COIN-OR::LEMON - Graph Library

source: lemon-0.x/lemon/smart_graph.h @ 1718:6a958ab38386

Last change on this file since 1718:6a958ab38386 was 1718:6a958ab38386, checked in by Balazs Dezso, 14 years ago

Extending observer interface
It will be used in the indegmap, outdegmap types

File size: 11.4 KB
Line 
1/* -*- C++ -*-
2 * lemon/smart_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Research Group on Combinatorial Optimization, EGRES).
6 *
7 * Permission to use, modify and distribute this software is granted
8 * provided that this copyright notice appears in all copies. For
9 * precise terms see the accompanying LICENSE file.
10 *
11 * This software is provided "AS IS" with no warranty of any kind,
12 * express or implied, and with no claim as to its suitability for any
13 * purpose.
14 *
15 */
16
17#ifndef LEMON_SMART_GRAPH_H
18#define LEMON_SMART_GRAPH_H
19
20///\ingroup graphs
21///\file
22///\brief SmartGraph and UndirSmartGraph classes.
23
24#include <vector>
25
26#include <lemon/invalid.h>
27
28#include <lemon/bits/clearable_graph_extender.h>
29#include <lemon/bits/extendable_graph_extender.h>
30#include <lemon/bits/iterable_graph_extender.h>
31#include <lemon/bits/alteration_notifier.h>
32#include <lemon/bits/default_map.h>
33
34#include <lemon/bits/undir_graph_extender.h>
35
36#include <lemon/utility.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 maxId(Node) const { return nodes.size()-1; }
94    /// Maximum edge ID.
95   
96    /// Maximum edge ID.
97    ///\sa id(Edge)
98    int maxId(Edge) 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 maxId(Node). The range of the ID's is not surely continuous
107    /// and the greatest node ID can be actually less then \ref maxId(Node).
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 maxId(Edge). The range of the ID's is not surely continuous
116    /// and the greatest edge ID can be actually less then \ref maxId(Edge).
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    static Node fromId(int id, Node) { return Node(id);}
123
124    static Edge fromId(int id, Edge) { return Edge(id);}
125
126    Node addNode() {
127      Node n; n.n=nodes.size();
128      nodes.push_back(NodeT()); //FIXME: Hmmm...
129      return n;
130    }
131   
132    Edge addEdge(Node u, Node v) {
133      Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...
134      edges[e.n].source=u.n; edges[e.n].target=v.n;
135      edges[e.n].next_out=nodes[u.n].first_out;
136      edges[e.n].next_in=nodes[v.n].first_in;
137      nodes[u.n].first_out=nodes[v.n].first_in=e.n;
138
139      return e;
140    }
141
142    void clear() {
143      edges.clear();
144      nodes.clear();
145    }
146
147
148    class Node {
149      friend class SmartGraphBase;
150      friend class SmartGraph;
151
152    protected:
153      int n;
154      ///\e
155
156      ///\todo It should be removed (or at least define a setToId() instead).
157      ///
158      Node(int nn) {n=nn;}
159    public:
160      Node() {}
161      Node (Invalid) { n=-1; }
162      bool operator==(const Node i) const {return n==i.n;}
163      bool operator!=(const Node i) const {return n!=i.n;}
164      bool operator<(const Node i) const {return n<i.n;}
165    };
166   
167
168    class Edge {
169      friend class SmartGraphBase;
170      friend class SmartGraph;
171
172    protected:
173      int n;
174      ///\todo It should be removed (or at least define a setToId() instead).
