d09b504bc5
# Conflicts: # .github/workflows/ci-build.yml # .github/workflows/release-linux.yml # .github/workflows/release-macos.yml # .github/workflows/release-source.yml # .github/workflows/release.yml # CMakeLists.txt # COMPILING.md # src/ai/ai_core.cpp # src/ai/ai_gui.cpp # src/bridge_gui.cpp # src/company_gui.cpp # src/console_cmds.cpp # src/core/CMakeLists.txt # src/core/smallmap_type.hpp # src/disaster_vehicle.h # src/effectvehicle_base.h # src/fontcache.cpp # src/game/game_core.cpp # src/game/game_gui.cpp # src/gamelog.cpp # src/gamelog_internal.h # src/group_gui.cpp # src/linkgraph/linkgraph.h # src/misc.cpp # src/network/core/config.h # src/network/core/udp.cpp # src/network/network_chat_gui.cpp # src/network/network_content_gui.cpp # src/network/network_gui.cpp # src/newgrf.cpp # src/newgrf_gui.cpp # src/newgrf_profiling.cpp # src/newgrf_profiling.h # src/object_gui.cpp # src/openttd.cpp # src/openttd.h # src/order_gui.cpp # src/os/windows/font_win32.cpp # src/rail_gui.cpp # src/road.cpp # src/road_gui.cpp # src/saveload/afterload.cpp # src/saveload/saveload.h # src/script/api/script_controller.cpp # src/script/api/script_roadtypelist.cpp # src/script/script_config.cpp # src/script/script_config.hpp # src/script/script_instance.cpp # src/script/script_scanner.cpp # src/script/squirrel.cpp # src/script/squirrel_helper.hpp # src/settings_gui.cpp # src/settings_internal.h # src/settings_type.h # src/table/settings/network_private_settings.ini # src/timetable_gui.cpp # src/vehicle.cpp # src/vehicle_base.h # src/window_gui.h
88 lines
2.8 KiB
C++
88 lines
2.8 KiB
C++
/** @file mcf.h Declaration of Multi-Commodity-Flow solver */
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#ifndef MCF_H
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#define MCF_H
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#include "linkgraphjob_base.h"
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#include <vector>
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typedef std::vector<Path *> PathVector;
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/**
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* Multi-commodity flow calculating base class.
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*/
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class MultiCommodityFlow {
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protected:
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/**
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* Constructor.
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* @param job Link graph job being executed.
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*/
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MultiCommodityFlow(LinkGraphJob &job) : job(job),
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max_saturation(job.Settings().short_path_saturation)
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{}
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template<class Tannotation, class Tedge_iterator>
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void Dijkstra(NodeID from, PathVector &paths);
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uint PushFlow(DemandAnnotation &anno, Path *path, uint min_step_size, uint accuracy, uint max_saturation);
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void CleanupPaths(NodeID source, PathVector &paths);
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LinkGraphJob &job; ///< Job we're working with.
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uint max_saturation; ///< Maximum saturation for edges.
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};
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/**
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* First pass of the MCF calculation. Saturates shortest paths first, creates
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* new paths if needed, eliminates cycles. This calculation is of exponential
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* complexity in the number of nodes but the constant factors are sufficiently
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* small to make it usable for most real-life link graph components. You can
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* deal with performance problems that might occur here in multiple ways:
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* - The overall accuracy is used here to determine how much flow is assigned
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* in each loop. The lower the accuracy, the more flow is assigned, the less
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* loops it takes to assign all flow.
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* - The short_path_saturation setting determines when this pass stops. The
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* lower you set it, the less flow will be assigned in this pass, the less
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* time it will take.
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* - You can increase the recalculation interval to allow for longer running
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* times without creating lags.
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*/
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class MCF1stPass : public MultiCommodityFlow {
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private:
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bool EliminateCycles();
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bool EliminateCycles(PathVector &path, NodeID origin_id, NodeID next_id);
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void EliminateCycle(PathVector &path, Path *cycle_begin, uint flow);
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uint FindCycleFlow(const PathVector &path, const Path *cycle_begin);
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public:
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MCF1stPass(LinkGraphJob &job);
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};
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/**
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* Second pass of the MCF calculation. Saturates paths with most capacity left
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* first and doesn't create any paths along edges that haven't been visited in
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* the first pass. This is why it doesn't have to do any cycle detection and
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* elimination. As cycle detection is the most intense problem in the first
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* pass this pass is cheaper. The accuracy is used here, too.
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*/
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class MCF2ndPass : public MultiCommodityFlow {
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public:
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MCF2ndPass(LinkGraphJob &job);
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};
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/**
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* Link graph handler for MCF. Creates MultiCommodityFlow instance according to
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* the template parameter.
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*/
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template<class Tpass>
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class MCFHandler : public ComponentHandler {
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public:
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/**
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* Run the calculation.
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* @param graph Component to be calculated.
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*/
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virtual void Run(LinkGraphJob &job) const { Tpass pass(job); }
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};
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#endif /* MCF_H */
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