inline bool StallAtNode(const DataFacadeT &facade,
const NodeID node,
const EdgeWeight weight,
QueryHeap &query_heap) const
{
for (auto edge : facade.GetAdjacentEdgeRange(node))
{
const auto &data = facade.GetEdgeData(edge);
const bool reverse_flag = ((!forward_direction) ? data.forward : data.backward);
if (reverse_flag)
{
const NodeID to = facade.GetTarget(edge);
const int edge_weight = data.weight;
BOOST_ASSERT_MSG(edge_weight > 0, "edge_weight invalid");
if (query_heap.WasInserted(to))
{
if (query_heap.GetKey(to) + edge_weight < weight)
{
return true;
}
}
}
}
return false;
}
inline void RelaxOutgoingEdges(const DataFacadeT &facade,
const NodeID node,
const EdgeWeight weight,
QueryHeap &query_heap) const
{
for (auto edge : facade.GetAdjacentEdgeRange(node))
{
const auto &data = facade.GetEdgeData(edge);
const bool direction_flag = (forward_direction ? data.forward : data.backward);
if (direction_flag)
{
const NodeID to = facade.GetTarget(edge);
const int edge_weight = data.weight;
BOOST_ASSERT_MSG(edge_weight > 0, "edge_weight invalid");
const int to_weight = weight + edge_weight;
// New Node discovered -> Add to Heap + Node Info Storage
if (!query_heap.WasInserted(to))
{
query_heap.Insert(to, to_weight, node);
}
// Found a shorter Path -> Update weight
else if (to_weight < query_heap.GetKey(to))
{
// new parent
query_heap.GetData(to).parent = node;
query_heap.DecreaseKey(to, to_weight);
}
}
}
}
void BackwardRoutingStep(const unsigned target_id,
QueryHeap &query_heap,
SearchSpaceWithBuckets &search_space_with_buckets) const
{
const NodeID node = query_heap.DeleteMin();
const int target_distance = query_heap.GetKey(node);
// store settled nodes in search space bucket
search_space_with_buckets[node].emplace_back(target_id, target_distance);
if (StallAtNode<false>(node, target_distance, query_heap))
{
return;
}
RelaxOutgoingEdges<false>(node, target_distance, query_heap);
}
void ForwardRoutingStep(const DataFacadeT &facade,
const unsigned row_idx,
const unsigned number_of_targets,
QueryHeap &query_heap,
const SearchSpaceWithBuckets &search_space_with_buckets,
std::vector<EdgeWeight> &result_table) const
{
const NodeID node = query_heap.DeleteMin();
const int source_weight = query_heap.GetKey(node);
// check if each encountered node has an entry
const auto bucket_iterator = search_space_with_buckets.find(node);
// iterate bucket if there exists one
if (bucket_iterator != search_space_with_buckets.end())
{
const std::vector<NodeBucket> &bucket_list = bucket_iterator->second;
for (const NodeBucket ¤t_bucket : bucket_list)
{
// get target id from bucket entry
const unsigned column_idx = current_bucket.target_id;
const int target_weight = current_bucket.weight;
auto ¤t_weight = result_table[row_idx * number_of_targets + column_idx];
// check if new weight is better
const EdgeWeight new_weight = source_weight + target_weight;
if (new_weight < 0)
{
const EdgeWeight loop_weight = super::GetLoopWeight(facade, node);
const int new_weight_with_loop = new_weight + loop_weight;
if (loop_weight != INVALID_EDGE_WEIGHT && new_weight_with_loop >= 0)
{
current_weight = std::min(current_weight, new_weight_with_loop);
}
}
else if (new_weight < current_weight)
{
result_table[row_idx * number_of_targets + column_idx] = new_weight;
}
}
}
if (StallAtNode<true>(facade, node, source_weight, query_heap))
{
return;
}
