RegModels.PowerEval Method

Overload List

#	Signature	Description
1	procedure PowerEval(const B: TVec; const X: TVec; const YHat: TVec);	Evaluate power function model (vectorized version).
2	procedure PowerEval(const B: TDoubleArray; const X: TVec; const YHat: TVec);	Evaluates b[0]*X^b[1] for given values in X vector, parameters in B array, and returns the results in XHat vector.
3	function PowerEval(const B: TDoubleArray; X: Double): Double;	Evaluates power function.

Overload 1: procedure PowerEval(const B: TVec; const X: TVec; const YHat: TVec);

Evaluate power function model (vectorized version).

#	Name	Type
1	B	TVec
2	X	TVec
3	YHat	TVec

Result: stored in self (calling object)

Overload 2: procedure PowerEval(const B: TDoubleArray; const X: TVec; const YHat: TVec);

Evaluates b[0]*X^b[1] for given values in X vector, parameters in B array, and returns the results in XHat vector.

#	Name	Type
1	B	TDoubleArray
2	X	TVec
3	YHat	TVec

Result: stored in self (calling object)

Remarks:

Size and Complex properties of XHat vector are adjusted automatically.

Note
Use this version if you want to evaluate power function for multiple values at the same time. This is a lot faster than calling single value version for each x value.

Examples

Uses MtxExpr, MtxVecTee, Series, RegModels;
procedure Example(Series1: TLineSeries);
var Y,X: Vector;
begin
    X.Size(100);
    X.Ramp(-5.0, 0.1); // x= -5.0, -4.9, ..., +4.9
    // Y = b[0] + b[1]*X
    PowerEval([1,3],X,Y);
    DrawValues(X,Y,Series1,false);
end;

See Also: RegModels.PowerDeriv, RegModels.PowerFit

Overload 3: function PowerEval(const B: TDoubleArray; X: Double): Double;

Evaluates power function.

#	Name	Type	Description
1	B	TDoubleArray
2	X	Double	scalar

Returns: Double - b[0]*X^b[1] for given value X and parameters in B array.

Examples

Uses RegModels, Math387;
procedure Example;
var y: double;
begin
    y := PowerEval([-5,3.5], 2.0);
    // y = -5.0*(2.0)^(3.5) = -56.568542495
end;