lemon-0.x: comparison lemon/cost

equal deleted inserted replaced

-:6e3bace54039
+:d21de5f4cf49
 /// \tparam SupplyMap The type of the supply map.
 ///
 /// \warning
 /// - Edge capacities and costs should be \e non-negative \e integers.
 /// - Supply values should be \e signed \e integers.
-/// - \c LowerMap::Value must be convertible to \c CapacityMap::Value.
+/// - The value types of the maps should be convertible to each other.
-/// - \c CapacityMap::Value and \c SupplyMap::Value must be
+/// - \c CostMap::Value must be signed type.
-///   convertible to each other.
-/// - All value types must be convertible to \c CostMap::Value, which
-///   must be signed type.
 ///
 /// \note Edge costs are multiplied with the number of nodes during
 /// the algorithm so overflow problems may arise more easily than with
 /// other minimum cost flow algorithms.
 /// If it is available, <tt>long long int</tt> type is used instead of
 typedef typename Graph::template EdgeMap<LCost> LargeCostMap;
 public:
 /// The type of the flow map.
-typedef CapacityEdgeMap FlowMap;
+typedef typename Graph::template EdgeMap<Capacity> FlowMap;
 /// The type of the potential map.
 typedef typename Graph::template NodeMap<LCost> PotentialMap;
 private:
 /// \brief Map adaptor class for handling residual edge costs.
 ///
 /// \ref ResidualCostMap is a map adaptor class for handling
 /// residual edge costs.
-class ResidualCostMap : public MapBase<ResEdge, LCost>
+template <typename Map>
+class ResidualCostMap : public MapBase<ResEdge, typename Map::Value>
 {
 private:
-const LargeCostMap &_cost_map;
+const Map &_cost_map;
 public:
 ///\e
-ResidualCostMap(const LargeCostMap &cost_map) :
+ResidualCostMap(const Map &cost_map) :
 _cost_map(cost_map) {}
 ///\e
-LCost operator[](const ResEdge &e) const {
+typename Map::Value operator[](const ResEdge &e) const {
 return ResGraph::forward(e) ?  _cost_map[e] : -_cost_map[e];
 }
 }; //class ResidualCostMap
 // Scaling factor
 static const int ALPHA = 4;
 // Paramters for heuristics
-static const int BF_HEURISTIC_EPSILON_BOUND    = 5000;
+static const int BF_HEURISTIC_EPSILON_BOUND = 5000;
-static const int BF_HEURISTIC_BOUND_FACTOR = 3;
+static const int BF_HEURISTIC_BOUND_FACTOR  = 3;
 private:
 // The directed graph the algorithm runs on
 const Graph &_graph;
 // The modified supply map
 SupplyNodeMap _supply;
 bool _valid_supply;
 // Edge map of the current flow
-FlowMap _flow;
+FlowMap *_flow;
+bool _local_flow;
 // Node map of the current potentials
-PotentialMap _potential;
+PotentialMap *_potential;
+bool _local_potential;
 // The residual graph
-ResGraph _res_graph;
+ResGraph *_res_graph;
 // The residual cost map
-ResidualCostMap _res_cost;
+ResidualCostMap<LargeCostMap> _res_cost;
 // The reduced cost map
-ReducedCostMap _red_cost;
+ReducedCostMap *_red_cost;
 // The excess map
 SupplyNodeMap _excess;
 // The epsilon parameter used for cost scaling
 LCost _epsilon;
 public:
-/// \brief General constructor of the class (with lower bounds).
+/// \brief General constructor (with lower bounds).
 ///
-/// General constructor of the class (with lower bounds).
+/// General constructor (with lower bounds).
 ///
 /// \param graph The directed graph the algorithm runs on.
 /// \param lower The lower bounds of the edges.
 /// \param capacity The capacities (upper bounds) of the edges.