175      ///
176      Edge(int nn) {n=nn;}
177    public:
178      Edge() { }
179      Edge (Invalid) { n=-1; }
180      bool operator==(const Edge i) const {return n==i.n;}
181      bool operator!=(const Edge i) const {return n!=i.n;}
182      bool operator<(const Edge i) const {return n<i.n;}
183    };
184
185    void first(Node& node) const {
186      node.n = nodes.size() - 1;
187    }
188
189    static void next(Node& node) {
190      --node.n;
191    }
192
193    void first(Edge& edge) const {
194      edge.n = edges.size() - 1;
195    }
196
197    static void next(Edge& edge) {
198      --edge.n;
199    }
200
201    void firstOut(Edge& edge, const Node& node) const {
202      edge.n = nodes[node.n].first_out;
203    }
204
205    void nextOut(Edge& edge) const {
206      edge.n = edges[edge.n].next_out;
207    }
208
209    void firstIn(Edge& edge, const Node& node) const {
210      edge.n = nodes[node.n].first_in;
211    }
212   
213    void nextIn(Edge& edge) const {
214      edge.n = edges[edge.n].next_in;
215    }
216
217    Edge _findEdge(Node u,Node v, Edge prev = INVALID)
218    {
219      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
220      while(e!=-1 && edges[e].target!=v.n) e = edges[e].next_out;
221      prev.n=e;
222      return prev;
223    }
224
225    Node _split(Node n, bool connect = true)
226    {
227      Node b = addNode();
228      nodes[b.n].first_out=nodes[n.n].first_out;
229      nodes[n.n].first_out=-1;
230      for(int i=nodes[b.n].first_out;i!=-1;i++) edges[i].source=b.n;
231      if(connect) addEdge(n,b);
232      return b;
233    }
234
235  };
236
237  typedef ClearableGraphExtender<
238    ExtendableGraphExtender<
239    MappableGraphExtender<
240    IterableGraphExtender<
241    AlterableGraphExtender<SmartGraphBase> > > > > ExtendedSmartGraphBase;
242
243  /// \addtogroup graphs
244  /// @{
245
246  ///A smart graph class.
247
248  ///This is a simple and fast graph implementation.
249  ///It is also quite memory efficient, but at the price
250  ///that <b> it does support only limited (only stack-like)
251  ///node and edge deletions</b>.
252  ///It conforms to
253  ///the \ref concept::ExtendableGraph "ExtendableGraph" concept.
254  ///\sa concept::ExtendableGraph.
255  ///
256  ///\author Alpar Juttner
257  class SmartGraph : public ExtendedSmartGraphBase {
258  public:
259    /// Finds an edge between two nodes.
260   
261    /// Finds an edge from node \c u to node \c v.
262    ///
263    /// If \c prev is \ref INVALID (this is the default value), then
264    /// it finds the first edge from \c u to \c v. Otherwise it looks for
265    /// the next edge from \c u to \c v after \c prev.
266    /// \return The found edge or \ref INVALID if there is no such an edge.
267    ///
268    /// Thus you can iterate through each edge from \c u to \c v as it follows.
269    /// \code
270    /// for(Edge e=G.findEdge(u,v);e!=INVALID;e=G.findEdge(u,v,e)) {
271    ///   ...
272    /// }
273    /// \endcode
274    /// \todo Possibly it should be a global function.
275    Edge findEdge(Node u,Node v, Edge prev = INVALID)
276    {
277      return _findEdge(u,v,prev);
278    }
279   
280    class SnapShot;
281    friend class SnapShot;
282
283  protected:
284    void restoreSnapShot(const SnapShot &s)
285    {
286      while(s.edge_num<edges.size()) {
287        Parent::getNotifier(Edge()).erase(Edge(edges.size()-1));
288        nodes[edges.back().target].first_in=edges.back().next_in;
289        nodes[edges.back().source].first_out=edges.back().next_out;
290        edges.pop_back();
291      }
292      //nodes.resize(s.nodes_num);
293      while(s.node_num<nodes.size()) {
294        Parent::getNotifier(Node()).erase(Node(nodes.size()-1));
295        nodes.pop_back();
296      }
297    }   
298
299  public:
300
301    ///Split a node.
302   
303    ///This function splits a node. First a new node is added to the graph,
304    ///then the source of each outgoing edge of \c n is moved to this new node.
