vec_math
Class PhaseRegression

java.lang.Object
  util.PropertyContainer
      util.PropertyResources
          util.PropertyBundles
              vec_math.AbstractFit
                  vec_math.PhaseRegression

All Implemented Interfaces:

Cloneable, Initializable, LocalizedSupplying, PropertySupplying, ResourceSupplying, ModelFitting

public class PhaseRegression
extends AbstractFit

An analyser that fits a cosine wave with phase shift, but fixed period to the input data. If writtn as

   y_fit=c_0+a_0*cos(ωt)+b_0*sin(ωt),
   

the fitting function y_fit is linear in all its three parameters a_0, b_0, and c_0. This fit can be performed using GeneralRegression#harmonic. We assign variable names according to OFFSET, AMPLITUDE, and PHASE, where phase and amplitude are calculated from the linear parameters as

   amplitude²=a_0²+b_0²
   tan(ωt_0)=b_0/a_0;
   

Nested Class Summary

private static class

PhaseRegression.PhaseModel Our data model.

Nested classes/interfaces inherited from class util.PropertyResources

PropertyResources.URLResource

Field Summary

static String	AMPLITUDE The name of the amplitude constant.
private static int	DEFERRORINDEX Default error index.
private static int	DEFTINDEX Default time index.
private static String	DEFUNITAMPLITUDE Default units of the parameters.
private static String	DEFUNITOFFSET Default units of the parameters.
private static String	DEFUNITPHASE Default units of the parameters.
private static int	DEFYINDEX Default y index.
private List<Variable>	fitted The fitted values to C+A*cos(2pi/P*t+PHI).
static String	KEY_ERRORINDEX The index of the measure error, defaults to none.
static String	KEY_PERIOD This is the main fitting parameter.
static String	KEY_TINDEX The index of the time, defaults to zero.
static String	KEY_UNITAMPLITUDE The units of the parameters.
static String	KEY_UNITOFFSET The units of the parameters.
static String	KEY_UNITPHASE The units of the parameters.
static String	KEY_YINDEX The index of the measure, defaults to one.
static String	OFFSET The name of the offset constant.
static String	PERIOD period constant.
static String	PHASE The name of the phase constant.
private PhaseRegression.PhaseModel	phasemodel The model.
private double	q The q-value of the fit, available after fit().

Fields inherited from class vec_math.AbstractFit

KEY_DEFAULTERROR, KEY_DEFAULTFORMAT, KEY_ERRORFORMAT, KEY_PARAMETERFORMAT

Fields inherited from class util.PropertyBundles

KEY_LOCALECOUNTRY, KEY_LOCALELANGUAGE, KEY_RESOURCEBUNDLES

Fields inherited from class util.PropertyResources

KEY_NOINITONCREATE, localurl, locate, POSTFIX_DIR, POSTFIX_EXT, POSTFIX_FILE, POSTFIX_LIST, POSTFIX_URL, urlset

Fields inherited from class util.PropertyContainer

KEY_LISTSEPARATOR, KEY_MAPKEYVALUECHAR, KEY_MAPSEPARATOR

Fields inherited from interface util.ResourceSupplying

KEY_URLRESOURCES, KEY_URLUSECONFIG, KEY_URLUSECURRENT, KEY_URLUSEHOME

Fields inherited from interface util.PropertySupplying

CONFIG, KEY_CLASS

Constructor Summary

PhaseRegression(Map<String,String> prop)
Constructs a new regression analyser.

Method Summary

List<Variable>	fit() We fit the amplitude and phase plus mgnitude offset only, the period stays constant.
DataModel	getDataModel() Returns the phase model.
List<Variable>	getFittedParameters() Returns the fitted parameters.
DataModel	prepareFit(VectorG[] in) Visualization means performing a linear Regression using GeneralRegression#harmonic.
double	qualityOfFit() Significance is the q-value of the regression.
boolean	setConstant(Variable p) We need tthe period as a constant.

Methods inherited from class vec_math.AbstractFit

formatError, formatValue, getChi2, getModelParameterErrors, getModelParameterValues, getR2, getRms, init, setInitialCondition

Methods inherited from class util.PropertyBundles

clone, getLocalized, getLocalized, getLocalizedString, getLocalizedString, loadResource

Methods inherited from class util.PropertyResources

createFrom, createFrom, createFrom, getApplet, getAsResources, getLocalClassLoader, getPropertiesToKey, getPropertiesToKey, getResource, getResourceAsStream, getResourceFromKey, getResources, keyCreate, keyCreate, reload, setApplet