 /// \param cost The cost (length) values of the edges.
 const LowerMap &lower,
 const CapacityMap &capacity,
 const CostMap &cost,
 const SupplyMap &supply ) :
 _graph(graph), _lower(&lower), _capacity(graph), _orig_cost(cost),
-_cost(graph), _supply(graph), _flow(graph, 0), _potential(graph, 0),
+_cost(graph), _supply(graph), _flow(0), _local_flow(false),
-_res_graph(graph, _capacity, _flow), _res_cost(_cost),
+_potential(0), _local_potential(false), _res_cost(_cost),
-_red_cost(graph, _cost, _potential), _excess(graph, 0)
+_excess(graph, 0)
 {
 // Removing non-zero lower bounds
 _capacity = subMap(capacity, lower);
 Supply sum = 0;
 for (NodeIt n(_graph); n != INVALID; ++n) {
 sum += s;
 }
 _valid_supply = sum == 0;
 }
-/// \brief General constructor of the class (without lower bounds).
+/// \brief General constructor (without lower bounds).
 ///
-/// General constructor of the class (without lower bounds).
+/// General constructor (without lower bounds).
 ///
 /// \param graph The directed graph the algorithm runs on.
 /// \param capacity The capacities (upper bounds) of the edges.
 /// \param cost The cost (length) values of the edges.
 /// \param supply The supply values of the nodes (signed).
 CostScaling( const Graph &graph,
 const CapacityMap &capacity,
 const CostMap &cost,
 const SupplyMap &supply ) :
 _graph(graph), _lower(NULL), _capacity(capacity), _orig_cost(cost),
-_cost(graph), _supply(supply), _flow(graph, 0), _potential(graph, 0),
+_cost(graph), _supply(supply), _flow(0), _local_flow(false),
-_res_graph(graph, _capacity, _flow), _res_cost(_cost),
+_potential(0), _local_potential(false), _res_cost(_cost),
-_red_cost(graph, _cost, _potential), _excess(graph, 0)
+_excess(graph, 0)
 {
 // Checking the sum of supply values
 Supply sum = 0;
 for (NodeIt n(_graph); n != INVALID; ++n) sum += _supply[n];
 _valid_supply = sum == 0;
 }
-/// \brief Simple constructor of the class (with lower bounds).
+/// \brief Simple constructor (with lower bounds).
 ///
-/// Simple constructor of the class (with lower bounds).
+/// Simple constructor (with lower bounds).
 ///
 /// \param graph The directed graph the algorithm runs on.
 /// \param lower The lower bounds of the edges.
 /// \param capacity The capacities (upper bounds) of the edges.
 /// \param cost The cost (length) values of the edges.
 const CapacityMap &capacity,
 const CostMap &cost,
 Node s, Node t,
 Supply flow_value ) :
 _graph(graph), _lower(&lower), _capacity(graph), _orig_cost(cost),
-_cost(graph), _supply(graph), _flow(graph, 0), _potential(graph, 0),
+_cost(graph), _supply(graph), _flow(0), _local_flow(false),
-_res_graph(graph, _capacity, _flow), _res_cost(_cost),
+_potential(0), _local_potential(false), _res_cost(_cost),
-_red_cost(graph, _cost, _potential), _excess(graph, 0)
+_excess(graph, 0)
 {
 // Removing nonzero lower bounds
 _capacity = subMap(capacity, lower);
 for (NodeIt n(_graph); n != INVALID; ++n) {
 Supply sum = 0;
 _supply[n] = sum;
 }
 _valid_supply = true;
 }
-/// \brief Simple constructor of the class (without lower bounds).
+/// \brief Simple constructor (without lower bounds).
 ///
-/// Simple constructor of the class (without lower bounds).
+/// Simple constructor (without lower bounds).
 ///
 /// \param graph The directed graph the algorithm runs on.
 /// \param capacity The capacities (upper bounds) of the edges.
 /// \param cost The cost (length) values of the edges.
 /// \param s The source node.
 const CapacityMap &capacity,
 const CostMap &cost,
 Node s, Node t,
 Supply flow_value ) :
 _graph(graph), _lower(NULL), _capacity(capacity), _orig_cost(cost),
-_cost(graph), _supply(graph, 0), _flow(graph, 0), _potential(graph, 0),
+_cost(graph), _supply(graph, 0), _flow(0), _local_flow(false),
-_res_graph(graph, _capacity, _flow), _res_cost(_cost),
+_potential(0), _local_potential(false), _res_cost(_cost),
-_red_cost(graph, _cost, _potential), _excess(graph, 0)
+_excess(graph, 0)
 {
 _supply[s] =  flow_value;
 _supply[t] = -flow_value;
 _valid_supply = true;
 }
+/// Destructor.
