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osrm-backend/include/engine/plugins/trip.hpp

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#ifndef TRIP_HPP
#define TRIP_HPP
#include "engine/plugins/plugin_base.hpp"
#include "engine/object_encoder.hpp"
#include "extractor/tarjan_scc.hpp"
#include "engine/trip/trip_nearest_neighbour.hpp"
#include "engine/trip/trip_farthest_insertion.hpp"
#include "engine/trip/trip_brute_force.hpp"
#include "engine/search_engine.hpp"
#include "util/matrix_graph_wrapper.hpp" // wrapper to use tarjan
// scc on dist table
#include "engine/descriptors/descriptor_base.hpp" // to make json output
#include "engine/descriptors/json_descriptor.hpp" // to make json output
#include "util/make_unique.hpp"
#include "util/timing_util.hpp" // to time runtime
//#include "util/simple_logger.hpp" // for logging output
#include "util/dist_table_wrapper.hpp" // to access the dist
// table more easily
#include "osrm/json_container.hpp"
#include <boost/assert.hpp>
#include <cstdlib>
#include <algorithm>
#include <memory>
#include <string>
#include <utility>
#include <vector>
#include <iterator>
template <class DataFacadeT> class RoundTripPlugin final : public BasePlugin
{
private:
std::string descriptor_string;
DataFacadeT *facade;
std::unique_ptr<SearchEngine<DataFacadeT>> search_engine_ptr;
int max_locations_trip;
public:
explicit RoundTripPlugin(DataFacadeT *facade, int max_locations_trip)
: descriptor_string("trip"), facade(facade), max_locations_trip(max_locations_trip)
{
search_engine_ptr = osrm::make_unique<SearchEngine<DataFacadeT>>(facade);
}
const std::string GetDescriptor() const override final { return descriptor_string; }
std::vector<PhantomNode> GetPhantomNodes(const RouteParameters &route_parameters)
{
const bool checksum_OK = (route_parameters.check_sum == facade->GetCheckSum());
const auto &input_bearings = route_parameters.bearings;
std::vector<PhantomNode> phantom_node_list;
phantom_node_list.reserve(route_parameters.coordinates.size());
// find phantom nodes for all input coords
for (const auto i : osrm::irange<std::size_t>(0, route_parameters.coordinates.size()))
{
// if client hints are helpful, encode hints
if (checksum_OK && i < route_parameters.hints.size() &&
!route_parameters.hints[i].empty())
{
PhantomNode current_phantom_node;
ObjectEncoder::DecodeFromBase64(route_parameters.hints[i], current_phantom_node);
if (current_phantom_node.is_valid(facade->GetNumberOfNodes()))
{
phantom_node_list.push_back(std::move(current_phantom_node));
continue;
}
}
const int bearing = input_bearings.size() > 0 ? input_bearings[i].first : 0;
const int range = input_bearings.size() > 0
? (input_bearings[i].second ? *input_bearings[i].second : 10)
: 180;
auto results = facade->NearestPhantomNodes(route_parameters.coordinates[i], 1, bearing, range);
if (results.empty())
{
break;
}
phantom_node_list.push_back(std::move(results.front().phantom_node));
BOOST_ASSERT(phantom_node_list.back().is_valid(facade->GetNumberOfNodes()));
}
return phantom_node_list;
}
// Object to hold all strongly connected components (scc) of a graph
// to access all graphs with component ID i, get the iterators by:
// auto start = std::begin(scc_component.component) + scc_component.range[i];
// auto end = std::begin(scc_component.component) + scc_component.range[i+1];
struct SCC_Component
{
// in_component: all NodeIDs sorted by component ID
// in_range: index where a new component starts
//
// example: NodeID 0, 1, 2, 4, 5 are in component 0
// NodeID 3, 6, 7, 8 are in component 1
// => in_component = [0, 1, 2, 4, 5, 3, 6, 7, 8]
// => in_range = [0, 5]
SCC_Component(std::vector<NodeID> in_component, std::vector<size_t> in_range)
: component(std::move(in_component)), range(std::move(in_range))
{
range.push_back(component.size());
BOOST_ASSERT_MSG(component.size() >= range.size(),
"scc component and its ranges do not match");
BOOST_ASSERT_MSG(component.size() > 0, "there's no scc component");
BOOST_ASSERT_MSG(*std::max_element(range.begin(), range.end()) <= component.size(),
