org.apache.mahout.math
Class PermutedVectorView

java.lang.Object
  org.apache.mahout.math.AbstractVector
      org.apache.mahout.math.PermutedVectorView

All Implemented Interfaces:

Cloneable, Iterable<Vector.Element>, Vector

public class PermutedVectorView
extends AbstractVector

Provides a permuted view of a vector.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.mahout.math.AbstractVector

AbstractVector.LocalElement

Nested classes/interfaces inherited from interface org.apache.mahout.math.Vector

Vector.Element

Field Summary

Fields inherited from class org.apache.mahout.math.AbstractVector

lengthSquared

Constructor Summary

PermutedVectorView(Vector vector, int[] pivot)

PermutedVectorView(Vector vector, int[] pivot, int[] unpivot)

Method Summary

int	getNumNondefaultElements() Return the number of values in the recipient
double	getQuick(int index) Return the value at the given index, without checking bounds
boolean	isDense()
boolean	isSequentialAccess()
Iterator<Vector.Element>	iterateNonZero() Iterates over all non-zero elements.
Iterator<Vector.Element>	iterator() Iterates over all elements * NOTE: Implementations may choose to reuse the Element returned for performance reasons, so if you need a copy of it, you should call AbstractVector.getElement(int) for the given index
Vector	like() Return an empty vector of the same underlying class as the receiver
protected Matrix	matrixLike(int rows, int columns) Subclasses must override to return an appropriately sparse or dense result
void	setQuick(int index, double value) Set the value at the given index, without checking bounds

Methods inherited from class org.apache.mahout.math.AbstractVector

aggregate, aggregate, asFormatString, assign, assign, assign, assign, assign, assign, clone, cross, divide, dot, dotSelf, equals, get, getDistanceSquared, getElement, getLengthSquared, hashCode, logNormalize, logNormalize, logNormalize, maxValue, maxValueIndex, minus, minValue, minValueIndex, norm, normalize, normalize, plus, plus, set, size, times, times, toString, toString, viewPart, zSum

Methods inherited from class java.lang.Object

finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

PermutedVectorView

public PermutedVectorView(Vector vector,
                          int[] pivot,
                          int[] unpivot)

PermutedVectorView

public PermutedVectorView(Vector vector,
                          int[] pivot)

Method Detail

matrixLike

protected Matrix matrixLike(int rows,
                            int columns)

Subclasses must override to return an appropriately sparse or dense result

Specified by:

matrixLike in class AbstractVector

Parameters:

rows - the row cardinality

columns - the column cardinality

Returns:

a Matrix

isDense

public boolean isDense()

Returns:

true iff this implementation should be considered dense -- that it explicitly represents every value

isSequentialAccess

public boolean isSequentialAccess()

Returns:

true iff this implementation should be considered to be iterable in index order in an efficient way. In particular this implies that iterator() and iterateNonZero() return elements in ascending order by index.

iterator

public Iterator<Vector.Element> iterator()

Iterates over all elements

* NOTE: Implementations may choose to reuse the Element returned for performance reasons, so if you need a copy of it, you should call AbstractVector.getElement(int) for the given index

Returns:

An Iterator over all elements

iterateNonZero

public Iterator<Vector.Element> iterateNonZero()

Iterates over all non-zero elements.

NOTE: Implementations may choose to reuse the Element returned for performance reasons, so if you need a copy of it, you should call AbstractVector.getElement(int) for the given index

Returns:

An Iterator over all non-zero elements

getQuick

public double getQuick(int index)

Return the value at the given index, without checking bounds

Parameters:

index - an int index

Returns:

the double at the index

like

public Vector like()

Return an empty vector of the same underlying class as the receiver

Returns:

a Vector

setQuick

public void setQuick(int index,
                     double value)

Set the value at the given index, without checking bounds

Parameters:

index - an int index into the receiver

value - a double value to set

getNumNondefaultElements

public int getNumNondefaultElements()

Return the number of values in the recipient

Returns:

an int