1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/lemon/prim.h Fri Jan 27 08:17:25 2006 +0000
1.3 @@ -0,0 +1,792 @@
1.4 +/* -*- C++ -*-
1.5 + * lemon/prim.h - Part of LEMON, a generic C++ optimization library
1.6 + *
1.7 + * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
1.8 + * (Egervary Research Group on Combinatorial Optimization, EGRES).
1.9 + *
1.10 + * Permission to use, modify and distribute this software is granted
1.11 + * provided that this copyright notice appears in all copies. For
1.12 + * precise terms see the accompanying LICENSE file.
1.13 + *
1.14 + * This software is provided "AS IS" with no warranty of any kind,
1.15 + * express or implied, and with no claim as to its suitability for any
1.16 + * purpose.
1.17 + *
1.18 + */
1.19 +
1.20 +#ifndef LEMON_PRIM_H
1.21 +#define LEMON_PRIM_H
1.22 +
1.23 +///\ingroup spantree
1.24 +///\file
1.25 +///\brief Prim algorithm to compute minimum spanning tree.
1.26 +
1.27 +#include <lemon/list_graph.h>
1.28 +#include <lemon/bin_heap.h>
1.29 +#include <lemon/invalid.h>
1.30 +#include <lemon/error.h>
1.31 +#include <lemon/maps.h>
1.32 +#include <lemon/traits.h>
1.33 +
1.34 +#include <lemon/concept/ugraph.h>
1.35 +
1.36 +namespace lemon {
1.37 +
1.38 + ///Default traits class of Prim class.
1.39 +
1.40 + ///Default traits class of Prim class.
1.41 + ///\param GR Graph type.
1.42 + ///\param LM Type of cost map.
1.43 + template<class GR, class LM>
1.44 + struct PrimDefaultTraits{
1.45 + ///The graph type the algorithm runs on.
1.46 + typedef GR UGraph;
1.47 + ///The type of the map that stores the edge costs.
1.48 +
1.49 + ///The type of the map that stores the edge costs.
1.50 + ///It must meet the \ref concept::ReadMap "ReadMap" concept.
1.51 + typedef LM CostMap;
1.52 + //The type of the cost of the edges.
1.53 + typedef typename LM::Value Value;
1.54 + /// The cross reference type used by heap.
1.55 +
1.56 + /// The cross reference type used by heap.
1.57 + /// Usually it is \c UGraph::NodeMap<int>.
1.58 + typedef typename UGraph::template NodeMap<int> HeapCrossRef;
1.59 + ///Instantiates a HeapCrossRef.
1.60 +
1.61 + ///This function instantiates a \ref HeapCrossRef.
1.62 + /// \param G is the graph, to which we would like to define the
1.63 + /// HeapCrossRef.
1.64 + static HeapCrossRef *createHeapCrossRef(const GR &_graph){
1.65 + return new HeapCrossRef(_graph);
1.66 + }
1.67 +
1.68 + ///The heap type used by Prim algorithm.
1.69 +
1.70 + ///The heap type used by Prim algorithm.
1.71 + ///
1.72 + ///\sa BinHeap
1.73 + ///\sa Prim
1.74 + typedef BinHeap<typename UGraph::Node, typename LM::Value,
1.75 + HeapCrossRef, std::less<Value> > Heap;
1.76 +
1.77 + static Heap *createHeap(HeapCrossRef& _ref){
1.78 + return new Heap(_ref);
1.79 + }
1.80 +
1.81 + ///\brief The type of the map that stores the last
1.82 + ///edges of the minimum spanning tree.
1.83 + ///
1.84 + ///The type of the map that stores the last
1.85 + ///edges of the minimum spanning tree.
1.86 + ///It must meet the \ref concept::WriteMap "WriteMap" concept.
1.87 + ///
1.88 + typedef typename UGraph::template NodeMap<typename GR::UEdge> PredMap;
1.89 + ///Instantiates a PredMap.
1.90 +
1.91 + ///This function instantiates a \ref PredMap.
1.92 + ///\param G is the graph, to which we would like to define the PredMap.
1.93 + static PredMap *createPredMap(const GR &_graph){
1.94 + return new PredMap(_graph);
1.95 + }
1.96 +
1.97 + ///The type of the map that stores whether an edge is in the
1.98 + ///spanning tree or not.
1.99 +
1.100 + ///The type of the map that stores whether an edge is in the
1.101 + ///spanning tree or not.
