osrm-backend/src/engine/routing_algorithms/routing_base_ch.cpp

429 lines
17 KiB
C++

#include "engine/routing_algorithms/routing_base_ch.hpp"
namespace osrm
{
namespace engine
{
namespace routing_algorithms
{
namespace ch
{
/**
* Unpacks a single edge (NodeID->NodeID) from the CH graph down to it's original non-shortcut
* route.
* @param from the node the CH edge starts at
* @param to the node the CH edge finishes at
* @param unpacked_path the sequence of original NodeIDs that make up the expanded CH edge
*/
void unpackEdge(const DataFacade<Algorithm> &facade,
const NodeID from,
const NodeID to,
std::vector<NodeID> &unpacked_path)
{
std::array<NodeID, 2> path{{from, to}};
unpackPath(facade,
path.begin(),
path.end(),
[&unpacked_path](const std::pair<NodeID, NodeID> &edge, const auto & /* data */) {
unpacked_path.emplace_back(edge.first);
});
unpacked_path.emplace_back(to);
}
void retrievePackedPathFromHeap(const SearchEngineData<Algorithm>::QueryHeap &forward_heap,
const SearchEngineData<Algorithm>::QueryHeap &reverse_heap,
const NodeID middle_node_id,
std::vector<NodeID> &packed_path)
{
retrievePackedPathFromSingleHeap(forward_heap, middle_node_id, packed_path);
std::reverse(packed_path.begin(), packed_path.end());
packed_path.emplace_back(middle_node_id);
retrievePackedPathFromSingleHeap(reverse_heap, middle_node_id, packed_path);
}
void retrievePackedPathFromSingleHeap(const SearchEngineData<Algorithm>::QueryHeap &search_heap,
const NodeID middle_node_id,
std::vector<NodeID> &packed_path)
{
NodeID current_node_id = middle_node_id;
// all initial nodes will have itself as parent, or a node not in the heap
// in case of a core search heap. We need a distinction between core entry nodes
// and start nodes since otherwise start node specific code that assumes
// node == node.parent (e.g. the loop code) might get actived.
while (current_node_id != search_heap.GetData(current_node_id).parent &&
search_heap.WasInserted(search_heap.GetData(current_node_id).parent))
{
current_node_id = search_heap.GetData(current_node_id).parent;
packed_path.emplace_back(current_node_id);
}
}
// assumes that heaps are already setup correctly.
// ATTENTION: This only works if no additional offset is supplied next to the Phantom Node
// Offsets.
// In case additional offsets are supplied, you might have to force a loop first.
// A forced loop might be necessary, if source and target are on the same segment.
// If this is the case and the offsets of the respective direction are larger for the source
// than the target
// then a force loop is required (e.g. source_phantom.forward_segment_id ==
// target_phantom.forward_segment_id
// && source_phantom.GetForwardWeightPlusOffset() > target_phantom.GetForwardWeightPlusOffset())
// requires
// a force loop, if the heaps have been initialized with positive offsets.
void search(SearchEngineData<Algorithm> & /*engine_working_data*/,
const DataFacade<Algorithm> &facade,
SearchEngineData<Algorithm>::QueryHeap &forward_heap,
SearchEngineData<Algorithm>::QueryHeap &reverse_heap,
EdgeWeight &weight,
std::vector<NodeID> &packed_leg,
const bool force_loop_forward,
const bool force_loop_reverse,
const PhantomNodes & /*phantom_nodes*/,
const EdgeWeight weight_upper_bound)
{
if (forward_heap.Empty() || reverse_heap.Empty())
{
weight = INVALID_EDGE_WEIGHT;
return;
}
NodeID middle = SPECIAL_NODEID;
weight = weight_upper_bound;
// get offset to account for offsets on phantom nodes on compressed edges
const auto min_edge_offset = std::min(0, forward_heap.MinKey());
BOOST_ASSERT(min_edge_offset <= 0);
// we only every insert negative offsets for nodes in the forward heap
BOOST_ASSERT(reverse_heap.MinKey() >= 0);
// run two-Target Dijkstra routing step.
while (0 < (forward_heap.Size() + reverse_heap.Size()))
{
if (!forward_heap.Empty())
{
routingStep<FORWARD_DIRECTION>(facade,
forward_heap,
reverse_heap,
middle,
weight,
min_edge_offset,
force_loop_forward,
force_loop_reverse);
}
if (!reverse_heap.Empty())
{
routingStep<REVERSE_DIRECTION>(facade,
reverse_heap,
forward_heap,
middle,
weight,
min_edge_offset,
force_loop_reverse,
force_loop_forward);
}
}
// No path found for both target nodes?
if (weight_upper_bound <= weight || SPECIAL_NODEID == middle)
{
weight = INVALID_EDGE_WEIGHT;
return;
}
// Was a paths over one of the forward/reverse nodes not found?
