com.tagtraum.jipes.math

Class SymmetricBandMatrix

java.lang.Object

com.tagtraum.jipes.math.AbstractMatrix

com.tagtraum.jipes.math.MutableAbstractMatrix

com.tagtraum.jipes.math.SymmetricMatrix

com.tagtraum.jipes.math.SymmetricBandMatrix

All Implemented Interfaces:

Matrix, MutableMatrix

public class SymmetricBandMatrix
extends SymmetricMatrix

Matrix for data that is mirrored along the diagonal, but only in a diagonal band along the diagonal - all other values are zero. Any data set in one half of the matrix is automatically set in the other half without doubling memory consumption. The bandwidth of the matrix is defined as the number of diagonals with non-zero entries. Since this implementation is symmetric, possible bandwidths are 1, 3, 5, etc. In other words: the number of diagonals k1 below the main diagonal, the number of diagonals k2 above the main diagonal, plus the main diagonal. bandwidth := k1 + k2 + 1

Author:

Hendrik Schreiber

See Also:

Banded Matrix on Wikipedia

Field Summary

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

offset

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

buffer, columns, rows, zeroPadded

Constructor Summary

Constructors

Modifier	Constructor and Description
	SymmetricBandMatrix(int length, int bandwidth, boolean direct, boolean zeroPadded) Creates a square, symmetric band matrix with the given number of rows and columns.
	SymmetricBandMatrix(int length, int bandwidth, float defaultValue) Creates a square, symmetric band matrix with the given number of rows and columns.
protected	SymmetricBandMatrix(int length, int bandwidth, MatrixBackingBuffer buffer, boolean zeroPadded, float defaultValue, boolean allocate)
	SymmetricBandMatrix(int length, int bandwidth, MatrixBackingBuffer buffer, float defaultValue, boolean zeroPadded) Creates a square, symmetric band matrix with the given number of rows and columns.

Method Summary

Modifier and Type	Method and Description
protected void	allocate(MatrixBackingBuffer buffer) Calls MatrixBackingBuffer.allocate(int) on the used buffer.
void	copy(float[] values) Copies values from the provided array row by row to this matrix.
void	copy(Matrix fromMatrix) Copies values from another Matrix to this matrix.
void	copy(Matrix fromMatrix, int fromRow, int fromColumn, int toRow, int toColumn, int rows, int columns) Copies values from a defined offset from another matrix to a defined offset of this matrix.
void	fill(float value) Fills the matrix with the given values and adjusts the defaultValue returned for elements outside the band.
float	get(int row, int column) Gets the value from row and column.
void	set(int row, int column, float value) Sets the given value.
protected int	toIndex(int row, int column)
String	toString()

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

isInvalid

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

copy, set, setColumn, setRow

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

add, checkBounds, columnSum, enlarge, equals, get, getColumn, getNumberOfColumns, getNumberOfRows, getRow, hadamardMultiply, hashCode, isValidXORZeroPadded, isZeroPadded, multiply, multiply, rowSum, subtract, sum, 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.MutableMatrix

setColumn, setRow

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

add, columnSum, enlarge, getColumn, getNumberOfColumns, getNumberOfRows, getRow, hadamardMultiply, isZeroPadded, multiply, multiply, rowSum, subtract, sum, translate, transpose

Constructor Detail

SymmetricBandMatrix

public SymmetricBandMatrix(int length,
                           int bandwidth,
                           float defaultValue)

Creates a square, symmetric band matrix with the given number of rows and columns. Memory is allocated from the Java heap. The matrix is not zero-padded.

Parameters:

length - rows == columns (square)

bandwidth - bandwidth == k1 + k2 + 1, with k1 and k2 being the number of diagonals above and below the main diagonal

defaultValue - value to return for elements outside the band

SymmetricBandMatrix

public SymmetricBandMatrix(int length,
                           int bandwidth,
                           MatrixBackingBuffer buffer,
                           float defaultValue,
                           boolean zeroPadded)

Creates a square, symmetric band matrix with the given number of rows and columns. Memory is allocated via the given backing buffer. The matrix may be zero-padded.

Parameters:

length - rows == columns (square)

bandwidth - bandwidth == k1 + k2 + 1, with k1 and k2 being the number of diagonals above and below the main diagonal

buffer - backing buffer

defaultValue - value to return for elements outside the band

zeroPadded - zero pad?

SymmetricBandMatrix

public SymmetricBandMatrix(int length,
                           int bandwidth,
                           boolean direct,
                           boolean zeroPadded)

Creates a square, symmetric band matrix with the given number of rows and columns. Memory is allocated via a FloatBackingBuffer either directly/natively or on the Java heap. The matrix may be zero-padded.

Parameters:

length - rows == columns (square)

bandwidth - bandwidth == k1 + k2 + 1, with k1 and k2 being the number of diagonals above and below the main diagonal

direct - allocate memory natively or on the Java heap

zeroPadded - zero pad?

SymmetricBandMatrix

protected SymmetricBandMatrix(int length,
                              int bandwidth,
                              MatrixBackingBuffer buffer,
                              boolean zeroPadded,
                              float defaultValue,
                              boolean allocate)

Method Detail

allocate

protected void allocate(MatrixBackingBuffer buffer)

Description copied from class: MutableAbstractMatrix

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

Overrides:

allocate in class SymmetricMatrix

Parameters:

buffer - buffer

fill

public void fill(float value)

Fills the matrix with the given values and adjusts the defaultValue returned for elements outside the band.

Specified by:

fill in interface MutableMatrix

Overrides:

fill in class MutableAbstractMatrix

Parameters:

value - value

copy

public void copy(float[] values)

Description copied from interface: MutableMatrix

Copies values from the provided array row by row to this matrix.

Specified by:

copy in interface MutableMatrix

Overrides:

copy in class MutableAbstractMatrix

Parameters:

values - values

copy

public void copy(Matrix fromMatrix)

Description copied from interface: MutableMatrix

Copies values from another Matrix to this matrix. If this matrix does not support the setting of certain elements (e.g. SymmetricBandMatrix), the method fails silently, i.e. no values are copied, and no exception is raised.

Specified by:

copy in interface MutableMatrix

Overrides:

copy in class MutableAbstractMatrix

Parameters:

fromMatrix - other matrix

copy

public void copy(Matrix fromMatrix,
                 int fromRow,
                 int fromColumn,
                 int toRow,
                 int toColumn,
                 int rows,
                 int columns)

Description copied from interface: MutableMatrix

Copies values from a defined offset from another matrix to a defined offset of this matrix. If this matrix does not support the setting of certain elements (e.g. SymmetricBandMatrix), the method fails silently, i.e. no values are copied, and no exception is raised.

Specified by:

copy in interface MutableMatrix

Overrides:

copy in class MutableAbstractMatrix

Parameters:

fromMatrix - other matrix

fromRow - row start offset of from matrix

fromColumn - column start offset of from matrix

toRow - column start offset of this matrix

toColumn - column start offset of this matrix

rows - number of rows to copy

columns - number of column to copy

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 SymmetricMatrix

Parameters:

row - row

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 SymmetricMatrix

Parameters:

row - row

column - column

value - value

toIndex

protected int toIndex(int row,
                      int column)

Overrides:

toIndex in class SymmetricMatrix

toString

public String toString()

Overrides:

toString in class SymmetricMatrix