IModelling.Subtract

Syntax

Subtract(Parameters: Array): Variant;

Parameters

Parameters. Variables, which difference must be calculated.

Comments

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:

Description

The Subtract method returns difference of corresponding points for two or more variables.

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, Inp_2: 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;
    Inp_2 := TermInfo.TermInnerText;
    Expr := Determ.Expression;
    Expr.References := "Ms";
    Expr.AsString := "Subtract(" + Inp_1 + "," + Inp_2 + ", SetPeriod(2000,2010), True)";
    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 the difference of corresponding points for the first and the second input variables without taking into account empty values from 2000 to 2010.

Example of Use in Expressions

Expression 1:

Subtract({Brazil|BCA},{China|BCA},{Sudan|BCA})

Result: difference of corresponding observations of the Brazil|BCA, China|BCA and Sudan|BCA series.

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

Expression 2:

Subtract(X1,X2,True)

Result: difference of corresponding X1 and X2 factor points ignoring empty values.

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

Expression 3:

Subtract(4,2,5,-3)

Result: 0.

Application: it can be used in any expressions.

See also:

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