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Optimise Flow Algorithm/Datastructures in use

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This commit is contained in:
Moritz Kobitzsch
2017-01-26 10:34:01 +01:00
committed by Patrick Niklaus
parent dd60ae31ae
commit 786be6f570
23 changed files with 794 additions and 425 deletions
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include/partition/bisection_graph.hpp
+38 -38
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@@ -2,16 +2,16 @@
#define OSRM_BISECTION_GRAPH_HPP_
#include "util/coordinate.hpp"
#include "util/static_graph.hpp"
#include "util/typedefs.hpp"
#include "partition/partition_graph.hpp"
#include "extractor/edge_based_edge.hpp"
#include <cstddef>
#include <algorithm>
#include <iterator>
#include <tuple>
#include <utility>
namespace osrm
@@ -23,77 +23,77 @@ namespace partition
// The coordinate will be used in the partitioning step.
struct BisectionNode
{
// StaticGraph Node requirement (see static graph traits): .first_edge
std::size_t first_edge;
BisectionNode(util::Coordinate coordinate_ = {util::FloatLongitude{0}, util::FloatLatitude{0}},
const NodeID original_id_ = SPECIAL_NODEID)
: coordinate(std::move(coordinate_)), original_id(original_id_)
{
}
// the coordinate the node is located at
util::Coordinate coordinate;
// the node id to access the bisection result
NodeID original_id;
};
// Graph edge and data for Max-Flow Min-Cut augmentation.
struct BisectionEdge
{
BisectionEdge(const NodeID target_ = SPECIAL_NODEID) : target(target_) {}
// StaticGraph Edge requirement (see static graph traits): .target, .data
NodeID target;
// TODO: add data for augmentation here. In case we want to keep it completely external, the
// static graph can be modified to no longer require a .data member by SFINAE-ing out features
// based on the available compile time traits.
std::int32_t data;
};
// The graph layout we use as a basis for partitioning.
using BisectionGraph = util::FlexibleStaticGraph<BisectionNode, BisectionEdge>;
using RemappableGraphNode = NodeEntryWrapper<BisectionNode>;
using BisectionInputEdge = GraphConstructionWrapper<BisectionEdge>;
using BisectionGraph = RemappableGraph<RemappableGraphNode, BisectionEdge>;
template <typename RandomIt> void sortBySourceThenTarget(RandomIt first, RandomIt last)
inline BisectionGraph makeBisectionGraph(const std::vector<util::Coordinate> &coordinates,
const std::vector<BisectionInputEdge> &edges)
{
std::sort(first, last, [](const auto &lhs, const auto &rhs) {
return std::tie(lhs.source, lhs.target) < std::tie(rhs.source, rhs.target);
});
}
template <typename InputEdge>
std::vector<BisectionNode> computeNodes(const std::vector<util::Coordinate> &coordinates,
const std::vector<InputEdge> &edges)
{
std::vector<BisectionNode> result;
result.reserve(coordinates.size() + 1 /*sentinel*/);
std::vector<BisectionGraph::NodeT> result_nodes;
result_nodes.reserve(coordinates.size());
std::vector<BisectionGraph::EdgeT> result_edges;
result_edges.reserve(edges.size());
// find the end of edges that belong to node_id
const auto advance_edge_itr = [&edges](const std::size_t node_id, auto edge_itr) {
const auto advance_edge_itr = [&edges, &result_edges](const std::size_t node_id,
auto edge_itr) {
while (edge_itr != edges.end() && edge_itr->source == node_id)
{
result_edges.push_back(edge_itr->Reduce());
++edge_itr;
}
return edge_itr;
};
// create a bisection node, requires the ID of the node as well as the lower bound to its edges
const auto make_bisection_node = [&edges, &coordinates](const std::size_t node_id,
const auto edge_itr) -> BisectionNode {
return {static_cast<std::size_t>(std::distance(edges.begin(), edge_itr)),
