Java Code Examples for it.unimi.dsi.webgraph.ImmutableGraph#numNodes()

public static int reachable(final ImmutableGraph graph, final int startingNode) {
	final int n = graph.numNodes();
	final boolean[] known = new boolean[n];
	final IntArrayFIFOQueue queue = new IntArrayFIFOQueue();

	queue.enqueue(startingNode);
	known[startingNode] = true;
	int visited = 0;

	while (!queue.isEmpty()) {
		final int currentNode = queue.dequeueInt();
		visited++;
		final LazyIntIterator iterator = graph.successors(currentNode);
		for (int succ; (succ = iterator.nextInt()) != -1;) {
			if (!known[succ]) {
				known[succ] = true;
				queue.enqueue(succ);
			}
		}
	}

	return visited;
}
 

/** Given <code>g</code>, returns a Fenwick tree for the nodes of <code>g</code> whose counter number <code>i+1</code> corresponds to node <code>i</code>
 *  and it is initialized to <code>d</code> or to <code>D-d+1</code> (the latter iff <code>reverse</code> is true),
 *  where <code>D</code> is the maximum indegree in <code>g</code>, and <code>d</code> is <code>i</code>'s indegree.
 *
 * @param g a graph.
 * @param reverse if true, we generate the <em>reverse</em> distribution.
 * @return a Fenwick tree as above.
 */
public static FenwickTree getPreferentialDistribution(final ImmutableGraph g, final boolean reverse) {
	final int n = g.numNodes();
	final int[] indegree = new int[n];
	int maxIndegree = 0;
	final NodeIterator nodeIterator = g.nodeIterator();
	while (nodeIterator.hasNext()) {
		nodeIterator.nextInt();
		final LazyIntIterator successors = nodeIterator.successors();
		int target;
		while ((target = successors.nextInt()) >= 0) {
			indegree[target]++;
			if (indegree[target] > maxIndegree) maxIndegree = indegree[target];
		}
	}
	final FenwickTree t = new FenwickTree(n);
	for (int i = 0; i < indegree.length; i++)
		t.incrementCount(i + 1, reverse? maxIndegree - indegree[i] + 1 : indegree[i]);

	return t;
}
 

public static int reachable(final ImmutableGraph graph, final int startingNode) {
	final int n = graph.numNodes();
	final boolean[] known = new boolean[n];
	final IntArrayFIFOQueue queue = new IntArrayFIFOQueue();

	queue.enqueue(startingNode);
	known[startingNode] = true;
	int visited = 0;

	while (!queue.isEmpty()) {
		final int currentNode = queue.dequeueInt();
		visited++;
		final LazyIntIterator iterator = graph.successors(currentNode);
		for (int succ; (succ = iterator.nextInt()) != -1;) {
			if (!known[succ]) {
				known[succ] = true;
				queue.enqueue(succ);
			}
		}
	}

	return visited;
}
 

/** Creates a new instance using a specific initial permutation and specified number of threads.
 *
 * <p>If <code>exact</code> is true, the final permutation is
 * <em>exactly</em> the same as if you first permute the graph with <code>startPerm</code> and
 * then apply LLP with an {@code null} starting permutation.
 *
 * @param symGraph a symmetric, loopless graph.
 * @param startPerm an initial permutation of the graph, or {@code null} for no permutation.
 * @param numberOfThreads the number of threads to be used (0 for automatic sizing).
 * @param seed a random seed.
 * @param exact a boolean flag that forces the algorithm to run exactly.
 */
public LayeredLabelPropagation(final ImmutableGraph symGraph, final int[] startPerm, final int numberOfThreads, final long seed, final boolean exact) throws IOException {
	this.symGraph = symGraph;
	this.n = symGraph.numNodes();
	this.startPerm = startPerm;
	this.seed = seed;
	this.r = new XoRoShiRo128PlusRandom(seed);
	this.exact = exact;
	this.label = new AtomicIntegerArray(n);
	this.volume = new AtomicIntegerArray(n);
	cumulativeOutdegrees = new EliasFanoCumulativeOutdegreeList(symGraph, symGraph.numArcs(), 1);

	this.gapCost = new MutableDouble();
	this.updateList = Util.identity(n);
	simpleUncaughtExceptionHandler = new SimpleUncaughtExceptionHandler();
	labelling = File.createTempFile(this.getClass().getName(), "labelling");
	labelling.deleteOnExit();

	this.numberOfThreads = numberOfThreads != 0 ? numberOfThreads : Runtime.getRuntime().availableProcessors();
	this.canChange = new boolean[n];
	this.modified = new AtomicInteger(0);
	this.objectiveFunction = new double[this.numberOfThreads];
}
 

@Override
protected int[][] parseSet() throws IOException
{
	
	ImmutableGraph in_graph = WikiGraphs.get(lang, IndexType.IN_GRAPH);
	int[][] arrayGraph = new int[in_graph.numNodes()][];
	for(int i=0; i<arrayGraph.length; i++)
	{
		int i_deg = in_graph.outdegree(i);
		if (i_deg > 0){
			arrayGraph[i] = new int[i_deg];
			LazyIntIterator iter = in_graph.successors(i);
			for (int j=0; j<arrayGraph[i].length; j++)
				arrayGraph[i][j] = iter.nextInt();
		}
	}

	return arrayGraph;
}
 

/** Builds the server.
 *
 * @param graph the graph.
 * @param map a string map representing the URLs of the graph.
 */
public ImmutableGraphNamedGraphServer(final ImmutableGraph graph, StringMap<? extends CharSequence> map) {
	if (graph.numNodes() != map.size()) throw new IllegalArgumentException("The graph has " + graph.numNodes() + " nodes, but the map has " + map.size() + " keys.");
	this.graph = graph;
	this.map = map;
	this.list = map.list();
}