Subtract(Parameters: Array): Variant;
Subtract(Context: Prognoz.Platform.Interop.Fore.ForeRuntimeContext; Parameters: System.Array): object;
Context. Context. The parameter is used only in Fore.NET.
Parameters. Variables, which difference must be calculated.
Variables in Parameters must be separated via comma.
A calculated 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:
True. Calculation does not take into account empty values.
False. Default value. Calculation takes into account empty values.
The Subtract method returns difference of corresponding points for two or more variables.
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, 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;
Imports Prognoz.Platform.Interop.ForeSystem;
Imports Prognoz.Platform.Interop.Ms;
…
Public Shared Sub Main(Params: StartParams);
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 := Params.Metabase;
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.mfttSerie;
Inp_1 := TermInfo.TermInnerText;
TransVar := Transf.Inputs.Item[1];
Slice := TransVar.Slices.Item[0];
TermInfo := Transf.CreateTermInfo();
TermInfo.Slice := Slice;
TermInfo.Type := MsFormulaTermType.mfttPointwise;
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 System.Diagnostics.Debug.WriteLine("Model is not saved: error in formula");
End If;
End Sub;
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.
Expression 1:
Subtract({Brazil|BCA},{China|BCA},{Sudan|BCA})
Result: the difference of corresponding observations of the series: Brazil|BCA, China|BCA and Sudan|BCA.
Use: it can be used in formulas of calculated series of time series database and in formulas of attribute-based models of modeling container.
Expression 2:
Subtract(X1,X2,True)
Result: the difference of corresponding points of the X1 and X2 factors without taking into account empty values.
Use: it can be used in model variable-based formulas of modeling container.
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