COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/smart_graph.h @ 2126:2c8adbee9fa6

Last change on this file since 2126:2c8adbee9fa6 was 2123:85c6f5e82108, checked in by Alpar Juttner, 13 years ago

Minor doc improvements

File size: 15.5 KB
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1/* -*- C++ -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library
4 *
5 * Copyright (C) 2003-2006
6 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
7 * (Egervary Research Group on Combinatorial Optimization, EGRES).
8 *
9 * Permission to use, modify and distribute this software is granted
10 * provided that this copyright notice appears in all copies. For
11 * precise terms see the accompanying LICENSE file.
12 *
13 * This software is provided "AS IS" with no warranty of any kind,
14 * express or implied, and with no claim as to its suitability for any
15 * purpose.
16 *
17 */
18
19#ifndef LEMON_SMART_GRAPH_H
20#define LEMON_SMART_GRAPH_H
21
22///\ingroup graphs
23///\file
24///\brief SmartGraph and SmartUGraph classes.
25
26#include <vector>
27
28#include <lemon/bits/invalid.h>
29
30#include <lemon/bits/base_extender.h>
31#include <lemon/bits/graph_extender.h>
32
33#include <lemon/bits/utility.h>
34#include <lemon/error.h>
35
36#include <lemon/bits/graph_extender.h>
37
38namespace lemon {
39
40  class SmartGraph;
41  ///Base of SmartGraph
42
43  ///Base of SmartGraph
44  ///
45  class SmartGraphBase {
46
47    friend class SmatGraph;
48
49  protected:
50    struct NodeT
51    {
52      int first_in,first_out;     
53      NodeT() : first_in(-1), first_out(-1) {}
54    };
55    struct EdgeT
56    {
57      int target, source, next_in, next_out;     
58      //FIXME: is this necessary?
59      EdgeT() : next_in(-1), next_out(-1) {} 
60    };
61
62    std::vector<NodeT> nodes;
63
64    std::vector<EdgeT> edges;
65   
66   
67  public:
68
69    typedef SmartGraphBase Graph;
70
71    class Node;
72    class Edge;
73
74   
75  public:
76
77    SmartGraphBase() : nodes(), edges() { }
78    SmartGraphBase(const SmartGraphBase &_g)
79      : nodes(_g.nodes), edges(_g.edges) { }
80   
81    typedef True NodeNumTag;
82    typedef True EdgeNumTag;
83
84    ///Number of nodes.
85    int nodeNum() const { return nodes.size(); }
86    ///Number of edges.
87    int edgeNum() const { return edges.size(); }
88
89    /// Maximum node ID.
90   
91    /// Maximum node ID.
92    ///\sa id(Node)
93    int maxNodeId() const { return nodes.size()-1; }
94    /// Maximum edge ID.
95   
96    /// Maximum edge ID.
97    ///\sa id(Edge)
98    int maxEdgeId() const { return edges.size()-1; }
99
100    Node source(Edge e) const { return edges[e.n].source; }
101    Node target(Edge e) const { return edges[e.n].target; }
102
103    /// Node ID.
104   
105    /// The ID of a valid Node is a nonnegative integer not greater than
106    /// \ref maxNodeId(). The range of the ID's is not surely continuous
107    /// and the greatest node ID can be actually less then \ref maxNodeId().
108    ///
109    /// The ID of the \ref INVALID node is -1.
110    ///\return The ID of the node \c v.
111    static int id(Node v) { return v.n; }
112    /// Edge ID.
113   
114    /// The ID of a valid Edge is a nonnegative integer not greater than
115    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
116    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
117    ///
118    /// The ID of the \ref INVALID edge is -1.
119    ///\return The ID of the edge \c e.
120    static int id(Edge e) { return e.n; }
121
122    /// \brief Returns the node from its \c id.
123    ///
124    /// Returns the node from its \c id. If there is not node
125    /// with the given id the effect of the function is undefinied.
126    static Node nodeFromId(int id) { return Node(id);}
127
128    /// \brief Returns the edge from its \c id.
129    ///
130    /// Returns the edge from its \c id. If there is not edge
131    /// with the given id the effect of the function is undefinied.
132    static Edge edgeFromId(int id) { return Edge(id);}
133
134    Node addNode() {
135      Node n; n.n=nodes.size();
136      nodes.push_back(NodeT()); //FIXME: Hmmm...
137      return n;
138    }
139   
140    Edge addEdge(Node u, Node v) {
141      Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...
