RegModels.PowerFit Method

Fits simple exponential equation to data.

Syntax

Visual Basic

public static void PowerFit([In] TVec B, [In] TVec X, [In] TVec Y, [In] TVec Weights);

Parameters	Description
[In] TVec B	Returns regression coefficients for power function.
[In] TVec X	Vector of independent variable.
[In] TVec Y	Vector of dependent variable.
[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:

See Also

PowerDeriv, PowerEval

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.Point series1, Steema.TeeChart.Styles.Point series 2) { Vector X = new Vector(100,false); Vector Y = new Vector(0); Vector YHat = new Vector(0); Vector B = new Vector(0); X.Ramp(-5.0, 0.1); // x= -5.0, -4.9, ..., +4.9 Y.Size(X); Y.RandGauss(3.5,0.1); // sample data RegModels.PowerFit(B,X,Y,null); // calculate coefficients // evaluate y RegModels.PowerEval(B, X, YHat); MtxVecTee.DrawValues(X,Y,series1,false); // original data MtxVecTee.DrawValueS(X,YHat,series2,false); // fitted data } }

Group

RegModels Methods

Links

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

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