"scc component ranges are out of bound");
BOOST_ASSERT_MSG(*std::min_element(range.begin(), range.end()) >= 0,
"invalid scc component range");
BOOST_ASSERT_MSG(std::is_sorted(std::begin(range), std::end(range)),
"invalid component ranges");
};
// constructor to use when whole graph is one single scc
SCC_Component(std::vector<NodeID> in_component)
: component(std::move(in_component)), range({0, component.size()}){};
std::size_t GetNumberOfComponents() const
{
BOOST_ASSERT_MSG(range.size() > 0, "there's no range");
return range.size() - 1;
}
const std::vector<NodeID> component;
std::vector<std::size_t> range;
};
// takes the number of locations and its distance matrix,
// identifies and splits the graph in its strongly connected components (scc)
// and returns an SCC_Component
SCC_Component SplitUnaccessibleLocations(const std::size_t number_of_locations,
const DistTableWrapper<EdgeWeight> &result_table)
{
if (std::find(std::begin(result_table), std::end(result_table), INVALID_EDGE_WEIGHT) ==
std::end(result_table))
{
// whole graph is one scc
std::vector<NodeID> location_ids(number_of_locations);
std::iota(std::begin(location_ids), std::end(location_ids), 0);
return SCC_Component(std::move(location_ids));
}
// Run TarjanSCC
auto wrapper = std::make_shared<MatrixGraphWrapper<EdgeWeight>>(result_table.GetTable(),
number_of_locations);
auto scc = TarjanSCC<MatrixGraphWrapper<EdgeWeight>>(wrapper);
scc.run();
const auto number_of_components = scc.get_number_of_components();
std::vector<std::size_t> range_insertion;
std::vector<std::size_t> range;
range_insertion.reserve(number_of_components);
range.reserve(number_of_components);
std::vector<NodeID> components(number_of_locations, 0);
std::size_t prefix = 0;
for (std::size_t j = 0; j < number_of_components; ++j)
{
range_insertion.push_back(prefix);
range.push_back(prefix);
prefix += scc.get_component_size(j);
}
for (std::size_t i = 0; i < number_of_locations; ++i)
{
components[range_insertion[scc.get_component_id(i)]] = i;
++range_insertion[scc.get_component_id(i)];
}
return SCC_Component(std::move(components), std::move(range));
}
void SetLocPermutationOutput(const std::vector<NodeID> &permutation,
osrm::json::Object &json_result)
{
osrm::json::Array json_permutation;
json_permutation.values.insert(std::end(json_permutation.values), std::begin(permutation),
std::end(permutation));
json_result.values["permutation"] = json_permutation;
}
InternalRouteResult ComputeRoute(const std::vector<PhantomNode> &phantom_node_list,
const RouteParameters &route_parameters,
const std::vector<NodeID> &trip)
{
InternalRouteResult min_route;
// given he final trip, compute total distance and return the route and location permutation
PhantomNodes viapoint;
const auto start = std::begin(trip);
const auto end = std::end(trip);
// computes a roundtrip from the nodes in trip
for (auto it = start; it != end; ++it)
{
const auto from_node = *it;
// if from_node is the last node, compute the route from the last to the first location
const auto to_node = std::next(it) != end ? *std::next(it) : *start;
viapoint = PhantomNodes{phantom_node_list[from_node], phantom_node_list[to_node]};
min_route.segment_end_coordinates.emplace_back(viapoint);
}
BOOST_ASSERT(min_route.segment_end_coordinates.size() == trip.size());
std::vector<bool> uturns(trip.size() + 1);
std::transform(trip.begin(), trip.end(), uturns.begin(),
[&route_parameters](const NodeID idx)
{
return route_parameters.uturns[idx];
});
uturns.back() = route_parameters.uturns[trip.front()];
search_engine_ptr->shortest_path(min_route.segment_end_coordinates, uturns, min_route);
BOOST_ASSERT_MSG(min_route.shortest_path_length < INVALID_EDGE_WEIGHT, "unroutable route");
return min_route;
}
Status HandleRequest(const RouteParameters &route_parameters,
osrm::json::Object &json_result) override final
{
if (max_locations_trip > 0 &&
(static_cast<int>(route_parameters.coordinates.size()) > max_locations_trip))
{
json_result.values["status_message"] =
"Number of entries " + std::to_string(route_parameters.coordinates.size()) +
" is higher than current maximum (" + std::to_string(max_locations_trip) + ")";
return Status::Error;
}
// check if all inputs are coordinates
if (!check_all_coordinates(route_parameters.coordinates))
{
json_result.values["status_message"] = "Invalid coordinates";
return Status::Error;
}
const auto &input_bearings = route_parameters.bearings;
if (input_bearings.size() > 0 &&
route_parameters.coordinates.size() != input_bearings.size())
{
json_result.values["status_message"] =
"Number of bearings does not match number of coordinates";
return Status::Error;
}
// get phantom nodes
auto phantom_node_list = GetPhantomNodes(route_parameters);
if (phantom_node_list.size() != route_parameters.coordinates.size())
{
BOOST_ASSERT(phantom_node_list.size() < route_parameters.coordinates.size());
json_result.values["status_message"] =
std::string("Could not find a matching segment for coordinate ") +
std::to_string(phantom_node_list.size());
return Status::NoSegment;
}
const auto number_of_locations = phantom_node_list.size();
// compute the distance table of all phantom nodes
const auto result_table = DistTableWrapper<EdgeWeight>(
*search_engine_ptr->distance_table(phantom_node_list, phantom_node_list),
number_of_locations);
if (result_table.size() == 0)
{
return Status::Error;
}
const constexpr std::size_t BF_MAX_FEASABLE = 10;
BOOST_ASSERT_MSG(result_table.size() == number_of_locations * number_of_locations,
"Distance Table has wrong size");
// get scc components
SCC_Component scc = SplitUnaccessibleLocations(number_of_locations, result_table);
using NodeIDIterator = typename std::vector<NodeID>::const_iterator;
std::vector<std::vector<NodeID>> route_result;
route_result.reserve(scc.GetNumberOfComponents());
TIMER_START(TRIP_TIMER);
// run Trip computation for every SCC
for (std::size_t k = 0; k < scc.GetNumberOfComponents(); ++k)
{
const auto component_size = scc.range[k + 1] - scc.range[k];
BOOST_ASSERT_MSG(component_size >= 0, "invalid component size");
if (component_size > 1)
{
std::vector<NodeID> scc_route;
NodeIDIterator start = std::begin(scc.component) + scc.range[k];
NodeIDIterator end = std::begin(scc.component) + scc.range[k + 1];
if (component_size < BF_MAX_FEASABLE)
{
scc_route =
osrm::trip::BruteForceTrip(start, end, number_of_locations, result_table);
}
else
{
scc_route = osrm::trip::FarthestInsertionTrip(start, end, number_of_locations,
result_table);
}
// use this output if debugging of route is needed:
// SimpleLogger().Write() << "Route #" << k << ": " << [&scc_route]()
// {
// std::string s = "";
// for (auto x : scc_route)
// {
// s += std::to_string(x) + " ";
// }
// return s;
// }();
route_result.push_back(std::move(scc_route));
}
else
{
// if component only consists of one node, add it to the result routes
route_result.emplace_back(scc.component[scc.range[k]]);
}
}
// compute all round trip routes
std::vector<InternalRouteResult> comp_route;
comp_route.reserve(route_result.size());
for (auto &elem : route_result)
{
comp_route.push_back(ComputeRoute(phantom_node_list, route_parameters, elem));
}
TIMER_STOP(TRIP_TIMER);
// prepare JSON output
// create a json object for every trip
osrm::json::Array trip;
for (std::size_t i = 0; i < route_result.size(); ++i)
{
std::unique_ptr<BaseDescriptor<DataFacadeT>> descriptor =
osrm::make_unique<JSONDescriptor<DataFacadeT>>(facade);
descriptor->SetConfig(route_parameters);
osrm::json::Object scc_trip;
// set permutation output
SetLocPermutationOutput(route_result[i], scc_trip);
// set viaroute output
descriptor->Run(comp_route[i], scc_trip);
trip.values.push_back(std::move(scc_trip));
}
if (trip.values.empty())
{
json_result.values["status_message"] = "Cannot find trips";
return Status::EmptyResult;
}
json_result.values["trips"] = std::move(trip);
json_result.values["status_message"] = "Found trips";
return Status::Ok;
}
};
#endif // TRIP_HPP
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