1.102 + ///By default it is a NullMap.
1.103 + typedef NullMap<typename UGraph::UEdge,bool> TreeMap;
1.104 + ///Instantiates a TreeMap.
1.105 +
1.106 + ///This function instantiates a \ref TreeMap.
1.107 + ///\param g is the graph, to which
1.108 + ///we would like to define the \ref TreeMap
1.109 + static TreeMap *createTreeMap(const GR &){
1.110 + return new TreeMap();
1.111 + }
1.112 +
1.113 + ///The type of the map that stores whether a nodes is processed.
1.114 +
1.115 + ///The type of the map that stores whether a nodes is processed.
1.116 + ///It must meet the \ref concept::WriteMap "WriteMap" concept.
1.117 + ///By default it is a NodeMap<bool>.
1.118 + typedef NullMap<typename UGraph::Node,bool> ProcessedMap;
1.119 + ///Instantiates a ProcessedMap.
1.120 +
1.121 + ///This function instantiates a \ref ProcessedMap.
1.122 + ///\param g is the graph, to which
1.123 + ///we would like to define the \ref ProcessedMap
1.124 +#ifdef DOXYGEN
1.125 + static ProcessedMap *createProcessedMap(const GR &_graph)
1.126 +#else
1.127 + static ProcessedMap *createProcessedMap(const GR &)
1.128 +#endif
1.129 + {
1.130 + return new ProcessedMap();
1.131 + }
1.132 + };
1.133 +
1.134 + ///%Prim algorithm class to find a minimum spanning tree.
1.135 +
1.136 + /// \ingroup spantree
1.137 + ///This class provides an efficient implementation of %Prim algorithm.
1.138 + ///
1.139 + ///The running time is O(e*log n) where e is the number of edges and
1.140 + ///n is the number of nodes in the graph.
1.141 + ///
1.142 + ///The edge costs are passed to the algorithm using a
1.143 + ///\ref concept::ReadMap "ReadMap",
1.144 + ///so it is easy to change it to any kind of cost.
1.145 + ///
1.146 + ///The type of the cost is determined by the
1.147 + ///\ref concept::ReadMap::Value "Value" of the cost map.
1.148 + ///
1.149 + ///It is also possible to change the underlying priority heap.
1.150 + ///
1.151 + ///\param GR The graph type the algorithm runs on. The default value
1.152 + ///is \ref ListUGraph. The value of GR is not used directly by
1.153 + ///Prim, it is only passed to \ref PrimDefaultTraits.
1.154 + ///
1.155 + ///\param LM This read-only UEdgeMap determines the costs of the
1.156 + ///edges. It is read once for each edge, so the map may involve in
1.157 + ///relatively time consuming process to compute the edge cost if
1.158 + ///it is necessary. The default map type is \ref
1.159 + ///concept::UGraph::UEdgeMap "UGraph::UEdgeMap<int>". The value
1.160 + ///of LM is not used directly by Prim, it is only passed to \ref
1.161 + ///PrimDefaultTraits.
1.162 + ///
1.163 + ///\param TR Traits class to set
1.164 + ///various data types used by the algorithm. The default traits
1.165 + ///class is \ref PrimDefaultTraits
1.166 + ///"PrimDefaultTraits<GR,LM>". See \ref
1.167 + ///PrimDefaultTraits for the documentation of a Prim traits
1.168 + ///class.
1.169 + ///
1.170 + ///\author Balazs Attila Mihaly
1.171 +
1.172 +#ifdef DOXYGEN
1.173 + template <typename GR,
1.174 + typename LM,
1.175 + typename TR>
1.176 +#else
1.177 + template <typename GR=ListUGraph,
1.178 + typename LM=typename GR::template UEdgeMap<int>,
1.179 + typename TR=PrimDefaultTraits<GR,LM> >
1.180 +#endif
1.181 + class Prim {
1.182 + public:
1.183 + /**
1.184 + * \brief \ref Exception for uninitialized parameters.
1.185 + *
1.186 + * This error represents problems in the initialization
1.187 + * of the parameters of the algorithms.
1.188 + */
1.189 + class UninitializedParameter : public lemon::UninitializedParameter {
1.190 + public:
1.191 + virtual const char* exceptionName() const {
1.192 + return "lemon::Prim::UninitializedParameter";
1.193 + }
1.194 + };
1.195 +
1.196 + typedef TR Traits;
1.197 + ///The type of the underlying graph.
