edu.ucla.sspace.matrix

Class RowMaskedMatrix

java.lang.Object

edu.ucla.sspace.matrix.RowMaskedMatrix

All Implemented Interfaces:

Matrix

Direct Known Subclasses:

SparseRowMaskedMatrix

public class RowMaskedMatrix
extends Object
implements Matrix

A tiled view of a Matrix instance where selected rows of the instance a represented as a single, contiguous matrix. This effectively creates a Matrix out of a possibly non-contiguous selection of the rows of the original. This class is intended to be use when a large matrix has been created and submatrices of the large matrix need to be treated as full Matrix instances; rather than copy the data, this class provides a way of representing the original data as a partial view.

All methods are write-through to the original backing matrix.

This matrix recomputes the mapping if the Matrix being masked is also a RowMaskedMatrix, thus preventing a recursive call to row lookups.

Author:

David Jurgens

Nested Class Summary

Nested classes/interfaces inherited from interface edu.ucla.sspace.matrix.Matrix

Matrix.Type

Constructor Summary

Constructors

Constructor and Description
RowMaskedMatrix(Matrix matrix, BitSet included) Creates a partial view of the provided matrix using the bits set to true as the rows that should be included
RowMaskedMatrix(Matrix matrix, int[] reordering) Creates a partial view of the provided matrix using the integers in the array of indices.
RowMaskedMatrix(Matrix matrix, LinkedHashSet<Integer> included) Creates a partial view of the provided matrix using the integers in the ordered set.
RowMaskedMatrix(Matrix matrix, Set<Integer> included) Creates a partial view of the provided matrix using the integers in the set to specify which rows should be included in the matrix.

Method Summary

Methods

Modifier and Type	Method and Description
Matrix	backingMatrix() Returns the backingMatrix that is being masked.
int	columns() Returns the number of columns in this Matrix.
double	get(int row, int col) Returns the value of the Matrix at the provided row and column.
double[]	getColumn(int column) Returns the entire column.
DoubleVector	getColumnVector(int column) Returns the column as a vector.
protected int	getRealRow(int virtualRow) Returns the row in the backing matrix that the virtualRow value is mapped to in the row-masked matrix.
double[]	getRow(int row) Returns the entire row.
DoubleVector	getRowVector(int row) Returns a DoubleVector for an entire row.
int[]	reordering() Returns the mapping from indices in this RowMaskedMatrix to the real indices in the backingMatrix.
int	rows() Returns the number of rows in this Matrix.
void	set(int row, int col, double val) Sets the location at the row and column to the provided value.
void	setColumn(int column, double[] values) Sets the values for the column of this Matrix using the provided array.
void	setColumn(int column, DoubleVector values) Sets the values for the column of this Matrix using the provided DoubleVector.
void	setRow(int row, double[] columns) Sets the values for the row of this Matrix using the provided array.
void	setRow(int row, DoubleVector values) Sets the values for the row of this Matrix using the provided DoubleVector.
double[][]	toDenseArray() Converts the Matrix to a two dimensional array.

Methods inherited from class java.lang.Object

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

Constructor Detail

RowMaskedMatrix

public RowMaskedMatrix(Matrix matrix,
               BitSet included)

Creates a partial view of the provided matrix using the bits set to true as the rows that should be included

Throws:

IllegalArgumentException - if included has a bit set whose index is greater than the number of rows present in matrix

RowMaskedMatrix

public RowMaskedMatrix(Matrix matrix,
               Set<Integer> included)

Creates a partial view of the provided matrix using the integers in the set to specify which rows should be included in the matrix. Note that the ordering of the rows in the set does not matter; rows will be mapped to the respective indices based on the numeric ordering of the values in the set.

Throws:

IllegalArgumentException - if included specifies a value that is less than 0 or greater than the number of rows present in matrix

RowMaskedMatrix

public RowMaskedMatrix(Matrix matrix,
               LinkedHashSet<Integer> included)

Creates a partial view of the provided matrix using the integers in the ordered set. The ordering of the given set is used to determine the order of the rows in the resulting matrix.

