Diff(Input: ITimeSeries): Variant;
Input. Variable.
The Diff method calculates the rate of change for variable points to the previous period: X[t]-X[t-1].
Executing the example requires that the repository contains a modeling container with the MS identifier. A model with the MODEL_D identifier calculated by the method of determinate equation and containing at least one input variable must be available in this container.
Sub UserProc;
Var
Mb: IMetabase;
ModelSpace, ModelObj: IMetabaseObject;
Transf: IMsFormulaTransform;
Formula: IMsFormula;
Model: IMsModel;
Determ: IMsDeterministicTransform;
TransVar: IMsFormulaTransformVariable;
Slice: IMsFormulaTransformSlice;
TermInfo: IMsFormulaTermInfo;
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;
Expr := Determ.Expression;
Expr.References := "Ms";
Expr.AsString := "Diff(" + TermInfo.TermInnerText + ")";
If Expr.Valid
Then ModelObj.Save;
Else Debug.WriteLine(The model is not saved: error in the formula);
End If;
End Sub UserProc;
After executing the example the model calculates increase of the first input variable points to the previous period.
Expression 1:
Diff({Brazil|BCA})
Result: the rate of change of Brazil|BCA time series observations is calculated to the previous period.
Use: it can be used in formulas of calculated series of time series database and model formulas of modeling container that is a child of the time series database.
Expression 2:
Diff(X1)
Result: the rate of change of value of X1 time series points is calculated to the previous period.
Use: it can be used in model formulas of modeling container.
See also: