COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/smart_graph.h @ 1284:b941d044f87b

Last change on this file since 1284:b941d044f87b was 1284:b941d044f87b, checked in by Alpar Juttner, 15 years ago

SmartGraph? can also split() a node!

File size: 11.4 KB
Line 
1/* -*- C++ -*-
2 * src/lemon/smart_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2005 Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
5 * (Egervary Combinatorial Optimization Research Group, 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 SymSmartGraph classes.
23
24#include <vector>
25
26#include <lemon/invalid.h>
27
28#include <lemon/clearable_graph_extender.h>
29#include <lemon/extendable_graph_extender.h>
30#include <lemon/iterable_graph_extender.h>
31#include <lemon/alteration_notifier.h>
32#include <lemon/default_map.h>
33
34#include <lemon/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) : nodes(_g.nodes), edges(_g.edges) { }
79   
80    typedef True NodeNumTag;
81    typedef True EdgeNumTag;
82
83    ///Number of nodes.
84    int nodeNum() const { return nodes.size(); }
85    ///Number of edges.
86    int edgeNum() const { return edges.size(); }
87
88    /// Maximum node ID.
89   
90    /// Maximum node ID.
91    ///\sa id(Node)
92    int maxId(Node = INVALID) const { return nodes.size()-1; }
93    /// Maximum edge ID.
94   
95    /// Maximum edge ID.
96    ///\sa id(Edge)
97    int maxId(Edge = INVALID) const { return edges.size()-1; }
98
99    Node source(Edge e) const { return edges[e.n].source; }
100    Node target(Edge e) const { return edges[e.n].target; }
101
102    /// Node ID.
103   
104    /// The ID of a valid Node is a nonnegative integer not greater than
105    /// \ref maxNodeId(). The range of the ID's is not surely continuous
106    /// and the greatest node ID can be actually less then \ref maxNodeId().
107    ///
108    /// The ID of the \ref INVALID node is -1.
109    ///\return The ID of the node \c v.
110    static int id(Node v) { return v.n; }
111    /// Edge ID.
112   
113    /// The ID of a valid Edge is a nonnegative integer not greater than
114    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
115    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
116    ///
117    /// The ID of the \ref INVALID edge is -1.
118    ///\return The ID of the edge \c e.
119    static int id(Edge e) { return e.n; }
120
121    static Node fromId(int id, Node) { return Node(id);}
122
123    static Edge fromId(int id, Edge) { return Edge(id);}
124
125    Node addNode() {
126      Node n; n.n=nodes.size();
127      nodes.push_back(NodeT()); //FIXME: Hmmm...
128      return n;
129    }
130   
131    Edge addEdge(Node u, Node v) {
132      Edge e; e.n=edges.size(); edges.push_back(EdgeT()); //FIXME: Hmmm...
133      edges[e.n].source=u.n; edges[e.n].target=v.n;
134      edges[e.n].next_out=nodes[u.n].first_out;
135      edges[e.n].next_in=nodes[v.n].first_in;
136      nodes[u.n].first_out=nodes[v.n].first_in=e.n;
137
138      return e;
139    }
140
141    void clear() {
142      edges.clear();
143      nodes.clear();
144    }
145
146
147    class Node {
148      friend class SmartGraphBase;
149      friend class SmartGraph;
150
151    protected:
152      int n;
153      ///\todo It should be removed (or at least define a setToId() instead).
154      ///
155      Node(int nn) {n=nn;}
156    public:
157      Node() {}
158      Node (Invalid) { n=-1; }
159      bool operator==(const Node i) const {return n==i.n;}
160      bool operator!=(const Node i) const {return n!=i.n;}
161      bool operator<(const Node i) const {return n<i.n;}
162    };
163   
164
165    class Edge {
166      friend class SmartGraphBase;
167      friend class SmartGraph;
168
169    protected:
170      int n;
171      ///\todo It should be removed (or at least define a setToId() instead).
172      ///
173      Edge(int nn) {n=nn;}
174    public:
175      Edge() { }
176      Edge (Invalid) { n=-1; }
177      bool operator==(const Edge i) const {return n==i.n;}
178      bool operator!=(const Edge i) const {return n!=i.n;}
179      bool operator<(const Edge i) const {return n<i.n;}
180    };
181
182    void first(Node& node) const {
183      node.n = nodes.size() - 1;
184    }
185
186    static void next(Node& node) {
187      --node.n;
188    }
189
190    void first(Edge& edge) const {
191      edge.n = edges.size() - 1;
192    }
193
194    static void next(Edge& edge) {
195      --edge.n;
196    }
197
198    void firstOut(Edge& edge, const Node& node) const {
199      edge.n = nodes[node.n].first_out;
200    }
201
202    void nextOut(Edge& edge) const {
203      edge.n = edges[edge.n].next_out;
204    }
205
206    void firstIn(Edge& edge, const Node& node) const {
207      edge.n = nodes[node.n].first_in;
208    }
209   
210    void nextIn(Edge& edge) const {
211      edge.n = edges[edge.n].next_in;
212    }
213
214    Edge _findEdge(Node u,Node v, Edge prev = INVALID)
215    {
216      int e = (prev.n==-1)? nodes[u.n].first_out : edges[prev.n].next_out;
217      while(e!=-1 && edges[e].target!=v.n) e = edges[e].next_out;
218      prev.n=e;
219      return prev;
220    }
221
222    Node _split(Node n, bool connect = true)
223    {
224      Node b = addNode();
225      nodes[b.n].first_out=nodes[n.n].first_out;
226      nodes[n.n].first_out=-1;
227      for(int i=nodes[b.n].first_out;i!=-1;i++) edges[i].source=b.n;
228      if(connect) addEdge(n,b);
229      return b;
230    }
231
232  };
233
234  typedef AlterableGraphExtender<SmartGraphBase> AlterableSmartGraphBase;
235  typedef IterableGraphExtender<AlterableSmartGraphBase> IterableSmartGraphBase;