coordinates[node_id]};
const auto edge_itr) {
std::size_t range_begin = std::distance(edges.begin(), edge_itr);
return BisectionGraph::NodeT(range_begin, range_begin, coordinates[node_id], node_id);
};
auto edge_itr = edges.begin();
for (std::size_t node_id = 0; node_id < coordinates.size(); ++node_id)
{
result.emplace_back(make_bisection_node(node_id,edge_itr));
edge_itr = advance_edge_itr(node_id,edge_itr);
result_nodes.emplace_back(make_bisection_node(node_id, edge_itr));
edge_itr = advance_edge_itr(node_id, edge_itr);
result_nodes.back().edges_end = std::distance(edges.begin(), edge_itr);
}
auto null_island = util::Coordinate(util::FloatLongitude{0.0}, util::FloatLatitude{0.0});
auto sentinel = BisectionNode{edges.size(), std::move(null_island)};
result.emplace_back(std::move(sentinel));
return result;
return BisectionGraph(std::move(result_nodes), std::move(result_edges));
}
template <typename InputEdge>
std::vector<BisectionEdge> adaptToBisectionEdge(std::vector<InputEdge> edges)
std::vector<BisectionInputEdge> adaptToBisectionEdge(std::vector<InputEdge> edges)
{
std::vector<BisectionEdge> result(edges.size());
std::vector<BisectionInputEdge> result;
result.reserve(edges.size());
std::transform(begin(edges), end(edges), begin(result), [](const auto &edge) {
return BisectionEdge{edge.target, 1};
std::transform(begin(edges), end(edges), std::back_inserter(result), [](const auto &edge) {
return BisectionInputEdge{edge.source, edge.target};
});
return result;
include/partition/dinic_max_flow.hpp
+24 -18
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@@ -31,36 +31,42 @@ namespace partition
class DinicMaxFlow
{
public:
using PartitionResult = struct
using Level = std::uint32_t;
using MinCut = struct
{
std::size_t num_nodes_source;
std::size_t num_edges;
std::vector<bool> flags;
};
using SourceSinkNodes = std::set<NodeID>;
using LevelGraph = std::unordered_map<NodeID, std::uint32_t>;
using FlowEdges = std::unordered_set<std::pair<NodeID, NodeID>>;
using SourceSinkNodes = std::unordered_set<NodeID>;
using LevelGraph = std::vector<Level>;
using FlowEdges = std::vector<std::set<NodeID>>;
PartitionResult operator()(const GraphView &view,
const SourceSinkNodes &sink_nodes,
const SourceSinkNodes &source_nodes) const;
MinCut operator()(const GraphView &view,
const SourceSinkNodes &sink_nodes,
const SourceSinkNodes &source_nodes) const;
private:
LevelGraph ComputeLevelGraph(const GraphView &view,
const std::vector<NodeID> &border_source_nodes,
const SourceSinkNodes &source_nodes,
const SourceSinkNodes &sink_nodes,
const FlowEdges &flow) const;
void AugmentFlow(FlowEdges &flow,
const GraphView &view,
const SourceSinkNodes &source_nodes,
const SourceSinkNodes &sink_nodes,
const LevelGraph &levels) const;
std::uint32_t BlockingFlow(FlowEdges &flow,
LevelGraph &levels,
const GraphView &view,
const SourceSinkNodes &source_nodes,
const std::vector<NodeID> &border_sink_nodes) const;
bool findPath(const NodeID from,
std::vector<NodeID> &path,
const GraphView &view,
const LevelGraph &levels,
const FlowEdges &flow,
const SourceSinkNodes &sink_nodes) const;
std::vector<NodeID> GetAugmentingPath(LevelGraph &levels,
const NodeID from,
const GraphView &view,
const FlowEdges &flow,
const SourceSinkNodes &sink_nodes) const;
// Builds an actual cut result from a level graph
MinCut MakeCut(const GraphView &view, const LevelGraph &levels) const;
};
} // namespace partition
include/partition/graph_view.hpp
+21 -59
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@@ -8,88 +8,50 @@
#include <boost/iterator/iterator_facade.hpp>
#include <cstddef>
#include <cstdint>
namespace osrm
{
namespace partition
{
// Predicate for EdgeIDs checking their partition ids for equality.
