TrustRank in Java(using WebGraph)

TrustRank is a biased PageRank method, which starts from some good seeds to propagate trust. It is very easy to implement based on PageRank.

I implement it in Java using the WebGraph and LAW jar package, following is the code:

/*

* TrustRank implement
[/code]

*/

package cn.edu.dlut.wisdom;

import it.unimi.dsi.law.rank.PageRank;

import it.unimi.dsi.law.rank.PageRankPowerMethod;

import it.unimi.dsi.law.rank.PageRank.IterationNumberStoppingCriterion;

import it.unimi.dsi.law.rank.PageRank.NormDeltaStoppingCriterion;

import it.unimi.dsi.webgraph.*;

import it.unimi.dsi.fastutil.doubles.*;

import it.unimi.dsi.fastutil.ints.IntSet;

/**

*

* @author You Wang

*/

public class TrustRank {

    /**

* Graph on which TR will run

    */

private ImmutableGraph g;

    /**

* PageRank implementation

    */

private PageRankPowerMethod pr;

    /**

* to be used as stopping criterion

    */

private double threshold = PageRank.DEFAULT_THRESHOLD;

    /**

* number of iteration

    */

private int numberOfIteration = PageRank.DEFAULT_MAX_ITER;

private double alpha = PageRank.DEFAULT_ALPHA;

    /**

    *

* @param g Graph on which TR will run

    */

public TrustRank(ImmutableGraph g) {

this.g = g;

pr = new PageRankPowerMethod(g);

}

public void setThreshold(double t) {

threshold = t;

}

public void setAlpha(double alpha) {

this.alpha = alpha;

}

public void setIteration(int n) {

numberOfIteration = n;

}

public double[] getRank() {

return pr.rank;

}

    /**

* set the biased good seeds

* @param seeds

    */

public void setGoodSeeds(IntSet seeds) {

int numNodes = g.numNodes();

double[] arr = new double[numNodes];

int seedSize = seeds.size();

for (int i = 0; i < numNodes; i++)

if (seeds.contains(i))

arr[i] = 1/seedSize;

pr.start = DoubleArrayList.wrap(arr);

}

    /**

* compute the TR scores

* @throws Exception

    */

public void compute() throws Exception {

pr.alpha = alpha;

pr.stepUntil(PageRank.or(new NormDeltaStoppingCriterion(threshold),

new IterationNumberStoppingCriterion(numberOfIteration)));

}

}

If you hava any question, please just put a review, or contact me by e-mail.