1.198 + typedef typename TR::UGraph UGraph;
1.199 + ///\e
1.200 + typedef typename UGraph::Node Node;
1.201 + ///\e
1.202 + typedef typename UGraph::NodeIt NodeIt;
1.203 + ///\e
1.204 + typedef typename UGraph::UEdge UEdge;
1.205 + ///\e
1.206 + typedef typename UGraph::IncEdgeIt IncEdgeIt;
1.207 +
1.208 + ///The type of the cost of the edges.
1.209 + typedef typename TR::CostMap::Value Value;
1.210 + ///The type of the map that stores the edge costs.
1.211 + typedef typename TR::CostMap CostMap;
1.212 + ///\brief The type of the map that stores the last
1.213 + ///predecessor edges of the spanning tree.
1.214 + typedef typename TR::PredMap PredMap;
1.215 + ///Edges of the spanning tree.
1.216 + typedef typename TR::TreeMap TreeMap;
1.217 + ///The type of the map indicating if a node is processed.
1.218 + typedef typename TR::ProcessedMap ProcessedMap;
1.219 + ///The cross reference type used for the current heap.
1.220 + typedef typename TR::HeapCrossRef HeapCrossRef;
1.221 + ///The heap type used by the prim algorithm.
1.222 + typedef typename TR::Heap Heap;
1.223 + private:
1.224 + /// Pointer to the underlying graph.
1.225 + const UGraph *graph;
1.226 + /// Pointer to the cost map
1.227 + const CostMap *cost;
1.228 + ///Pointer to the map of predecessors edges.
1.229 + PredMap *_pred;
1.230 + ///Indicates if \ref _pred is locally allocated (\c true) or not.
1.231 + bool local_pred;
1.232 + ///Pointer to the map of tree edges.
1.233 + TreeMap *_tree;
1.234 + ///Indicates if \ref _tree is locally allocated (\c true) or not.
1.235 + bool local_tree;
1.236 + ///Pointer to the map of processed status of the nodes.
1.237 + ProcessedMap *_processed;
1.238 + ///Indicates if \ref _processed is locally allocated (\c true) or not.
1.239 + bool local_processed;
1.240 + ///Pointer to the heap cross references.
1.241 + HeapCrossRef *_heap_cross_ref;
1.242 + ///Indicates if \ref _heap_cross_ref is locally allocated (\c true) or not.
1.243 + bool local_heap_cross_ref;
1.244 + ///Pointer to the heap.
1.245 + Heap *_heap;
1.246 + ///Indicates if \ref _heap is locally allocated (\c true) or not.
1.247 + bool local_heap;
1.248 +
1.249 + ///Creates the maps if necessary.
1.250 + void create_maps(){
1.251 + if(!_pred) {
1.252 + local_pred = true;
1.253 + _pred = Traits::createPredMap(*graph);
1.254 + }
1.255 + if(!_tree) {
1.256 + local_tree = true;
1.257 + _tree = Traits::createTreeMap(*graph);
1.258 + }
1.259 + if(!_processed) {
1.260 + local_processed = true;
1.261 + _processed = Traits::createProcessedMap(*graph);
1.262 + }
1.263 + if (!_heap_cross_ref) {
1.264 + local_heap_cross_ref = true;
1.265 + _heap_cross_ref = Traits::createHeapCrossRef(*graph);
1.266 + }
1.267 + if (!_heap) {
1.268 + local_heap = true;
1.269 + _heap = Traits::createHeap(*_heap_cross_ref);
1.270 + }
1.271 + }
1.272 +
1.273 + public :
1.274 +
1.275 + typedef Prim Create;
1.276 +
1.277 + ///\name Named template parameters
1.278 +
1.279 + ///@{
1.280 +
1.281 + template <class T>
1.282 + struct DefPredMapTraits : public Traits {
1.283 + typedef T PredMap;
1.284 + static PredMap *createPredMap(const UGraph &_graph){
1.285 + throw UninitializedParameter();
1.286 + }
1.287 + };
1.288 + ///\ref named-templ-param "Named parameter" for setting PredMap type
1.289 +
1.290 + ///\ref named-templ-param "Named parameter" for setting PredMap type
1.291 + ///
1.292 + template <class T>
1.293 + struct DefPredMap
1.294 + : public Prim< UGraph, CostMap, DefPredMapTraits<T> > {
1.295 + typedef Prim< UGraph, CostMap, DefPredMapTraits<T> > Create;
1.296 + };
1.297 +
1.298 + template <class T>
1.299 + struct DefProcessedMapTraits : public Traits {
1.300 + typedef T ProcessedMap;
