osrm-backend/src/extractor/edge_based_graph_factory.cpp

#include "extractor/edge_based_graph_factory.hpp"
#include "util/coordinate_calculation.hpp"
#include "util/percent.hpp"
#include "util/compute_angle.hpp"
#include "util/integer_range.hpp"
#include "util/lua_util.hpp"
#include "util/simple_logger.hpp"
#include "util/timing_util.hpp"
#include "util/osrm_exception.hpp"

#include "util/debug_geometry.hpp"

#include <boost/assert.hpp>

#include <fstream>
#include <iomanip>
#include <limits>

EdgeBasedGraphFactory::EdgeBasedGraphFactory(
    std::shared_ptr<NodeBasedDynamicGraph> node_based_graph,
    const CompressedEdgeContainer &compressed_edge_container,
    const std::unordered_set<NodeID> &barrier_nodes,
    const std::unordered_set<NodeID> &traffic_lights,
    std::shared_ptr<const RestrictionMap> restriction_map,
    const std::vector<QueryNode> &node_info_list,
    SpeedProfileProperties speed_profile)
    : m_max_edge_id(0), m_node_info_list(node_info_list),
      m_node_based_graph(std::move(node_based_graph)),
      m_restriction_map(std::move(restriction_map)), m_barrier_nodes(barrier_nodes),
      m_traffic_lights(traffic_lights), m_compressed_edge_container(compressed_edge_container),
      speed_profile(std::move(speed_profile))
{
}

void EdgeBasedGraphFactory::GetEdgeBasedEdges(DeallocatingVector<EdgeBasedEdge> &output_edge_list)
{
    BOOST_ASSERT_MSG(0 == output_edge_list.size(), "Vector is not empty");
    using std::swap; // Koenig swap
    swap(m_edge_based_edge_list, output_edge_list);
}

void EdgeBasedGraphFactory::GetEdgeBasedNodes(std::vector<EdgeBasedNode> &nodes)
{
#ifndef NDEBUG
    for (const EdgeBasedNode &node : m_edge_based_node_list)
    {
        BOOST_ASSERT(m_node_info_list.at(node.u).lat != INT_MAX);
        BOOST_ASSERT(m_node_info_list.at(node.u).lon != INT_MAX);
        BOOST_ASSERT(m_node_info_list.at(node.v).lon != INT_MAX);
        BOOST_ASSERT(m_node_info_list.at(node.v).lat != INT_MAX);
    }
#endif
    using std::swap; // Koenig swap
    swap(nodes, m_edge_based_node_list);
}

void EdgeBasedGraphFactory::GetStartPointMarkers(std::vector<bool> &node_is_startpoint)
{
    using std::swap; // Koenig swap
    swap(m_edge_based_node_is_startpoint, node_is_startpoint);
}

unsigned EdgeBasedGraphFactory::GetHighestEdgeID() { return m_max_edge_id; }

void EdgeBasedGraphFactory::InsertEdgeBasedNode(const NodeID node_u, const NodeID node_v)
{
    // merge edges together into one EdgeBasedNode
    BOOST_ASSERT(node_u != SPECIAL_NODEID);
    BOOST_ASSERT(node_v != SPECIAL_NODEID);

    // find forward edge id and
    const EdgeID edge_id_1 = m_node_based_graph->FindEdge(node_u, node_v);
    BOOST_ASSERT(edge_id_1 != SPECIAL_EDGEID);

    const EdgeData &forward_data = m_node_based_graph->GetEdgeData(edge_id_1);

    // find reverse edge id and
    const EdgeID edge_id_2 = m_node_based_graph->FindEdge(node_v, node_u);
    BOOST_ASSERT(edge_id_2 != SPECIAL_EDGEID);

    const EdgeData &reverse_data = m_node_based_graph->GetEdgeData(edge_id_2);

    if (forward_data.edge_id == SPECIAL_NODEID && reverse_data.edge_id == SPECIAL_NODEID)
    {
        return;
    }

