aima.core.nlp.ranking

Class HITS

java.lang.Object

aima.core.nlp.ranking.HITS

public class HITS
extends java.lang.Object

Artificial Intelligence A Modern Approach (3rd Edition): page 871.

 function HITS(query) returns pages (with hub and authority numbers)
   pages ← EXPAND-PAGES(RELEVANT-PAGES(query))
   for each p in pages do 
        p.AUTHORITY ← 1
        p.HUB ← 1
   repeat until convergence do
        for each p in pages do
                p.AUTHORITY ← Σi INLINKi(p).HUB
                p.HUB ← Σi OUTLINKi(p).AUTHORITY
        NORMALIZE(pages)
   return pages
 

Figure 22.1 The HITS algorithm for computing hubs and authorities with respect to a query. RELEVANT-PAGES fetches the pages that match the query, and EXPAND-PAGES add in every page that links to or is linked from one of the relevant pages. NORMALIZE divides each page's score by the sum of the squares of all pages' scores (separately for both the authority and hubs scores.

Author:

Jonathon Belotti (thundergolfer)

Constructor Summary

Constructors

Constructor and Description
HITS(java.util.Map<java.lang.String,Page> pTable)
HITS(java.util.Map<java.lang.String,Page> pTable, int rank_hist_depth, double delta_tolerance)

Method Summary

Modifier and Type	Method and Description
java.util.List<Page>	expandPages(java.util.List<Page> pages) Adds pages that are linked to or is linked from one of the pages passed as argument.
double	getAveDelta(double[] curr, double[] prev) Determine how much values in a list are changing.
Page	getMaxAuthority(java.util.List<Page> result) Return from a set of Pages the Page with the greatest Authority value
Page	getMaxHub(java.util.List<Page> result) Return from a set of Pages the Page with the greatest Hub value
java.util.List<Page>	hits(java.lang.String query)
boolean	matches(java.lang.String query, java.lang.String text) Simple check if query string is a substring of a block of text.
java.util.List<Page>	normalize(java.util.List<Page> pages) Divides each page's score by the sum of the squares of all pages' scores (separately for both the authority and hubs scores
java.util.List<Page>	relevantPages(java.lang.String query) Fetches and returns all pages that match the query
void	report(java.util.List<Page> result) Simple console display of HITS Algorithm results.
void	sortAuthority(java.util.List<Page> result) Organize the list of pages according to their descending Authority Scores
void	sortHub(java.util.List<Page> result) Organize the list of pages according to their descending Hub scores.
double	SumInlinkHubScore(Page page) Calculate the Authority score of a page by summing the Hub scores of that page's inlinks.
double	SumOutlinkAuthorityScore(Page page) Calculate the Hub score of a page by summing the Authority scores of that page's outlinks.

Methods inherited from class java.lang.Object

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

Constructor Detail

HITS

public HITS(java.util.Map<java.lang.String,Page> pTable,
            int rank_hist_depth,
            double delta_tolerance)

HITS

public HITS(java.util.Map<java.lang.String,Page> pTable)

Method Detail

hits

public java.util.List<Page> hits(java.lang.String query)

relevantPages

public java.util.List<Page> relevantPages(java.lang.String query)

Fetches and returns all pages that match the query

Parameters:

query -

Returns:

Throws:

UnsupportedEncodingException

matches

public boolean matches(java.lang.String query,
                       java.lang.String text)

Simple check if query string is a substring of a block of text.

Parameters:

query -

text -

Returns:

expandPages

public java.util.List<Page> expandPages(java.util.List<Page> pages)

Adds pages that are linked to or is linked from one of the pages passed as argument.

Parameters:

pages -

Returns:

normalize

public java.util.List<Page> normalize(java.util.List<Page> pages)

Divides each page's score by the sum of the squares of all pages' scores (separately for both the authority and hubs scores

Parameters:

pages -

Returns:

SumInlinkHubScore

public double SumInlinkHubScore(Page page)

Calculate the Authority score of a page by summing the Hub scores of that page's inlinks.

Parameters:

page -

pagesTable -

Returns:

SumOutlinkAuthorityScore

public double SumOutlinkAuthorityScore(Page page)

Calculate the Hub score of a page by summing the Authority scores of that page's outlinks.

Parameters:

page -

pagesTable -

Returns:

getAveDelta

public double getAveDelta(double[] curr,
                          double[] prev)

Determine how much values in a list are changing. Useful for detecting convergence of data values.

Parameters:

r -

Returns:

getMaxHub

public Page getMaxHub(java.util.List<Page> result)

Return from a set of Pages the Page with the greatest Hub value

Parameters:

pageTable -

Returns:

getMaxAuthority

public Page getMaxAuthority(java.util.List<Page> result)

Return from a set of Pages the Page with the greatest Authority value

Parameters:

pageTable -

Returns:

sortHub

public void sortHub(java.util.List<Page> result)

Organize the list of pages according to their descending Hub scores.

Parameters:

result -

sortAuthority

public void sortAuthority(java.util.List<Page> result)

Organize the list of pages according to their descending Authority Scores

Parameters:

result -

report

public void report(java.util.List<Page> result)

Simple console display of HITS Algorithm results.

Parameters:

result -