Model

Mind the following features on creating a model and working with it:

The object class Model- MetabaseObjectClass.KE_CLASS_MSMODEL.
The user must specify parent container because a model can be stored only within a container.
By default each created model contains annual frequency.

The IMsModel interface is used to work with a model using the Fore language. Using properties and methods of this interface, the user can set sample and forecasting periods for the model, as well as calculation method and set up other parameters.

NOTE. The examples given below require the objects listed in variable description section.

The user needs to set the output variable and its slice to work with parameters of model calculation method. The variable should be added to the collection of model input variables. After this the object implemented by the IMsFormula interface can be obtained for setting up model calculation options:

Sub Main;

Var

Model: IMsModel;

TransfModel: IMsFormulaTransform;

Varr: IMsVariable;

ModellingVar: IMsFormulaTransformVariable;

Tree: IMsFormulaTransformSlicesTree;

Slice: IMsFormulaTransformSlice;

Selector: IMsFormulaTransformSelector;

Formula: IMsFormula;

Begin

TransfModel := Model.Transform;

ModellingVar := TransfModel.Outputs.Add(Varr As IVariableStub);

Tree := ModellingVar.SlicesTree(ModellingVar);

Slice := Tree.CreateSlice(1);

Selector := TransfModel.CreateSelector;

Selector.Slice := Slice;

Formula := TransfModel.Transform(Selector);

End Sub Main;

Using properties and methods of the IMsFormula interface it is possible to change calendar frequency, determine and set up parameters for model calculation period.

The model calculation method is implemented by the IMsMethod interface. This interface is a base one for all calculation methods:

Cast the IMsMethod interface to any child interface to set up a specific calculation method. For example, to calculate the Baxter-King filter, the IMsMethod interface should be cast to the IMsBandpassFilterTransform interface:

Sub Main;

Var

Formula: IMsFormula;

BPFilter: IMsBandpassFilterTransform;

Begin

Formula.Kind := MsFormulaKind.BandpassFilter;

BPFilter := Formula.Method As IMsBandpassFilterTransform;

End Sub Main;

Further programming of model parameters depends on model calculation method. For more details refer to description of appropriate interfaces.

Creating a Model

After creating variables the user can start creating the Balance of Trade, billion USD model and setting up its calculation options.

Output variable: Balance of Trade, billion USD.
Input variables: Total Export, billion USD, Total Import, billion USD.
Model type: determinate equation.
Calculation formula: difference between values of the Total Export, billion USD and Total Import, billion USD variables.

To run this module to create and set up the model Balance of Trade, billion USD, add links to the following assemblies: Ms, Metabase,Dimensions.

Sub Main;

Var

MB: IMetabase;

MsDescr, VarDescr: IMetabaseObjectDescriptor;

CrInf: IMetabaseObjectCreateInfo;

MObj: IMetabaseObject;

Model: IMsModel;

TransfModel: IMsFormulaTransform;

Varr: IMsVariable;

Var_Balance, Var_Exp, Var_Imp: IMsFormulaTransformVariable;

Tree: IMsFormulaTransformSlicesTree;

Slice: IMsFormulaTransformSlice;

Selector: IMsFormulaTransformSelector;

Formula: IMsFormula;

Determ: IMsDeterministicTransform;

Inputs: IMsFormulaTransformVariables;

Term_Exp, Term_Imp: IMsFormulaTerm;

Begin

MB := MetabaseClass.Active;

// Create model

CrInf := Mb.CreateCreateInfo;

CrInf.ClassId := MetabaseObjectClass.KE_CLASS_MSMODEL;

CrInf.Id := "BALANCE_MODEL";

CrInf.Name := Balance of trade, billion USD;

MsDescr := Mb.ItemById("MODEL_SPACE");

CrInf.Parent := MsDescr;

MObj := Mb.CreateObject(CrInf).Edit;

Model := MObj As IMsModel;

// Get object to set up model parameters

TransfModel := Model.Transform;

// Determine output variable

VarDescr := MB.ItemByIdNamespace("BALANCE", MsDescr.Key);

Varr := VarDescr.Bind As IMsVariable;

Var_Balance := TransfModel.Outputs.Add(Varr As IVariableStub);

Tree := Var_Balance.SlicesTree(Var_Balance);

Slice := Tree.CreateSlice(1);

Selector := TransfModel.CreateSelector;

Selector.Slice := Slice;

// Get object to set up parameters of model calculation

Formula := TransfModel.Transform(Selector);

Formula.Kind := MsFormulaKind.Deterministic;

Formula.Level := DimCalendarLevel.Year;

// Sset up calculation of determinate equation

Determ := Formula.Method As IMsDeterministicTransform;

Inputs := TransfModel.Inputs;

// Add the Total Export, billion USD input variable to model

VarDescr := MB.ItemByIdNamespace("EXPORT", MsDescr.Key);

Varr := VarDescr.Bind As IMsVariable;

Var_Exp := Inputs.Add(Varr As IVariableStub);

Tree := Var_Exp.SlicesTree(Var_Exp);

Slice := Tree.CreateSlice(1);

Term_Exp := Determ.Operands.Add(Slice);

// Add the Total Import, billion USD input variable to model

VarDescr := MB.ItemByIdNamespace("IMPORT", MsDescr.Key);

Varr := VarDescr.Bind As IMsVariable;

Var_Imp := Inputs.Add(Varr As IVariableStub);

Tree := Var_Imp.SlicesTree(Var_Imp);

Slice := Tree.CreateSlice(1);

Term_Imp := Determ.Operands.Add(Slice);

// Determine formula for model calculation

Determ.Expression.AsString := Term_Exp.TermToInnerText + " - " + Term_Imp.TermToInnerText;

MObj.Save;

Debug.WriteLine(The + MObj.Name +model +with the MObj.Id identifier + 'is created and set upd+);

End Sub Main;

After executing this module the Balance of Trade, billion USD model is created and set up with the BALANCE_MODEL identifier, and this information is displayed in the console window.

The next step is metamodel creation.