BOOST_ASSERT_MSG((SPECIAL_NODEID != middle && INVALID_EDGE_WEIGHT != weight), "no path found");
// make sure to correctly unpack loops
if (weight != forward_heap.GetKey(middle) + reverse_heap.GetKey(middle))
{
// self loop makes up the full path
packed_leg.push_back(middle);
packed_leg.push_back(middle);
}
else
{
retrievePackedPathFromHeap(forward_heap, reverse_heap, middle, packed_leg);
}
}
// Requires the heaps for be empty
// If heaps should be adjusted to be initialized outside of this function,
// the addition of force_loop parameters might be required
double getNetworkDistance(SearchEngineData<Algorithm> &engine_working_data,
const DataFacade<Algorithm> &facade,
SearchEngineData<Algorithm>::QueryHeap &forward_heap,
SearchEngineData<Algorithm>::QueryHeap &reverse_heap,
const PhantomNode &source_phantom,
const PhantomNode &target_phantom,
EdgeWeight weight_upper_bound)
{
forward_heap.Clear();
reverse_heap.Clear();
insertNodesInHeaps(forward_heap, reverse_heap, {source_phantom, target_phantom});
EdgeWeight weight = INVALID_EDGE_WEIGHT;
std::vector<NodeID> packed_path;
search(engine_working_data,
facade,
forward_heap,
reverse_heap,
weight,
packed_path,
DO_NOT_FORCE_LOOPS,
DO_NOT_FORCE_LOOPS,
{source_phantom, target_phantom},
weight_upper_bound);
if (weight == INVALID_EDGE_WEIGHT)
{
return std::numeric_limits<double>::max();
}
std::vector<PathData> unpacked_path;
unpackPath(facade,
packed_path.begin(),
packed_path.end(),
{source_phantom, target_phantom},
unpacked_path);
return getPathDistance(facade, unpacked_path, source_phantom, target_phantom);
}
} // namespace ch
namespace corech
{
// Assumes that heaps are already setup correctly.
// A forced loop might be necessary, if source and target are on the same segment.
// If this is the case and the offsets of the respective direction are larger for the source
// than the target
// then a force loop is required (e.g. source_phantom.forward_segment_id ==
// target_phantom.forward_segment_id
// && source_phantom.GetForwardWeightPlusOffset() > target_phantom.GetForwardWeightPlusOffset())
// requires
// a force loop, if the heaps have been initialized with positive offsets.
void search(SearchEngineData<Algorithm> &engine_working_data,
const DataFacade<Algorithm> &facade,
SearchEngineData<Algorithm>::QueryHeap &forward_heap,
SearchEngineData<Algorithm>::QueryHeap &reverse_heap,
EdgeWeight &weight,
std::vector<NodeID> &packed_leg,
const bool force_loop_forward,
const bool force_loop_reverse,
const PhantomNodes & /*phantom_nodes*/,
EdgeWeight weight_upper_bound)
{
NodeID middle = SPECIAL_NODEID;
weight = weight_upper_bound;
using CoreEntryPoint = std::tuple<NodeID, EdgeWeight, NodeID>;
std::vector<CoreEntryPoint> forward_entry_points;
std::vector<CoreEntryPoint> reverse_entry_points;
// get offset to account for offsets on phantom nodes on compressed edges
const auto min_edge_offset = std::min(0, forward_heap.MinKey());
// we only every insert negative offsets for nodes in the forward heap
BOOST_ASSERT(reverse_heap.MinKey() >= 0);
// run two-Target Dijkstra routing step.
while (0 < (forward_heap.Size() + reverse_heap.Size()))
{
if (!forward_heap.Empty())
{
if (facade.IsCoreNode(forward_heap.Min()))
{
const NodeID node = forward_heap.DeleteMin();
const EdgeWeight key = forward_heap.GetKey(node);
forward_entry_points.emplace_back(node, key, forward_heap.GetData(node).parent);
}
else
{
ch::routingStep<FORWARD_DIRECTION>(facade,
forward_heap,
reverse_heap,
middle,
weight,
min_edge_offset,
force_loop_forward,
force_loop_reverse);
}
}
if (!reverse_heap.Empty())
{
if (facade.IsCoreNode(reverse_heap.Min()))
{
const NodeID node = reverse_heap.DeleteMin();
const EdgeWeight key = reverse_heap.GetKey(node);
reverse_entry_points.emplace_back(node, key, reverse_heap.GetData(node).parent);
}
else
{
ch::routingStep<REVERSE_DIRECTION>(facade,
reverse_heap,
forward_heap,
middle,
weight,
min_edge_offset,
force_loop_reverse,
force_loop_forward);
}
}
}
const auto insertInCoreHeap = [](const CoreEntryPoint &p, auto &core_heap) {
NodeID id;
EdgeWeight weight;
NodeID parent;
// TODO this should use std::apply when we get c++17 support
std::tie(id, weight, parent) = p;
core_heap.Insert(id, weight, parent);