    BOOST_ASSERT(m_compressed_edge_container.HasEntryForID(edge_id_1) ==
                 m_compressed_edge_container.HasEntryForID(edge_id_2));
    if (m_compressed_edge_container.HasEntryForID(edge_id_1))
    {
        BOOST_ASSERT(m_compressed_edge_container.HasEntryForID(edge_id_2));

        // reconstruct geometry and put in each individual edge with its offset
        const auto &forward_geometry = m_compressed_edge_container.GetBucketReference(edge_id_1);
        const auto &reverse_geometry = m_compressed_edge_container.GetBucketReference(edge_id_2);
        BOOST_ASSERT(forward_geometry.size() == reverse_geometry.size());
        BOOST_ASSERT(0 != forward_geometry.size());
        const unsigned geometry_size = static_cast<unsigned>(forward_geometry.size());
        BOOST_ASSERT(geometry_size > 1);

        // reconstruct bidirectional edge with individual weights and put each into the NN index

        std::vector<int> forward_dist_prefix_sum(forward_geometry.size(), 0);
        std::vector<int> reverse_dist_prefix_sum(reverse_geometry.size(), 0);

        // quick'n'dirty prefix sum as std::partial_sum needs addtional casts
        // TODO: move to lambda function with C++11
        int temp_sum = 0;

        for (const auto i : osrm::irange(0u, geometry_size))
        {
            forward_dist_prefix_sum[i] = temp_sum;
            temp_sum += forward_geometry[i].second;

            BOOST_ASSERT(forward_data.distance >= temp_sum);
        }

        temp_sum = 0;
        for (const auto i : osrm::irange(0u, geometry_size))
        {
            temp_sum += reverse_geometry[reverse_geometry.size() - 1 - i].second;
            reverse_dist_prefix_sum[i] = reverse_data.distance - temp_sum;
            // BOOST_ASSERT(reverse_data.distance >= temp_sum);
        }

        NodeID current_edge_source_coordinate_id = node_u;

        // traverse arrays from start and end respectively
        for (const auto i : osrm::irange(0u, geometry_size))
        {
            BOOST_ASSERT(current_edge_source_coordinate_id ==
                         reverse_geometry[geometry_size - 1 - i].first);
            const NodeID current_edge_target_coordinate_id = forward_geometry[i].first;
            BOOST_ASSERT(current_edge_target_coordinate_id != current_edge_source_coordinate_id);

            // build edges
            m_edge_based_node_list.emplace_back(
                forward_data.edge_id, reverse_data.edge_id, current_edge_source_coordinate_id,
                current_edge_target_coordinate_id, forward_data.name_id, forward_geometry[i].second,
                reverse_geometry[geometry_size - 1 - i].second, forward_dist_prefix_sum[i],
                reverse_dist_prefix_sum[i], m_compressed_edge_container.GetPositionForID(edge_id_1),
                false, INVALID_COMPONENTID, i, forward_data.travel_mode, reverse_data.travel_mode);
            m_edge_based_node_is_startpoint.push_back(forward_data.startpoint ||
                                                      reverse_data.startpoint);
            current_edge_source_coordinate_id = current_edge_target_coordinate_id;

            BOOST_ASSERT(m_edge_based_node_list.back().IsCompressed());

            BOOST_ASSERT(node_u != m_edge_based_node_list.back().u ||
                         node_v != m_edge_based_node_list.back().v);

            BOOST_ASSERT(node_u != m_edge_based_node_list.back().v ||
                         node_v != m_edge_based_node_list.back().u);
        }

        BOOST_ASSERT(current_edge_source_coordinate_id == node_v);
        BOOST_ASSERT(m_edge_based_node_list.back().IsCompressed());
    }
    else
    {
        BOOST_ASSERT(!m_compressed_edge_container.HasEntryForID(edge_id_2));

        if (forward_data.edge_id != SPECIAL_NODEID)
        {
            BOOST_ASSERT(!forward_data.reversed);
        }
        else
        {
            BOOST_ASSERT(forward_data.reversed);
        }

        if (reverse_data.edge_id != SPECIAL_NODEID)
        {
            BOOST_ASSERT(!reverse_data.reversed);
        }
        else
        {
            BOOST_ASSERT(reverse_data.reversed);
        }