+~CostScaling() {
+if (_local_flow) delete _flow;
+if (_local_potential) delete _potential;
+delete _res_graph;
+delete _red_cost;
+}
+/// \brief Sets the flow map.
+///
+/// Sets the flow map.
+///
+/// \return \c (*this)
+CostScaling& flowMap(FlowMap &map) {
+if (_local_flow) {
+delete _flow;
+_local_flow = false;
+}
+_flow = &map;
+return *this;
+}
+/// \brief Sets the potential map.
+///
+/// Sets the potential map.
+///
+/// \return \c (*this)
+CostScaling& potentialMap(PotentialMap &map) {
+if (_local_potential) {
+delete _potential;
+_local_potential = false;
+}
+_potential = &map;
+return *this;
+}
+/// \name Execution control
+/// The only way to execute the algorithm is to call the run()
+/// function.
+/// @{
 /// \brief Runs the algorithm.
 ///
 /// Runs the algorithm.
 ///
 /// \return \c true if a feasible flow can be found.
 bool run() {
-init() && start();
+return init() && start();
 }
+/// @}
+/// \name Query Functions
+/// The result of the algorithm can be obtained using these
+/// functions.
+/// \n run() must be called before using them.
+/// @{
 /// \brief Returns a const reference to the edge map storing the
 /// found flow.
 ///
 /// Returns a const reference to the edge map storing the found flow.
 ///
 /// \pre \ref run() must be called before using this function.
 const FlowMap& flowMap() const {
-return _flow;
+return *_flow;
 }
 /// \brief Returns a const reference to the node map storing the
 /// found potentials (the dual solution).
 ///
 /// Returns a const reference to the node map storing the found
 /// potentials (the dual solution).
 ///
 /// \pre \ref run() must be called before using this function.
 const PotentialMap& potentialMap() const {
-return _potential;
+return *_potential;
+}
+/// \brief Returns the flow on the edge.
+///
+/// Returns the flow on the edge.
+///
+/// \pre \ref run() must be called before using this function.
+Capacity flow(const Edge& edge) const {
+return (*_flow)[edge];
+}
+/// \brief Returns the potential of the node.
+///
+/// Returns the potential of the node.
+///
+/// \pre \ref run() must be called before using this function.
+Cost potential(const Node& node) const {
+return (*_potential)[node];
 }
 /// \brief Returns the total cost of the found flow.
 ///
 /// Returns the total cost of the found flow. The complexity of the
 ///
 /// \pre \ref run() must be called before using this function.
 Cost totalCost() const {
 Cost c = 0;
 for (EdgeIt e(_graph); e != INVALID; ++e)
-c += _flow[e] * _orig_cost[e];
+c += (*_flow)[e] * _orig_cost[e];
 return c;
 }
+/// @}
 private:
 /// Initializes the algorithm.
 bool init() {
 if (!_valid_supply) return false;
+// Initializing flow and potential maps
+if (!_flow) {
+_flow = new FlowMap(_graph);
+_local_flow = true;
+}
+if (!_potential) {
+_potential = new PotentialMap(_graph);
+_local_potential = true;
+}
+_red_cost = new ReducedCostMap(_graph, _cost, *_potential);
+_res_graph = new ResGraph(_graph, _capacity, *_flow);
 // Initializing the scaled cost map and the epsilon parameter
 Cost max_cost = 0;
 int node_num = countNodes(_graph);
 for (EdgeIt e(_graph); e != INVALID; ++e) {
 _epsilon = max_cost * node_num;
 // Finding a feasible flow using Circulation
 Circulation< Graph, ConstMap<Edge, Capacity>, CapacityEdgeMap,
 SupplyMap >
-circulation( _graph, constMap<Edge>((Capacity)0), _capacity,
+circulation( _graph, constMap<Edge>(Capacity(0)), _capacity,
 _supply );
-return circulation.flowMap(_flow).run();
+return circulation.flowMap(*_flow).run();
 }
 /// Executes the algorithm.
