ch.akuhn.matrix

Class SparseMatrix

java.lang.Object

ch.akuhn.matrix.Matrix

ch.akuhn.matrix.SparseMatrix

public class SparseMatrix
extends Matrix

A sparse matrix

Author:

Adrian Kuhn

Constructor Summary

Constructors

Constructor and Description
SparseMatrix(double[][] values) Construct with the given values
SparseMatrix(int rows, int columns) Construct with the given size

Method Summary

Modifier and Type	Method and Description
double	add(int row, int column, double sum) Add to the value at the given row/column
int	addColumn() Add a new column to the end, increasing the number of columns by 1
int	addRow() Add a new row to the end, increasing the number of rows by 1
protected int	addRow(double[] values)
void	addToRow(int row, Vector values) Add the given values to the given row
double[][]	asDenseDoubleDouble() Convert to a dense 2d double array
int	columnCount() Get the number of columns
boolean	equals(Object obj)
double	get(int row, int column)
int	hashCode()
Vector	mult(Vector dense) Returns y = Ax.
Matrix	newInstance(int rows, int cols)
double	put(int row, int column, double value) Set the value at the given row/column
static SparseMatrix	random(int n, int m, double density) Create a random matrix
static SparseMatrix	readFrom(Scanner scan) Read matrix from Scanner
Vector	row(int row) Get the given row as a vector
int	rowCount()
Iterable<Vector>	rows() Get an Iterable over the rows
void	setRow(int row, SparseVector values) Sets the row, no check is made on SparseVector.size() Use with care.
Vector	transposeMultiply(Vector dense) Returns y = (A^T)x.
void	trim() Trim each row
int	used()

Methods inherited from class ch.akuhn.matrix.Matrix

asArray, asColumnMajorArray, column, columns, dense, density, elementCount, from, getHistogram, indexOf, isSquare, max, mean, min, newInstance, rowwiseMean, sparse, storeSparseOn, storeSparseOn, toString, transposeNonTransposeMultiply, unwrap

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

SparseMatrix

public SparseMatrix(double[][] values)

Construct with the given values

Parameters:

values -

SparseMatrix

public SparseMatrix(int rows,
                    int columns)

Construct with the given size

Parameters:

rows -

columns -

Method Detail

add

public double add(int row,
                  int column,
                  double sum)

Description copied from class: Matrix

Add to the value at the given row/column

Overrides:

add in class Matrix

Returns:

the new value

addColumn

public int addColumn()

Add a new column to the end, increasing the number of columns by 1

Returns:

number of cols BEFORE new one was added

addRow

public int addRow()

Add a new row to the end, increasing the number of rows by 1

Returns:

number of rows BEFORE new one was added

addRow

protected int addRow(double[] values)

addToRow

public void addToRow(int row,
                     Vector values)

Add the given values to the given row

Parameters:

row -

values -

asDenseDoubleDouble

public double[][] asDenseDoubleDouble()

Convert to a dense 2d double array

Returns:

2d double array

columnCount

public int columnCount()

Description copied from class: Matrix

Get the number of columns

Specified by:

columnCount in class Matrix

Returns:

the number of columns

equals

public boolean equals(Object obj)

Overrides:

equals in class Object

get

public double get(int row,
                  int column)

Specified by:

get in class Matrix

Returns:

the value at the given row and column

hashCode

public int hashCode()

Overrides:

hashCode in class Object

put

public double put(int row,
                  int column,
                  double value)

Description copied from class: Matrix

Set the value at the given row/column

Specified by:

put in class Matrix

Returns:

the value being set

rows

public Iterable<Vector> rows()

Description copied from class: Matrix

Get an Iterable over the rows

Overrides:

rows in class Matrix

Returns:

an Iterable over the rows

row

public Vector row(int row)

Description copied from class: Matrix

Get the given row as a vector

Overrides:

row in class Matrix

Returns:

the row

rowCount

public int rowCount()

Specified by:

rowCount in class Matrix

Returns:

the number of rows

setRow

public void setRow(int row,
                   SparseVector values)

Sets the row, no check is made on SparseVector.size() Use with care.

Parameters:

row -

values -

used

public int used()

Specified by:

used in class Matrix

Returns:

the number of non-zero elements

trim

public void trim()

Trim each row

readFrom

public static SparseMatrix readFrom(Scanner scan)

Read matrix from Scanner

Parameters:

scan -

Returns:

the matrix

random

public static SparseMatrix random(int n,
                                  int m,
                                  double density)

Create a random matrix

Parameters:

n -

m -

density -

Returns:

the matrix

mult

public Vector mult(Vector dense)

Description copied from class: Matrix

Returns y = Ax.

Overrides:

mult in class Matrix

Returns:

the result

transposeMultiply

public Vector transposeMultiply(Vector dense)

Description copied from class: Matrix

Returns y = (A^T)x.

Overrides:

transposeMultiply in class Matrix

Returns:

the result

newInstance

public Matrix newInstance(int rows,
                          int cols)

Specified by:

newInstance in class Matrix

Returns:

an empty instance of this matrix type