Top Description Fields Constructors Methods
org.apache.commons.math3.stat.regression

public Class RegressionResults

extends Object
implements Serializable
Class Inheritance
All Implemented Interfaces
java.io.Serializable
Imports
java.io.Serializable, java.util.Arrays, org.apache.commons.math3.util.FastMath, .MathArrays, org.apache.commons.math3.exception.OutOfRangeException

Results of a Multiple Linear Regression model fit.
Since
3.0

Field Summary

Modifier and TypeField and Description
private static final int
ADJRSQ_IDX

INDEX of Adjusted R Squared

private final boolean
containsConstant

boolean flag indicator of whether a constant was included

private final double[]
globalFitInfo

array storing global results, SSE, MSE, RSQ, adjRSQ

private final boolean
isSymmetricVCD

boolean flag for variance covariance matrix in symm compressed storage

private static final int
MSE_IDX

INDEX of Mean Squared Error

private final long
nobs

number of observations on which results are based

private final double[]
parameters

regression slope parameters

private final int
rank

rank of the solution

private static final int
RSQ_IDX

INDEX of R-Squared of regression

private static final long
private static final int
SSE_IDX

INDEX of Sum of Squared Errors

private static final int
SST_IDX

INDEX of Sum of Squares of Model

private final double[][]
varCovData

variance covariance matrix of parameters

Constructor Summary

AccessConstructor and Description
private
RegressionResults()

Set the default constructor to private access to prevent inadvertent instantiation

public
RegressionResults(final double[]
a double array with the regression slope estimates
parameters
,
final double[][]
the variance covariance matrix, stored either in a square matrix or as a compressed
varcov
,
final boolean
a flag which denotes that the variance covariance matrix is in symmetric compressed format
isSymmetricCompressed
,
final long
the number of observations of the regression estimation
nobs
,
final int
the number of independent variables in the regression
rank
,
final double
the sum of the independent variable
sumy
,
final double
the sum of the squared independent variable
sumysq
,
final double
sum of squared errors
sse
,
final boolean
true model has constant, false model does not have constant
containsConstant
,
final boolean
if true a deep copy of all input data is made, if false only references are copied and the RegressionResults become mutable
copyData
)

Constructor for Regression Results.

Method Summary

Modifier and TypeMethod and Description
public double

Returns:

adjusted R-Squared statistic
getAdjustedRSquared
()

Returns the adjusted R-squared statistic, defined by the formula

R2adj = 1 - [SSR (n - 1)] / [SSTO (n - p)]
public double

Returns:

the covariance of the parameter estimates.
getCovarianceOfParameters
(int
ith regression parameter.
i
,
int
jth regression parameter.
j
)

Returns the covariance between regression parameters i and j.

public double

Returns:

sum of squared errors associated with the regression model
getErrorSumSquares
()

Returns the sum of squared errors (SSE) associated with the regression model.

public double

Returns:

sum of squared deviations of y values
getMeanSquareError
()

Returns the sum of squared errors divided by the degrees of freedom, usually abbreviated MSE.

public long

Returns:

Number of observations, -1 if an error condition prevents estimation
getN
()

Returns the number of observations added to the regression model.

public int

Returns:

number of regressors, -1 if not estimated
getNumberOfParameters
()

Returns the number of parameters estimated in the model.

public double

Returns:

the parameters estimated for regressor at index.
getParameterEstimate
(int
Index.
index
)

Returns the parameter estimate for the regressor at the given index.

public double[]

Returns:

array of parameter estimates, null if no estimation occurred
getParameterEstimates
()

Returns a copy of the regression parameters estimates.

public double

Returns:

sum of squared deviations of predicted y values
getRegressionSumSquares
()

Returns the sum of squared deviations of the predicted y values about their mean (which equals the mean of y).

public double

Returns:

r-square, a double in the interval [0, 1]
getRSquared
()

Returns the coefficient of multiple determination, usually denoted r-square.

public double

Returns:

the standard errors associated with parameters estimated at index.
getStdErrorOfEstimate
(int
Index.
index
)

Returns the standard error of the parameter estimate at index, usually denoted s(bindex).

public double[]