142      edges[e.n].source=u.n; edges[e.n].target=v.n;
143      edges[e.n].next_out=nodes[u.n].first_out;
144      edges[e.n].next_in=nodes[v.n].first_in;
145      nodes[u.n].first_out=nodes[v.n].first_in=e.n;
146
147      return e;
148    }
149
150    void clear() {
151      edges.clear();
152      nodes.clear();
153    }
154
155
156    class Node {
157      friend class SmartGraphBase;
158      friend class SmartGraph;
159
160    protected:
161      int n;
162      Node(int nn) {n=nn;}
163    public:
164      Node() {}
165      Node (Invalid) { n=-1; }
166      bool operator==(const Node i) const {return n==i.n;}
167      bool operator!=(const Node i) const {return n!=i.n;}
168      bool operator<(const Node i) const {return n<i.n;}
169    };
170   
171
172    class Edge {
173      friend class SmartGraphBase;
174      friend class SmartGraph;
175
176    protected:
177      int n;
178      Edge(int nn) {n=nn;}
179    public:
180      Edge() { }
181      Edge (Invalid) { n=-1; }
182      bool operator==(const Edge i) const {return n==i.n;}
183      bool operator!=(const Edge i) const {return n!=i.n;}
184      bool operator<(const Edge i) const {return n<i.n;}
185    };
186
187    void first(Node& node) const {
188      node.n = nodes.size() - 1;
189    }
190
191    static void next(Node& node) {
192      --node.n;
193    }
194
195    void first(Edge& edge) const {
196      edge.n = edges.size() - 1;
197    }
198
199    static void next(Edge& edge) {
200      --edge.n;
201    }
202
203    void firstOut(Edge& edge, const Node& node) const {
204      edge.n = nodes[node.n].first_out;
205    }
206
207    void nextOut(Edge& edge) const {
208      edge.n = edges[edge.n].next_out;
209    }
210
211    void firstIn(Edge& edge, const Node& node) const {
212      edge.n = nodes[node.n].first_in;
213    }
214   
215    void nextIn(Edge& edge) const {
216      edge.n = edges[edge.n].next_in;
217    }
218
219    Node _split(Node n, bool connect = true)
220    {
221      Node b = addNode();
222      nodes[b.n].first_out=nodes[n.n].first_out;
223      nodes[n.n].first_out=-1;
224      for(int i=nodes[b.n].first_out;i!=-1;i++) edges[i].source=b.n;
225      if(connect) addEdge(n,b);
226      return b;
227    }
228
229  };
230
231  typedef GraphExtender<SmartGraphBase> ExtendedSmartGraphBase;
232
233  /// \ingroup graphs
234
235  ///A smart graph class.
236
237  ///This is a simple and fast graph implementation.
238  ///It is also quite memory efficient, but at the price
239  ///that <b> it does support only limited (only stack-like)
240  ///node and edge deletions</b>.
241  ///It conforms to
242  ///the \ref concept::Graph "Graph concept".
243  ///\sa concept::Graph.
244  ///
245  ///\author Alpar Juttner
246  class SmartGraph : public ExtendedSmartGraphBase {
247  public:
248
249    typedef ExtendedSmartGraphBase Parent;
250
251    class Snapshot;
252    friend class Snapshot;
253
254  protected:
255    void restoreSnapshot(const Snapshot &s)
256    {
257      while(s.edge_num<edges.size()) {
258        Parent::getNotifier(Edge()).erase(Edge(edges.size()-1));
259        nodes[edges.back().target].first_in=edges.back().next_in;
260        nodes[edges.back().source].first_out=edges.back().next_out;
261        edges.pop_back();
262      }
263      //nodes.resize(s.nodes_num);
264      while(s.node_num<nodes.size()) {
265        Parent::getNotifier(Node()).erase(Node(nodes.size()-1));
266        nodes.pop_back();
267      }
268    }   
269
270  public:
271
272    ///Split a node.
273   
274    ///This function splits a node. First a new node is added to the graph,
275    ///then the source of each outgoing edge of \c n is moved to this new node.
276    ///If \c connect is \c true (this is the default value), then a new edge
277    ///from \c n to the newly created node is also added.
278    ///\return The newly created node.
279    ///
280    ///\note The <tt>Edge</tt>s
281    ///referencing a moved edge remain
282    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
283    ///may be invalidated.
284    ///\warning This functionality cannot be used together with the Snapshot
285    ///feature.
286    ///\todo It could be implemented in a bit faster way.
287    Node split(Node n, bool connect = true)
288    {
289      Node b = _split(n,connect);
290      return b;
291    }
292 
293
294    ///Class to make a snapshot of the graph and to restrore to it later.
295
296    ///Class to make a snapshot of the graph and to restrore to it later.
297    ///
298    ///The newly added nodes and edges can be removed using the
299    ///restore() function.
300    ///\note After you restore a state, you cannot restore
301    ///a later state, in other word you cannot add again the edges deleted
302    ///by restore() using another Snapshot instance.
