osrm-backend/src/engine/routing_algorithms/many_to_many.cpp
2017-08-21 13:00:12 +02:00

410 lines
15 KiB
C++

#include "engine/routing_algorithms/many_to_many.hpp"
#include "engine/routing_algorithms/routing_base_ch.hpp"
#include <boost/assert.hpp>
#include <limits>
#include <memory>
#include <unordered_map>
#include <vector>
namespace osrm
{
namespace engine
{
namespace routing_algorithms
{
namespace
{
struct NodeBucket
{
unsigned target_id; // essentially a row in the weight matrix
EdgeWeight weight;
EdgeWeight duration;
NodeBucket(const unsigned target_id, const EdgeWeight weight, const EdgeWeight duration)
: target_id(target_id), weight(weight), duration(duration)
{
}
};
// FIXME This should be replaced by an std::unordered_multimap, though this needs benchmarking
using SearchSpaceWithBuckets = std::unordered_map<NodeID, std::vector<NodeBucket>>;
inline bool addLoopWeight(const DataFacade<ch::Algorithm> &facade,
const NodeID node,
EdgeWeight &weight,
EdgeDuration &duration)
{ // Special case for CH when contractor creates a loop edge node->node
BOOST_ASSERT(weight < 0);
const auto loop_weight = ch::getLoopWeight<false>(facade, node);
if (loop_weight != INVALID_EDGE_WEIGHT)
{
const auto new_weight_with_loop = weight + loop_weight;
if (new_weight_with_loop >= 0)
{
weight = new_weight_with_loop;
duration += ch::getLoopWeight<true>(facade, node);
return true;
}
}
// No loop found or adjusted weight is negative
return false;
}
template <bool DIRECTION>
void relaxOutgoingEdges(const DataFacade<ch::Algorithm> &facade,
const NodeID node,
const EdgeWeight weight,
const EdgeDuration duration,
typename SearchEngineData<ch::Algorithm>::ManyToManyQueryHeap &query_heap,
const PhantomNode &)
{
if (ch::stallAtNode<DIRECTION>(facade, node, weight, query_heap))
{
return;
}
for (auto edge : facade.GetAdjacentEdgeRange(node))
{
const auto &data = facade.GetEdgeData(edge);
if (DIRECTION == FORWARD_DIRECTION ? data.forward : data.backward)
{
const NodeID to = facade.GetTarget(edge);
const EdgeWeight edge_weight = data.weight;
const EdgeWeight edge_duration = data.duration;
BOOST_ASSERT_MSG(edge_weight > 0, "edge_weight invalid");
const EdgeWeight to_weight = weight + edge_weight;
const EdgeWeight to_duration = duration + edge_duration;
// New Node discovered -> Add to Heap + Node Info Storage
if (!query_heap.WasInserted(to))
{
query_heap.Insert(to, to_weight, {node, to_duration});
}
// Found a shorter Path -> Update weight
else if (to_weight < query_heap.GetKey(to))
{
// new parent
query_heap.GetData(to) = {node, to_duration};
query_heap.DecreaseKey(to, to_weight);
}
}
}
}
inline bool
addLoopWeight(const DataFacade<mld::Algorithm> &, const NodeID, EdgeWeight &, EdgeDuration &)
{ // MLD overlay does not introduce loop edges
return false;
}
template <bool DIRECTION>
void relaxOutgoingEdges(const DataFacade<mld::Algorithm> &facade,
const NodeID node,
const EdgeWeight weight,
const EdgeDuration duration,
typename SearchEngineData<mld::Algorithm>::ManyToManyQueryHeap &query_heap,
const PhantomNode &phantom_node)
{
BOOST_ASSERT(!facade.ExcludeNode(node));
const auto &partition = facade.GetMultiLevelPartition();
const auto &cells = facade.GetCellStorage();
const auto &metric = facade.GetCellMetric();
auto highest_diffrent_level = [&partition, node](const SegmentID &phantom_node) {
if (phantom_node.enabled)
return partition.GetHighestDifferentLevel(phantom_node.id, node);
return INVALID_LEVEL_ID;
};
const auto level = std::min(highest_diffrent_level(phantom_node.forward_segment_id),
highest_diffrent_level(phantom_node.reverse_segment_id));
const auto &node_data = query_heap.GetData(node);
if (level >= 1 && !node_data.from_clique_arc)
{
const auto &cell = cells.GetCell(metric, level, partition.GetCell(level, node));
if (DIRECTION == FORWARD_DIRECTION)
{ // Shortcuts in forward direction
