# linkgraph.cpp

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    00001 /* $Id$ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * OpenTTD is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2.
    00006  * OpenTTD is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
    00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
    00008  */
    00009
    00012 #include "../stdafx.h"
    00013 #include "../map_func.h"
    00014 #include "../core/bitmath_func.hpp"
    00015 #include "../debug.h"
    00016 #include "../window_func.h"
    00017 #include "../window_gui.h"
    00018 #include "linkgraph.h"
    00019 #include "demands.h"
    00020 #include "mcf.h"
    00021 #include "flowmapper.h"
    00022 #include <queue>
    00023
    00027 LinkGraph _link_graphs[NUM_CARGO];
    00028
    00032 LinkGraphJob::HandlerList LinkGraphJob::_handlers;
    00033
    00040 inline void Node::Init(StationID st, uint sup, uint dem)
    00041 {
    00042   this->supply = sup;
    00043   this->undelivered_supply = sup;
    00044   this->demand = dem;
    00045   this->station = st;
    00046
    00047   for (PathSet::iterator i = this->paths.begin(); i != this->paths.end(); ++i) {
    00048     delete *i;
    00049   }
    00050   this->paths.clear();
    00051   this->flows.clear();
    00052 }
    00053
    00059 inline void Edge::Init(uint distance, uint capacity)
    00060 {
    00061   this->distance = distance;
    00062   this->capacity = capacity;
    00063   this->demand = 0;
    00064   this->unsatisfied_demand = 0;
    00065   this->flow = 0;
    00066   this->next_edge = INVALID_NODE;
    00067 }
    00068
    00069
    00077 void LinkGraph::CreateComponent(Station *first)
    00078 {
    00079   std::map<Station *, NodeID> index;
    00080   index[first] = this->AddNode(first);
    00081
    00082   std::queue<Station *> search_queue;
    00083   search_queue.push(first);
    00084
    00085   /* Find all stations belonging to the current component. */
    00086   while (!search_queue.empty()) {
    00087     Station *source = search_queue.front();
    00088     search_queue.pop();
    00089
    00090     const LinkStatMap &links = source->goods[this->cargo].link_stats;
    00091     for (LinkStatMap::const_iterator i = links.begin(); i != links.end(); ++i) {
    00092       Station *target = Station::GetIfValid(i->first);
    00093       if (target == NULL) continue;
    00094
    00095       std::map<Station *, NodeID>::iterator index_it = index.find(target);
    00096       if (index_it == index.end()) {
    00097         search_queue.push(target);
    00098         NodeID node = this->AddNode(target);
    00099         index[target] = node;
    00100
    00101         this->AddEdge(index[source], node, i->second.Capacity());
    00102       } else {
    00103         this->AddEdge(index[source], index_it->second, i->second.Capacity());
    00104       }
    00105     }
    00106   }
    00107
    00108   /* Here the list of nodes and edges for this component is complete. */
    00109   this->SpawnThread();
    00110 }
    00111
    00125 void LinkGraph::NextComponent()
    00126 {
    00127   /* Check for no stations to avoid problems with Station::GetPoolSize()
    00128    * being 0 later and to avoid searching an empty pool.
    00129    */
    00130   if (Station::GetNumItems() == 0) return;
    00131
    00132   /* Don't mess with running jobs (might happen when changing interval).*/
    00133   if (this->GetSize() > 0) return;
    00134
    00135   /* The station pool may shrink when saving and subsequently loading a game as
    00136    * NULL entries at the end are cut off then. If the current station id points
    00137    * to one of those NULL entries we have to clamp it here to avoid an infinite
    00138    * loop later.
    00139    */
    00140   StationID last_station_id = min(this->current_station_id, Station::GetPoolSize() - 1);
    00141   LinkGraphComponentID current_component_id = this->LinkGraphComponent::index;
    00142
    00143   do {
    00144     if (++this->current_station_id >= Station::GetPoolSize()) {
    00145       /* Wrap around and recycle the component IDs. Use different
    00146        * divisibility by 2 than in the last run so that we can find out
    00147        * which stations haven't been seen in this run.
