IModelling.R

Syntax

R(Period: IMsPeriod;

Code: String;

Inputs: Array): Variant;

Parameters

Period. Period, at which the method is calculated

Code. Expression for method calculation.

Inputs. Array of input variables.

Description

The R method transforms data using R package methods.

Comments

Integration with R must be set up in the repository to use this method. To set up integration, see the Integration with R section.

Features of setting parameters:

Period. If the parameter is set to Null, the method is calculated at the entire time period.
Code. Expression is set in the R language. For detailed description of R language see R documentation. Input variables in an expression are indicated as X1, X2 and so on, where 1, 2 is the index of the variable in the Inputs array. Indexing in the array is continuous and starts with zero.

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.

Integration with R must be set up in the repository.

Add links to the Metabase and Ms system assemblies.

Sub UserR;
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;Stat";
    // Set model calculation expression
    Expr.AsString := "R(SetPeriod(" +
        """" + "01.01.2000" + """" + "," + """" + "01.01.2015" + """" + ")," +
        """" + "Y <- X1 + 1;" + """" + "," + TermInfo.TermInnerText + ") ";
    // 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 UserR;

After executing the example the determinate equation model is will be calculated using R.

Example of Use in Expressions

Expression 1:

r(setperiod("01.01.2000", "01.01.2015"), "Y <- X1 + 1;", {Chicago - population[t]})

Result: values of the Chicago - population time series are increased by one using R package methods.

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

Expression 2:

R(SetPeriod("01.01.2000", "01.01.2015"), "Y <- X1 + 1;", X1, X2)

Result: value of the X1 variable is increased by one using R package methods.

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