Examples with GraphDatabaseService org.neo4j.graphdb.GraphDatabaseService used on opensource projects

Example 21 with GraphDatabaseService

use of org.neo4j.graphdb.GraphDatabaseService in project neo4j by neo4j.

the class TraversalAStar method findPaths.

private Iterable<WeightedPath> findPaths(Node start, Node end, boolean multiplePaths) {
    PathInterest interest;
    if (multiplePaths) {
        interest = stopAfterLowestWeight ? PathInterestFactory.allShortest() : PathInterestFactory.all();
    } else {
        interest = PathInterestFactory.single();
    }
    GraphDatabaseService db = start.getGraphDatabase();
    TraversalDescription traversalDescription = db.traversalDescription().uniqueness(Uniqueness.NONE).expand(expander, initialState);
    lastTraverser = traversalDescription.order(new SelectorFactory(end, interest)).evaluator(includeWhereEndNodeIs(end)).traverse(start);
    return new Iterable<WeightedPath>() {

        @Override
        public Iterator<WeightedPath> iterator() {
            return new WeightedPathIterator(lastTraverser.iterator(), costEvaluator, stopAfterLowestWeight);
        }
    };
}

Example 22 with GraphDatabaseService

use of org.neo4j.graphdb.GraphDatabaseService in project neo4j by neo4j.

the class TraversalShortestPath method instantiateTraverser.

@Override
protected Traverser instantiateTraverser(Node start, Node end) {
    GraphDatabaseService db = start.getGraphDatabase();
    TraversalDescription sideBase = db.traversalDescription().breadthFirst().uniqueness(NODE_PATH);
    return db.bidirectionalTraversalDescription().mirroredSides(sideBase.expand(expander)).sideSelector(LEVEL_STOP_DESCENT_ON_RESULT, maxDepth).collisionEvaluator(toDepth(maxDepth)).traverse(start, end);
}

Example 23 with GraphDatabaseService

use of org.neo4j.graphdb.GraphDatabaseService in project neo4j by neo4j.

the class AStarPerformanceIT method somePerformanceTesting.

@Test
public void somePerformanceTesting() throws Exception {
    // GIVEN
    int numberOfNodes = 200000;
    GeoDataGenerator generator = new GeoDataGenerator(numberOfNodes, 5d, 1000, 1000);
    generator.generate(directory);
    // WHEN
    long[][] points = new long[][] { new long[] { 9415, 158154 }, new long[] { 89237, 192863 }, new long[] { 68072, 150484 }, new long[] { 186309, 194495 }, new long[] { 152097, 99289 }, new long[] { 92150, 161182 }, new long[] { 188446, 115873 }, new long[] { 85033, 7772 }, new long[] { 291, 86707 }, new long[] { 188345, 158468 } };
    GraphDatabaseService db = new TestGraphDatabaseFactory().newEmbeddedDatabase(directory.getAbsoluteFile());
    PathFinder<WeightedPath> algo = aStar(allTypesAndDirections(), doubleCostEvaluator("weight", 0), GeoDataGenerator.estimateEvaluator());
    for (int i = 0; i < 10; i++) {
        System.out.println("----- " + i);
        for (long[] p : points) {
            try (Transaction tx = db.beginTx()) {
                Node start = db.getNodeById(p[0]);
                Node end = db.getNodeById(p[1]);
                long time = currentTimeMillis();
                WeightedPath path = algo.findSinglePath(start, end);
                time = currentTimeMillis() - time;
                System.out.println("time: " + time + ", len:" + path.length() + ", weight:" + path.weight());
                tx.success();
            }
        }
    }
    // THEN
    db.shutdown();
}

Example 24 with GraphDatabaseService

use of org.neo4j.graphdb.GraphDatabaseService in project neo4j by neo4j.

the class AllPaths method instantiateTraverser.

@Override
protected Traverser instantiateTraverser(Node start, Node end) {
    //        // Legacy single-directional traversal (for reference or something)
    //        return traversal().expand( expander ).depthFirst().uniqueness( uniqueness() )
    //                .evaluator( toDepth( maxDepth ) ).evaluator( Evaluators.includeWhereEndNodeIs( end ) )
    //                .traverse( start );
    // Bidirectional traversal
    GraphDatabaseService db = start.getGraphDatabase();
    TraversalDescription base = db.traversalDescription().depthFirst().uniqueness(uniqueness());
    return db.bidirectionalTraversalDescription().startSide(base.expand(expander).evaluator(toDepth(maxDepth / 2))).endSide(base.expand(expander.reverse()).evaluator(toDepth(maxDepth - maxDepth / 2))).traverse(start, end);
}

Example 25 with GraphDatabaseService

use of org.neo4j.graphdb.GraphDatabaseService in project neo4j by neo4j.

the class DijkstraBidirectional method traverser.

private Traverser traverser(Node start, final Node end, PathInterest interest) {
    final MutableDouble shortestSoFar = new MutableDouble(Double.MAX_VALUE);
    final MutableDouble startSideShortest = new MutableDouble(0);
    final MutableDouble endSideShortest = new MutableDouble(0);
    PathExpander dijkstraExpander = new DijkstraBidirectionalPathExpander(expander, shortestSoFar, true, startSideShortest, endSideShortest, epsilon);
    GraphDatabaseService db = start.getGraphDatabase();
    TraversalDescription side = db.traversalDescription().expand(dijkstraExpander, stateFactory).order(new DijkstraSelectorFactory(interest, costEvaluator)).evaluator(new DijkstraBidirectionalEvaluator(costEvaluator)).uniqueness(Uniqueness.NODE_PATH);
    TraversalDescription startSide = side;
    TraversalDescription endSide = side.reverse();
    BidirectionalTraversalDescription traversal = db.bidirectionalTraversalDescription().startSide(startSide).endSide(endSide).collisionEvaluator(Evaluators.all()).collisionPolicy(new BranchCollisionPolicy() {

        @Override
        public BranchCollisionDetector create(Evaluator evaluator, Predicate<Path> pathPredicate) {
            return new DijkstraBranchCollisionDetector(evaluator, costEvaluator, shortestSoFar, epsilon, pathPredicate);
        }
    });
    lastTraverser = traversal.traverse(start, end);
    return lastTraverser;
}