 bool start() {
 1 : _epsilon / ALPHA )
 {
 // Performing price refinement heuristic using Bellman-Ford
 // algorithm
 if (_epsilon <= BF_HEURISTIC_EPSILON_BOUND) {
-typedef ShiftMap<ResidualCostMap> ShiftCostMap;
+typedef ShiftMap< ResidualCostMap<LargeCostMap> > ShiftCostMap;
 ShiftCostMap shift_cost(_res_cost, _epsilon);
-BellmanFord<ResGraph, ShiftCostMap> bf(_res_graph, shift_cost);
+BellmanFord<ResGraph, ShiftCostMap> bf(*_res_graph, shift_cost);
 bf.init(0);
 bool done = false;
 int K = int(BF_HEURISTIC_BOUND_FACTOR * sqrt(node_num));
 for (int i = 0; i < K && !done; ++i)
 done = bf.processNextWeakRound();
 if (done) {
 for (NodeIt n(_graph); n != INVALID; ++n)
-_potential[n] = bf.dist(n);
+(*_potential)[n] = bf.dist(n);
 continue;
 }
 }
 // Saturating edges not satisfying the optimality condition
 Capacity delta;
 for (EdgeIt e(_graph); e != INVALID; ++e) {
-if (_capacity[e] - _flow[e] > 0 && _red_cost[e] < 0) {
+if (_capacity[e] - (*_flow)[e] > 0 && (*_red_cost)[e] < 0) {
-delta = _capacity[e] - _flow[e];
+delta = _capacity[e] - (*_flow)[e];
 _excess[_graph.source(e)] -= delta;
 _excess[_graph.target(e)] += delta;
-_flow[e] = _capacity[e];
+(*_flow)[e] = _capacity[e];
 }
-if (_flow[e] > 0 && -_red_cost[e] < 0) {
+if ((*_flow)[e] > 0 && -(*_red_cost)[e] < 0) {
-_excess[_graph.target(e)] -= _flow[e];
+_excess[_graph.target(e)] -= (*_flow)[e];
-_excess[_graph.source(e)] += _flow[e];
+_excess[_graph.source(e)] += (*_flow)[e];
-_flow[e] = 0;
+(*_flow)[e] = 0;
 }
 }
 // Finding active nodes (i.e. nodes with positive excess)
 for (NodeIt n(_graph); n != INVALID; ++n)
 bool relabel_enabled = true;
 // Performing push operations if there are admissible edges
 if (_excess[n] > 0) {
 for (OutEdgeIt e(_graph, n); e != INVALID; ++e) {
-if (_capacity[e] - _flow[e] > 0 && _red_cost[e] < 0) {
+if (_capacity[e] - (*_flow)[e] > 0 && (*_red_cost)[e] < 0) {
-delta = _capacity[e] - _flow[e] <= _excess[n] ?
+delta = _capacity[e] - (*_flow)[e] <= _excess[n] ?
-_capacity[e] - _flow[e] : _excess[n];
+_capacity[e] - (*_flow)[e] : _excess[n];
 t = _graph.target(e);
 // Push-look-ahead heuristic
 Capacity ahead = -_excess[t];
 for (OutEdgeIt oe(_graph, t); oe != INVALID; ++oe) {
-if (_capacity[oe] - _flow[oe] > 0 && _red_cost[oe] < 0)
+if (_capacity[oe] - (*_flow)[oe] > 0 && (*_red_cost)[oe] < 0)
-ahead += _capacity[oe] - _flow[oe];
+ahead += _capacity[oe] - (*_flow)[oe];
 }
 for (InEdgeIt ie(_graph, t); ie != INVALID; ++ie) {
-if (_flow[ie] > 0 && -_red_cost[ie] < 0)
+if ((*_flow)[ie] > 0 && -(*_red_cost)[ie] < 0)
-ahead += _flow[ie];
+ahead += (*_flow)[ie];
 }
 if (ahead < 0) ahead = 0;
 // Pushing flow along the edge
 if (ahead < delta) {
-_flow[e] += ahead;
+(*_flow)[e] += ahead;
 _excess[n] -= ahead;
 _excess[t] += ahead;
 active_nodes.push_front(t);
 hyper[t] = true;
 relabel_enabled = false;
 break;
 } else {
