// 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);
}
// TODO: reorder parameters
// compute and unpack <s,..,v> and <v,..,t> by exploring search spaces
// from v and intersecting against queues. only half-searches have to be
// done at this stage
void ComputeLengthAndSharingOfViaPath(const NodeID via_node,
int *real_length_of_via_path,
int *sharing_of_via_path,
const std::vector<NodeID> &packed_shortest_path,
const EdgeWeight min_edge_offset)
{
engine_working_data.InitializeOrClearSecondThreadLocalStorage(
super::facade->GetNumberOfNodes());
QueryHeap &existing_forward_heap = *engine_working_data.forward_heap_1;
QueryHeap &existing_reverse_heap = *engine_working_data.reverse_heap_1;
QueryHeap &new_forward_heap = *engine_working_data.forward_heap_2;
QueryHeap &new_reverse_heap = *engine_working_data.reverse_heap_2;
std::vector<NodeID> packed_s_v_path;
std::vector<NodeID> packed_v_t_path;
std::vector<NodeID> partially_unpacked_shortest_path;
std::vector<NodeID> partially_unpacked_via_path;
NodeID s_v_middle = SPECIAL_NODEID;
int upper_bound_s_v_path_length = INVALID_EDGE_WEIGHT;
new_reverse_heap.Insert(via_node, 0, via_node);
// compute path <s,..,v> by reusing forward search from s
while (!new_reverse_heap.Empty())
{
super::RoutingStep(new_reverse_heap, existing_forward_heap, &s_v_middle,
&upper_bound_s_v_path_length, min_edge_offset, false);
}
// compute path <v,..,t> by reusing backward search from node t
NodeID v_t_middle = SPECIAL_NODEID;
int upper_bound_of_v_t_path_length = INVALID_EDGE_WEIGHT;
new_forward_heap.Insert(via_node, 0, via_node);
while (!new_forward_heap.Empty())
{
super::RoutingStep(new_forward_heap, existing_reverse_heap, &v_t_middle,
&upper_bound_of_v_t_path_length, min_edge_offset, true);
}
*real_length_of_via_path = upper_bound_s_v_path_length + upper_bound_of_v_t_path_length;
if (SPECIAL_NODEID == s_v_middle || SPECIAL_NODEID == v_t_middle)
{
return;
}
// 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);
// partial unpacking, compute sharing
// First partially unpack s-->v until paths deviate, note length of common path.
const int64_t s_v_min_path_size =
std::min(packed_s_v_path.size(), packed_shortest_path.size()) - 1;
for (const int64_t current_node : osrm::irange<int64_t>(0, s_v_min_path_size))
{
if (packed_s_v_path[current_node] == packed_shortest_path[current_node] &&
packed_s_v_path[current_node + 1] == packed_shortest_path[current_node + 1])
{
EdgeID edgeID = facade->FindEdgeInEitherDirection(
packed_s_v_path[current_node], packed_s_v_path[current_node + 1]);
*sharing_of_via_path += facade->GetEdgeData(edgeID).distance;
}
else
{
if (packed_s_v_path[current_node] == packed_shortest_path[current_node])
{
super::UnpackEdge(packed_s_v_path[current_node],
packed_s_v_path[current_node + 1],
partially_unpacked_via_path);
super::UnpackEdge(packed_shortest_path[current_node],
packed_shortest_path[current_node + 1],
partially_unpacked_shortest_path);
break;
}
}
}
// traverse partially unpacked edge and note common prefix
const int64_t packed_path_length =
std::min(partially_unpacked_via_path.size(), partially_unpacked_shortest_path.size()) -
1;
for (int64_t current_node = 0; (current_node < packed_path_length) &&
(partially_unpacked_via_path[current_node] ==
partially_unpacked_shortest_path[current_node] &&
partially_unpacked_via_path[current_node + 1] ==
partially_unpacked_shortest_path[current_node + 1]);
++current_node)
{
EdgeID selected_edge =
facade->FindEdgeInEitherDirection(partially_unpacked_via_path[current_node],
partially_unpacked_via_path[current_node + 1]);
*sharing_of_via_path += facade->GetEdgeData(selected_edge).distance;
}
// Second, partially unpack v-->t in reverse order until paths deviate and note lengths
int64_t via_path_index = packed_v_t_path.size() - 1;
int64_t shortest_path_index = packed_shortest_path.size() - 1;
for (; via_path_index > 0 && shortest_path_index > 0;
--via_path_index, --shortest_path_index)
{
if (packed_v_t_path[via_path_index - 1] ==
packed_shortest_path[shortest_path_index - 1] &&
packed_v_t_path[via_path_index] == packed_shortest_path[shortest_path_index])
{
EdgeID edgeID = facade->FindEdgeInEitherDirection(
packed_v_t_path[via_path_index - 1], packed_v_t_path[via_path_index]);
*sharing_of_via_path += facade->GetEdgeData(edgeID).distance;
}
else
{
if (packed_v_t_path[via_path_index] == packed_shortest_path[shortest_path_index])
{
super::UnpackEdge(packed_v_t_path[via_path_index - 1],
packed_v_t_path[via_path_index], partially_unpacked_via_path);
super::UnpackEdge(packed_shortest_path[shortest_path_index - 1],
packed_shortest_path[shortest_path_index],
partially_unpacked_shortest_path);
break;
}
}
}
via_path_index = partially_unpacked_via_path.size() - 1;
shortest_path_index = partially_unpacked_shortest_path.size() - 1;
for (; via_path_index > 0 && shortest_path_index > 0;
--via_path_index, --shortest_path_index)
{
if (partially_unpacked_via_path[via_path_index - 1] ==
partially_unpacked_shortest_path[shortest_path_index - 1] &&
partially_unpacked_via_path[via_path_index] ==
partially_unpacked_shortest_path[shortest_path_index])
{
EdgeID edgeID = facade->FindEdgeInEitherDirection(
partially_unpacked_via_path[via_path_index - 1],
partially_unpacked_via_path[via_path_index]);
*sharing_of_via_path += facade->GetEdgeData(edgeID).distance;
}
else
{
break;
}
}
// finished partial unpacking spree! Amount of sharing is stored to appropriate pointer
// variable
}