Package org.ejml.sparse.csc.decomposition.lu

Class LuUpLooking_DSCC

java.lang.Object

org.ejml.sparse.csc.decomposition.lu.LuUpLooking_DSCC

All Implemented Interfaces:

DecompositionInterface<DMatrixSparseCSC>, DecompositionSparseInterface<DMatrixSparseCSC>, LUDecomposition<DMatrixSparseCSC>, LUSparseDecomposition<DMatrixSparseCSC>, LUSparseDecomposition_F64<DMatrixSparseCSC>

public class LuUpLooking_DSCC
extends Object
implements LUSparseDecomposition_F64<DMatrixSparseCSC>

LU Decomposition using a left looking algorithm for DMatrixSparseCSC.

NOTE: Based mostly on the algorithm described on page 86 in csparse. cs_lu

NOTE: See in code comment for a modification from csparse.

Constructor Summary

Constructors

Constructor	Description
LuUpLooking_DSCC(@Nullable ComputePermutation<DMatrixSparseCSC> reduceFill)

Method Summary

Modifier and Type	Method	Description
Complex_F64	computeDeterminant()	Computes the matrix's determinant using the LU decomposition.
boolean	decompose(DMatrixSparseCSC A)	Computes the decomposition of the input matrix.
IGrowArray	getGw()
IGrowArray	getGxi()
DMatrixSparseCSC	getL()
DMatrixSparseCSC	getLower(@Nullable DMatrixSparseCSC lower)	Returns the L matrix from the decomposition.
int[]	getPinv()
ComputePermutation<DMatrixSparseCSC>	getReduceFill()
int[]	getReducePermutation()
DMatrixSparseCSC	getRowPivot(@Nullable DMatrixSparseCSC pivot)	For numerical stability there are often row interchanges.
int[]	getRowPivotV(@Nullable IGrowArray pivot)	Returns the row pivot vector
DMatrixSparseCSC	getU()
DMatrixSparseCSC	getUpper(@Nullable DMatrixSparseCSC upper)	Returns the U matrix from the decomposition.
boolean	inputModified()	Checks if the input matrix to DecompositionInterface.decompose(org.ejml.data.Matrix) is modified during the decomposition process.
boolean	isReduceFill()
boolean	isSingular()	Returns true if the decomposition detected a singular matrix.
boolean	isStructureLocked()	Checks to see if the structure is locked.
void	setStructureLocked(boolean locked)	Save results from structural analysis step.

Methods inherited from class java.lang.Object

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

Constructor Details

LuUpLooking_DSCC

public LuUpLooking_DSCC(@Nullable
 @Nullable ComputePermutation<DMatrixSparseCSC> reduceFill)

Method Details

decompose

public boolean decompose(DMatrixSparseCSC A)

Description copied from interface: DecompositionInterface

Computes the decomposition of the input matrix. Depending on the implementation the input matrix might be stored internally or modified. If it is modified then the function DecompositionInterface.inputModified() will return true and the matrix should not be modified until the decomposition is no longer needed.

Specified by:

decompose in interface DecompositionInterface<DMatrixSparseCSC>

Parameters:

A - The matrix which is being decomposed. Modification is implementation dependent.

Returns:

Returns if it was able to decompose the matrix.

computeDeterminant

public Complex_F64 computeDeterminant()

Description copied from interface: LUSparseDecomposition_F64

Computes the matrix's determinant using the LU decomposition.

Specified by:

computeDeterminant in interface LUSparseDecomposition_F64<DMatrixSparseCSC>

Returns:

The determinant.

getLower

public DMatrixSparseCSC getLower(@Nullable
 @Nullable DMatrixSparseCSC lower)

Description copied from interface: LUDecomposition

Returns the L matrix from the decomposition. Should only be called after DecompositionInterface.decompose(org.ejml.data.Matrix) has been called.

If parameter 'lower' is not null, then that matrix is used to store the L matrix. Otherwise a new matrix is created.

Specified by:

getLower in interface LUDecomposition<DMatrixSparseCSC>

Parameters:

lower - Storage for T matrix. If null then a new matrix is returned. Modified.

Returns:

The L matrix.

getUpper

public DMatrixSparseCSC getUpper(@Nullable
 @Nullable DMatrixSparseCSC upper)

Description copied from interface: LUDecomposition

Returns the U matrix from the decomposition. Should only be called after DecompositionInterface.decompose(org.ejml.data.Matrix) has been called.

If parameter 'upper' is not null, then that matrix is used to store the U matrix. Otherwise a new matrix is created.

Specified by:

getUpper in interface LUDecomposition<DMatrixSparseCSC>

Parameters:

upper - Storage for U matrix. If null then a new matrix is returned. Modified.

Returns:

The U matrix.

getRowPivot

public DMatrixSparseCSC getRowPivot(@Nullable
 @Nullable DMatrixSparseCSC pivot)

Description copied from interface: LUDecomposition

For numerical stability there are often row interchanges. This computes a pivot matrix that will undo those changes.

Specified by:

getRowPivot in interface LUDecomposition<DMatrixSparseCSC>

Parameters:

pivot - Storage for the pivot matrix. If null then a new matrix is returned. Modified.

Returns:

The pivot matrix.

getRowPivotV

public int[] getRowPivotV(@Nullable
 @Nullable IGrowArray pivot)

Description copied from interface: LUDecomposition

Returns the row pivot vector

Specified by:

getRowPivotV in interface LUDecomposition<DMatrixSparseCSC>

Parameters:

pivot - (Optional) Storage for pivot vector

Returns:

The pivot vector

isSingular

public boolean isSingular()

Description copied from interface: LUDecomposition

Returns true if the decomposition detected a singular matrix. This check will not work 100% of the time due to machine precision issues.

Specified by:

isSingular in interface LUDecomposition<DMatrixSparseCSC>

Returns:

True if the matrix is singular and false if it is not.

inputModified

public boolean inputModified()

Description copied from interface: DecompositionInterface

Checks if the input matrix to DecompositionInterface.decompose(org.ejml.data.Matrix) is modified during the decomposition process.

Specified by:

inputModified in interface DecompositionInterface<DMatrixSparseCSC>

Returns:

true if the input matrix to decompose() is modified.

getGxi

public IGrowArray getGxi()

getGw

public IGrowArray getGw()

getPinv

public int[] getPinv()

getL

public DMatrixSparseCSC getL()

getU

public DMatrixSparseCSC getU()

isReduceFill

public boolean isReduceFill()

getReduceFill

public ComputePermutation<DMatrixSparseCSC> getReduceFill()

getReducePermutation

public int[] getReducePermutation()

setStructureLocked

public void setStructureLocked(boolean locked)

Description copied from interface: DecompositionSparseInterface

Save results from structural analysis step. This can reduce computations if a matrix with the exactly same non-zero pattern is decomposed in the future. If a matrix has yet to be processed then the structure of the next matrix is saved. If a matrix has already been processed then the structure of the most recently processed matrix will be saved.

Specified by:

setStructureLocked in interface DecompositionSparseInterface<DMatrixSparseCSC>

isStructureLocked

public boolean isStructureLocked()

Description copied from interface: DecompositionSparseInterface

Checks to see if the structure is locked.

Specified by:

isStructureLocked in interface DecompositionSparseInterface<DMatrixSparseCSC>

Returns:

true if locked or false if not locked.