org.apache.commons.math.linear

Interface QRDecomposition

All Known Implementing Classes:

QRDecompositionImpl

public interface QRDecomposition

An interface to classes that implement an algorithm to calculate the QR-decomposition of a real matrix.

This interface is based on the class with similar name from the JAMA library, with the following changes:

• a getQT method has been added,
• the solve and isFullRank methods have been replaced by a getSolver method and the equivalent methods provided by the returned DecompositionSolver.

Since:

1.2

See Also:

MathWorld, Wikipedia

Method Summary

Modifier and Type	Method and Description
RealMatrix	getH() Returns the Householder reflector vectors.
RealMatrix	getQ() Returns the matrix Q of the decomposition.
RealMatrix	getQT() Returns the transpose of the matrix Q of the decomposition.
RealMatrix	getR() Returns the matrix R of the decomposition.
DecompositionSolver	getSolver() Get a solver for finding the A × X = B solution in least square sense.

Method Detail

getR

RealMatrix getR()

Returns the matrix R of the decomposition.

R is an upper-triangular matrix

Returns:

the R matrix

getQ

RealMatrix getQ()

Returns the matrix Q of the decomposition.

Q is an orthogonal matrix

Returns:

the Q matrix

getQT

RealMatrix getQT()

Returns the transpose of the matrix Q of the decomposition.

Q is an orthogonal matrix

Returns:

the Q matrix

getH

RealMatrix getH()

Returns the Householder reflector vectors.

H is a lower trapezoidal matrix whose columns represent each successive Householder reflector vector. This matrix is used to compute Q.

Returns:

a matrix containing the Householder reflector vectors

getSolver

DecompositionSolver getSolver()

Get a solver for finding the A × X = B solution in least square sense.

Returns:

a solver