr.References := "Ms";
    // Set model calculation expression
    Expr.AsString := "PchX(" + TermInfo.TermInnerText + ", 3)";
    // Check if the expression is correct
    If Expr.Valid
        // If the expression is set correctly, save the model
        Then ModelObj.Save;
        // If the expression is incorrect, display a message to the console window
        Else Debug.WriteLine("Model is not saved: error in the formula");
    End If;
End Sub UserNvl;

After executing the example the model will calculate the rate of change of the first input variable points to the period shifted from the current one by three points.

Example of Use in Expressions

Expression 1:

PchX({Brazil|BCA},3)

Result: the rate of change of Brazil|BCA factor observations is calculated to the period shifted from the current one by three points.

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

Expression 2:

PchX(X1,2)

Result: the rate of change of X1 factor points is calculated to the previous period shifted from the current one by two points.

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