fr.cnes.sirius.patrius.math.fitting

Class HarmonicFitter

java.lang.Object

fr.cnes.sirius.patrius.math.fitting.CurveFitter<HarmonicOscillator.Parametric>

fr.cnes.sirius.patrius.math.fitting.HarmonicFitter

public class HarmonicFitter
extends CurveFitter<HarmonicOscillator.Parametric>

Class that implements a curve fitting specialized for sinusoids. Harmonic fitting is a very simple case of curve fitting. The estimated coefficients are the amplitude a, the pulsation ω and the phase φ: f (t) = a cos (ω t + φ). They are searched by a least square estimator initialized with a rough guess based on integrals.

Since:

2.0

Version:

$Id: HarmonicFitter.java 18108 2017-10-04 06:45:27Z bignon $

Nested Class Summary

Nested Classes

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

Constructor Summary

Constructors

Constructor and Description
HarmonicFitter(MultivariateVectorOptimizer optimizer) Simple constructor.

Method Summary

Modifier and Type	Method and Description
double[]	fit() Fit an harmonic function to the observed points.
double[]	fit(double[] initialGuess) Fit an harmonic function to the observed points.

Methods inherited from class fr.cnes.sirius.patrius.math.fitting.CurveFitter

addObservedPoint, addObservedPoint, addObservedPoint, clearObservations, fit, fit, getObservations

Methods inherited from class java.lang.Object

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

Constructor Detail

HarmonicFitter

public HarmonicFitter(MultivariateVectorOptimizer optimizer)

Simple constructor.

Parameters:

optimizer - Optimizer to use for the fitting.

Method Detail

fit

public double[] fit(double[] initialGuess)

Fit an harmonic function to the observed points.

Parameters:

initialGuess - First guess values in the following order:

• Amplitude
• Angular frequency
• Phase

Returns:

the parameters of the harmonic function that best fits the observed points (in the same order as above).

fit

public double[] fit()

Fit an harmonic function to the observed points. An initial guess will be automatically computed.

Returns:

the parameters of the harmonic function that best fits the observed points (see the other fit method.

Throws:

NumberIsTooSmallException - if the sample is too short for the the first guess to be computed.

ZeroException - if the first guess cannot be computed because the abscissa range is zero.