RegModels.FracFit Method

Fits rational fraction equation to data.

Syntax

Visual Basic

public static void FracFit([In] TVec B, [In] TVec X, [In] TVec Y, int DegNom, int DegDenom, bool Constant, [In] TVec Weights);

Parameters

Parameters	Description
[In] TVec B	Returns regression coefficients for rational function.
[In] TVec X	Vector of independent variable.
[In] TVec Y	Vector of dependent variable.
int DegNom	Nominator degree.
int DegDenom	Denominator degree.
bool Constant	If false, B[0] i.e. constant term in nominator is set to 0.0.
[In] TVec Weights	Weights (optional). Weights are used only if they are set.

Remarks

The routine fits equations to data by minimizing the sum of squared residuals. The observed values obey the following equation:

where n and d are nominator and denominator polynomial degrees.

See Also

FracEval

Example

In the following example we generate some data. Then we fit power function to this data and retreive it's regression coefficients.

using Dew.Math; using Dew.Stats.Units; namespace Dew.Examples { private void Example(Steema.TeeChart.Styles.Line line1, Steema.TeeChart.Styles.Line line2) { Vector X = new Vector(100); Vector Y = new Vector(100); Vector B = new Vector(0); Vector YHat = new Vector(0); X.Ramp(-5.0, 0.05); // x= -5.0, -4.95, ... -0.05 Y.RandGauss(3.5, 0.12); // sample data // calculate coefficients RegModels.FracFit(B,X,Y,2,4,false,null); // evaluate y by using calculated coefficients RegModels.FracEval(B,X, YHat,2,false); MtxVecTee.DrawValues(X,Y,line1,false); MtxVecTee.DrawValues(X,YHat,line2,false); } }

Group

RegModels Methods

Links

RegModels Class, RegModels Members, Dew.Stats.Units Namespace, RegModels Methods, Example, See Also

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