        BOOST_ASSERT(forward_data.edge_id != SPECIAL_NODEID ||
                     reverse_data.edge_id != SPECIAL_NODEID);

        m_edge_based_node_list.emplace_back(
            forward_data.edge_id, reverse_data.edge_id, node_u, node_v, forward_data.name_id,
            forward_data.distance, reverse_data.distance, 0, 0, SPECIAL_EDGEID, false,
            INVALID_COMPONENTID, 0, forward_data.travel_mode, reverse_data.travel_mode);
        m_edge_based_node_is_startpoint.push_back(forward_data.startpoint ||
                                                  reverse_data.startpoint);
        BOOST_ASSERT(!m_edge_based_node_list.back().IsCompressed());
    }
}

void EdgeBasedGraphFactory::FlushVectorToStream(
    std::ofstream &edge_data_file, std::vector<OriginalEdgeData> &original_edge_data_vector) const
{
    if (original_edge_data_vector.empty())
    {
        return;
    }
    edge_data_file.write((char *)&(original_edge_data_vector[0]),
                         original_edge_data_vector.size() * sizeof(OriginalEdgeData));
    original_edge_data_vector.clear();
}

#ifdef DEBUG_GEOMETRY
void EdgeBasedGraphFactory::Run(const std::string &original_edge_data_filename,
                                lua_State *lua_state,
                                const std::string &edge_segment_lookup_filename,
                                const std::string &edge_penalty_filename,
                                const bool generate_edge_lookup,
                                const std::string &debug_turns_path)
#else
void EdgeBasedGraphFactory::Run(const std::string &original_edge_data_filename,
                                lua_State *lua_state,
                                const std::string &edge_segment_lookup_filename,
                                const std::string &edge_penalty_filename,
                                const bool generate_edge_lookup)
#endif
{
    TIMER_START(renumber);
    m_max_edge_id = RenumberEdges() - 1;
    TIMER_STOP(renumber);

    TIMER_START(generate_nodes);
    GenerateEdgeExpandedNodes();
    TIMER_STOP(generate_nodes);

    TIMER_START(generate_edges);
#ifdef DEBUG_GEOMETRY
    GenerateEdgeExpandedEdges(original_edge_data_filename, lua_state, edge_segment_lookup_filename,
                              edge_penalty_filename, generate_edge_lookup, debug_turns_path);
#else
    GenerateEdgeExpandedEdges(original_edge_data_filename, lua_state, edge_segment_lookup_filename,
                              edge_penalty_filename, generate_edge_lookup);
#endif

    TIMER_STOP(generate_edges);

    SimpleLogger().Write() << "Timing statistics for edge-expanded graph:";
    SimpleLogger().Write() << "Renumbering edges: " << TIMER_SEC(renumber) << "s";
    SimpleLogger().Write() << "Generating nodes: " << TIMER_SEC(generate_nodes) << "s";
    SimpleLogger().Write() << "Generating edges: " << TIMER_SEC(generate_edges) << "s";
}

/// Renumbers all _forward_ edges and sets the edge_id.
/// A specific numbering is not important. Any unique ID will do.
/// Returns the number of edge based nodes.
unsigned EdgeBasedGraphFactory::RenumberEdges()
{
    // renumber edge based node of outgoing edges
    unsigned numbered_edges_count = 0;
    for (const auto current_node : osrm::irange(0u, m_node_based_graph->GetNumberOfNodes()))
    {
        for (const auto current_edge : m_node_based_graph->GetAdjacentEdgeRange(current_node))
        {
            EdgeData &edge_data = m_node_based_graph->GetEdgeData(current_edge);

            // only number incoming edges
            if (edge_data.reversed)
            {
                continue;
            }