auto destination = cell.GetDestinationNodes().begin();
auto shortcut_durations = cell.GetOutDuration(node);
for (auto shortcut_weight : cell.GetOutWeight(node))
{
BOOST_ASSERT(destination != cell.GetDestinationNodes().end());
BOOST_ASSERT(!shortcut_durations.empty());
const NodeID to = *destination;
if (shortcut_weight != INVALID_EDGE_WEIGHT && node != to)
{
const auto to_weight = weight + shortcut_weight;
const auto to_duration = duration + shortcut_durations.front();
if (!query_heap.WasInserted(to))
{
query_heap.Insert(to, to_weight, {node, true, to_duration});
}
else if (to_weight < query_heap.GetKey(to))
{
query_heap.GetData(to) = {node, true, to_duration};
query_heap.DecreaseKey(to, to_weight);
}
}
++destination;
shortcut_durations.advance_begin(1);
}
BOOST_ASSERT(shortcut_durations.empty());
}
else
{ // Shortcuts in backward direction
auto source = cell.GetSourceNodes().begin();
auto shortcut_durations = cell.GetInDuration(node);
for (auto shortcut_weight : cell.GetInWeight(node))
{
BOOST_ASSERT(source != cell.GetSourceNodes().end());
BOOST_ASSERT(!shortcut_durations.empty());
const NodeID to = *source;
if (shortcut_weight != INVALID_EDGE_WEIGHT && node != to)
{
const auto to_weight = weight + shortcut_weight;
const auto to_duration = duration + shortcut_durations.front();
if (!query_heap.WasInserted(to))
{
query_heap.Insert(to, to_weight, {node, true, to_duration});
}
else if (to_weight < query_heap.GetKey(to))
{
query_heap.GetData(to) = {node, true, to_duration};
query_heap.DecreaseKey(to, to_weight);
}
}
++source;
shortcut_durations.advance_begin(1);
}
BOOST_ASSERT(shortcut_durations.empty());
}
}
for (const auto edge : facade.GetBorderEdgeRange(level, node))
{
const auto &data = facade.GetEdgeData(edge);
if (DIRECTION == FORWARD_DIRECTION ? data.forward : data.backward)
{
const NodeID to = facade.GetTarget(edge);
if (facade.ExcludeNode(to))
{
continue;
}
const EdgeWeight edge_weight = data.weight;
const EdgeWeight edge_duration = data.duration;
BOOST_ASSERT_MSG(edge_weight > 0, "edge_weight invalid");
const EdgeWeight to_weight = weight + edge_weight;
const EdgeWeight to_duration = duration + edge_duration;
// New Node discovered -> Add to Heap + Node Info Storage
if (!query_heap.WasInserted(to))
{
query_heap.Insert(to, to_weight, {node, false, to_duration});
}
// Found a shorter Path -> Update weight
else if (to_weight < query_heap.GetKey(to))
{
// new parent
query_heap.GetData(to) = {node, false, to_duration};
query_heap.DecreaseKey(to, to_weight);
}
}
}
}
template <typename Algorithm>
void forwardRoutingStep(const DataFacade<Algorithm> &facade,
const unsigned row_idx,
const unsigned number_of_targets,
typename SearchEngineData<Algorithm>::ManyToManyQueryHeap &query_heap,
const SearchSpaceWithBuckets &search_space_with_buckets,
std::vector<EdgeWeight> &weights_table,
std::vector<EdgeWeight> &durations_table,
const PhantomNode &phantom_node)
{
const NodeID node = query_heap.DeleteMin();
const EdgeWeight source_weight = query_heap.GetKey(node);
const EdgeWeight source_duration = query_heap.GetData(node).duration;
// 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 &current_bucket : bucket_list)
{
// get target id from bucket entry
const unsigned column_idx = current_bucket.target_id;
const EdgeWeight target_weight = current_bucket.weight;
const EdgeWeight target_duration = current_bucket.duration;
auto &current_weight = weights_table[row_idx * number_of_targets + column_idx];
auto &current_duration = durations_table[row_idx * number_of_targets + column_idx];
// check if new weight is better
auto new_weight = source_weight + target_weight;
auto new_duration = source_duration + target_duration;
if (new_weight < 0)
{
if (addLoopWeight(facade, node, new_weight, new_duration))
{
current_weight = std::min(current_weight, new_weight);
current_duration = std::min(current_duration, new_duration);
