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:

Since:
1.2
MathWorld, Wikipedia
• ### Method Summary

All Methods
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