com.tagtraum.jipes.math

Class SparseRowMatrix

java.lang.Object

com.tagtraum.jipes.math.AbstractMatrix

com.tagtraum.jipes.math.MutableAbstractMatrix

com.tagtraum.jipes.math.SparseRowMatrix

All Implemented Interfaces:

Matrix, MutableMatrix

public class SparseRowMatrix
extends MutableAbstractMatrix

Matrix that optimizes memory for matrices that contain sparse rows. I.e. most rows have at least one value and the method Matrix.getRow(int) runs much more quickly than Matrix.getColumn(int). The same is true for MutableMatrix.setRow(int, float[]) and its column counterpart.

Author:

Hendrik Schreiber

Field Summary

Fields inherited from class com.tagtraum.jipes.math.AbstractMatrix

buffer, columns, rows, zeroPadded

Constructor Summary

Constructors

Constructor and Description
SparseRowMatrix(int rows, int columns) Creates a sparse matrix with the given dimensions.
SparseRowMatrix(int rows, int columns, boolean zeroPadded) Creates a sparse matrix with the given dimensions.

Method Summary

Modifier and Type	Method and Description
protected void	allocate(MatrixBackingBuffer buffer) Calls MatrixBackingBuffer.allocate(int) on the used buffer.
float[]	columnSum() Compute the sum for each column.
float	get(int row, int column) Gets the value from row and column.
float[]	getRow(int row) Gets the values from row.
float[]	rowSum() Compute the sum for each row.
void	set(int row, int column, float value) Sets the given value.
void	setRow(int row, float[] values) Sets the given values.
float	sum() Compute the sum of all elements.
String	toString()

Methods inherited from class com.tagtraum.jipes.math.MutableAbstractMatrix

copy, copy, copy, copy, fill, set, setColumn

Methods inherited from class com.tagtraum.jipes.math.AbstractMatrix

add, checkBounds, enlarge, equals, get, getColumn, getNumberOfColumns, getNumberOfRows, hadamardMultiply, hashCode, isInvalid, isValidXORZeroPadded, isZeroPadded, multiply, multiply, subtract, toIndex, translate, transpose

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.tagtraum.jipes.math.Matrix

add, enlarge, getColumn, getNumberOfColumns, getNumberOfRows, hadamardMultiply, isZeroPadded, multiply, multiply, subtract, translate, transpose

Constructor Detail

SparseRowMatrix

public SparseRowMatrix(int rows,
                       int columns,
                       boolean zeroPadded)

Creates a sparse matrix with the given dimensions.

Parameters:

rows - number of rows

columns - number of columns

zeroPadded - zero-pad or not?

SparseRowMatrix

public SparseRowMatrix(int rows,
                       int columns)

Creates a sparse matrix with the given dimensions. The matrix is not zero-padded.

Parameters:

rows - number of rows

columns - number of columns

Method Detail

get

public float get(int row,
                 int column)

Description copied from interface: Matrix

Gets the value from row and column. If the matrix supports zero-padding, this method may return 0f for undefined rows or columns.

Specified by:

get in interface Matrix

Overrides:

get in class AbstractMatrix

Parameters:

row - row

column - column

Returns:

value

getRow

public float[] getRow(int row)

Description copied from interface: Matrix

Gets the values from row. If the matrix supports zero-padding, this method may return 0f for undefined rows or columns.

Specified by:

getRow in interface Matrix

Overrides:

getRow in class AbstractMatrix

Parameters:

row - row

Returns:

value

set

public void set(int row,
                int column,
                float value)

Description copied from interface: MutableMatrix

Sets the given value.

Specified by:

set in interface MutableMatrix

Overrides:

set in class MutableAbstractMatrix

Parameters:

row - row

column - column

value - value

setRow

public void setRow(int row,
                   float[] values)

Description copied from interface: MutableMatrix

Sets the given values.

Specified by:

setRow in interface MutableMatrix

Overrides:

setRow in class MutableAbstractMatrix

Parameters:

row - row

values - values

sum

public float sum()

Description copied from interface: Matrix

Compute the sum of all elements.

Specified by:

sum in interface Matrix

Overrides:

sum in class AbstractMatrix

Returns:

sum

rowSum

public float[] rowSum()

Description copied from interface: Matrix

Compute the sum for each row.

Specified by:

rowSum in interface Matrix

Overrides:

rowSum in class AbstractMatrix

Returns:

sum for all rows

columnSum

public float[] columnSum()

Description copied from interface: Matrix

Compute the sum for each column.

Specified by:

columnSum in interface Matrix

Overrides:

columnSum in class AbstractMatrix

Returns:

sum for all columns

allocate

protected void allocate(MatrixBackingBuffer buffer)

Description copied from class: MutableAbstractMatrix

Calls MatrixBackingBuffer.allocate(int) on the used buffer.

Specified by:

allocate in class MutableAbstractMatrix

Parameters:

buffer - buffer

toString

public String toString()

Overrides:

toString in class AbstractMatrix