RelaxOutgoingEdges<true>(facade, node, source_weight, query_heap);
}
void BackwardRoutingStep(const DataFacadeT &facade,
const unsigned column_idx,
QueryHeap &query_heap,
SearchSpaceWithBuckets &search_space_with_buckets) const
{
const NodeID node = query_heap.DeleteMin();
const int target_weight = query_heap.GetKey(node);
// store settled nodes in search space bucket
search_space_with_buckets[node].emplace_back(column_idx, target_weight);
if (StallAtNode<false>(facade, node, target_weight, query_heap))
{
return;
}
RelaxOutgoingEdges<false>(facade, node, target_weight, query_heap);
}
// allows a uturn at the target_phantom
// searches source forward/reverse -> target forward/reverse
void SearchWithUTurn(QueryHeap &forward_heap,
QueryHeap &reverse_heap,
const bool search_from_forward_node,
const bool search_from_reverse_node,
const bool search_to_forward_node,
const bool search_to_reverse_node,
const PhantomNode &source_phantom,
const PhantomNode &target_phantom,
const int total_distance_to_forward,
const int total_distance_to_reverse,
int &new_total_distance,
std::vector<NodeID> &leg_packed_path) const
{
forward_heap.Clear();
reverse_heap.Clear();
if (search_from_forward_node)
{
forward_heap.Insert(source_phantom.forward_node_id,
total_distance_to_forward -
source_phantom.GetForwardWeightPlusOffset(),
source_phantom.forward_node_id);
}
if (search_from_reverse_node)
{
forward_heap.Insert(source_phantom.reverse_node_id,
total_distance_to_reverse -
source_phantom.GetReverseWeightPlusOffset(),
source_phantom.reverse_node_id);
}
if (search_to_forward_node)
{
reverse_heap.Insert(target_phantom.forward_node_id,
target_phantom.GetForwardWeightPlusOffset(),
target_phantom.forward_node_id);
}
if (search_to_reverse_node)
{
reverse_heap.Insert(target_phantom.reverse_node_id,
target_phantom.GetReverseWeightPlusOffset(),
target_phantom.reverse_node_id);
}
BOOST_ASSERT(forward_heap.Size() > 0);
BOOST_ASSERT(reverse_heap.Size() > 0);
super::Search(forward_heap, reverse_heap, new_total_distance, leg_packed_path,
forceLoop(FORWARD_DIRECTION, source_phantom, target_phantom),
forceLoop(REVERSE_DIRECTION, source_phantom, target_phantom));
}
void ForwardRoutingStep(const unsigned source_id,
const unsigned number_of_locations,
QueryHeap &query_heap,
const SearchSpaceWithBuckets &search_space_with_buckets,
std::shared_ptr<std::vector<EdgeWeight>> result_table) const
{
const NodeID node = query_heap.DeleteMin();
const int source_distance = query_heap.GetKey(node);
// check if each encountered node has an entry
const auto bucket_iterator = search_space_with_buckets.find(node);
// iterate bucket if there exists one
if (bucket_iterator != search_space_with_buckets.end())
{
const std::vector<NodeBucket> &bucket_list = bucket_iterator->second;
for (const NodeBucket ¤t_bucket : bucket_list)
{
// get target id from bucket entry
const unsigned target_id = current_bucket.target_id;
const int target_distance = current_bucket.distance;
const EdgeWeight current_distance =
(*result_table)[source_id * number_of_locations + target_id];
// check if new distance is better
const EdgeWeight new_distance = source_distance + target_distance;
if (new_distance >= 0 && new_distance < current_distance)
{
(*result_table)[source_id * number_of_locations + target_id] =
(source_distance + target_distance);
}
}
}
if (StallAtNode<true>(node, source_distance, query_heap))
