org.apache.mahout.math
Class SparseColumnMatrix

java.lang.Object
  extended by org.apache.mahout.math.AbstractMatrix
      extended by org.apache.mahout.math.SparseColumnMatrix
All Implemented Interfaces:
Cloneable, Iterable<MatrixSlice>, Matrix, VectorIterable

public class SparseColumnMatrix
extends AbstractMatrix

sparse matrix with general element values whose columns are accessible quickly. Implemented as a column array of SparseVectors.


Nested Class Summary
 
Nested classes/interfaces inherited from class org.apache.mahout.math.AbstractMatrix
AbstractMatrix.TransposeViewVector
 
Field Summary
 
Fields inherited from class org.apache.mahout.math.AbstractMatrix
COL, columnLabelBindings, columns, ROW, rowLabelBindings, rows
 
Constructor Summary
SparseColumnMatrix(int rows, int columns)
          Construct a matrix of the given cardinality
SparseColumnMatrix(int rows, int columns, RandomAccessSparseVector[] columnVectors)
          Construct a matrix of the given cardinality with the given data columns
 
Method Summary
 Matrix assignColumn(int column, Vector other)
          Assign the other vector values to the column of the receiver
 Matrix assignRow(int row, Vector other)
          Assign the other vector values to the row of the receiver
 Matrix clone()
          Return a copy of the recipient
 int[] getNumNondefaultElements()
          Return the number of values in the recipient
 double getQuick(int row, int column)
          Return the value at the given indexes, without checking bounds
 Matrix like()
          Return an empty matrix of the same underlying class as the receiver
 Matrix like(int rows, int columns)
          Returns an empty matrix of the same underlying class as the receiver and of the specified size.
 int numSlices()
          Abstracted out for the iterator
 void setQuick(int row, int column, double value)
          Set the value at the given index, without checking bounds
 Matrix transpose()
          Return a new matrix that is the transpose of the receiver
 Vector viewColumn(int column)
          Returns a view of a row.
 Matrix viewPart(int[] offset, int[] size)
          Return a view into part of a matrix.
 
Methods inherited from class org.apache.mahout.math.AbstractMatrix
aggregate, aggregateColumns, aggregateRows, asFormatString, assign, assign, assign, assign, assign, columnSize, determinant, divide, get, get, getColumnLabelBindings, getRowLabelBindings, iterateAll, iterator, minus, numCols, numRows, plus, plus, rowSize, set, set, set, set, set, set, setColumnLabelBindings, setRowLabelBindings, times, times, times, timesSquared, toString, viewDiagonal, viewPart, viewRow, zSum
 
Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
 

Constructor Detail

SparseColumnMatrix

public SparseColumnMatrix(int rows,
                          int columns,
                          RandomAccessSparseVector[] columnVectors)
Construct a matrix of the given cardinality with the given data columns

Parameters:
columns - a RandomAccessSparseVector[] array of columns
columnVectors -

SparseColumnMatrix

public SparseColumnMatrix(int rows,
                          int columns)
Construct a matrix of the given cardinality

Parameters:
rows -
columns -
Method Detail

clone

public Matrix clone()
Description copied from interface: Matrix
Return a copy of the recipient

Specified by:
clone in interface Matrix
Overrides:
clone in class AbstractMatrix
Returns:
a new Matrix

numSlices

public int numSlices()
Abstracted out for the iterator

Specified by:
numSlices in interface VectorIterable
Overrides:
numSlices in class AbstractMatrix
Returns:
AbstractMatrix.numCols()

getQuick

public double getQuick(int row,
                       int column)
Description copied from interface: Matrix
Return the value at the given indexes, without checking bounds

Parameters:
row - an int row index
column - an int column index
Returns:
the double at the index

like

public Matrix like()
Description copied from interface: Matrix
Return an empty matrix of the same underlying class as the receiver

Returns:
a Matrix

like

public Matrix like(int rows,
                   int columns)
Description copied from interface: Matrix
Returns an empty matrix of the same underlying class as the receiver and of the specified size.

Parameters:
rows - the int number of rows
columns - the int number of columns

setQuick

public void setQuick(int row,
                     int column,
                     double value)
Description copied from interface: Matrix
Set the value at the given index, without checking bounds

Parameters:
row - an int row index into the receiver
column - an int column index into the receiver
value - a double value to set

getNumNondefaultElements

public int[] getNumNondefaultElements()
Description copied from interface: Matrix
Return the number of values in the recipient

Specified by:
getNumNondefaultElements in interface Matrix
Overrides:
getNumNondefaultElements in class AbstractMatrix
Returns:
an int[2] containing [row, column] count

viewPart

public Matrix viewPart(int[] offset,
                       int[] size)
Description copied from interface: Matrix
Return a view into part of a matrix. Changes to the view will change the original matrix.

Specified by:
viewPart in interface Matrix
Overrides:
viewPart in class AbstractMatrix
Parameters:
offset - an int[2] offset into the receiver
size - the int[2] size of the desired result
Returns:
a matrix that shares storage with part of the original matrix.

assignColumn

public Matrix assignColumn(int column,
                           Vector other)
Description copied from interface: Matrix
Assign the other vector values to the column of the receiver

Parameters:
column - the int row to assign
other - a Vector
Returns:
the modified receiver

assignRow

public Matrix assignRow(int row,
                        Vector other)
Description copied from interface: Matrix
Assign the other vector values to the row of the receiver

Parameters:
row - the int row to assign
other - a Vector
Returns:
the modified receiver

viewColumn

public Vector viewColumn(int column)
Description copied from class: AbstractMatrix
Returns a view of a row. Changes to the view will affect the original.

Specified by:
viewColumn in interface Matrix
Overrides:
viewColumn in class AbstractMatrix
Parameters:
column - Which column to return.
Returns:
A vector that references the desired column.

transpose

public Matrix transpose()
Description copied from interface: Matrix
Return a new matrix that is the transpose of the receiver

Specified by:
transpose in interface Matrix
Overrides:
transpose in class AbstractMatrix
Returns:
the transpose


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