edu.ucla.sspace.vector

Class SparseHashVector<T extends Number>

java.lang.Object

edu.ucla.sspace.vector.AbstractVector<T>

edu.ucla.sspace.vector.SparseHashVector<T>

All Implemented Interfaces:

SparseVector<T>, Vector<T>, Serializable

public class SparseHashVector<T extends Number>
extends AbstractVector<T>
implements SparseVector<T>, Serializable

A SparseVector implementation backed by a HashMap. This provides amoritized constant time access to all get and set operations, while using more space than the CompactSparseVector or AmortizedSparseVector classes.

See SparseHashArray for implementation details.

Author:

David Jurgens

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
protected double	magnitude The magnitude of the vector or -1 if the value is currently invalid needs to be recomputed
protected SparseHashArray<Number>	vector The backing array that holds the vector values

Constructor Summary

Constructors

Constructor and Description
SparseHashVector(int length) Create a SparseHashVector with the given size, having no non-zero values.
SparseHashVector(T[] array) Create a SparseHashVector from an array, saving only the non zero entries.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object o) Returns true if the object is a Vector of the same length and whose corresponding indices have equivalent values.
int[]	getNonZeroIndices() Returns all the indices whose values are non-zero
Number	getValue(int index) Return the value of the vector at the given index as a Number.
int	length() Return the size of the Vector.
double	magnitude() Returns the magnitude of this vector
void	set(int index, Number value) Set the value in the vector (optional operation).

Methods inherited from class edu.ucla.sspace.vector.AbstractVector

add, hashCode, toString

Methods inherited from class java.lang.Object

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

Methods inherited from interface edu.ucla.sspace.vector.Vector

hashCode

Field Detail

vector

protected SparseHashArray<Number> vector

The backing array that holds the vector values

magnitude

protected double magnitude

The magnitude of the vector or -1 if the value is currently invalid needs to be recomputed

Constructor Detail

SparseHashVector

public SparseHashVector(int length)

Create a SparseHashVector with the given size, having no non-zero values.

Parameters:

length - The length of this Vector

SparseHashVector

public SparseHashVector(T[] array)

Create a SparseHashVector from an array, saving only the non zero entries.

Parameters:

array - the values of this vector

Method Detail

equals

public boolean equals(Object o)

Returns true if the object is a Vector of the same length and whose corresponding indices have equivalent values.

Specified by:

equals in interface Vector<T extends Number>

Overrides:

equals in class AbstractVector<T extends Number>

getNonZeroIndices

public int[] getNonZeroIndices()

Returns all the indices whose values are non-zero

Specified by:

getNonZeroIndices in interface SparseVector<T extends Number>

getValue

public Number getValue(int index)

Return the value of the vector at the given index as a Number.

Specified by:

getValue in interface Vector<T extends Number>

Parameters:

index - index to retrieve.

Returns:

value at index.

length

public int length()

Return the size of the Vector.

Specified by:

length in interface Vector<T extends Number>

Returns:

size of the vector.

magnitude

public double magnitude()

Returns the magnitude of this vector

Specified by:

magnitude in interface Vector<T extends Number>

Overrides:

magnitude in class AbstractVector<T extends Number>

set

public void set(int index,
       Number value)

Set the value in the vector (optional operation).

Specified by:

set in interface Vector<T extends Number>

Overrides:

set in class AbstractVector<T extends Number>

Parameters:

index - index to set.

value - value to set in the vector.