    00148        */
    00149       this->current_station_id = 0;
    00150       current_component_id = (current_component_id + 1) % 2;
    00151     }
    00152
    00153     /* Find first station of next component */
    00154     Station *station = Station::GetIfValid(this->current_station_id);
    00155     if (station != NULL) continue;
    00156     const GoodsEntry &ge = station->goods[this->cargo];
    00157
    00158     /* Same divisibility by 2: We've seen that station before. */
    00159     if (ge.last_component != INVALID_LINKGRAPH_COMPONENT &&
    00160         (ge.last_component + current_component_id) % 2 == 0) {
    00161       continue;
    00162     }
    00163
    00164     /* Different divisibility by 2: This station has not been seen
    00165      * in the current run over the link graph. */
    00166     if (!ge.link_stats.empty()) {
    00167       this->LinkGraphComponent::Init(current_component_id + 2);
    00168       this->CreateComponent(station);
    00169       return;
    00170     }
    00171
    00172   } while (this->current_station_id != last_station_id);
    00173 }
    00174
    00180 void OnTick_LinkGraph()
    00181 {
    00182   if (_date_fract != LinkGraph::COMPONENTS_SPAWN_TICK &&
    00183       _date_fract != LinkGraph::COMPONENTS_JOIN_TICK) {
    00184     return;
    00185   }
    00186
    00187   /* This creates a round robin distribution of all link graphs' turns over the
    00188    * available dates. */
    00189   for (uint cargo = _date % _settings_game.linkgraph.recalc_interval; cargo < NUM_CARGO;
    00190       cargo += _settings_game.linkgraph.recalc_interval) {
    00191
    00192     /* Don't calculate a link graph if the distribution is manual */
    00193     if (_settings_game.linkgraph.GetDistributionType(cargo) == DT_MANUAL) continue;
    00194
    00195     if (_date_fract == LinkGraph::COMPONENTS_SPAWN_TICK) {
    00196       _link_graphs[cargo].NextComponent();
    00197     } else /* LinkGraph::COMPONENTS_JOIN_TICK */ {
    00198       _link_graphs[cargo].Join();
    00199     }
    00200   }
    00201 }
    00202
    00211 NodeID LinkGraphComponent::AddNode(Station *st)
    00212 {
    00213   GoodsEntry &good = st->goods[this->cargo];
    00214   good.last_component = this->index;
    00215
    00216   bool do_resize = (this->nodes.size() == this->num_nodes);
    00217
    00218   if (do_resize) {
    00219     this->nodes.push_back(Node());
    00220     this->edges.push_back(std::vector<Edge>(this->num_nodes + 1));
    00221   }
    00222
    00223   this->nodes[this->num_nodes].Init(st->index, good.supply,
    00224       HasBit(good.acceptance_pickup, GoodsEntry::GES_ACCEPTANCE));
    00225
    00226   std::vector<Edge> &new_edges = this->edges[this->num_nodes];
    00227
    00228   /* reset the first edge starting at the new node */
    00229   new_edges[this->num_nodes].next_edge = INVALID_NODE;
    00230
    00231   for (NodeID i = 0; i < this->num_nodes; ++i) {
    00232     uint distance = DistanceManhattan(st->xy, Station::Get(this->nodes[i].station)->xy);
    00233     if (do_resize) this->edges[i].push_back(Edge());
    00234     new_edges[i].Init(distance);
    00235     this->edges[i][this->num_nodes].Init(distance);
    00236   }
    00237   return this->num_nodes++;
    00238 }
    00239
    00246 inline void LinkGraphComponent::AddEdge(NodeID from, NodeID to, uint capacity)
    00247 {
    00248   assert(from != to);
    00249   Edge &edge = this->edges[from][to];
    00250   Edge &first = this->edges[from][from];
    00251   edge.capacity = capacity;
    00252   edge.next_edge = first.next_edge;
    00253   first.next_edge = to;
    00254 }
    00255
    00265 void LinkGraphComponent::SetSize()
    00266 {
    00267   if (this->nodes.size() < this->num_nodes) {
    00268     for (EdgeMatrix::iterator i = this->edges.begin(); i != this->edges.end(); ++i) {
    00269       i->resize(this->num_nodes);
    00270     }
    00271     this->nodes.resize(this->num_nodes);
    00272     this->edges.resize(this->num_nodes, std::vector<Edge>(this->num_nodes));
    00273   }
    00274
    00275   for (uint i = 0; i < this->num_nodes; ++i) {
    00276     this->nodes[i].Init();
    00277     for (uint j = 0; j < this->num_nodes; ++j) {
    00278       this->edges[i][j].Init();
    00279     }
    00280   }
    00281 }
    00282
    00286 LinkGraphComponent::LinkGraphComponent() :
    00287     settings(_settings_game.linkgraph),
    00288     cargo(INVALID_CARGO),
    00289     num_nodes(0),
    00290     index(INVALID_LINKGRAPH_COMPONENT)
    00291 {}
    00292
    00296 void LinkGraphComponent::Init(LinkGraphComponentID id)
    00297 {
    00298   assert(this->num_nodes == 0);
    00299   this->index = id;
    00300   this->settings = _settings_game.linkgraph;
    00301 }
    00302
    00303
    00312 void Node::ExportFlows(FlowMap::iterator &it, FlowStatMap &station_flows, CargoID cargo)
    00313 {
    00314   FlowStat *dest = NULL;
    00315   StationID source = it->first;
    00316   FlowViaMap &source_flows = it->second;
    00317   if (!Station::IsValidID(source)) {
    00318     source_flows.clear();
    00319   } else {
    00320     Station *curr_station = Station::Get(this->station);
    00321     for (FlowViaMap::iterator update = source_flows.begin(); update != source_flows.end();) {
    00322       StationID next = update->first;
    00323       int planned = update->second;
    00324       assert(planned >= 0);
    00325
    00326       Station *via = Station::GetIfValid(next);
    00327       if (planned > 0 && via != NULL) {
    00328         if (next == this->station ||
    00329             curr_station->goods[cargo].link_stats.find(next) !=
    00330             curr_station->goods[cargo].link_stats.end()) {
    00331           if (dest == NULL) {
    00332             dest = &(station_flows.insert(std::make_pair(it->first, FlowStat(next, planned))).first->second);
    00333           } else {
    00334             dest->AddShare(next, planned);
    00335           }
    00336         }
    00337       }
    00338       source_flows.erase(update++);
    00339     }
    00340   }
    00341
    00342   assert(source_flows.empty());
    00343
    00344   this->flows.erase(it++);
    00345 }
    00346
    00351 void Node::ExportFlows(CargoID cargo)
    00352 {
    00353   FlowStatMap &station_flows = Station::Get(this->station)->goods[cargo].flows;
    00354   station_flows.clear();
    00355
    00356   /* loop over flows in the node's map and insert them into the station */
    00357   for (FlowMap::iterator it(this->flows.begin()); it != this->flows.end();) {
    00358     this->ExportFlows(it, station_flows, cargo);
    00359   }
    00360   assert(this->flows.empty());
    00361 }
    00362
    00366 void LinkGraph::Join()
    00367 {
    00368   this->LinkGraphJob::Join();
    00369
    00370   for (NodeID node_id = 0; node_id < this->GetSize(); ++node_id) {
    00371     Node &node = this->GetNode(node_id);
    00372     if (Station::IsValidID(node.station)) {
    00373       node.ExportFlows(this->cargo);
    00374       InvalidateWindowData(WC_STATION_VIEW, node.station, this->GetCargo());
    00375     }
    00376   }
    00377
    00378   this->LinkGraphComponent::Clear();
    00379 }
    00380
    00385 /* static */ void LinkGraphJob::RunLinkGraphJob(void *j)
    00386 {
    00387   LinkGraphJob *job = (LinkGraphJob *)j;
    00388   for (HandlerList::iterator i = LinkGraphJob::_handlers.begin(); i != LinkGraphJob::_handlers.end(); ++i) {
    00389     (*i)->Run(job);
    00390   }
    00391 }
    00392