1.301 + static ProcessedMap *createProcessedMap(const UGraph &_graph){
1.302 + throw UninitializedParameter();
1.303 + }
1.304 + };
1.305 + ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
1.306 +
1.307 + ///\ref named-templ-param "Named parameter" for setting ProcessedMap type
1.308 + ///
1.309 + template <class T>
1.310 + struct DefProcessedMap
1.311 + : public Prim< UGraph, CostMap, DefProcessedMapTraits<T> > {
1.312 + typedef Prim< UGraph, CostMap, DefProcessedMapTraits<T> > Create;
1.313 + };
1.314 +
1.315 + struct DefGraphProcessedMapTraits : public Traits {
1.316 + typedef typename UGraph::template NodeMap<bool> ProcessedMap;
1.317 + static ProcessedMap *createProcessedMap(const UGraph &_graph){
1.318 + return new ProcessedMap(_graph);
1.319 + }
1.320 + };
1.321 +
1.322 +
1.323 + template <class H, class CR>
1.324 + struct DefHeapTraits : public Traits {
1.325 + typedef CR HeapCrossRef;
1.326 + typedef H Heap;
1.327 + static HeapCrossRef *createHeapCrossRef(const UGraph &) {
1.328 + throw UninitializedParameter();
1.329 + }
1.330 + static Heap *createHeap(HeapCrossRef &){
1.331 + return UninitializedParameter();
1.332 + }
1.333 + };
1.334 + ///\ref named-templ-param "Named parameter" for setting heap and cross
1.335 + ///reference type
1.336 +
1.337 + ///\ref named-templ-param "Named parameter" for setting heap and cross
1.338 + ///reference type
1.339 + ///
1.340 + template <class H, class CR = typename UGraph::template NodeMap<int> >
1.341 + struct DefHeap
1.342 + : public Prim< UGraph, CostMap, DefHeapTraits<H, CR> > {
1.343 + typedef Prim< UGraph, CostMap, DefHeapTraits<H, CR> > Create;
1.344 + };
1.345 +
1.346 + template <class H, class CR>
1.347 + struct DefStandardHeapTraits : public Traits {
1.348 + typedef CR HeapCrossRef;
1.349 + typedef H Heap;
1.350 + static HeapCrossRef *createHeapCrossRef(const UGraph &_graph) {
1.351 + return new HeapCrossRef(_graph);
1.352 + }
1.353 + static Heap *createHeap(HeapCrossRef &ref){
1.354 + return new Heap(ref);
1.355 + }
1.356 + };
1.357 + ///\ref named-templ-param "Named parameter" for setting heap and cross
1.358 + ///reference type with automatic allocation
1.359 +
1.360 + ///\ref named-templ-param "Named parameter" for setting heap and cross
1.361 + ///reference type. It can allocate the heap and the cross reference
1.362 + ///object if the cross reference's constructor waits for the graph as
1.363 + ///parameter and the heap's constructor waits for the cross reference.
1.364 + template <class H, class CR = typename UGraph::template NodeMap<int> >
1.365 + struct DefStandardHeap
1.366 + : public Prim< UGraph, CostMap, DefStandardHeapTraits<H, CR> > {
1.367 + typedef Prim< UGraph, CostMap, DefStandardHeapTraits<H, CR> >
1.368 + Create;
1.369 + };
1.370 +
1.371 + template <class TM>
1.372 + struct DefTreeMapTraits : public Traits {
1.373 + typedef TM TreeMap;
1.374 + static TreeMap *createTreeMap(const UGraph &) {
1.375 + throw UninitializedParameter();
1.376 + }
1.377 + };
1.378 + ///\ref named-templ-param "Named parameter" for setting TreeMap
1.379 +
1.380 + ///\ref named-templ-param "Named parameter" for setting TreeMap
1.381 + ///
1.382 + template <class TM>
1.383 + struct DefTreeMap
1.384 + : public Prim< UGraph, CostMap, DefTreeMapTraits<TM> > {
1.385 + typedef Prim< UGraph, CostMap, DefTreeMapTraits<TM> > Create;
1.386 + };
1.387 +
1.388 + struct DefGraphTreeMapTraits : public Traits {
1.389 + typedef typename UGraph::template NodeMap<bool> TreeMap;
1.390 + static TreeMap *createTreeMap(const UGraph &_graph){
1.391 + return new TreeMap(_graph);
1.392 + }
1.393 + };
1.394 +
1.395 + ///@}
1.396 +
1.397 +
1.398 + protected:
1.399 +
1.400 + Prim() {}
1.401 +
1.402 + public:
1.403 +
1.404 + ///Constructor.