// Used in filter iterator below to discard edges in different partitions.
struct HasSamePartitionID
{
HasSamePartitionID(const RecursiveBisectionState::BisectionID bisection_id,
const BisectionGraph &bisection_graph,
const RecursiveBisectionState &recursive_bisection_state);
bool operator()(const EdgeID eid) const;
private:
const RecursiveBisectionState::BisectionID bisection_id;
const BisectionGraph &bisection_graph;
const RecursiveBisectionState &recursive_bisection_state;
};
// Random Access Iterator on top of contiguous integral EdgeIDs
class EdgeIDIterator : public boost::iterator_facade<EdgeIDIterator,
EdgeID const,
boost::random_access_traversal_tag>
{
public:
EdgeIDIterator() : position(SPECIAL_EDGEID) {}
explicit EdgeIDIterator(EdgeID position_) : position(position_) {}
private:
friend class boost::iterator_core_access;
// Implements the facade's core operations required for random access iterators:
// http://www.boost.org/doc/libs/1_63_0/libs/iterator/doc/iterator_facade.html#core-operations
void increment() { ++position; }
void decrement() { --position; }
void advance(difference_type offset) { position += offset; }
bool equal(const EdgeIDIterator &other) const { return position == other.position; }
reference dereference() const { return position; }
difference_type distance_to(const EdgeIDIterator &other) const
{
return static_cast<difference_type>(other.position - position);
}
value_type position;
};
// Non-owning immutable sub-graph view into a base graph.
// The part of the graph to select is determined by the recursive bisection state.
class GraphView
{
public:
using EdgeIterator = boost::filter_iterator<HasSamePartitionID, EdgeIDIterator>;
GraphView(const BisectionGraph &graph,
const RecursiveBisectionState &bisection_state,
const RecursiveBisectionState::IDIterator begin,
const RecursiveBisectionState::IDIterator end);
const BisectionGraph::ConstNodeIterator begin,
const BisectionGraph::ConstNodeIterator end);
GraphView(const BisectionGraph &graph);
// Number of nodes _in this sub-graph.
std::size_t NumberOfNodes() const;
RecursiveBisectionState::IDIterator Begin() const;
RecursiveBisectionState::IDIterator End() const;
EdgeIterator EdgeBegin(const NodeID nid) const;
EdgeIterator EdgeEnd(const NodeID nid) const;
NodeID GetTarget(const EdgeID eid) const;
BisectionGraph::ConstNodeIterator Begin() const;
BisectionGraph::ConstNodeIterator End() const;
const BisectionNode &GetNode(const NodeID nid) const;
const BisectionEdge &GetEdge(const EdgeID eid) const;
NodeID GetID(const BisectionGraph::NodeT &node) const;
inline auto Edges(const NodeID nid) const { return bisection_graph.Edges(*(begin + nid)); }
inline auto BeginEdges(const NodeID nid) const
{
return bisection_graph.BeginEdges(*(begin + nid));
}
inline auto EndEdges(const NodeID nid) const
{
return bisection_graph.EndEdges(*(begin + nid));
}
private:
const BisectionGraph &bisection_graph;
const RecursiveBisectionState &bisection_state;
const RecursiveBisectionState::IDIterator begin;
const RecursiveBisectionState::IDIterator end;
const BisectionGraph::ConstNodeIterator begin;
const BisectionGraph::ConstNodeIterator end;
};
} // namespace partition
include/partition/inertial_flow.hpp
+5 -2
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@@ -1,6 +1,7 @@
#ifndef OSRM_PARTITION_INERTIAL_FLOW_HPP_
#define OSRM_PARTITION_INERTIAL_FLOW_HPP_
#include "partition/dinic_max_flow.hpp"
#include "partition/graph_view.hpp"
#include <unordered_set>
@@ -16,7 +17,9 @@ class InertialFlow
public:
InertialFlow(const GraphView &view);
std::vector<bool> ComputePartition(const double balance, const double source_sink_rate);
DinicMaxFlow::MinCut ComputePartition(const std::size_t num_slopes,
const double balance,
const double source_sink_rate);
private:
// Spatially ordered sources and sink ids.
@@ -32,7 +35,7 @@ class InertialFlow
SpatialOrder MakeSpatialOrder(double ratio, double slope) const;
// Makes n cuts with different spatial orders and returns the best.
