Examples with Dijkstra org.neo4j.graphalgo.impl.path.Dijkstra used on opensource projects

Example 6 with Dijkstra

use of org.neo4j.graphalgo.impl.path.Dijkstra in project graphdb by neo4j-attic.

the class DijkstraTest method canGetMultiplePathsInASmallRoadNetwork.

@Test
public void canGetMultiplePathsInASmallRoadNetwork() throws Exception {
    Node nodeA = graph.makeNode("A");
    Node nodeB = graph.makeNode("B");
    Node nodeC = graph.makeNode("C");
    Node nodeD = graph.makeNode("D");
    Node nodeE = graph.makeNode("E");
    Node nodeF = graph.makeNode("F");
    graph.makeEdge("A", "B", "length", 2d);
    graph.makeEdge("A", "C", "length", 2.5d);
    graph.makeEdge("C", "D", "length", 7.3d);
    graph.makeEdge("B", "D", "length", 2.5d);
    graph.makeEdge("D", "E", "length", 3d);
    graph.makeEdge("C", "E", "length", 5d);
    graph.makeEdge("E", "F", "length", 5d);
    graph.makeEdge("C", "F", "length", 12d);
    graph.makeEdge("A", "F", "length", 25d);
    Dijkstra algo = new Dijkstra(Traversal.expanderForAllTypes(), CommonEvaluators.doubleCostEvaluator("length"));
    // Try the search in both directions.
    for (Node[] nodes : new Node[][] { { nodeA, nodeF }, { nodeF, nodeA } }) {
        int found = 0;
        Iterator<WeightedPath> paths = algo.findAllPaths(nodes[0], nodes[1]).iterator();
        for (int i = 0; i < 2; i++) {
            assertTrue("expected more paths", paths.hasNext());
            Path path = paths.next();
            if (path.length() != found && path.length() == 3) {
                assertContains(path.nodes(), nodeA, nodeC, nodeE, nodeF);
            } else if (path.length() != found && path.length() == 4) {
                assertContains(path.nodes(), nodeA, nodeB, nodeD, nodeE, nodeF);
            } else {
                fail("unexpected path length: " + path.length());
            }
            found = path.length();
        }
        assertFalse("expected at most two paths", paths.hasNext());
    }
}

Example 7 with Dijkstra

use of org.neo4j.graphalgo.impl.path.Dijkstra in project graphdb by neo4j-attic.

the class DijkstraTest method canGetMultiplePathsInTriangleGraph.

@Test
public void canGetMultiplePathsInTriangleGraph() throws Exception {
    Node nodeA = graph.makeNode("A");
    Node nodeB = graph.makeNode("B");
    Node nodeC = graph.makeNode("C");
    Set<Relationship> expectedFirsts = new HashSet<Relationship>();
    expectedFirsts.add(graph.makeEdge("A", "B", "length", 1d));
    expectedFirsts.add(graph.makeEdge("A", "B", "length", 1d));
    Relationship expectedSecond = graph.makeEdge("B", "C", "length", 2d);
    graph.makeEdge("A", "C", "length", 5d);
    Dijkstra algo = new Dijkstra(Traversal.expanderForAllTypes(), CommonEvaluators.doubleCostEvaluator("length"));
    Iterator<WeightedPath> paths = algo.findAllPaths(nodeA, nodeC).iterator();
    for (int i = 0; i < 2; i++) {
        assertTrue("expected more paths", paths.hasNext());
        Path path = paths.next();
        assertPath(path, nodeA, nodeB, nodeC);
        Iterator<Relationship> relationships = path.relationships().iterator();
        assertTrue("found shorter path than expected", relationships.hasNext());
        assertTrue("path contained unexpected relationship", expectedFirsts.remove(relationships.next()));
        assertTrue("found shorter path than expected", relationships.hasNext());
        assertEquals(expectedSecond, relationships.next());
        assertFalse("found longer path than expected", relationships.hasNext());
    }
    assertFalse("expected at most two paths", paths.hasNext());
}