1.405 +
1.406 + ///\param _graph the graph the algorithm will run on.
1.407 + ///\param _cost the cost map used by the algorithm.
1.408 + Prim(const UGraph& _graph, const CostMap& _cost) :
1.409 + graph(&_graph), cost(&_cost),
1.410 + _pred(NULL), local_pred(false),
1.411 + _tree(NULL), local_tree(false),
1.412 + _processed(NULL), local_processed(false),
1.413 + _heap_cross_ref(NULL), local_heap_cross_ref(false),
1.414 + _heap(NULL), local_heap(false)
1.415 + {
1.416 + checkConcept<concept::UGraph, UGraph>();
1.417 + }
1.418 +
1.419 + ///Destructor.
1.420 + ~Prim(){
1.421 + if(local_pred) delete _pred;
1.422 + if(local_tree) delete _tree;
1.423 + if(local_processed) delete _processed;
1.424 + if(local_heap_cross_ref) delete _heap_cross_ref;
1.425 + if(local_heap) delete _heap;
1.426 + }
1.427 +
1.428 + ///\brief Sets the cost map.
1.429 +
1.430 + ///Sets the cost map.
1.431 + ///\return <tt> (*this) </tt>
1.432 + Prim &costMap(const CostMap &m){
1.433 + cost = &m;
1.434 + return *this;
1.435 + }
1.436 +
1.437 + ///\brief Sets the map storing the predecessor edges.
1.438 +
1.439 + ///Sets the map storing the predecessor edges.
1.440 + ///If you don't use this function before calling \ref run(),
1.441 + ///it will allocate one. The destuctor deallocates this
1.442 + ///automatically allocated map, of course.
1.443 + ///\return <tt> (*this) </tt>
1.444 + Prim &predMap(PredMap &m){
1.445 + if(local_pred) {
1.446 + delete _pred;
1.447 + local_pred=false;
1.448 + }
1.449 + _pred = &m;
1.450 + return *this;
1.451 + }
1.452 +
1.453 + ///\brief Sets the map storing the tree edges.
1.454 +
1.455 + ///Sets the map storing the tree edges.
1.456 + ///If you don't use this function before calling \ref run(),
1.457 + ///it will allocate one. The destuctor deallocates this
1.458 + ///automatically allocated map, of course.
1.459 + ///By default this is a NullMap.
1.460 + ///\return <tt> (*this) </tt>
1.461 + Prim &treeMap(TreeMap &m){
1.462 + if(local_tree) {
1.463 + delete _tree;
1.464 + local_tree=false;
1.465 + }
1.466 + _tree = &m;
1.467 + return *this;
1.468 + }
1.469 +
1.470 + ///\brief Sets the heap and the cross reference used by algorithm.
1.471 +
1.472 + ///Sets the heap and the cross reference used by algorithm.
1.473 + ///If you don't use this function before calling \ref run(),
1.474 + ///it will allocate one. The destuctor deallocates this
1.475 + ///automatically allocated map, of course.
1.476 + ///\return <tt> (*this) </tt>
1.477 + Prim &heap(Heap& heap, HeapCrossRef &crossRef){
1.478 + if(local_heap_cross_ref) {
1.479 + delete _heap_cross_ref;
1.480 + local_heap_cross_ref=false;
1.481 + }
1.482 + _heap_cross_ref = &crossRef;
1.483 + if(local_heap) {
1.484 + delete _heap;
1.485 + local_heap=false;
1.486 + }
1.487 + _heap = &heap;
1.488 + return *this;
1.489 + }
1.490 +
1.491 + public:
1.492 + ///\name Execution control
1.493 + ///The simplest way to execute the algorithm is to use
1.494 + ///one of the member functions called \c run(...).
1.495 + ///\n
1.496 + ///If you need more control on the execution,
1.497 + ///first you must call \ref init(), then you can add several source nodes
1.498 + ///with \ref addSource().
1.499 + ///Finally \ref start() will perform the actual path
1.500 + ///computation.
1.501 +
1.502 + ///@{
1.503 +
1.504 + ///\brief Initializes the internal data structures.