{
return;
}
RelaxOutgoingEdges<true>(node, source_distance, query_heap);
}
// conduct T-Test
bool ViaNodeCandidatePassesTTest(QueryHeap &existing_forward_heap,
QueryHeap &existing_reverse_heap,
QueryHeap &new_forward_heap,
QueryHeap &new_reverse_heap,
const RankedCandidateNode &candidate,
const int length_of_shortest_path,
int *length_of_via_path,
NodeID *s_v_middle,
NodeID *v_t_middle,
const EdgeWeight min_edge_offset) const
{
new_forward_heap.Clear();
new_reverse_heap.Clear();
std::vector<NodeID> packed_s_v_path;
std::vector<NodeID> packed_v_t_path;
*s_v_middle = SPECIAL_NODEID;
int upper_bound_s_v_path_length = INVALID_EDGE_WEIGHT;
// compute path <s,..,v> by reusing forward search from s
new_reverse_heap.Insert(candidate.node, 0, candidate.node);
while (new_reverse_heap.Size() > 0)
{
super::RoutingStep(new_reverse_heap, existing_forward_heap, s_v_middle,
&upper_bound_s_v_path_length, min_edge_offset, false);
}
if (INVALID_EDGE_WEIGHT == upper_bound_s_v_path_length)
{
return false;
}
// compute path <v,..,t> by reusing backward search from t
*v_t_middle = SPECIAL_NODEID;
int upper_bound_of_v_t_path_length = INVALID_EDGE_WEIGHT;
new_forward_heap.Insert(candidate.node, 0, candidate.node);
while (new_forward_heap.Size() > 0)
{
super::RoutingStep(new_forward_heap, existing_reverse_heap, v_t_middle,
&upper_bound_of_v_t_path_length, min_edge_offset, true);
}
if (INVALID_EDGE_WEIGHT == upper_bound_of_v_t_path_length)
{
return false;
}
*length_of_via_path = upper_bound_s_v_path_length + upper_bound_of_v_t_path_length;
// retrieve packed paths
super::RetrievePackedPathFromHeap(existing_forward_heap, new_reverse_heap, *s_v_middle,
packed_s_v_path);
super::RetrievePackedPathFromHeap(new_forward_heap, existing_reverse_heap, *v_t_middle,
packed_v_t_path);
NodeID s_P = *s_v_middle, t_P = *v_t_middle;
if (SPECIAL_NODEID == s_P)
{
return false;
}
if (SPECIAL_NODEID == t_P)
{
return false;
}
const int T_threshold = static_cast<int>(VIAPATH_EPSILON * length_of_shortest_path);
int unpacked_until_distance = 0;
std::stack<SearchSpaceEdge> unpack_stack;
// Traverse path s-->v
for (std::size_t i = packed_s_v_path.size() - 1; (i > 0) && unpack_stack.empty(); --i)
{
const EdgeID current_edge_id =
facade->FindEdgeInEitherDirection(packed_s_v_path[i - 1], packed_s_v_path[i]);
const int length_of_current_edge = facade->GetEdgeData(current_edge_id).distance;
if ((length_of_current_edge + unpacked_until_distance) >= T_threshold)
{
unpack_stack.emplace(packed_s_v_path[i - 1], packed_s_v_path[i]);
}
else
{
unpacked_until_distance += length_of_current_edge;
s_P = packed_s_v_path[i - 1];
}
}
while (!unpack_stack.empty())
{
const SearchSpaceEdge via_path_edge = unpack_stack.top();
unpack_stack.pop();
EdgeID edge_in_via_path_id =
facade->FindEdgeInEitherDirection(via_path_edge.first, via_path_edge.second);
if (SPECIAL_EDGEID == edge_in_via_path_id)
{
return false;
}
const EdgeData ¤t_edge_data = facade->GetEdgeData(edge_in_via_path_id);
const bool current_edge_is_shortcut = current_edge_data.shortcut;
if (current_edge_is_shortcut)
{
const NodeID via_path_middle_node_id = current_edge_data.id;
const EdgeID second_segment_edge_id = facade->FindEdgeInEitherDirection(
via_path_middle_node_id, via_path_edge.second);
const int second_segment_length =
facade->GetEdgeData(second_segment_edge_id).distance;
// attention: !unpacking in reverse!