-_flow[e] += delta;
+(*_flow)[e] += delta;
 _excess[n] -= delta;
 _excess[t] += delta;
 if (_excess[t] > 0 && _excess[t] <= delta)
 active_nodes.push_back(t);
 }
 }
 }
 if (_excess[n] > 0) {
 for (InEdgeIt e(_graph, n); e != INVALID; ++e) {
-if (_flow[e] > 0 && -_red_cost[e] < 0) {
+if ((*_flow)[e] > 0 && -(*_red_cost)[e] < 0) {
-delta = _flow[e] <= _excess[n] ? _flow[e] : _excess[n];
+delta = (*_flow)[e] <= _excess[n] ? (*_flow)[e] : _excess[n];
 t = _graph.source(e);
 // Push-look-ahead heuristic
 Capacity ahead = -_excess[t];
 for (OutEdgeIt oe(_graph, t); oe != INVALID; ++oe) {
-if (_capacity[oe] - _flow[oe] > 0 && _red_cost[oe] < 0)
+if (_capacity[oe] - (*_flow)[oe] > 0 && (*_red_cost)[oe] < 0)
-ahead += _capacity[oe] - _flow[oe];
+ahead += _capacity[oe] - (*_flow)[oe];
 }
 for (InEdgeIt ie(_graph, t); ie != INVALID; ++ie) {
-if (_flow[ie] > 0 && -_red_cost[ie] < 0)
+if ((*_flow)[ie] > 0 && -(*_red_cost)[ie] < 0)
-ahead += _flow[ie];
+ahead += (*_flow)[ie];
 }
 if (ahead < 0) ahead = 0;
 // Pushing flow along the edge
 if (ahead < delta) {
-_flow[e] -= ahead;
+(*_flow)[e] -= ahead;
 _excess[n] -= ahead;
 _excess[t] += ahead;
 active_nodes.push_front(t);
 hyper[t] = true;
 relabel_enabled = false;
 break;
 } else {
-_flow[e] -= delta;
+(*_flow)[e] -= delta;
 _excess[n] -= delta;
 _excess[t] += delta;
 if (_excess[t] > 0 && _excess[t] <= delta)
 active_nodes.push_back(t);
 }
 if (relabel_enabled && (_excess[n] > 0 || hyper[n])) {
 // Performing relabel operation if the node is still active
 LCost min_red_cost = std::numeric_limits<LCost>::max();
 for (OutEdgeIt oe(_graph, n); oe != INVALID; ++oe) {
-if ( _capacity[oe] - _flow[oe] > 0 &&
+if ( _capacity[oe] - (*_flow)[oe] > 0 &&
-_red_cost[oe] < min_red_cost )
+(*_red_cost)[oe] < min_red_cost )
-min_red_cost = _red_cost[oe];
+min_red_cost = (*_red_cost)[oe];
 }
 for (InEdgeIt ie(_graph, n); ie != INVALID; ++ie) {
-if (_flow[ie] > 0 && -_red_cost[ie] < min_red_cost)
+if ((*_flow)[ie] > 0 && -(*_red_cost)[ie] < min_red_cost)
-min_red_cost = -_red_cost[ie];
+min_red_cost = -(*_red_cost)[ie];
 }
-_potential[n] -= min_red_cost + _epsilon;
+(*_potential)[n] -= min_red_cost + _epsilon;
 hyper[n] = false;
 }
 // Removing active nodes with non-positive excess
 while ( active_nodes.size() > 0 &&
 active_nodes.pop_front();
 }
 }
 }
+// Computing node potentials for the original costs
+ResidualCostMap<CostMap> res_cost(_orig_cost);
+BellmanFord< ResGraph, ResidualCostMap<CostMap> >
+bf(*_res_graph, res_cost);
+bf.init(0); bf.start();
+for (NodeIt n(_graph); n != INVALID; ++n)
+(*_potential)[n] = bf.dist(n);
 // Handling non-zero lower bounds
 if (_lower) {
 for (EdgeIt e(_graph); e != INVALID; ++e)
-_flow[e] += (*_lower)[e];
+(*_flow)[e] += (*_lower)[e];
 }
 return true;
 }
 }; //class CostScaling

changeset 2581	054566ac0934
parent 2577	2c6204d4b0f6
child 2588	4d3bc1d04c1d