303    ///
304    class Snapshot
305    {
306      SmartGraph *g;
307    protected:
308      friend class SmartGraph;
309      unsigned int node_num;
310      unsigned int edge_num;
311    public:
312      ///Default constructor.
313     
314      ///Default constructor.
315      ///To actually make a snapshot you must call save().
316      ///
317      Snapshot() : g(0) {}
318      ///Constructor that immediately makes a snapshot
319     
320      ///This constructor immediately makes a snapshot of the graph.
321      ///\param _g The graph we make a snapshot of.
322      Snapshot(SmartGraph &_g) :g(&_g) {
323        node_num=g->nodes.size();
324        edge_num=g->edges.size();
325      }
326
327      ///Make a snapshot.
328
329      ///Make a snapshot of the graph.
330      ///
331      ///This function can be called more than once. In case of a repeated
332      ///call, the previous snapshot gets lost.
333      ///\param _g The graph we make the snapshot of.
334      void save(SmartGraph &_g)
335      {
336        g=&_g;
337        node_num=g->nodes.size();
338        edge_num=g->edges.size();
339      }
340
341      ///Undo the changes until a snapshot.
342     
343      ///Undo the changes until a snapshot created by save().
344      ///
345      ///\note After you restored a state, you cannot restore
346      ///a later state, in other word you cannot add again the edges deleted
347      ///by restore().
348      ///
349      ///\todo This function might be called undo().
350     
351      void restore()
352      {
353        g->restoreSnapshot(*this);
354      }
355    };
356  };
357
358
359  /**************** Undirected List Graph ****************/
360
361  typedef UGraphExtender<UndirGraphExtender<SmartGraphBase> >
362  ExtendedSmartUGraphBase;
363
364  /// \ingroup graphs
365  ///
366  /// \brief A smart undirected graph class.
367  ///
368  /// This is a simple and fast undirected graph implementation.
369  /// It is also quite memory efficient, but at the price
370  /// that <b> it does support only limited (only stack-like)
371  /// node and edge deletions</b>.
372  /// Except from this it conforms to
373  /// the \ref concept::UGraph "UGraph concept".
374  /// \sa concept::UGraph.
375  ///
376  /// \todo Snapshot hasn't been implemented yet.
377  ///
378  class SmartUGraph : public ExtendedSmartUGraphBase {
379  };
380
381
382  class SmartBpUGraphBase {
383  public:
384
385    class NodeSetError : public LogicError {
386      virtual const char* exceptionName() const {
387        return "lemon::SmartBpUGraph::NodeSetError";
388      }
389    };
390
391  protected:
392
393    struct NodeT {
394      int first;
395      NodeT() {}
396      NodeT(int _first) : first(_first) {}
397    };
398
399    struct UEdgeT {
400      int aNode, next_out;
401      int bNode, next_in;
402    };
403
404    std::vector<NodeT> aNodes;
405    std::vector<NodeT> bNodes;
406
407    std::vector<UEdgeT> edges;
408
409  public:
410 
411    class Node {
412      friend class SmartBpUGraphBase;
413    protected:
414      int id;
415
416      Node(int _id) : id(_id) {}
417    public:
418      Node() {}
419      Node(Invalid) { id = -1; }
420      bool operator==(const Node i) const {return id==i.id;}
421      bool operator!=(const Node i) const {return id!=i.id;}
422      bool operator<(const Node i) const {return id<i.id;}
423    };
424
425    class UEdge {
426      friend class SmartBpUGraphBase;
427    protected:
428      int id;
429
430      UEdge(int _id) { id = _id;}
431    public:
432      UEdge() {}
433      UEdge (Invalid) { id = -1; }
434      bool operator==(const UEdge i) const {return id==i.id;}
435      bool operator!=(const UEdge i) const {return id!=i.id;}
436      bool operator<(const UEdge i) const {return id<i.id;}
437    };
438
439    void firstANode(Node& node) const {
440      node.id = 2 * aNodes.size() - 2;
441      if (node.id < 0) node.id = -1;
442    }
443    void nextANode(Node& node) const {
444      node.id -= 2;
445      if (node.id < 0) node.id = -1;
446    }
447
448    void firstBNode(Node& node) const {
449      node.id = 2 * bNodes.size() - 1;
450    }
451    void nextBNode(Node& node) const {
452      node.id -= 2;
453    }
454
455    void first(Node& node) const {
456      if (aNodes.size() > 0) {
457        node.id = 2 * aNodes.size() - 2;
458      } else {
459        node.id = 2 * bNodes.size() - 1;
460      }
461    }
462    void next(Node& node) const {
463      node.id -= 2;
464      if (node.id == -2) {
465        node.id = 2 * bNodes.size() - 1;
466      }
467    }
468 
469    void first(UEdge& edge) const {
470      edge.id = edges.size() - 1;
471    }
472    void next(UEdge& edge) const {
473      --edge.id;
474    }
475
476    void firstFromANode(UEdge& edge, const Node& node) const {
477      LEMON_ASSERT((node.id & 1) == 0, NodeSetError());
478      edge.id = aNodes[node.id >> 1].first;
479    }
480    void nextFromANode(UEdge& edge) const {
481      edge.id = edges[edge.id].next_out;
482    }
483
484    void firstFromBNode(UEdge& edge, const Node& node) const {
485      LEMON_ASSERT((node.id & 1) == 1, NodeSetError());
486      edge.id = bNodes[node.id >> 1].first;
487    }
488    void nextFromBNode(UEdge& edge) const {
489      edge.id = edges[edge.id].next_in;
490    }
491
492    static int id(const Node& node) {
493      return node.id;
494    }
495    static Node nodeFromId(int id) {
496      return Node(id);
497    }
498    int maxNodeId() const {
499      return aNodes.size() > bNodes.size() ?