};
engine_working_data.InitializeOrClearSecondThreadLocalStorage(facade.GetNumberOfNodes());
auto &forward_core_heap = *engine_working_data.forward_heap_2;
auto &reverse_core_heap = *engine_working_data.reverse_heap_2;
for (const auto &p : forward_entry_points)
{
insertInCoreHeap(p, forward_core_heap);
}
for (const auto &p : reverse_entry_points)
{
insertInCoreHeap(p, reverse_core_heap);
}
// get offset to account for offsets on phantom nodes on compressed edges
EdgeWeight min_core_edge_offset = 0;
if (forward_core_heap.Size() > 0)
{
min_core_edge_offset = std::min(min_core_edge_offset, forward_core_heap.MinKey());
}
if (reverse_core_heap.Size() > 0 && reverse_core_heap.MinKey() < 0)
{
min_core_edge_offset = std::min(min_core_edge_offset, reverse_core_heap.MinKey());
}
BOOST_ASSERT(min_core_edge_offset <= 0);
// run two-target Dijkstra routing step on core with termination criterion
while (0 < forward_core_heap.Size() && 0 < reverse_core_heap.Size() &&
weight > (forward_core_heap.MinKey() + reverse_core_heap.MinKey()))
{
ch::routingStep<FORWARD_DIRECTION, ch::DISABLE_STALLING>(facade,
forward_core_heap,
reverse_core_heap,
middle,
weight,
min_core_edge_offset,
force_loop_forward,
force_loop_reverse);
ch::routingStep<REVERSE_DIRECTION, ch::DISABLE_STALLING>(facade,
reverse_core_heap,
forward_core_heap,
middle,
weight,
min_core_edge_offset,
force_loop_reverse,
force_loop_forward);
}
// No path found for both target nodes?
if (weight_upper_bound <= weight || SPECIAL_NODEID == middle)
{
weight = INVALID_EDGE_WEIGHT;
return;
}
// Was a paths over one of the forward/reverse nodes not found?
BOOST_ASSERT_MSG((SPECIAL_NODEID != middle && INVALID_EDGE_WEIGHT != weight), "no path found");
// we need to unpack sub path from core heaps
if (facade.IsCoreNode(middle))
{
if (weight != forward_core_heap.GetKey(middle) + reverse_core_heap.GetKey(middle))
{
// self loop
BOOST_ASSERT(forward_core_heap.GetData(middle).parent == middle &&
reverse_core_heap.GetData(middle).parent == middle);
packed_leg.push_back(middle);
packed_leg.push_back(middle);
}
else
{
std::vector<NodeID> packed_core_leg;
ch::retrievePackedPathFromHeap(
forward_core_heap, reverse_core_heap, middle, packed_core_leg);
BOOST_ASSERT(packed_core_leg.size() > 0);
ch::retrievePackedPathFromSingleHeap(forward_heap, packed_core_leg.front(), packed_leg);
std::reverse(packed_leg.begin(), packed_leg.end());
packed_leg.insert(packed_leg.end(), packed_core_leg.begin(), packed_core_leg.end());
ch::retrievePackedPathFromSingleHeap(reverse_heap, packed_core_leg.back(), packed_leg);
}
}
else
{
if (weight != forward_heap.GetKey(middle) + reverse_heap.GetKey(middle))
{
// self loop
BOOST_ASSERT(forward_heap.GetData(middle).parent == middle &&
reverse_heap.GetData(middle).parent == middle);
packed_leg.push_back(middle);
packed_leg.push_back(middle);
}
else
{
ch::retrievePackedPathFromHeap(forward_heap, reverse_heap, middle, packed_leg);
}
}
}
// Requires the heaps for be empty
// If heaps should be adjusted to be initialized outside of this function,
// the addition of force_loop parameters might be required
double getNetworkDistance(SearchEngineData<Algorithm> &engine_working_data,
const DataFacade<Algorithm> &facade,
SearchEngineData<Algorithm>::QueryHeap &forward_heap,
SearchEngineData<Algorithm>::QueryHeap &reverse_heap,
const PhantomNode &source_phantom,
const PhantomNode &target_phantom,
EdgeWeight weight_upper_bound)
{
forward_heap.Clear();
reverse_heap.Clear();
insertNodesInHeaps(forward_heap, reverse_heap, {source_phantom, target_phantom});
EdgeWeight weight = INVALID_EDGE_WEIGHT;
std::vector<NodeID> packed_path;
search(engine_working_data,
facade,
forward_heap,
reverse_heap,
weight,
packed_path,
DO_NOT_FORCE_LOOPS,
DO_NOT_FORCE_LOOPS,
{source_phantom, target_phantom},
weight_upper_bound);
if (weight == INVALID_EDGE_WEIGHT)
return std::numeric_limits<double>::max();
std::vector<PathData> unpacked_path;
ch::unpackPath(facade,
packed_path.begin(),
packed_path.end(),
{source_phantom, target_phantom},
unpacked_path);
return getPathDistance(facade, unpacked_path, source_phantom, target_phantom);
}
} // namespace corech
} // namespace routing_algorithms
} // namespace engine
} // namespace osrm