            BOOST_ASSERT(numbered_edges_count < m_node_based_graph->GetNumberOfEdges());
            edge_data.edge_id = numbered_edges_count;
            ++numbered_edges_count;

            BOOST_ASSERT(SPECIAL_NODEID != edge_data.edge_id);
        }
    }

    return numbered_edges_count;
}

/// Creates the nodes in the edge expanded graph from edges in the node-based graph.
void EdgeBasedGraphFactory::GenerateEdgeExpandedNodes()
{
    Percent progress(m_node_based_graph->GetNumberOfNodes());

    // loop over all edges and generate new set of nodes
    for (const auto node_u : osrm::irange(0u, m_node_based_graph->GetNumberOfNodes()))
    {
        BOOST_ASSERT(node_u != SPECIAL_NODEID);
        BOOST_ASSERT(node_u < m_node_based_graph->GetNumberOfNodes());
        progress.printStatus(node_u);
        for (EdgeID e1 : m_node_based_graph->GetAdjacentEdgeRange(node_u))
        {
            const EdgeData &edge_data = m_node_based_graph->GetEdgeData(e1);
            BOOST_ASSERT(e1 != SPECIAL_EDGEID);
            const NodeID node_v = m_node_based_graph->GetTarget(e1);

            BOOST_ASSERT(SPECIAL_NODEID != node_v);
            // pick only every other edge, since we have every edge as an outgoing
            // and incoming egde
            if (node_u > node_v)
            {
                continue;
            }

            BOOST_ASSERT(node_u < node_v);

            // if we found a non-forward edge reverse and try again
            if (edge_data.edge_id == SPECIAL_NODEID)
            {
                InsertEdgeBasedNode(node_v, node_u);
            }
            else
            {
                InsertEdgeBasedNode(node_u, node_v);
            }
        }
    }

    BOOST_ASSERT(m_edge_based_node_list.size() == m_edge_based_node_is_startpoint.size());

    SimpleLogger().Write() << "Generated " << m_edge_based_node_list.size()
                           << " nodes in edge-expanded graph";
}

/// Actually it also generates OriginalEdgeData and serializes them...
#ifdef DEBUG_GEOMETRY
void EdgeBasedGraphFactory::GenerateEdgeExpandedEdges(
    const std::string &original_edge_data_filename,
    lua_State *lua_state,
    const std::string &edge_segment_lookup_filename,
    const std::string &edge_fixed_penalties_filename,
    const bool generate_edge_lookup,
    const std::string &debug_turns_path)
#else
void EdgeBasedGraphFactory::GenerateEdgeExpandedEdges(
    const std::string &original_edge_data_filename,
    lua_State *lua_state,
    const std::string &edge_segment_lookup_filename,
    const std::string &edge_fixed_penalties_filename,
    const bool generate_edge_lookup)
#endif
{
    SimpleLogger().Write() << "generating edge-expanded edges";

    unsigned node_based_edge_counter = 0;
    unsigned original_edges_counter = 0;

    std::ofstream edge_data_file(original_edge_data_filename.c_str(), std::ios::binary);
    std::ofstream edge_segment_file;
    std::ofstream edge_penalty_file;

    if (generate_edge_lookup)
    {
        edge_segment_file.open(edge_segment_lookup_filename.c_str(), std::ios::binary);
        edge_penalty_file.open(edge_fixed_penalties_filename.c_str(), std::ios::binary);
    }

    // writes a dummy value that is updated later
    edge_data_file.write((char *)&original_edges_counter, sizeof(unsigned));

    std::vector<OriginalEdgeData> original_edge_data_vector;
    original_edge_data_vector.reserve(1024 * 1024);

    // Loop over all turns and generate new set of edges.
    // Three nested loop look super-linear, but we are dealing with a (kind of)
    // linear number of turns only.
    unsigned restricted_turns_counter = 0;
    unsigned skipped_uturns_counter = 0;
    unsigned skipped_barrier_turns_counter = 0;
    unsigned compressed = 0;

    Percent progress(m_node_based_graph->GetNumberOfNodes());