// Check if second segment is the one to go over treshold? if yes add second segment
// to stack, else push first segment to stack and add distance of second one.
if (unpacked_until_distance + second_segment_length >= T_threshold)
{
unpack_stack.emplace(via_path_middle_node_id, via_path_edge.second);
}
else
{
unpacked_until_distance += second_segment_length;
unpack_stack.emplace(via_path_edge.first, via_path_middle_node_id);
}
}
else
{
// edge is not a shortcut, set the start node for T-Test to end of edge.
unpacked_until_distance += current_edge_data.distance;
s_P = via_path_edge.first;
}
}
int t_test_path_length = unpacked_until_distance;
unpacked_until_distance = 0;
// Traverse path s-->v
BOOST_ASSERT(!packed_v_t_path.empty());
for (unsigned i = 0, packed_path_length = static_cast<unsigned>(packed_v_t_path.size() - 1);
(i < packed_path_length) && unpack_stack.empty(); ++i)
{
const EdgeID edgeID =
facade->FindEdgeInEitherDirection(packed_v_t_path[i], packed_v_t_path[i + 1]);
int length_of_current_edge = facade->GetEdgeData(edgeID).distance;
if (length_of_current_edge + unpacked_until_distance >= T_threshold)
{
unpack_stack.emplace(packed_v_t_path[i], packed_v_t_path[i + 1]);
}
else
{
unpacked_until_distance += length_of_current_edge;
t_P = packed_v_t_path[i + 1];
}
}
while (!unpack_stack.empty())
{
const SearchSpaceEdge via_path_edge = unpack_stack.top();
unpack_stack.pop();
EdgeID edge_in_via_path_id =
facade->FindEdgeInEitherDirection(via_path_edge.first, via_path_edge.second);
if (SPECIAL_EDGEID == edge_in_via_path_id)
{
return false;
}
const EdgeData ¤t_edge_data = facade->GetEdgeData(edge_in_via_path_id);
const bool IsViaEdgeShortCut = current_edge_data.shortcut;
if (IsViaEdgeShortCut)
{
const NodeID middleOfViaPath = current_edge_data.id;
EdgeID edgeIDOfFirstSegment =
facade->FindEdgeInEitherDirection(via_path_edge.first, middleOfViaPath);
int lengthOfFirstSegment = facade->GetEdgeData(edgeIDOfFirstSegment).distance;
// Check if first segment is the one to go over treshold? if yes first segment to
// stack, else push second segment to stack and add distance of first one.
if (unpacked_until_distance + lengthOfFirstSegment >= T_threshold)
{
unpack_stack.emplace(via_path_edge.first, middleOfViaPath);
}
else
{
unpacked_until_distance += lengthOfFirstSegment;
unpack_stack.emplace(middleOfViaPath, via_path_edge.second);
}
}
else
{
// edge is not a shortcut, set the start node for T-Test to end of edge.
unpacked_until_distance += current_edge_data.distance;
t_P = via_path_edge.second;
}
}
t_test_path_length += unpacked_until_distance;
// Run actual T-Test query and compare if distances equal.
engine_working_data.InitializeOrClearThirdThreadLocalStorage(
super::facade->GetNumberOfNodes());
QueryHeap &forward_heap3 = *engine_working_data.forward_heap_3;
QueryHeap &reverse_heap3 = *engine_working_data.reverse_heap_3;
int upper_bound = INVALID_EDGE_WEIGHT;
NodeID middle = SPECIAL_NODEID;
forward_heap3.Insert(s_P, 0, s_P);
reverse_heap3.Insert(t_P, 0, t_P);
// exploration from s and t until deletemin/(1+epsilon) > _lengt_oO_sShortest_path
while ((forward_heap3.Size() + reverse_heap3.Size()) > 0)
{
if (!forward_heap3.Empty())
{
super::RoutingStep(forward_heap3, reverse_heap3, &middle, &upper_bound,
min_edge_offset, true);
}
if (!reverse_heap3.Empty())
{
super::RoutingStep(reverse_heap3, forward_heap3, &middle, &upper_bound,
min_edge_offset, false);
}
}
return (upper_bound <= t_test_path_length);
}