1.505 +
1.506 + ///Initializes the internal data structures.
1.507 + ///
1.508 + void init(){
1.509 + create_maps();
1.510 + _heap->clear();
1.511 + for ( NodeIt u(*graph) ; u!=INVALID ; ++u ) {
1.512 + _pred->set(u,INVALID);
1.513 + _processed->set(u,false);
1.514 + _heap_cross_ref->set(u,Heap::PRE_HEAP);
1.515 + }
1.516 + }
1.517 +
1.518 + ///\brief Adds a new source node.
1.519 +
1.520 + ///Adds a new source node to the priority heap.
1.521 + ///
1.522 + ///It checks if the node has already been added to the heap and
1.523 + ///it is pushed to the heap only if it was not in the heap.
1.524 + void addSource(Node s){
1.525 + if(_heap->state(s) != Heap::IN_HEAP) {
1.526 + _heap->push(s,Value());
1.527 + }
1.528 + }
1.529 + ///\brief Processes the next node in the priority heap
1.530 +
1.531 + ///Processes the next node in the priority heap.
1.532 + ///
1.533 + ///\return The processed node.
1.534 + ///
1.535 + ///\warning The priority heap must not be empty!
1.536 + Node processNextNode(){
1.537 + Node v=_heap->top();
1.538 + _heap->pop();
1.539 + _processed->set(v,true);
1.540 +
1.541 + for(IncEdgeIt e(*graph,v); e!=INVALID; ++e) {
1.542 + Node w=graph->oppositeNode(v,e);
1.543 + switch(_heap->state(w)) {
1.544 + case Heap::PRE_HEAP:
1.545 + _heap->push(w,(*cost)[e]);
1.546 + _pred->set(w,e);
1.547 + break;
1.548 + case Heap::IN_HEAP:
1.549 + if ( (*cost)[e] < (*_heap)[w] ) {
1.550 + _heap->decrease(w,(*cost)[e]);
1.551 + _pred->set(w,e);
1.552 + }
1.553 + break;
1.554 + case Heap::POST_HEAP:
1.555 + break;
1.556 + }
1.557 + }
1.558 + if ((*_pred)[v]!=INVALID)_tree->set((*_pred)[v],true);
1.559 + return v;
1.560 + }
1.561 +
1.562 + ///\brief Next node to be processed.
1.563 +
1.564 + ///Next node to be processed.
1.565 + ///
1.566 + ///\return The next node to be processed or INVALID if the priority heap
1.567 + /// is empty.
1.568 + Node nextNode(){
1.569 + return _heap->empty()?_heap->top():INVALID;
1.570 + }
1.571 +
1.572 + ///\brief Returns \c false if there are nodes to be processed in the priority heap
1.573 + ///
1.574 + ///Returns \c false if there are nodes
1.575 + ///to be processed in the priority heap
1.576 + bool emptyQueue() { return _heap->empty(); }
1.577 + ///\brief Returns the number of the nodes to be processed in the priority heap
1.578 +
1.579 + ///Returns the number of the nodes to be processed in the priority heap
1.580 + ///
1.581 + int queueSize() { return _heap->size(); }
1.582 +
1.583 + ///\brief Executes the algorithm.
1.584 +
1.585 + ///Executes the algorithm.
1.586 + ///
1.587 + ///\pre init() must be called and at least one node should be added
1.588 + ///with addSource() before using this function.
1.589 + ///
1.590 + ///This method runs the %Prim algorithm from the node(s)
1.591 + ///in order to compute the
1.592 + ///minimum spanning tree.
1.593 + ///
1.594 + void start(){
1.595 + while ( !_heap->empty() ) processNextNode();
1.596 + }
1.597 +
1.598 + ///\brief Executes the algorithm until a condition is met.
1.599 +
1.600 + ///Executes the algorithm until a condition is met.
1.601 + ///
1.602 + ///\pre init() must be called and at least one node should be added
1.603 + ///with addSource() before using this function.
1.604 + ///
1.605 + ///\param nm must be a bool (or convertible) node map. The algorithm
1.606 + ///will stop when it reaches a node \c v with <tt>nm[v]==true</tt>.
1.607 + template<class NodeBoolMap>
1.608 + void start(const NodeBoolMap &nm){
1.609 + while ( !_heap->empty() && !nm[_heap->top()] ) processNextNode();
1.610 + if ( !_heap->empty() ) _processed->set(_heap->top(),true);
1.611 + }
1.612 +
1.613 + ///\brief Runs %Prim algorithm.