#ifdef DEBUG_GEOMETRY
    DEBUG_TURNS_START(debug_turns_path);
#endif

    for (const auto node_u : osrm::irange(0u, m_node_based_graph->GetNumberOfNodes()))
    {
        // progress.printStatus(node_u);
        for (const EdgeID e1 : m_node_based_graph->GetAdjacentEdgeRange(node_u))
        {
            if (m_node_based_graph->GetEdgeData(e1).reversed)
            {
                continue;
            }

            ++node_based_edge_counter;
            const NodeID node_v = m_node_based_graph->GetTarget(e1);
            const NodeID only_restriction_to_node =
                m_restriction_map->CheckForEmanatingIsOnlyTurn(node_u, node_v);
            const bool is_barrier_node = m_barrier_nodes.find(node_v) != m_barrier_nodes.end();

            for (const EdgeID e2 : m_node_based_graph->GetAdjacentEdgeRange(node_v))
            {
                if (m_node_based_graph->GetEdgeData(e2).reversed)
                {
                    continue;
                }
                const NodeID node_w = m_node_based_graph->GetTarget(e2);

                if ((only_restriction_to_node != SPECIAL_NODEID) &&
                    (node_w != only_restriction_to_node))
                {
                    // We are at an only_-restriction but not at the right turn.
                    ++restricted_turns_counter;
                    continue;
                }

                if (is_barrier_node)
                {
                    if (node_u != node_w)
                    {
                        ++skipped_barrier_turns_counter;
                        continue;
                    }
                }
                else
                {
                    if ((node_u == node_w) && (m_node_based_graph->GetOutDegree(node_v) > 1))
                    {
                        ++skipped_uturns_counter;
                        continue;
                    }
                }

                // only add an edge if turn is not a U-turn except when it is
                // at the end of a dead-end street
                if (m_restriction_map->CheckIfTurnIsRestricted(node_u, node_v, node_w) &&
                    (only_restriction_to_node == SPECIAL_NODEID) &&
                    (node_w != only_restriction_to_node))
                {
                    // We are at an only_-restriction but not at the right turn.
                    ++restricted_turns_counter;
                    continue;
                }

                // only add an edge if turn is not prohibited
                const EdgeData &edge_data1 = m_node_based_graph->GetEdgeData(e1);
                const EdgeData &edge_data2 = m_node_based_graph->GetEdgeData(e2);

                BOOST_ASSERT(edge_data1.edge_id != edge_data2.edge_id);
                BOOST_ASSERT(!edge_data1.reversed);
                BOOST_ASSERT(!edge_data2.reversed);

                // the following is the core of the loop.
                unsigned distance = edge_data1.distance;
                if (m_traffic_lights.find(node_v) != m_traffic_lights.end())
                {
                    distance += speed_profile.traffic_signal_penalty;

                    DEBUG_SIGNAL(node_v, m_node_info_list, speed_profile.traffic_signal_penalty);
                }

                // unpack last node of first segment if packed
                const auto first_coordinate =
                    m_node_info_list[(m_compressed_edge_container.HasEntryForID(e1)
                                          ? m_compressed_edge_container.GetLastEdgeSourceID(e1)
                                          : node_u)];

                // unpack first node of second segment if packed
                const auto third_coordinate =
                    m_node_info_list[(m_compressed_edge_container.HasEntryForID(e2)
                                          ? m_compressed_edge_container.GetFirstEdgeTargetID(e2)
                                          : node_w)];

                const double turn_angle = ComputeAngle::OfThreeFixedPointCoordinates(
                    first_coordinate, m_node_info_list[node_v], third_coordinate);

                const int turn_penalty = GetTurnPenalty(turn_angle, lua_state);
                TurnInstruction turn_instruction = AnalyzeTurn(node_u, node_v, node_w, turn_angle);
                if (turn_instruction == TurnInstruction::UTurn)
                {
                    distance += speed_profile.u_turn_penalty;

                    DEBUG_UTURN(node_v, m_node_info_list, speed_profile.u_turn_penalty);
                }