Returns:

an array standard errors associated with parameters estimates, null if no estimation occurred
getStdErrorOfEstimates
()

Returns the standard error of the parameter estimates, usually denoted s(bi).

public double

Returns:

sum of squared deviations of y values
getTotalSumSquares
()

Returns the sum of squared deviations of the y values about their mean.

private double

Returns:

the requested variance-covariance matrix entry
getVcvElement
(int
first variable index
i
,
int
second variable index
j
)

Gets the i-jth element of the variance-covariance matrix.

public boolean

Returns:

true if the model has an intercept term
hasIntercept
()

Returns true if the regression model has been computed including an intercept.

Inherited from java.lang.Object:
cloneequalsfinalizegetClasshashCodenotifynotifyAlltoStringwaitwaitwait

Field Detail

ADJRSQ_IDXback to summary
private static final int ADJRSQ_IDX

INDEX of Adjusted R Squared

containsConstantback to summary
private final boolean containsConstant

boolean flag indicator of whether a constant was included

globalFitInfoback to summary
private final double[] globalFitInfo

array storing global results, SSE, MSE, RSQ, adjRSQ

isSymmetricVCDback to summary
private final boolean isSymmetricVCD

boolean flag for variance covariance matrix in symm compressed storage

MSE_IDXback to summary
private static final int MSE_IDX

INDEX of Mean Squared Error

nobsback to summary
private final long nobs

number of observations on which results are based

parametersback to summary
private final double[] parameters

regression slope parameters

rankback to summary
private final int rank

rank of the solution

Annotations
@SuppressWarnings:unused
RSQ_IDXback to summary
private static final int RSQ_IDX

INDEX of R-Squared of regression

serialVersionUIDback to summary
private static final long serialVersionUID

UID

SSE_IDXback to summary
private static final int SSE_IDX

INDEX of Sum of Squared Errors

SST_IDXback to summary
private static final int SST_IDX

INDEX of Sum of Squares of Model

varCovDataback to summary
private final double[][] varCovData

variance covariance matrix of parameters

Constructor Detail

RegressionResultsback to summary
private RegressionResults()

Set the default constructor to private access to prevent inadvertent instantiation

Annotations
@SuppressWarnings:unused
RegressionResultsback to summary
public RegressionResults(final double[] parameters, final double[][] varcov, final boolean isSymmetricCompressed, final long nobs, final int rank, final double sumy, final double sumysq, final double sse, final boolean containsConstant, final boolean copyData)

Constructor for Regression Results.

Parameters
parameters:double[]

a double array with the regression slope estimates

varcov:double[][]

the variance covariance matrix, stored either in a square matrix or as a compressed

isSymmetricCompressed:boolean

a flag which denotes that the variance covariance matrix is in symmetric compressed format

nobs:long

the number of observations of the regression estimation

rank:int

the number of independent variables in the regression

sumy:double

the sum of the independent variable

sumysq:double

the sum of the squared independent variable

sse:double

sum of squared errors

containsConstant:boolean

true model has constant, false model does not have constant

copyData:boolean

if true a deep copy of all input data is made, if false only references are copied and the RegressionResults become mutable

Method Detail

getAdjustedRSquaredback to summary
public double getAdjustedRSquared()

Returns the adjusted R-squared statistic, defined by the formula

R2adj = 1 - [SSR (n - 1)] / [SSTO (n - p)]
where SSR is the sum of squared residuals}, SSTO is the total sum of squares}, n is the number of observations and p is the number of parameters estimated (including the intercept).

If the regression is estimated without an intercept term, what is returned is

 1 - (1 - getRSquared() ) * (n / (n - p)) 

Returns:double

adjusted R-Squared statistic

getCovarianceOfParametersback to summary
public double getCovarianceOfParameters(int i, int j) throws OutOfRangeException

Returns the covariance between regression parameters i and j.

If there are problems with an ill conditioned design matrix then the covariance which involves redundant columns will be assigned Double.NaN.

Parameters
i:int

ith regression parameter.

j:int

jth regression parameter.

Returns:double

the covariance of the parameter estimates.

