com.tagtraum.jipes.math

Class SparseColumnMatrix

java.lang.Object

com.tagtraum.jipes.math.AbstractMatrix

com.tagtraum.jipes.math.MutableAbstractMatrix

com.tagtraum.jipes.math.SparseColumnMatrix

All Implemented Interfaces:

Matrix, MutableMatrix

public class SparseColumnMatrix
extends MutableAbstractMatrix

Matrix that optimizes memory for matrices that contain sparse columns. I.e. most columns have at least one value and the method Matrix.getColumn(int) runs much more quickly than Matrix.getRow(int). The same is true for MutableMatrix.setColumn(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
SparseColumnMatrix(int rows, int columns) Creates a sparse matrix with the given dimensions.
SparseColumnMatrix(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[]	getColumn(int column) Gets the value from column.
float[]	rowSum() Compute the sum for each row.
void	set(int row, int column, float value) Sets the given value.
void	setColumn(int column, 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, setRow

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

add, checkBounds, enlarge, equals, get, getNumberOfColumns, getNumberOfRows, getRow, 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, getNumberOfColumns, getNumberOfRows, getRow, hadamardMultiply, isZeroPadded, multiply, multiply, subtract, translate, transpose

Constructor Detail

SparseColumnMatrix

public SparseColumnMatrix(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?

SparseColumnMatrix

public SparseColumnMatrix(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

getColumn

public float[] getColumn(int column)

Description copied from interface: Matrix

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

Specified by:

getColumn in interface Matrix

Overrides:

getColumn in class AbstractMatrix

Parameters:

column - column

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

setColumn

public void setColumn(int column,
                      float[] values)

Description copied from interface: MutableMatrix

Sets the given values.

Specified by:

setColumn in interface MutableMatrix

Overrides:

setColumn in class MutableAbstractMatrix

Parameters:

column - column

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

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

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

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