osrm-backend/include/partition/annotated_partition.hpp
2017-03-01 16:09:29 +00:00

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#ifndef OSRM_PARTITION_ANNOTATE_HPP_
#define OSRM_PARTITION_ANNOTATE_HPP_
#include "partition/bisection_graph.hpp"
#include "util/typedefs.hpp"
#include <cstdint>
#include <utility>
#include <vector>
namespace osrm
{
namespace partition
{
// takes the result of a recursive bisection and turns it into an annotated partition for MLD. These
// annotated partitions provide a mapping from every node in the graph to a consecutively
// numbered cell in each level of the multi level partition. Instead of using the bisection directly
// (which can result in a unbalanced tree structure)
//
// _____o______
// / \ 
// o ____o____
// / \ / \ 
// a b o _o_
// / \ / \ 
// c d o o
// / \ / \ 
// e f g h
//
// we build a balanced structure that will result in a multi-cut on any level. We transform this
// layout into:
//
// _____o__________
// / | \ 
// o | \ 
// / \ | \ 
// a b o _o_
// / \ / \ 
// c d o o
// / \ / \ 
// e f g h
class AnnotatedPartition
{
public:
// Used to generate an implicit tree representation
struct SizedID
{
BisectionID id;
std::size_t count;
bool operator<(const SizedID &other) const { return id < other.id; };
};
// Metrics that describe a single level
struct LevelMetrics
{
std::size_t border_nodes;
std::size_t border_arcs;
// impresses imbalance, if not all nodes are in that cell anymore
std::size_t contained_nodes;
std::size_t number_of_cells;
std::size_t max_border_nodes_per_cell;
std::size_t max_border_arcs_per_cell;
std::size_t total_memory_cells;
std::vector<std::size_t> cell_sizes;
std::ostream &print(std::ostream &os) const
{
os << "[level]\n"
<< "\t#border nodes: " << border_nodes << " #border arcs: " << border_arcs
<< " #cells: " << number_of_cells << " #contained nodes: " << contained_nodes << "\n"
<< "\tborder nodes: max: " << max_border_nodes_per_cell
<< " avg : " << static_cast<double>(border_nodes) / number_of_cells
<< " border arcs: max: " << max_border_arcs_per_cell << " "
<< " avg: " << static_cast<double>(border_arcs) / number_of_cells << "\n"
<< "\tmemory consumption: " << total_memory_cells / (1024.0 * 1024.0) << " MB."
<< "\n";
os << "\tcell sizes:";
for (auto s : cell_sizes)
os << " " << s;
os << std::endl;
return os;
}
std::ostream &logMachinereadable(std::ostream &os,
const std::string &identification,
std::size_t depth,
const bool print_header = false) const
{
if (print_header)
os << "[" << identification << "] # depth cells total_nodes border_nodes "
"max_border_nodes border_arcs max_border_arcs bytes "
"cell_sizes*\n";
os << "[" << identification << "] " << depth << " " << number_of_cells << " "
<< contained_nodes << " " << border_nodes << " " << max_border_nodes_per_cell << " "
<< border_arcs << " " << max_border_arcs_per_cell << " " << total_memory_cells;
for (auto s : cell_sizes)
os << " " << s;
os << "\n";
return os;
}
};
AnnotatedPartition(const BisectionGraph &graph, const std::vector<BisectionID> &bisection_ids);
private:
// print distribution of level graph as it is
void PrintBisection(const std::vector<SizedID> &implicit_tree,
const BisectionGraph &graph,
const std::vector<BisectionID> &bisection_ids) const;
// find levels that offer good distribution of average cell sizes
void SearchLevels(const std::vector<SizedID> &implicit_tree,
const BisectionGraph &graph,
const std::vector<BisectionID> &bisection_ids) const;
// set cell_ids[i] == INFTY to exclude element
LevelMetrics AnalyseLevel(const BisectionGraph &graph,
const std::vector<std::uint32_t> &cell_ids) const;
std::vector<std::uint32_t>
ComputeCellIDs(std::vector<std::pair<BisectionID, std::int32_t>> &prefixes,
const BisectionGraph &graph,
const std::vector<BisectionID> &bisection_ids) const;
};
} // namespace partition
} // namespace osrm
#endif // OSRM_PARTITION_ANNOTATE_HPP_