                DEBUG_TURN(node_v, m_node_info_list, first_coordinate, turn_angle, turn_penalty);

                distance += turn_penalty;

                const bool edge_is_compressed = m_compressed_edge_container.HasEntryForID(e1);

                if (edge_is_compressed)
                {
                    ++compressed;
                }

                original_edge_data_vector.emplace_back(
                    (edge_is_compressed ? m_compressed_edge_container.GetPositionForID(e1)
                                        : node_v),
                    edge_data1.name_id, turn_instruction, edge_is_compressed,
                    edge_data2.travel_mode);

                ++original_edges_counter;

                if (original_edge_data_vector.size() > 1024 * 1024 * 10)
                {
                    FlushVectorToStream(edge_data_file, original_edge_data_vector);
                }

                BOOST_ASSERT(SPECIAL_NODEID != edge_data1.edge_id);
                BOOST_ASSERT(SPECIAL_NODEID != edge_data2.edge_id);

                // NOTE: potential overflow here if we hit 2^32 routable edges
                BOOST_ASSERT(m_edge_based_edge_list.size() <= std::numeric_limits<NodeID>::max());
                m_edge_based_edge_list.emplace_back(edge_data1.edge_id, edge_data2.edge_id,
                                                    m_edge_based_edge_list.size(), distance, true,
                                                    false);

                // Here is where we write out the mapping between the edge-expanded edges, and
                // the node-based edges that are originally used to calculate the `distance`
                // for the edge-expanded edges.  About 40 lines back, there is:
                //
                //                 unsigned distance = edge_data1.distance;
                //
                // This tells us that the weight for an edge-expanded-edge is based on the weight
                // of the *source* node-based edge.  Therefore, we will look up the individual
                // segments of the source node-based edge, and write out a mapping between
                // those and the edge-based-edge ID.
                // External programs can then use this mapping to quickly perform
                // updates to the edge-expanded-edge based directly on its ID.
                if (generate_edge_lookup)
                {
                    unsigned fixed_penalty = distance - edge_data1.distance;
                    edge_penalty_file.write(reinterpret_cast<const char *>(&fixed_penalty),
                                            sizeof(fixed_penalty));
                    if (edge_is_compressed)
                    {
                        const auto node_based_edges =
                            m_compressed_edge_container.GetBucketReference(e1);
                        NodeID previous = node_u;

                        const unsigned node_count = node_based_edges.size() + 1;
                        edge_segment_file.write(reinterpret_cast<const char *>(&node_count),
                                                sizeof(node_count));
                        const QueryNode &first_node = m_node_info_list[previous];
                        edge_segment_file.write(reinterpret_cast<const char *>(&first_node.node_id),
                                                sizeof(first_node.node_id));

                        for (auto target_node : node_based_edges)
                        {
                            const QueryNode &from = m_node_info_list[previous];
                            const QueryNode &to = m_node_info_list[target_node.first];
                            const double segment_length =
                                coordinate_calculation::great_circle_distance(from.lat, from.lon,
                                                                              to.lat, to.lon);

                            edge_segment_file.write(reinterpret_cast<const char *>(&to.node_id),
                                                    sizeof(to.node_id));
                            edge_segment_file.write(reinterpret_cast<const char *>(&segment_length),
                                                    sizeof(segment_length));
                            edge_segment_file.write(
                                reinterpret_cast<const char *>(&target_node.second),
                                sizeof(target_node.second));
                            previous = target_node.first;
                        }
                    }
                    else
                    {
                        static const unsigned node_count = 2;
                        const QueryNode from = m_node_info_list[node_u];
                        const QueryNode to = m_node_info_list[node_v];
                        const double segment_length = coordinate_calculation::great_circle_distance(
                            from.lat, from.lon, to.lat, to.lon);
                        edge_segment_file.write(reinterpret_cast<const char *>(&node_count),
                                                sizeof(node_count));
                        edge_segment_file.write(reinterpret_cast<const char *>(&from.node_id),
                                                sizeof(from.node_id));
                        edge_segment_file.write(reinterpret_cast<const char *>(&to.node_id),
                                                sizeof(to.node_id));
                        edge_segment_file.write(reinterpret_cast<const char *>(&segment_length),
                                                sizeof(segment_length));
                        edge_segment_file.write(
                            reinterpret_cast<const char *>(&edge_data1.distance),
                            sizeof(edge_data1.distance));
                    }
                }
            }
        }
    }

