Class HarmonicCurveFitter

java.lang.Object

org.apache.commons.math3.fitting.AbstractCurveFitter

org.apache.commons.math3.fitting.HarmonicCurveFitter

public class HarmonicCurveFitter
extends AbstractCurveFitter

Fits points to a harmonic oscillator function.
The initial guess values must be passed in the following order:

• Amplitude
• Angular frequency
• phase

The optimal values will be returned in the same order.

Since:

3.3

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	HarmonicCurveFitter.ParameterGuesser	This class guesses harmonic coefficients from a sample.

Nested classes/interfaces inherited from class AbstractCurveFitter

AbstractCurveFitter.TheoreticalValuesFunction

Field Summary

Fields

Modifier and Type	Field	Description
private static final HarmonicOscillator.Parametric	FUNCTION	Parametric function to be fitted.
private final double[]	initialGuess	Initial guess.
private final int	maxIter	Maximum number of iterations of the optimization algorithm.

Constructor Summary

Constructors

Modifier	Constructor	Description
private	HarmonicCurveFitter(double[] initialGuess, int maxIter)	Contructor used by the factory methods.

Method Summary

Modifier and Type	Method	Description
static HarmonicCurveFitter	create()	Creates a default curve fitter.
protected LeastSquaresProblem	getProblem(Collection<WeightedObservedPoint> observations)	Creates a least squares problem corresponding to the appropriate curve.
HarmonicCurveFitter	withMaxIterations(int newMaxIter)	Configure the maximum number of iterations.
HarmonicCurveFitter	withStartPoint(double[] newStart)	Configure the start point (initial guess).

Methods inherited from class AbstractCurveFitter

fit, getOptimizer

Methods inherited from class Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

FUNCTION

private static final HarmonicOscillator.Parametric FUNCTION

Parametric function to be fitted.

initialGuess

private final double[] initialGuess

Initial guess.

maxIter

private final int maxIter

Maximum number of iterations of the optimization algorithm.

Constructor Details

HarmonicCurveFitter

private HarmonicCurveFitter(double[] initialGuess,
 int maxIter)

Contructor used by the factory methods.

Parameters:

initialGuess - Initial guess. If set to null, the initial guess will be estimated using the HarmonicCurveFitter.ParameterGuesser.

maxIter - Maximum number of iterations of the optimization algorithm.

Method Details

create

public static HarmonicCurveFitter create()

Creates a default curve fitter. The initial guess for the parameters will be HarmonicCurveFitter.ParameterGuesser computed automatically, and the maximum number of iterations of the optimization algorithm is set to Integer.MAX_VALUE.

Returns:

a curve fitter.

See Also:

• withStartPoint(double[])
• withMaxIterations(int)

withStartPoint

public HarmonicCurveFitter withStartPoint(double[] newStart)

Configure the start point (initial guess).

Parameters:

newStart - new start point (initial guess)

Returns:

a new instance.

withMaxIterations

public HarmonicCurveFitter withMaxIterations(int newMaxIter)

Configure the maximum number of iterations.

Parameters:

newMaxIter - maximum number of iterations

Returns:

a new instance.

getProblem

protected LeastSquaresProblem getProblem(Collection<WeightedObservedPoint> observations)

Creates a least squares problem corresponding to the appropriate curve.

Specified by:

getProblem in class AbstractCurveFitter

Parameters:

observations - Sample points.

Returns:

the least squares problem to use for fitting the curve to the given points.