Package org.apache.commons.math.linear

Class FieldLUDecompositionImpl<T extends FieldElement<T>>

java.lang.Object

org.apache.commons.math.linear.FieldLUDecompositionImpl<T>

Type Parameters:

T - the type of the field elements

All Implemented Interfaces:

FieldLUDecomposition<T>

public class FieldLUDecompositionImpl<T extends FieldElement<T>>
extends java.lang.Object
implements FieldLUDecomposition<T>

Calculates the LUP-decomposition of a square matrix.

The LUP-decomposition of a matrix A consists of three matrices L, U and P that satisfy: PA = LU, L is lower triangular, and U is upper triangular and P is a permutation matrix. All matrices are m×m.

Since field elements do not provide an ordering operator, the permutation matrix is computed here only in order to avoid a zero pivot element, no attempt is done to get the largest pivot element.

Since:

2.0

Constructor Summary

Constructors

Constructor	Description
FieldLUDecompositionImpl(FieldMatrix<T> matrix)	Calculates the LU-decomposition of the given matrix.

Method Summary

Modifier and Type	Method	Description
T	getDeterminant()	Return the determinant of the matrix
FieldMatrix<T>	getL()	Returns the matrix L of the decomposition.
FieldMatrix<T>	getP()	Returns the P rows permutation matrix.
int[]	getPivot()	Returns the pivot permutation vector.
FieldDecompositionSolver<T>	getSolver()	Get a solver for finding the A × X = B solution in exact linear sense.
FieldMatrix<T>	getU()	Returns the matrix U of the decomposition.

Methods inherited from class java.lang.Object

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

Constructor Detail

FieldLUDecompositionImpl

public FieldLUDecompositionImpl(FieldMatrix<T> matrix)
                         throws NonSquareMatrixException

Calculates the LU-decomposition of the given matrix.

Parameters:

matrix - The matrix to decompose.

Throws:

NonSquareMatrixException - if matrix is not square

Method Detail

getL

public FieldMatrix<T> getL()

Returns the matrix L of the decomposition.

L is an lower-triangular matrix

Specified by:

getL in interface FieldLUDecomposition<T extends FieldElement<T>>

Returns:

the L matrix (or null if decomposed matrix is singular)

getU

public FieldMatrix<T> getU()

Returns the matrix U of the decomposition.

U is an upper-triangular matrix

Specified by:

getU in interface FieldLUDecomposition<T extends FieldElement<T>>

Returns:

the U matrix (or null if decomposed matrix is singular)

getP

public FieldMatrix<T> getP()

Returns the P rows permutation matrix.

P is a sparse matrix with exactly one element set to 1.0 in each row and each column, all other elements being set to 0.0.

The positions of the 1 elements are given by the pivot permutation vector.

Specified by:

getP in interface FieldLUDecomposition<T extends FieldElement<T>>

Returns:

the P rows permutation matrix (or null if decomposed matrix is singular)

See Also:

FieldLUDecomposition.getPivot()

getPivot

public int[] getPivot()

Returns the pivot permutation vector.

Specified by:

getPivot in interface FieldLUDecomposition<T extends FieldElement<T>>

Returns:

the pivot permutation vector

See Also:

FieldLUDecomposition.getP()

getDeterminant

public T getDeterminant()

Return the determinant of the matrix

Specified by:

getDeterminant in interface FieldLUDecomposition<T extends FieldElement<T>>

Returns:

determinant of the matrix

getSolver

public FieldDecompositionSolver<T> getSolver()

Get a solver for finding the A × X = B solution in exact linear sense.

Specified by:

getSolver in interface FieldLUDecomposition<T extends FieldElement<T>>

Returns:

a solver