MinCut bestMinCut(std::size_t n, double ratio) const;
DinicMaxFlow::MinCut BestMinCut(std::size_t n, double ratio) const;
// The subgraph to partition into two parts.
const GraphView &view;
include/partition/partition_graph.hpp
+138
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@@ -0,0 +1,138 @@
#ifndef OSRM_PARTITION_GRAPH_HPP_
#define OSRM_PARTITION_GRAPH_HPP_
#include <algorithm>
#include <cstddef>
#include <functional>
#include <iterator>
#include <vector>
#include "util/typedefs.hpp"
#include <boost/range/iterator_range.hpp>
namespace osrm
{
namespace partition
{
// wrapper for nodes to augment with a tag storing first edge id
template <typename Base> class NodeEntryWrapper : public Base
{
public:
template <typename... Args>
NodeEntryWrapper(std::size_t edges_begin_, std::size_t edges_end_, Args &&... args)
: Base(std::forward<Args>(args)...), edges_begin(edges_begin_), edges_end(edges_end_)
{
}
std::size_t edges_begin;
std::size_t edges_end;
};
template <typename Base> class GraphConstructionWrapper : public Base
{
public:
template <typename... Args>
GraphConstructionWrapper(const NodeID source_, Args &&... args)
: Base(std::forward<Args>(args)...), source(source_)
{
}
NodeID source;
Base Reduce() const { return *this; }
};
template <typename RandomIt> void groupEdgesBySource(RandomIt first, RandomIt last)
{
std::sort(
first, last, [](const auto &lhs, const auto &rhs) { return lhs.source < rhs.source; });
}
template <typename NodeEntryT, typename EdgeEntryT> class RemappableGraph
{
public:
using NodeT = NodeEntryT;
using EdgeT = EdgeEntryT;
using NodeIterator = typename std::vector<NodeT>::iterator;
using ConstNodeIterator = typename std::vector<NodeT>::const_iterator;
using EdgeIterator = typename std::vector<EdgeT>::iterator;
using ConstEdgeIterator = typename std::vector<EdgeT>::const_iterator;
// Constructs an empty graph with a given number of nodes.
explicit RemappableGraph(std::vector<NodeT> nodes_, std::vector<EdgeT> edges_)
: nodes(std::move(nodes_)), edges(std::move(edges_))
{
}
unsigned NumberOfNodes() const { return nodes.size(); }
auto &Node(const NodeID nid) { return nodes[nid]; }
auto &Node(const NodeID nid) const { return nodes[nid]; }
auto &Edge(const EdgeID eid) { return edges[eid]; }
auto &Edge(const EdgeID eid) const { return edges[eid]; }
auto Edges(const NodeID nid)
{
return boost::make_iterator_range(edges.begin() + nodes[nid].edges_begin,
edges.begin() + nodes[nid].edges_end);
}
auto Edges(const NodeID nid) const
{
return boost::make_iterator_range(edges.begin() + nodes[nid].edges_begin,
edges.begin() + nodes[nid].edges_end);
}
auto Edges(const NodeT &node)
{
return boost::make_iterator_range(edges.begin() + node.edges_begin,
edges.begin() + node.edges_end);
}
auto Edges(const NodeT &node) const
{
return boost::make_iterator_range(edges.begin() + node.edges_begin,
edges.begin() + node.edges_end);
}
auto BeginEdges(const NodeID nid) const { return edges.begin() + nodes[nid].edges_begin; }
auto EndEdges(const NodeID nid) const { return edges.begin() + nodes[nid].edges_end; }
auto BeginEdges(const NodeT &node) const { return edges.begin() + node.edges_begin; }
auto EndEdges(const NodeT &node) const { return edges.begin() + node.edges_end; }
auto BeginEdges(const NodeT &node) { return edges.begin() + node.edges_begin; }
auto EndEdges(const NodeT &node) { return edges.begin() + node.edges_end; }
// iterate over all nodes
auto Nodes() { return boost::make_iterator_range(nodes.begin(), nodes.end()); }
auto Nodes() const { return boost::make_iterator_range(nodes.begin(), nodes.end()); }
NodeIterator Begin() { return nodes.begin(); }
NodeIterator End() { return nodes.end(); }
ConstNodeIterator CBegin() const { return nodes.cbegin(); }
ConstNodeIterator CEnd() const { return nodes.cend(); }
// removes the edges from the graph that return true for the filter, returns new end
template <typename FilterT> auto RemoveEdges(NodeT &node, FilterT filter)
{
BOOST_ASSERT(&node >= &nodes[0] && &node <= &nodes.back());
// required since we are not on std++17 yet, otherwise we are missing an argument_type
const auto negate_filter = [&](const EdgeT &edge) { return !filter(edge); };
const auto center = std::stable_partition(BeginEdges(node), EndEdges(node), negate_filter);
const auto remaining_edges = std::distance(BeginEdges(node), center);
node.edges_end = node.edges_begin + remaining_edges;
return center;
};
protected:
std::vector<NodeT> nodes;
std::vector<EdgeT> edges;
};
} // namespace partition
} // namespace osrm
#endif // OSRM_PARTITION_GRAPH_HPP_
include/partition/recursive_bisection.hpp
+8 -2
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@@ -2,9 +2,11 @@
#define OSRM_PARTITION_RECURSIVE_BISECTION_HPP_
#include "partition/bisection_graph.hpp"
#include "partition/graph_view.hpp"
#include "partition/recursive_bisection_state.hpp"
#include <cstddef>
#include <vector>
namespace osrm
{
@@ -17,11 +19,15 @@ class RecursiveBisection
RecursiveBisection(std::size_t maximum_cell_size,
double balance,
double boundary_factor,
const BisectionGraph &bisection_graph);
BisectionGraph &bisection_graph);
private:
const BisectionGraph &bisection_graph;
BisectionGraph &bisection_graph;
RecursiveBisectionState internal_state;
// on larger graphs, SCCs give perfect cuts (think Amerika vs Europe)
// This function performs an initial pre-partitioning using these sccs.
