public static void readData(File f) {
Scanner sc = null;
try {
sc = new Scanner(f);
while (sc.hasNextLine()) {
String line = sc.nextLine();
// Split the line by space
String[] links = line.trim().split("\\s+");
Link currentLink = linkMap.get(links[0]);
if (currentLink == null) {
currentLink = new Link(links[0]);
linkMap.put(links[0], currentLink);
}
for (int idx = 1; idx < links.length; idx++) {
Link inLink = linkMap.get(links[idx]);
if (inLink == null) {
inLink = new Link(links[idx]);
linkMap.put(links[idx], inLink);
}
currentLink.getInLinks().add(inLink);
inLink.getOutLinks().add(currentLink);
}
}
} catch (FileNotFoundException e) {
e.printStackTrace();
} finally {
if (sc != null) {
sc.close();
}
}
}
private static void process() {
double nLinks = linkMap.size();
int iteration = 1;
do {
double sinkPR = 0;
double perplexity = getPerplexity(getEntropyAndResetRank());
// System.out.println("Perplexity at iteration " + iteration + " = " + perplexity );
for (Link sink : sinks) {
sinkPR += sink.getOldPageRank();
}
for (Link link : linkMap.values()) {
double newPageRank = (1 - DAMPING_FACTOR) / nLinks;
newPageRank += DAMPING_FACTOR * sinkPR / nLinks;
for (Link inLink : link.getInLinks()) {
newPageRank += DAMPING_FACTOR * inLink.getOldPageRank() / inLink.getOutLinks().size();
}
link.setNewPageRank(newPageRank);
}
if (iteration == 1 || iteration == 10 || iteration == 100) {
System.out.println("Iteration : " + iteration);
System.out.println("Perplexity : " + perplexity);
for (Link link : linkMap.values()) {
System.out.println(link);
}
}
} while (++iteration <= 100);
}
private static void preProcess() {
double nLinks = linkMap.size();
double initialPgRank = Double.valueOf(1) / nLinks;
// First lets find out which are the sinks
for (Link currentLink : linkMap.values()) {
if (currentLink.getOutLinks().isEmpty()) {
sinks.add(currentLink);
}
currentLink.setNewPageRank(initialPgRank);
}
}