Methods inherited from class util.PropertyContainer

augment, augment, augment, defaultBoolean, defaultChar, defaultDouble, defaultFloat, defaultInt, defaultLong, defaultObject, defaultObject, defaultProperties, defaultProperty, getAsBoolean, getAsChar, getAsDouble, getAsEnums, getAsFloat, getAsInt, getAsList, getAsLong, getAsMap, getAsMap, getAsObject, getAsObject, getProperties, getProperty, has, isNew, parseObject, reload, removeProperty, rescanned, setObject, setProperties, setProperty, stringProperties, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface util.ResourceSupplying

getResource, getResourceAsStream, getResources

Methods inherited from interface util.PropertySupplying

defaultBoolean, defaultChar, defaultDouble, defaultFloat, defaultInt, defaultLong, defaultObject, defaultObject, defaultProperties, defaultProperty, getAsBoolean, getAsChar, getAsDouble, getAsFloat, getAsInt, getAsList, getAsLong, getAsMap, getAsObject, getAsObject, getProperties, getProperty, has, parseObject, removeProperty, setObject, setProperty, stringProperties

Field Detail

PERIOD

public static final String PERIOD

period constant.

See Also:

Constant Field Values

AMPLITUDE

public static final String AMPLITUDE

The name of the amplitude constant.

See Also:

Constant Field Values

OFFSET

public static final String OFFSET

The name of the offset constant.

See Also:

Constant Field Values

PHASE

public static final String PHASE

The name of the phase constant.

See Also:

Constant Field Values

KEY_UNITAMPLITUDE

public static final String KEY_UNITAMPLITUDE

The units of the parameters.

See Also:

Constant Field Values

KEY_UNITPHASE

public static final String KEY_UNITPHASE

The units of the parameters.

See Also:

Constant Field Values

KEY_UNITOFFSET

public static final String KEY_UNITOFFSET

The units of the parameters.

See Also:

Constant Field Values

KEY_PERIOD

public static final String KEY_PERIOD

This is the main fitting parameter.

See Also:

Constant Field Values

KEY_TINDEX

public static final String KEY_TINDEX

The index of the time, defaults to zero.

See Also:

Constant Field Values

KEY_YINDEX

public static final String KEY_YINDEX

The index of the measure, defaults to one.

See Also:

Constant Field Values

KEY_ERRORINDEX

public static final String KEY_ERRORINDEX

The index of the measure error, defaults to none.

See Also:

Constant Field Values

DEFTINDEX

private static final int DEFTINDEX

Default time index.

See Also:

Constant Field Values

DEFYINDEX

private static final int DEFYINDEX

Default y index.

See Also:

Constant Field Values

DEFERRORINDEX

private static final int DEFERRORINDEX

Default error index.

See Also:

Constant Field Values

DEFUNITAMPLITUDE

private static final String DEFUNITAMPLITUDE

Default units of the parameters.

See Also:

Constant Field Values

DEFUNITPHASE

private static final String DEFUNITPHASE

Default units of the parameters.

See Also:

Constant Field Values

DEFUNITOFFSET

private static final String DEFUNITOFFSET

Default units of the parameters.

See Also:

Constant Field Values

q

private double q

The q-value of the fit, available after fit().

fitted

private List<Variable> fitted

The fitted values to C+A*cos(2pi/P*t+PHI).

phasemodel

private PhaseRegression.PhaseModel phasemodel

The model.

Constructor Detail

PhaseRegression

public PhaseRegression(Map<String,String> prop)

Constructs a new regression analyser.

Method Detail

setConstant

public boolean setConstant(Variable p)

We need tthe period as a constant.

Specified by:

setConstant in interface ModelFitting

Overrides:

setConstant in class AbstractFit

Returns:

false, if the constant does not apply to this model.

prepareFit

public DataModel prepareFit(VectorG[] in)

Visualization means performing a linear Regression using GeneralRegression#harmonic. The three linear parameters are fit into three fitting parameters OFFSET, AMPLITUDE, and PHASE, where phase and amplitude are calculated from the linear parameters as

       amplitude²=a_0²+b_0²
       tan(ωt_0)=b_0/a_0;
       

The order of the returned array is at index zero amplitude, sigma amplitude, at index one, offset plus sigma, and at index two phase plus sigma.

Parameters:

in - An array of measurements. Each vector contains dependant and independant variables and eventually their errors.

Returns:

A three dimensional array of Vector2D.

fit

public List<Variable> fit()

We fit the amplitude and phase plus mgnitude offset only, the period stays constant. Thus, we return three parameters. For fitting the period starting with an intial condition, see PhaseFit. This fit has the advantage that by transforming the amplitude, phase function into a sin and cosine wave, we get a pure linear regression. This is done here, the result is transformed back to match the original (non-linear) model (holds also for parameter errors).

Returns:

Non-null, if a fit could be obtained.

getDataModel

public DataModel getDataModel()

Returns the phase model.

getFittedParameters

public List<Variable> getFittedParameters()

Returns the fitted parameters.

qualityOfFit

public double qualityOfFit()

Significance is the q-value of the regression. All parameters are ignored.

Specified by:

qualityOfFit in interface ModelFitting

Overrides:

qualityOfFit in class AbstractFit