305    ///If \c connect is \c true (this is the default value), then a new edge
306    ///from \c n to the newly created node is also added.
307    ///\return The newly created node.
308    ///
309    ///\note The <tt>Edge</tt>s
310    ///referencing a moved edge remain
311    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
312    ///may be invalidated.
313    ///\warning This functionality cannot be used together with the SnapShot
314    ///feature.
315    ///\todo It could be implemented in a bit faster way.
316    Node split(Node n, bool connect = true)
317    {
318      for (OutEdgeIt it(*this, n); it != INVALID; ++it) {
319        getNotifier(Edge()).signalChange(it);
320      }
321      Node b = _split(n,connect);
322      for (OutEdgeIt it(*this, b); it != INVALID; ++it) {
323        getNotifier(Edge()).commitChange(it);
324      }
325      return b;
326    }
327 
328
329    ///Class to make a snapshot of the graph and to restrore to it later.
330
331    ///Class to make a snapshot of the graph and to restrore to it later.
332    ///
333    ///The newly added nodes and edges can be removed using the
334    ///restore() function.
335    ///\note After you restore a state, you cannot restore
336    ///a later state, in other word you cannot add again the edges deleted
337    ///by restore() using another SnapShot instance.
338    ///
339    class SnapShot
340    {
341      SmartGraph *g;
342    protected:
343      friend class SmartGraph;
344      unsigned int node_num;
345      unsigned int edge_num;
346    public:
347      ///Default constructor.
348     
349      ///Default constructor.
350      ///To actually make a snapshot you must call save().
351      ///
352      SnapShot() : g(0) {}
353      ///Constructor that immediately makes a snapshot
354     
355      ///This constructor immediately makes a snapshot of the graph.
356      ///\param _g The graph we make a snapshot of.
357      SnapShot(SmartGraph &_g) :g(&_g) {
358        node_num=g->nodes.size();
359        edge_num=g->edges.size();
360      }
361
362      ///Make a snapshot.
363
364      ///Make a snapshot of the graph.
365      ///
366      ///This function can be called more than once. In case of a repeated
367      ///call, the previous snapshot gets lost.
368      ///\param _g The graph we make the snapshot of.
369      void save(SmartGraph &_g)
370      {
371        g=&_g;
372        node_num=g->nodes.size();
373        edge_num=g->edges.size();
374      }
375
376      ///Undo the changes until a snapshot.
377     
378      ///Undo the changes until a snapshot created by save().
379      ///
380      ///\note After you restored a state, you cannot restore
381      ///a later state, in other word you cannot add again the edges deleted
382      ///by restore().
383      ///
384      ///\todo This function might be called undo().
385     
386      void restore()
387      {
388        g->restoreSnapShot(*this);
389      }
390    };
391  };
392
393
394  /**************** Undirected List Graph ****************/
395
396  typedef ClearableUndirGraphExtender<
397    ExtendableUndirGraphExtender<
398    MappableUndirGraphExtender<
399    IterableUndirGraphExtender<
400    AlterableUndirGraphExtender<
401    UndirGraphExtender<SmartGraphBase> > > > > > ExtendedUndirSmartGraphBase;
402
403  ///A smart undirected graph class.
404
405  ///This is a simple and fast undirected graph implementation.
406  ///It is also quite memory efficient, but at the price
407  ///that <b> it does support only limited (only stack-like)
408  ///node and edge deletions</b>.
409  ///Except from this it conforms to
410  ///the \ref concept::UndirGraph "UndirGraph" concept.
411  ///\sa concept::UndirGraph.
412  ///
413  ///\todo SnapShot hasn't been implemented yet.
414  ///
415  class UndirSmartGraph : public ExtendedUndirSmartGraphBase {
416  };
417
418 
419  /// @} 
420} //namespace lemon
421
422
423#endif //LEMON_SMART_GRAPH_H
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