Exceptions
OutOfRangeException:
if i or j is not in the interval [0, number of parameters).
getErrorSumSquaresback to summary
public double getErrorSumSquares()

Returns the sum of squared errors (SSE) associated with the regression model.

The return value is constrained to be non-negative - i.e., if due to rounding errors the computational formula returns a negative result, 0 is returned.

Preconditions:

  • numberOfParameters data pairs must have been added before invoking this method. If this method is invoked before a model can be estimated, Double,NaN is returned.

Returns:double

sum of squared errors associated with the regression model

getMeanSquareErrorback to summary
public double getMeanSquareError()

Returns the sum of squared errors divided by the degrees of freedom, usually abbreviated MSE.

If there are fewer than numberOfParameters + 1 data pairs in the model, or if there is no variation in x, this returns Double.NaN.

Returns:double

sum of squared deviations of y values

getNback to summary
public long getN()

Returns the number of observations added to the regression model.

Returns:long

Number of observations, -1 if an error condition prevents estimation

getNumberOfParametersback to summary
public int getNumberOfParameters()

Returns the number of parameters estimated in the model.

This is the maximum number of regressors, some techniques may drop redundant parameters

Returns:int

number of regressors, -1 if not estimated

getParameterEstimateback to summary
public double getParameterEstimate(int index) throws OutOfRangeException

Returns the parameter estimate for the regressor at the given index.

A redundant regressor will have its redundancy flag set, as well as a parameters estimated equal to Double.NaN

Parameters
index:int

Index.

Returns:double

the parameters estimated for regressor at index.

Exceptions
OutOfRangeException:
if index is not in the interval [0, number of parameters).
getParameterEstimatesback to summary
public double[] getParameterEstimates()

Returns a copy of the regression parameters estimates.

The parameter estimates are returned in the natural order of the data.

A redundant regressor will have its redundancy flag set, as will a parameter estimate equal to Double.NaN.

Returns:double[]

array of parameter estimates, null if no estimation occurred

getRegressionSumSquaresback to summary
public double getRegressionSumSquares()

Returns the sum of squared deviations of the predicted y values about their mean (which equals the mean of y).

This is usually abbreviated SSR or SSM. It is defined as SSM here

Preconditions:

  • At least two observations (with at least two different x values) must have been added before invoking this method. If this method is invoked before a model can be estimated, Double.NaN is returned.

Returns:double

sum of squared deviations of predicted y values

getRSquaredback to summary
public double getRSquared()

Returns the coefficient of multiple determination, usually denoted r-square.

Preconditions:

  • At least numberOfParameters observations (with at least numberOfParameters different x values) must have been added before invoking this method. If this method is invoked before a model can be estimated, Double,NaN is returned.

Returns:double

r-square, a double in the interval [0, 1]

getStdErrorOfEstimateback to summary
public double getStdErrorOfEstimate(int index) throws OutOfRangeException

Returns the standard error of the parameter estimate at index, usually denoted s(bindex).

Parameters
index:int

Index.

Returns:double

the standard errors associated with parameters estimated at index.

Exceptions
OutOfRangeException:
if index is not in the interval [0, number of parameters).
getStdErrorOfEstimatesback to summary
public double[] getStdErrorOfEstimates()

Returns the standard error of the parameter estimates, usually denoted s(bi).

If there are problems with an ill conditioned design matrix then the regressor which is redundant will be assigned Double.NaN.

Returns:double[]

an array standard errors associated with parameters estimates, null if no estimation occurred

getTotalSumSquaresback to summary
public double getTotalSumSquares()

Returns the sum of squared deviations of the y values about their mean.

This is defined as SSTO here.

If n < 2, this returns Double.NaN.

Returns:double

sum of squared deviations of y values

getVcvElementback to summary
private double getVcvElement(int i, int j)

Gets the i-jth element of the variance-covariance matrix.

Parameters
i:int

first variable index

j:int

second variable index

Returns:double

the requested variance-covariance matrix entry

hasInterceptback to summary
public boolean hasIntercept()

Returns true if the regression model has been computed including an intercept. In this case, the coefficient of the intercept is the first element of the parameter estimates.

Returns:boolean

true if the model has an intercept term