Throws:

IllegalArgumentException - if included specifies a value that is less than 0 or greater than the number of rows present in matrix

RowMaskedMatrix

public RowMaskedMatrix(Matrix matrix,
               int[] reordering)

Creates a partial view of the provided matrix using the integers in the array of indices.

Throws:

IllegalArgumentException - if included specifies a value that is less than 0 or greater than the number of rows present in matrix

Method Detail

getRealRow

protected int getRealRow(int virtualRow)

Returns the row in the backing matrix that the virtualRow value is mapped to in the row-masked matrix.

get

public double get(int row,
         int col)

Returns the value of the Matrix at the provided row and column.

Specified by:

get in interface Matrix

Parameters:

row - The row values of the cell to return.

col - The column value of the cell to return.

Returns:

The value at the cell specified by row and col.

getColumn

public double[] getColumn(int column)

Returns the entire column.

Specified by:

getColumn in interface Matrix

Parameters:

column - The column to return an array for.

Returns:

A double array representing the column at column.

getColumnVector

public DoubleVector getColumnVector(int column)

Returns the column as a vector. Whether updates to the vector are written through to the backing matrix is left open to the specific implementation. Implementations that maintain their data in a sparse format are encouraged to return a SparseVector instance.

Specified by:

getColumnVector in interface Matrix

Parameters:

column - The column to return a DoubleVector for.

Returns:

A DoubleVector representing the column at column.

getRow

public double[] getRow(int row)

Returns the entire row.

Specified by:

getRow in interface Matrix

Parameters:

row - The row to return an array for.

Returns:

A double array representing the row at row.

getRowVector

public DoubleVector getRowVector(int row)

Returns a DoubleVector for an entire row. Implementations should return an approriately typed DoubleVector. Whether updates to the vector are written through to the backing matrix is left open to the specific implementation. Implementations that maintain their data in a sparse format are encouraged to return a SparseVector instance.

Specified by:

getRowVector in interface Matrix

Parameters:

row - the index of the row to return.

Returns:

A DoubleVector representing the row at row.

columns

public int columns()

Returns the number of columns in this Matrix.

Specified by:

columns in interface Matrix

Returns:

The number of columns in this Matrix.

toDenseArray

public double[][] toDenseArray()

Converts the Matrix to a two dimensional array. Note that for large matrices, this may exhaust all available memory.

Specified by:

toDenseArray in interface Matrix

Returns:

A double array version of this Matrix.

rows

public int rows()

Returns the number of rows in this Matrix.

Specified by:

rows in interface Matrix

Returns:

The number of columns in this Matrix.

set

public void set(int row,
       int col,
       double val)

Sets the location at the row and column to the provided value.

Specified by:

set in interface Matrix

Parameters:

row - The row of the cell to update.

col - The column of the cell to update.

val - The new value of the specified cell.

setColumn

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

Sets the values for the column of this Matrix using the provided array. Note that the array itself is not made internal to the instance itself.

Specified by:

setColumn in interface Matrix

Parameters:

column - The column to update.

values - The values to update into column.

setColumn

public void setColumn(int column,
             DoubleVector values)

Sets the values for the column of this Matrix using the provided DoubleVector. Note that the DoubleVector itself is not made internal to the instance itself.

Specified by:

setColumn in interface Matrix

Parameters:

column - The column to update.

values - The values to update into column.

setRow

public void setRow(int row,
          double[] columns)

Sets the values for the row of this Matrix using the provided array. Note that the array itself is not made internal to the instance itself.

Specified by:

setRow in interface Matrix

Parameters:

row - The row to update.

columns - The values to update into row.

setRow

public void setRow(int row,
          DoubleVector values)

Sets the values for the row of this Matrix using the provided DoubleVector. Note that the DoubleVector itself is not made internal to the instance itself.

Specified by:

setRow in interface Matrix

Parameters:

row - The row to update.

values - The values to update into row.

backingMatrix

public Matrix backingMatrix()

Returns the backingMatrix that is being masked.

reordering

public int[] reordering()

Returns the mapping from indices in this RowMaskedMatrix to the real indices in the backingMatrix.