1.614 +
1.615 + ///This method runs the %Prim algorithm
1.616 + ///in order to compute the
1.617 + ///minimum spanning tree (or minimum spanning forest).
1.618 + ///The method also works on graphs that has more than one components.
1.619 + ///In this case it computes the minimum spanning forest.
1.620 + void run() {
1.621 + init();
1.622 + for(NodeIt it(*graph);it!=INVALID;++it){
1.623 + if(!processed(it)){
1.624 + addSource(it);
1.625 + start();
1.626 + }
1.627 + }
1.628 + }
1.629 +
1.630 + ///\brief Runs %Prim algorithm from node \c s.
1.631 +
1.632 + ///This method runs the %Prim algorithm from node \c s
1.633 + ///in order to
1.634 + ///compute the
1.635 + ///minimun spanning tree
1.636 + ///
1.637 + ///\note d.run(s) is just a shortcut of the following code.
1.638 + ///\code
1.639 + /// d.init();
1.640 + /// d.addSource(s);
1.641 + /// d.start();
1.642 + ///\endcode
1.643 + ///\note If the graph has more than one components, the method
1.644 + ///will compute the minimun spanning tree for only one component.
1.645 + ///
1.646 + ///See \ref run() if you want to compute the minimal spanning forest.
1.647 + void run(Node s){
1.648 + init();
1.649 + addSource(s);
1.650 + start();
1.651 + }
1.652 +
1.653 + ///@}
1.654 +
1.655 + ///\name Query Functions
1.656 + ///The result of the %Prim algorithm can be obtained using these
1.657 + ///functions.\n
1.658 + ///Before the use of these functions,
1.659 + ///either run() or start() must be called.
1.660 +
1.661 + ///@{
1.662 +
1.663 + ///\brief Returns the 'previous edge' of the minimum spanning tree.
1.664 +
1.665 + ///For a node \c v it returns the 'previous edge' of the minimum spanning tree,
1.666 + ///i.e. it returns the edge from where \c v was reached. For a source node
1.667 + ///or an unreachable node it is \ref INVALID.
1.668 + ///The minimum spanning tree used here is equal to the minimum spanning tree used
1.669 + ///in \ref predNode(). \pre \ref run() or \ref start() must be called before
1.670 + ///using this function.
1.671 + UEdge predEdge(Node v) const { return (*_pred)[v]; }
1.672 +
1.673 + ///\brief Returns the 'previous node' of the minimum spanning tree.
1.674 +
1.675 + ///For a node \c v it returns the 'previous node' of the minimum spanning tree,
1.676 + ///i.e. it returns the node from where \c v was reached. For a source node
1.677 + ///or an unreachable node it is \ref INVALID.
1.678 + //The minimum spanning tree used here is equal to the minimum spanning
1.679 + ///tree used in \ref predEdge(). \pre \ref run() or \ref start() must be called
1.680 + ///before using this function.
1.681 + Node predNode(Node v) const { return (*_pred)[v]==INVALID ? INVALID:
1.682 + graph->source((*_pred)[v]); }
1.683 +
1.684 + ///\brief Returns a reference to the NodeMap of the edges of the minimum spanning tree.
1.685 +
1.686 + ///Returns a reference to the NodeMap of the edges of the
1.687 + ///minimum spanning tree.
1.688 + ///\pre \ref run() or \ref start() must be called before using this function.
1.689 + const PredMap &predMap() const { return *_pred;}
1.690 +
1.691 + ///\brief Returns a reference to the tree edges map.
1.692 +
1.693 + ///Returns a reference to the TreeEdgeMap of the edges of the
1.694 + ///minimum spanning tree. The value of the map is \c true only if the edge is in
1.695 + ///the minimum spanning tree.
1.696 + ///\warning By default, the TreeEdgeMap is a NullMap.
1.697 + ///
1.698 + ///If it is not set before the execution of the algorithm, use the \ref
1.699 + ///treeMap(TreeMap&) function (after the execution) to set an UEdgeMap with the
1.700 + ///edges of the minimum spanning tree in O(n) time where n is the number of
1.701 + ///nodes in the graph.
1.702 + ///\pre \ref run() or \ref start() must be called before using this function.
1.703 + const TreeMap &treeMap() const { return *_tree;}
1.704 +
1.705 + ///\brief Sets the tree edges map.