    00396 /* static */ void LinkGraphJob::ClearHandlers()
    00397 {
    00398   for (HandlerList::iterator i = LinkGraphJob::_handlers.begin(); i != LinkGraphJob::_handlers.end(); ++i) {
    00399     delete *i;
    00400   }
    00401   LinkGraphJob::_handlers.clear();
    00402 }
    00403
    00411 void Path::Fork(Path *base, uint cap, int free_cap, uint dist)
    00412 {
    00413   this->capacity = min(base->capacity, cap);
    00414   this->free_capacity = min(base->free_capacity, free_cap);
    00415   this->distance = base->distance + dist;
    00416   assert(this->distance > 0);
    00417   if (this->parent != base) {
    00418     this->Detach();
    00419     this->parent = base;
    00420     this->parent->num_children++;
    00421   }
    00422   this->origin = base->origin;
    00423 }
    00424
    00433 uint Path::AddFlow(uint new_flow, LinkGraphComponent *graph, bool only_positive)
    00434 {
    00435   if (this->parent != NULL) {
    00436     Edge &edge = graph->GetEdge(this->parent->node, this->node);
    00437     if (only_positive) {
    00438       uint usable_cap = edge.capacity * graph->GetSettings().short_path_saturation / 100;
    00439       if (usable_cap > edge.flow) {
    00440         new_flow = min(new_flow, usable_cap - edge.flow);
    00441       } else {
    00442         return 0;
    00443       }
    00444     }
    00445     new_flow = this->parent->AddFlow(new_flow, graph, only_positive);
    00446     if (new_flow > 0) {
    00447       graph->GetNode(this->parent->node).paths.insert(this);
    00448     }
    00449     edge.flow += new_flow;
    00450   }
    00451   this->flow += new_flow;
    00452   return new_flow;
    00453 }
    00454
    00460 Path::Path(NodeID n, bool source) :
    00461   distance(source ? 0 : UINT_MAX),
    00462   capacity(0),
    00463   free_capacity(source ? INT_MAX : INT_MIN),
    00464   flow(0), node(n), origin(source ? n : INVALID_NODE),
    00465   num_children(0), parent(NULL)
    00466 {}
    00467
    00471 inline void LinkGraphJob::Join()
    00472 {
    00473   if (this->thread == NULL) return;
    00474   this->thread->Join();
    00475   delete this->thread;
    00476   this->thread = NULL;
    00477 }
    00478
    00483 void LinkGraphJob::SpawnThread()
    00484 {
    00485   assert(this->thread == NULL);
    00486   if (!ThreadObject::New(&(LinkGraphJob::RunLinkGraphJob), this, &(this->thread))) {
    00487     this->thread = NULL;
    00488     /* Of course this will hang a bit.
    00489      * On the other hand, if you want to play games which make this hang noticably
    00490      * on a platform without threads then you'll probably get other problems first.
    00491      * OK:
    00492      * If someone comes and tells me that this hangs for him/her, I'll implement a
    00493      * smaller grained "Step" method for all handlers and add some more ticks where
    00494      * "Step" is called. No problem in principle.
    00495      */
    00496     LinkGraphJob::RunLinkGraphJob(this);
    00497   }
    00498 }
    00499
    00505 void LinkGraph::Init(CargoID cargo)
    00506 {
    00507   this->LinkGraphJob::Join();
    00508   this->LinkGraphComponent::Clear();
    00509
    00510   this->current_station_id = 0;
    00511   this->LinkGraphComponent::cargo = cargo;
    00512 }
    00513
    00517 void InitializeLinkGraphs()
    00518 {
    00519   for (CargoID c = 0; c < NUM_CARGO; ++c) _link_graphs[c].Init(c);
    00520
    00521   LinkGraphJob::ClearHandlers();
    00522   LinkGraphJob::AddHandler(new DemandHandler);
    00523   LinkGraphJob::AddHandler(new MCFHandler<MCF1stPass>);
    00524   LinkGraphJob::AddHandler(new FlowMapper);
    00525   LinkGraphJob::AddHandler(new MCFHandler<MCF2ndPass>);
    00526   LinkGraphJob::AddHandler(new FlowMapper);
    00527 }