ISmNonLinearEquations.UseDerivatives

Syntax

UseDerivatives: Boolean;

Description

The UseDerivatives property determines whether analytical derivatives are used in solution search.

Comments

Available values:

True. Default value. Analytical derivatives are used to search solution.
False. Numeric derivatives are used to search solution.

Example

To execute the example, add a link to the Stat system assembly.

Sub UserProc;
Var
    Eqs: ISmNonLinearEquations;
    Funcs: Array [0..2] Of String;
    inits: Array[0..2] Of Double;
    res, i: Integer;
Begin
    Eqs := New SmNonLinearEquations.Create;
    funcs[0] := "X1-22+0.5*X2-X3";
    funcs[1] := "X2-26.5+2*X1+0.5*X3";
    funcs[2] := "X3+9-X1+6*X2";
    Eqs.Functions := Funcs;
    Eqs.CoefficientsOrder := "X1;X2;X3";
    inits[0] := 10; //x1
    inits[1] := 0; //x2
    inits[2] := -1; //x3
    Eqs.InitApproximation := inits;
    Eqs.MethodType := NonLinearEquationsType.HMethod;
    Eqs.UseDerivatives := True;
    Eqs.Tolerance := 0.0001;
    res := Eqs.Execute;
    If res <> 0 Then
        Debug.WriteLine(Eqs.Errors);
        Else
            For i := 0 To Eqs.Functions.Length-1 Do
                Debug.WriteLine((i+1).ToString + ". " + Eqs.Solution[i].ToString);
            End For;
    End If;
End Sub UserProc;

After executing the example the console window displays a solution for a system of non-linear equations:

1. 14

2. 2

3. -7