IModelling.StDv

Syntax

StDv(Parameters: Array): Variant;

Parameters

Parameters. Variable.

Description

The StDv method returns the standard deviation for the specified variable.

Comments

If more than one variable is specified in Parameters, standard deviation of corresponding variable points is calculated. For example, standard deviation of points of 2018 by all variables.

Variables in Parameters must be separated via comma.

A calculation period can be set for the method. To do this, use the IModelling.SetPeriod method, by specifying it at any place of input array.

To calculate the method without taking into account empty values, use the IgnoreMissing parameter by specifying it in any place of the input array. Available values of the parameter:

Example

Executing the example requires that the repository contains a modeling container with the MS identifier. This contains includes a model with the MODEL_D identifier that is calculated by the determinate equation method and contains more than 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;
    Inp_1: String;
    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;
    TermInfo.Type := MsFormulaTermType.Serie;
    Inp_1 := TermInfo.TermInnerText;
    TransVar := Transf.Inputs.Item(1);
    Slice := TransVar.Slices.Item(0);
    TermInfo := Transf.CreateTermInfo;
    TermInfo.Slice := Slice;
    TermInfo.Type := MsFormulaTermType.Pointwise;
    Expr := Determ.Expression;
    Expr.References := "Ms";
    Expr.AsString := TermInfo.TermInnerText + "+StDv(" + Inp_1 + ")";
    If Expr.Valid
        Then ModelObj.Save;
        Else Debug.WriteLine("The model is not saved: error in formula");
    End If;
End Sub UserProc;

After executing the example the model calculates values of the second input variable increased by standard deviation of the first input variable.

Example of Use in Expressions

Expression 1:

StDv({Brazil|BCA})

Result: standard deviation of the Brazil|BCA series observations is calculated.

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

Expression 2:

StDv(X1, X2, False, SetPeriod(2000,2010))

Result: standard deviation of corresponding points of the X1 and X2 factors is calculated taking into account empty values for the period from 2000 to 2010.

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

Expression 3:

StDv(1,2,3.5,4,5)

Result: 1,6.

Application: it can be used in any expressions.

See also:

IModelling | Standard Deviation | Time Series Database: Calculator | Modeling Container: Editing Regressor or Formula