Ejemplo n.º 1
0
  public BenchPerformance(String fileName, Graph graph) {
    r = Runtime.getRuntime();
    forceGC();
    long used1 = r.totalMemory() - r.freeMemory();
    g = graph;
    try {
      g.read(fileName);
    } catch (Exception e) {
      e.printStackTrace();
      System.exit(0);
    }
    System.out.println(
        "Graph read: " + g.getNodeCount() + " nodes and " + g.getEdgeCount() + " edges");

    for (Node n : g) n.clearAttributes();
    for (Edge e : g.getEachEdge()) e.clearAttributes();
    forceGC();
    long used2 = r.totalMemory() - r.freeMemory();
    measureValues = new EnumMap<Measures, Long>(Measures.class);
    measureValues.put(Measures.MEMORY, used2 - used1);

    nodeIds = new ArrayList<String>(g.getNodeCount());
    for (Node n : g) nodeIds.add(n.getId());
    // sort them to be sure that we always work with the same nodes
    Collections.sort(nodeIds);

    edgeIds = new ArrayList<String>(g.getEdgeCount());
    for (Edge e : g.getEachEdge()) edgeIds.add(e.getId());
    Collections.sort(edgeIds);
  }
Ejemplo n.º 2
0
    SynchronizedGraph(Graph g) {
      super(g);

      elementLock = new ReentrantLock();
      synchronizedNodes = new HashMap<String, Node>();
      synchronizedEdges = new HashMap<String, Edge>();

      for (Node n : g.getEachNode())
        synchronizedNodes.put(n.getId(), new SynchronizedNode(this, n));

      for (Edge e : g.getEachEdge())
        synchronizedEdges.put(e.getId(), new SynchronizedEdge(this, e));
    }
Ejemplo n.º 3
0
  /*
   * (non-Javadoc)
   *
   * @see org.graphstream.algorithm.Algorithm#compute()
   */
  @SuppressWarnings("unchecked")
  public void compute() {
    Node source = graph.getNode(this.source_id);

    // Step 1: Initialize graph

    for (Node n : graph) {
      if (n == source) n.addAttribute(identifier + ".distance", 0.0);
      else n.addAttribute(identifier + ".distance", Double.POSITIVE_INFINITY);

      // n.addAttribute(identifier+".predecessors",(Object)null);
    }

    // Step 2: relax edges repeatedly

    for (int i = 0; i < graph.getNodeCount(); i++) {
      for (Edge e : graph.getEachEdge()) {
        Node n0 = e.getNode0();
        Node n1 = e.getNode1();
        Double d0 = (Double) n0.getAttribute(identifier + ".distance");
        Double d1 = (Double) n1.getAttribute(identifier + ".distance");

        Double we = (Double) e.getAttribute(weightAttribute);
        if (we == null)
          throw new NumberFormatException(
              "org.graphstream.algorithm.BellmanFord: Problem with attribute \""
                  + weightAttribute
                  + "\" on edge "
                  + e);

        if (d0 != null) {
          if (d1 == null || d1 >= d0 + we) {
            n1.addAttribute(identifier + ".distance", d0 + we);
            ArrayList<Edge> predecessors =
                (ArrayList<Edge>) n1.getAttribute(identifier + ".predecessors");

            if (d1 != null && d1 == d0 + we) {
              if (predecessors == null) {
                predecessors = new ArrayList<Edge>();
              }
            } else {
              predecessors = new ArrayList<Edge>();
            }
            if (!predecessors.contains(e)) {
              predecessors.add(e);
            }

            n1.addAttribute(identifier + ".predecessors", predecessors);
          }
        }
      }
    }

    // Step 3: check for negative-weight cycles

    for (Edge e : graph.getEachEdge()) {
      Node n0 = e.getNode0();
      Node n1 = e.getNode1();
      Double d0 = (Double) n0.getAttribute(identifier + ".distance");
      Double d1 = (Double) n1.getAttribute(identifier + ".distance");

      Double we = (Double) e.getAttribute(weightAttribute);

      if (we == null) {
        throw new NumberFormatException(
            String.format(
                "%s: Problem with attribute \"%s\" on edge \"%s\"",
                BellmanFord.class.getName(), weightAttribute, e.getId()));
      }

      if (d1 > d0 + we) {
        throw new NumberFormatException(
            String.format(
                "%s: Problem: negative weight, cycle detected on edge \"%s\"",
                BellmanFord.class.getName(), e.getId()));
      }
    }
  }