std::vector<GraphView> FakeFirstPartitionWithSCC(const std::size_t small_component_size);
};
} // namespace partition
include/partition/recursive_bisection_state.hpp
+9 -12
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@@ -2,6 +2,7 @@
#define OSRM_PARTITION_RECURSIVE_BISECTION_STATE_HPP_
#include <cstddef>
#include <cstdint>
#include <vector>
#include "partition/bisection_graph.hpp"
@@ -62,26 +63,22 @@ class RecursiveBisectionState
public:
// The ID in the partition array
using BisectionID = std::uint32_t;
using IDIterator = std::vector<NodeID>::const_iterator;
using NodeIterator = BisectionGraph::ConstNodeIterator;
RecursiveBisectionState(const BisectionGraph &bisection_graph);
RecursiveBisectionState(BisectionGraph &bisection_graph);
~RecursiveBisectionState();
BisectionID GetBisectionID(const NodeID nid) const;
BisectionID GetBisectionID(const NodeID node) const;
// Bisects the node id array's sub-range based on the partition mask.
// Returns: partition point of the bisection: iterator to the second group's first element.
IDIterator ApplyBisection(const IDIterator begin,
const IDIterator end,
const std::vector<bool> &partition);
const IDIterator Begin() const;
const IDIterator End() const;
NodeIterator ApplyBisection(NodeIterator begin,
const NodeIterator end,
const std::size_t depth,
const std::vector<bool> &partition);
private:
const BisectionGraph &bisection_graph;
std::vector<NodeID> id_array;
BisectionGraph &bisection_graph;
std::vector<BisectionID> bisection_ids;
};
include/partition/reorder_first_last.hpp
+1 -1
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@@ -20,7 +20,7 @@ void reorderFirstLast(RandomIt first, RandomIt last, std::size_t n, Comparator c
{
BOOST_ASSERT_MSG(n <= (last - first) / std::size_t{2}, "overlapping subranges not allowed");
if (n == 0 or (last - first < 2))
if (n == 0 || (last - first < 2))
return;
// Reorder first n: guarantees that the predicate holds for the first elements.
include/partition/tarjan_graph_wrapper.hpp
+29
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@@ -0,0 +1,29 @@
#ifndef OSRM_PARTITION_TARJAN_GRAPH_WRAPPER_HPP_
#define OSRM_PARTITION_TARJAN_GRAPH_WRAPPER_HPP_
#include "partition/bisection_graph.hpp"
#include "util/integer_range.hpp"
#include "util/typedefs.hpp"
namespace osrm
{
namespace partition
{
class TarjanGraphWrapper
{
public:
TarjanGraphWrapper(const BisectionGraph &bisection_graph);
std::size_t GetNumberOfNodes() const;
util::range<EdgeID> GetAdjacentEdgeRange(const NodeID nid) const;
NodeID GetTarget(const EdgeID eid) const;
protected:
const BisectionGraph &bisection_graph;
};
} // namespace partition
} // namespace osrm
#endif // OSRM_PARTITION_TARJAN_GRAPH_WRAPPER_HPP_