500        aNodes.size() * 2 - 2 : bNodes.size() * 2 - 1;
501    }
502 
503    static int id(const UEdge& edge) {
504      return edge.id;
505    }
506    static UEdge uEdgeFromId(int id) {
507      return UEdge(id);
508    }
509    int maxUEdgeId() const {
510      return edges.size();
511    }
512 
513    static int aNodeId(const Node& node) {
514      return node.id >> 1;
515    }
516    static Node fromANodeId(int id) {
517      return Node(id << 1);
518    }
519    int maxANodeId() const {
520      return aNodes.size();
521    }
522
523    static int bNodeId(const Node& node) {
524      return node.id >> 1;
525    }
526    static Node fromBNodeId(int id) {
527      return Node((id << 1) + 1);
528    }
529    int maxBNodeId() const {
530      return bNodes.size();
531    }
532
533    Node aNode(const UEdge& edge) const {
534      return Node(edges[edge.id].aNode);
535    }
536    Node bNode(const UEdge& edge) const {
537      return Node(edges[edge.id].bNode);
538    }
539
540    static bool aNode(const Node& node) {
541      return (node.id & 1) == 0;
542    }
543
544    static bool bNode(const Node& node) {
545      return (node.id & 1) == 1;
546    }
547
548    Node addANode() {
549      NodeT nodeT;
550      nodeT.first = -1;
551      aNodes.push_back(nodeT);
552      return Node(aNodes.size() * 2 - 2);
553    }
554
555    Node addBNode() {
556      NodeT nodeT;
557      nodeT.first = -1;
558      bNodes.push_back(nodeT);
559      return Node(bNodes.size() * 2 - 1);
560    }
561
562    UEdge addEdge(const Node& source, const Node& target) {
563      LEMON_ASSERT(((source.id ^ target.id) & 1) == 1, NodeSetError());
564      UEdgeT edgeT;
565      if ((source.id & 1) == 0) {
566        edgeT.aNode = source.id;
567        edgeT.bNode = target.id;
568      } else {
569        edgeT.aNode = target.id;
570        edgeT.bNode = source.id;
571      }
572      edgeT.next_out = aNodes[edgeT.aNode >> 1].first;
573      aNodes[edgeT.aNode >> 1].first = edges.size();
574      edgeT.next_in = bNodes[edgeT.bNode >> 1].first;
575      bNodes[edgeT.bNode >> 1].first = edges.size();
576      edges.push_back(edgeT);
577      return UEdge(edges.size() - 1);
578    }
579
580    void clear() {
581      aNodes.clear();
582      bNodes.clear();
583      edges.clear();
584    }
585
586    typedef True NodeNumTag;
587    int nodeNum() const { return aNodes.size() + bNodes.size(); }
588    int aNodeNum() const { return aNodes.size(); }
589    int bNodeNum() const { return bNodes.size(); }
590
591    typedef True EdgeNumTag;
592    int uEdgeNum() const { return edges.size(); }
593
594  };
595
596
597  typedef BpUGraphExtender<SmartBpUGraphBase> ExtendedSmartBpUGraphBase;
598
599  /// \ingroup graphs
600  ///
601  /// \brief A smart bipartite undirected graph class.
602  ///
603  /// This is a simple and fast bipartite undirected graph implementation.
604  /// It is also quite memory efficient, but at the price
605  /// that <b> it does not support node and edge deletions</b>.
606  /// Except from this it conforms to
607  /// the \ref concept::BpUGraph "BpUGraph concept".
608  /// \sa concept::BpUGraph.
609  ///
610  class SmartBpUGraph : public ExtendedSmartBpUGraphBase {};
611
612 
613  /// @} 
614} //namespace lemon
615
616
617#endif //LEMON_SMART_GRAPH_H
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