edu.ucla.sspace.matrix

Class SparseRowMaskedMatrix

java.lang.Object

edu.ucla.sspace.matrix.RowMaskedMatrix

edu.ucla.sspace.matrix.SparseRowMaskedMatrix

All Implemented Interfaces:

Matrix, SparseMatrix

public class SparseRowMaskedMatrix
extends RowMaskedMatrix
implements SparseMatrix

A tiled view of a SparseMatrix instance where selected rows of the instance a represented as a single, contiguous matrix. This effectively creates a SparseMatrix 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 SparseMatrix 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

See Also:

RowMaskedMatrix

Nested Class Summary

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

Matrix.Type

Constructor Summary

Constructors

Constructor and Description
SparseRowMaskedMatrix(SparseMatrix matrix, BitSet included) Creates a partial view of the provided sparse matrix using the bits set to true as the rows that should be included
SparseRowMaskedMatrix(SparseMatrix matrix, int[] reordering) Creates a partial view of the provided sparse matrix using the the integer mapping to specify which rows should be included in the matrix.
SparseRowMaskedMatrix(SparseMatrix matrix, Set<Integer> included) Creates a partial view of the provided sparse 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
SparseDoubleVector	getColumnVector(int column) Returns the column as a vector.
SparseDoubleVector	getRowVector(int row) Returns a DoubleVector for an entire row.

Methods inherited from class edu.ucla.sspace.matrix.RowMaskedMatrix

backingMatrix, columns, get, getColumn, getRealRow, getRow, reordering, rows, set, setColumn, setColumn, setRow, setRow, toDenseArray

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.ucla.sspace.matrix.Matrix

columns, get, getColumn, getRow, rows, set, setColumn, setColumn, setRow, setRow, toDenseArray

Constructor Detail

SparseRowMaskedMatrix

public SparseRowMaskedMatrix(SparseMatrix matrix,
                     BitSet included)

Creates a partial view of the provided sparse 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

SparseRowMaskedMatrix

public SparseRowMaskedMatrix(SparseMatrix matrix,
                     Set<Integer> included)

Creates a partial view of the provided sparse 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

SparseRowMaskedMatrix

public SparseRowMaskedMatrix(SparseMatrix matrix,
                     int[] reordering)

Creates a partial view of the provided sparse matrix using the the integer mapping to specify which rows should be included in the matrix.

Throws:

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

Method Detail

getColumnVector

public SparseDoubleVector 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

Specified by:

getColumnVector in interface SparseMatrix

Overrides:

getColumnVector in class RowMaskedMatrix

Parameters:

column - The column to return a DoubleVector for.

Returns:

A DoubleVector representing the column at column.

getRowVector

public SparseDoubleVector 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

Specified by:

getRowVector in interface SparseMatrix

Overrides:

getRowVector in class RowMaskedMatrix

Parameters:

row - the index of the row to return.

Returns:

A DoubleVector representing the row at row.