ir.vsr
Class HashMapVector

java.lang.Object
  ir.vsr.HashMapVector

public class HashMapVector
extends java.lang.Object

A data structure for a term vector for a document stored as a HashMap that maps tokens to Weight's that store the weight of that token in the document.

Needed as an efficient, indexed representation of sparse document vectors.

Field Summary

java.util.Map<java.lang.String,Weight>

hashMap The HashMap that stores the mapping of tokens to Weights

Constructor Summary

HashMapVector()

Method Summary

void	add(HashMapVector vector) Destructively add the given vector to the current vector
void	addScaled(HashMapVector vector, double scalingFactor) Destructively add a scaled version of the given vector to the current vector
void	clear() Clears the vector back to all zeros
HashMapVector	copy() Produce a copy of this HashMapVector with a new HashMap and new Weight's
double	cosineTo(HashMapVector otherVector) Computes cosine of angle to otherVector.
double	cosineTo(HashMapVector otherVector, double length) Computes cosine of angle to otherVector when also given otherVector's Euclidian length (Allows saving computation if length already known.
java.util.Set<java.util.Map.Entry<java.lang.String,Weight>>	entrySet() Returns the Set of MapEntries in the hashMap
double	getWeight(java.lang.String token) Return the weight of the given token in the vector
double	increment(java.lang.String token) Increment the weight for the given token in the vector by 1.
double	increment(java.lang.String token, double amount) Increment the weight for the given token in the vector by the given amount.
double	increment(java.lang.String token, int amount) Increment the weight for the given token in the vector by the given int
double	length() Compute Euclidian length (sqrt of sum of squares) of vector
double	maxWeight() Returns the maximum weight of any token in the vector.
void	multiply(double factor) Destructively multiply the vector by a constant
void	print() Print out the vector showing the tokens and their weights
int	size() Returns the number of tokens in the vector.
void	subtract(HashMapVector vector) Destructively subtract the given vector from the current vector
java.lang.String	toString() Return String of the vector showing the tokens and their weights

Methods inherited from class java.lang.Object

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

Field Detail

hashMap

public java.util.Map<java.lang.String,Weight> hashMap

The HashMap that stores the mapping of tokens to Weights

Constructor Detail

HashMapVector

public HashMapVector()

Method Detail

size

public int size()

Returns the number of tokens in the vector.

clear

public void clear()

Clears the vector back to all zeros

entrySet

public java.util.Set<java.util.Map.Entry<java.lang.String,Weight>> entrySet()

Returns the Set of MapEntries in the hashMap

increment

public double increment(java.lang.String token,
                        double amount)

Increment the weight for the given token in the vector by the given amount.

getWeight

public double getWeight(java.lang.String token)

Return the weight of the given token in the vector

increment

public double increment(java.lang.String token)

Increment the weight for the given token in the vector by 1.

increment

public double increment(java.lang.String token,
                        int amount)

Increment the weight for the given token in the vector by the given int

add

public void add(HashMapVector vector)

Destructively add the given vector to the current vector

addScaled

public void addScaled(HashMapVector vector,
                      double scalingFactor)

Destructively add a scaled version of the given vector to the current vector

subtract

public void subtract(HashMapVector vector)

Destructively subtract the given vector from the current vector

multiply

public void multiply(double factor)

Destructively multiply the vector by a constant

copy

public HashMapVector copy()

Produce a copy of this HashMapVector with a new HashMap and new Weight's

maxWeight

public double maxWeight()

Returns the maximum weight of any token in the vector.

print

public void print()

Print out the vector showing the tokens and their weights

toString

public java.lang.String toString()

Return String of the vector showing the tokens and their weights

Overrides:

toString in class java.lang.Object

cosineTo

public double cosineTo(HashMapVector otherVector)

Computes cosine of angle to otherVector.

cosineTo

public double cosineTo(HashMapVector otherVector,
                       double length)

Computes cosine of angle to otherVector when also given otherVector's Euclidian length (Allows saving computation if length already known. more efficient when current vector is shorter than otherVector)

length

public double length()

Compute Euclidian length (sqrt of sum of squares) of vector