}
}
else if (new_weight < current_weight)
{
current_weight = new_weight;
current_duration = new_duration;
}
}
}
relaxOutgoingEdges<FORWARD_DIRECTION>(
facade, node, source_weight, source_duration, query_heap, phantom_node);
}
template <typename Algorithm>
void backwardRoutingStep(const DataFacade<Algorithm> &facade,
const unsigned column_idx,
typename SearchEngineData<Algorithm>::ManyToManyQueryHeap &query_heap,
SearchSpaceWithBuckets &search_space_with_buckets,
const PhantomNode &phantom_node)
{
const NodeID node = query_heap.DeleteMin();
const EdgeWeight target_weight = query_heap.GetKey(node);
const EdgeWeight target_duration = query_heap.GetData(node).duration;
// store settled nodes in search space bucket
search_space_with_buckets[node].emplace_back(column_idx, target_weight, target_duration);
relaxOutgoingEdges<REVERSE_DIRECTION>(
facade, node, target_weight, target_duration, query_heap, phantom_node);
}
}
template <typename Algorithm>
std::vector<EdgeWeight> manyToManySearch(SearchEngineData<Algorithm> &engine_working_data,
const DataFacade<Algorithm> &facade,
const std::vector<PhantomNode> &phantom_nodes,
const std::vector<std::size_t> &source_indices,
const std::vector<std::size_t> &target_indices)
{
const auto number_of_sources =
source_indices.empty() ? phantom_nodes.size() : source_indices.size();
const auto number_of_targets =
target_indices.empty() ? phantom_nodes.size() : target_indices.size();
const auto number_of_entries = number_of_sources * number_of_targets;
std::vector<EdgeWeight> weights_table(number_of_entries, INVALID_EDGE_WEIGHT);
std::vector<EdgeWeight> durations_table(number_of_entries, MAXIMAL_EDGE_DURATION);
engine_working_data.InitializeOrClearManyToManyThreadLocalStorage(facade.GetNumberOfNodes());
auto &query_heap = *(engine_working_data.many_to_many_heap);
SearchSpaceWithBuckets search_space_with_buckets;
unsigned column_idx = 0;
const auto search_target_phantom = [&](const PhantomNode &phantom) {
// clear heap and insert target nodes
query_heap.Clear();
insertTargetInHeap(query_heap, phantom);
// explore search space
while (!query_heap.Empty())
{
backwardRoutingStep(facade, column_idx, query_heap, search_space_with_buckets, phantom);
}
++column_idx;
};
// for each source do forward search
unsigned row_idx = 0;
const auto search_source_phantom = [&](const PhantomNode &phantom) {
// clear heap and insert source nodes
query_heap.Clear();
insertSourceInHeap(query_heap, phantom);
// explore search space
while (!query_heap.Empty())
{
forwardRoutingStep(facade,
row_idx,
number_of_targets,
query_heap,
search_space_with_buckets,
weights_table,
durations_table,
phantom);
}
++row_idx;
};
if (target_indices.empty())
{
for (const auto &phantom : phantom_nodes)
{
search_target_phantom(phantom);
}
}
else
{
for (const auto index : target_indices)
{
const auto &phantom = phantom_nodes[index];
search_target_phantom(phantom);
}
}
if (source_indices.empty())
{
for (const auto &phantom : phantom_nodes)
{
search_source_phantom(phantom);
}
}
else
{
for (const auto index : source_indices)
{
const auto &phantom = phantom_nodes[index];
search_source_phantom(phantom);
}
}
return durations_table;
}
template std::vector<EdgeWeight>
manyToManySearch(SearchEngineData<ch::Algorithm> &engine_working_data,
const DataFacade<ch::Algorithm> &facade,
const std::vector<PhantomNode> &phantom_nodes,
const std::vector<std::size_t> &source_indices,
const std::vector<std::size_t> &target_indices);
template std::vector<EdgeWeight>
manyToManySearch(SearchEngineData<mld::Algorithm> &engine_working_data,
const DataFacade<mld::Algorithm> &facade,
const std::vector<PhantomNode> &phantom_nodes,
const std::vector<std::size_t> &source_indices,
const std::vector<std::size_t> &target_indices);
} // namespace routing_algorithms
} // namespace engine
} // namespace osrm