RegModels.LnFit Method

Fits simple logarithm equation y(x)=b[0] + b[1]*ln(x) to data.

Syntax

Visual Basic

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

Parameters	Description
[In] TVec B	Returns regression coefficients for natural logarithm 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

LnEval

Example

In the following example we generate some data. Then we fit natural logarithm 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(0.5, 0.05); // x= 0.5, 0.55, ... Y.RandGauss(3.5, 0.12); // sample data // calculate coefficients RegModels.LnFit(B,X,Y,null); // evaluate y by using calculated coefficients RegModels.LnEval(B,X, YHat); 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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