Creating a Determinate Equation Model with Lagged Operands

Contents

Description

Consider an example of creating a model of determinate equation with operands, for which lag is set.

Requirements

Executing the example requires that the repository contains a modeling container with the MS identifier and a database with the TSDB identifier. This time series database must contain mandatory custom attributes of series being references to the dictionary.

Example

Sub UserProc;
Var
    Mb: IMetabase;
    CrInf: IMetabaseObjectCreateInfo;
    Model: IMsModel;
    Transform: IMsFormulaTransform;
    TransformVarables: IMsFormulaTransformVariables;
    RubrDescr: IMetabaseObjectDescriptor;
    Stub: IVariableStub;
    TransVar: IMsFormulaTransformVariable;
    Tree: IMsFormulaTransformSlicesTree;
    Slice: IMsFormulaTransformSlice;
    Selector: IMsFormulaTransformSelector;
    Formula: IMsFormula;
    Determ: IMsDeterministicTransform;
    TermX1, TermX2: IMsFormulaTerm;
    TermInfo: IMsFormulaTermInfo;
    Period: IMsModelPeriod;
Begin
    Mb := MetabaseClass.Active;
    // Specify basic parameters of the model as a repository object
    CrInf := Mb.CreateCreateInfo;
    CrInf.ClassId := MetabaseObjectClass.KE_CLASS_MSMODEL;
    // Specify model identifier
    CrInf.Id := Mb.GenerateId("MODEL_DETERMINISTIC_LAG", Mb.ItemById("MS").Key);
    // Specify model name
    CrInf.Name := "Determinate equation with lagged operands";
    // Specify modeling container which will contain the model
    CrInf.Parent := Mb.ItemById("MS");
    // Create a model
    Model := Mb.CreateObject(CrInf).Edit As IMsModel;
    // Get object to set up model parameters
    Transform := Model.Transform;
    // Get object to work with output variable
    TransformVarables := Transform.Outputs;
    // Get time series database (TSDB)
    RubrDescr := Mb.ItemById("TSDB");
    // Cast the obtained TSDB to the abstract data source
    Stub := RubrDescr.Bind As IVariableStub;
    // Use TSDB as a data source of output variable
    TransVar := TransformVarables.Add(Stub);
    // Specify output variable slice
    Tree := TransVar.SlicesTree(TransVar);
    Slice := Tree.CreateSlice(1);
    // Get model settings for output variable slice
    Selector := Transform.CreateSelector;
    Selector.Slice := Slice;
    Formula := Transform.Transform(Selector);
    // Specify calculation method - determinate equation
    Formula.Kind := MsFormulaKind.Deterministic;
    // Set the calendar frequency of calculation
    Formula.Level := DimCalendarLevel.Year;
    // Get object for setting up determinate equation
    Determ := Formula.Method As IMsDeterministicTransform;
    // Add the factor with the TSDB data source in the model
    TransVar := Transform.Inputs.Add(Stub);
    Tree := TransVar.SlicesTree(TransVar);
    Slice := Tree.CreateSlice(2);
    // Add the first factor to the collection of elements of expressions used for equation creation
    TermX1 := Determ.Operands.Add(Slice);
    // Get expression element parameters
    TermInfo := TermX1.TermInfo;
    // Set type of expression element: date-specific value
    TermInfo.Type := MsFormulaTermType.Date;
    // Set date for expression element
    TermInfo.SetDate(DateTime.ComposeDay(2014, 1, 1), "YYYY");
    // Set changed parameters for expression element
    TermX1.TermInfo := TermInfo;
    // Add the factor with the TSDB data source in the model
    TransVar := Transform.Inputs.Add(Stub);
    Tree := TransVar.SlicesTree(TransVar);
    Slice := Tree.CreateSlice(3);
    // Add the second factor to the collection of elements of expressions used for equation creation
    TermX2 := Determ.Operands.Add(Slice);
    // Get expression element parameters
    TermInfo := TermX2.TermInfo;
    // Set lag for expression element
    TermInfo.Lag := "-2";
    // Set changed parameters for expression element
    TermX2.TermInfo := TermInfo;
    // Set expression for determinate equation calculation
    Determ.Expression.AsString := "Iif(" + TermX1.TermToInnerText + ">-0.5, " +
        TermX2.TermToInnerText + "+1, " + TermX2.TermToInnerText + "-1)";
    // Specify model calculation periods
    Period := Transform.Period;
    Period.IdentificationStartDate := DateTime.ComposeDay(2000, 1, 1);
    Period.IdentificationEndDate := DateTime.ComposeDay(2014, 12, 31);
    Period.ForecastStartDate := DateTime.ComposeDay(2015, 1, 1);
    Period.ForecastEndDate := DateTime.ComposeDay(2020, 12, 31);
    // Save the model to the repository
    (Model As IMetabaseObject).Save;
End Sub UserProc;