1.706 +
1.707 + ///Sets the TreeMap of the edges of the minimum spanning tree.
1.708 + ///The map values belonging to the edges of the minimum
1.709 + ///spanning tree are set to \param tree_edge_value or \c true by default,
1.710 + ///the other map values remain untouched.
1.711 + ///
1.712 + ///\pre \ref run() or \ref start() must be called before using this function.
1.713 +
1.714 + template<class TreeMap>
1.715 + void quickTreeEdges(
1.716 + TreeMap& tree,
1.717 + const typename TreeMap::Value& tree_edge_value=true) const {
1.718 + for(NodeIt i(*graph);i!=INVALID;++i){
1.719 + if((*_pred)[i]!=INVALID) tree.set((*_pred)[i],tree_edge_value);
1.720 + }
1.721 + }
1.722 +
1.723 + ///\brief Sets the tree edges map.
1.724 +
1.725 + ///Sets the TreeMap of the edges of the minimum spanning tree.
1.726 + ///The map values belonging to the edges of the minimum
1.727 + ///spanning tree are set to \param tree_edge_value or \c true by default while
1.728 + ///the edge values not belonging to the minimum spanning tree are set to
1.729 + ///\param tree_default_value or \c false by default.
1.730 + ///
1.731 + ///\pre \ref run() or \ref start() must be called before using this function.
1.732 +
1.733 + template<class TreeMap>
1.734 + void treeEdges(
1.735 + TreeMap& tree,
1.736 + const typename TreeMap::Value& tree_edge_value=true,
1.737 + const typename TreeMap::Value& tree_default_value=false) const {
1.738 + for(typename ItemSetTraits<UGraph,UEdge>::ItemIt i(*graph);i!=INVALID;++i)
1.739 + tree.set(i,tree_default_value);
1.740 + for(NodeIt i(*graph);i!=INVALID;++i){
1.741 + if((*_pred)[i]!=INVALID) tree.set((*_pred)[i],tree_edge_value);
1.742 + }
1.743 + }
1.744 +
1.745 + ///\brief Checks if a node is reachable from the starting node.
1.746 +
1.747 + ///Returns \c true if \c v is reachable from the starting node.
1.748 + ///\warning The source nodes are inditated as unreached.
1.749 + ///\pre \ref run() or \ref start() must be called before using this function.
1.750 + ///
1.751 + bool reached(Node v) { return (*_heap_cross_ref)[v] != Heap::PRE_HEAP; }
1.752 +
1.753 + ///\brief Checks if a node is processed.
1.754 +
1.755 + ///Returns \c true if \c v is processed, i.e. \c v is already connencted to the
1.756 + ///minimum spanning tree.
1.757 + ///\pre \ref run() or \ref start() must be called before using this function.
1.758 + ///
1.759 + bool processed(Node v) { return (*_heap_cross_ref)[v] == Heap::POST_HEAP; }
1.760 +
1.761 +
1.762 + ///\brief Checks if an edge is in the spanning tree or not.
1.763 +
1.764 + ///Checks if an edge is in the spanning tree or not.
1.765 + ///\param e is the edge that will be checked
1.766 + ///\return \c true if e is in the spanning tree, \c false otherwise
1.767 + bool tree(UEdge e){
1.768 + return (*_pred)[*graph.source(e)]==e || (*_pred)[*graph.target(e)]==e;
1.769 + }
1.770 + ///@}
1.771 + };
1.772 +
1.773 +
1.774 + /// \ingroup spantree
1.775 + ///
1.776 + /// \brief Function type interface for Prim algorithm.
1.777 + ///
1.778 + /// Function type interface for Prim algorithm.
1.779 + /// \param graph the UGraph that the algorithm runs on
1.780 + /// \param cost the CostMap of the edges
1.781 + /// \retval tree the EdgeMap that contains whether an edge is in
1.782 + /// the spanning tree or not
1.783 + ///
1.784 + ///\sa Prim
1.785 + template<class Graph,class CostMap,class TreeMap>
1.786 + void prim(const Graph& graph, const CostMap& cost,TreeMap& tree){
1.787 + typename Prim<Graph,CostMap>::template DefTreeMap<TreeMap>::
1.788 + Create prm(graph,cost);
1.789 + prm.treeMap(tree);
1.790 + prm.run();
1.791 + };
1.792 +
1.793 +} //END OF NAMESPACE LEMON
1.794 +
1.795 +#endif