    DEBUG_TURNS_STOP();

    FlushVectorToStream(edge_data_file, original_edge_data_vector);

    edge_data_file.seekp(std::ios::beg);
    edge_data_file.write((char *)&original_edges_counter, sizeof(unsigned));
    edge_data_file.close();

    SimpleLogger().Write() << "Generated " << m_edge_based_node_list.size() << " edge based nodes";
    SimpleLogger().Write() << "Node-based graph contains " << node_based_edge_counter << " edges";
    SimpleLogger().Write() << "Edge-expanded graph ...";
    SimpleLogger().Write() << "  contains " << m_edge_based_edge_list.size() << " edges";
    SimpleLogger().Write() << "  skips " << restricted_turns_counter << " turns, "
                                                                        "defined by "
                           << m_restriction_map->size() << " restrictions";
    SimpleLogger().Write() << "  skips " << skipped_uturns_counter << " U turns";
    SimpleLogger().Write() << "  skips " << skipped_barrier_turns_counter << " turns over barriers";
}

int EdgeBasedGraphFactory::GetTurnPenalty(double angle, lua_State *lua_state) const
{

    if (speed_profile.has_turn_penalty_function)
    {
        try
        {
            // call lua profile to compute turn penalty
            double penalty =
                luabind::call_function<double>(lua_state, "turn_function", 180. - angle);
            return static_cast<int>(penalty);
        }
        catch (const luabind::error &er)
        {
            SimpleLogger().Write(logWARNING) << er.what();
        }
    }
    return 0;
}

TurnInstruction EdgeBasedGraphFactory::AnalyzeTurn(const NodeID node_u,
                                                   const NodeID node_v,
                                                   const NodeID node_w,
                                                   const double angle) const
{
    if (node_u == node_w)
    {
        return TurnInstruction::UTurn;
    }

    const EdgeID edge1 = m_node_based_graph->FindEdge(node_u, node_v);
    const EdgeID edge2 = m_node_based_graph->FindEdge(node_v, node_w);

    const EdgeData &data1 = m_node_based_graph->GetEdgeData(edge1);
    const EdgeData &data2 = m_node_based_graph->GetEdgeData(edge2);

    // roundabouts need to be handled explicitely
    if (data1.roundabout && data2.roundabout)
    {
        // Is a turn possible? If yes, we stay on the roundabout!
        if (1 == m_node_based_graph->GetDirectedOutDegree(node_v))
        {
            // No turn possible.
            return TurnInstruction::NoTurn;
        }
        return TurnInstruction::StayOnRoundAbout;
    }
    // Does turn start or end on roundabout?
    if (data1.roundabout || data2.roundabout)
    {
        // We are entering the roundabout
        if ((!data1.roundabout) && data2.roundabout)
        {
            return TurnInstruction::EnterRoundAbout;
        }
        // We are leaving the roundabout
        if (data1.roundabout && (!data2.roundabout))
        {
            return TurnInstruction::LeaveRoundAbout;
        }
    }

    // If street names stay the same and if we are certain that it is not a
    // a segment of a roundabout, we skip it.
    if (data1.name_id == data2.name_id && data1.travel_mode == data2.travel_mode)
    {
        // TODO: Here we should also do a small graph exploration to check for
        //      more complex situations
        if (0 != data1.name_id || m_node_based_graph->GetOutDegree(node_v) <= 2)
        {
            return TurnInstruction::NoTurn;
        }
    }

    return TurnInstructionsClass::GetTurnDirectionOfInstruction(angle);
}