236  typedef DefaultMappableGraphExtender<IterableSmartGraphBase> MappableSmartGraphBase;
237  typedef ExtendableGraphExtender<MappableSmartGraphBase> ExtendableSmartGraphBase;
238  typedef ClearableGraphExtender<ExtendableSmartGraphBase> ClearableSmartGraphBase;
239
240  /// \addtogroup graphs
241  /// @{
242
243  ///A smart graph class.
244
245  ///This is a simple and fast graph implementation.
246  ///It is also quite memory efficient, but at the price
247  ///that <b> it does support only limited (only stack-like)
248  ///node and edge deletions</b>.
249  ///It conforms to
250  ///the \ref concept::ExtendableGraph "ExtendableGraph" concept.
251  ///\sa concept::ExtendableGraph.
252  ///
253  ///\author Alpar Juttner
254  class SmartGraph : public ClearableSmartGraphBase {
255  public:
256    /// Finds an edge between two nodes.
257   
258    /// Finds an edge from node \c u to node \c v.
259    ///
260    /// If \c prev is \ref INVALID (this is the default value), then
261    /// it finds the first edge from \c u to \c v. Otherwise it looks for
262    /// the next edge from \c u to \c v after \c prev.
263    /// \return The found edge or \ref INVALID if there is no such an edge.
264    ///
265    /// Thus you can iterate through each edge from \c u to \c v as it follows.
266    /// \code
267    /// for(Edge e=G.findEdge(u,v);e!=INVALID;e=G.findEdge(u,v,e)) {
268    ///   ...
269    /// }
270    /// \endcode
271    /// \todo Possibly it should be a global function.
272    Edge findEdge(Node u,Node v, Edge prev = INVALID)
273    {
274      return _findEdge(u,v,prev);
275    }
276   
277    class SnapShot;
278    friend class SnapShot;
279
280  protected:
281    void restoreSnapShot(const SnapShot &s)
282    {
283      while(s.edge_num>edges.size()) {
284        Parent::getNotifier(Edge()).erase(Edge(edges.size()-1));
285        nodes[edges.back().target].first_in=edges.back().next_in;
286        nodes[edges.back().source].first_out=edges.back().next_out;
287        edges.pop_back();
288      }
289      //nodes.resize(s.nodes_num);
290      while(s.node_num>nodes.size()) {
291        Parent::getNotifier(Node()).erase(Node(nodes.size()-1));
292        nodes.pop_back();
293      }
294    }   
295
296  public:
297
298    ///Split a node.
299   
300    ///This function splits a node. First a new node is added to the graph,
301    ///then the source of each outgoing edge of \c n is moved to this new node.
302    ///If \c connect is \c true (this is the default value), then a new edge
303    ///from \c n to the newly created node is also added.
304    ///\return The newly created node.
305    ///
306    ///\note The <tt>Edge</tt>s
307    ///referencing a moved edge remain
308    ///valid. However <tt>InEdge</tt>'s and <tt>OutEdge</tt>'s
309    ///may be invalidated.
310    ///\warning This functionality cannot be used together with the SnapShot
311    ///feature.
312    ///\todo It could be implemented in a bit faster way.
313    Node split(Node n, bool connect = true)
314    {
315      return _split(n,connect);
316    }
317 
318
319    ///Class to make a snapshot of the graph and to restrore to it later.
320
321    ///Class to make a snapshot of the graph and to restrore to it later.
322    ///
323    ///The newly added nodes and edges can be removed using the
324    ///restore() function.
325    ///\note After you restore a state, you cannot restore
326    ///a later state, in other word you cannot add again the edges deleted
327    ///by restore() using another SnapShot instance.
328    ///
329    class SnapShot
330    {
331      SmartGraph *g;
332    protected:
333      friend class SmartGraph;
334      unsigned int node_num;
335      unsigned int edge_num;
336    public:
337      ///Default constructor.
338     
339      ///Default constructor.
340      ///To actually make a snapshot you must call save().
341      ///
342      SnapShot() : g(0) {}
343      ///Constructor that immediately makes a snapshot
344     
345      ///This constructor immediately makes a snapshot of the graph.
346      ///\param _g The graph we make a snapshot of.
347      SnapShot(SmartGraph &_g) :g(&_g) {
348        node_num=g->nodes.size();
349        edge_num=g->edges.size();
350      }
351
352      ///Make a snapshot.
353
354      ///Make a snapshot of the graph.
355      ///
356      ///This function can be called more than once. In case of a repeated
357      ///call, the previous snapshot gets lost.
358      ///\param _g The graph we make the snapshot of.
359      void save(SmartGraph &_g)
360      {
361        g=&_g;
362        node_num=g->nodes.size();
363        edge_num=g->edges.size();
364      }
365
366      ///Undo the changes until a snapshot.
367     
368      ///Undo the changes until a snapshot created by save().
369      ///
370      ///\param s an internal stucture given back by save()
371      ///\note After you restored a state, you cannot restore
372      ///a later state, in other word you cannot add again the edges deleted
373      ///by restore().
374      ///
375      ///\todo This function might be called undo().
376     
377      void restore()
378      {
379        g->restoreSnapShot(*this);
380      }
381    };
382  };
383
384
385  /**************** Undirected List Graph ****************/
386
387  typedef ClearableUndirGraphExtender<
388    ExtendableUndirGraphExtender<
389    MappableUndirGraphExtender<
390    IterableUndirGraphExtender<
391    AlterableUndirGraphExtender<
392    UndirGraphExtender<SmartGraphBase> > > > > > UndirSmartGraphBase;
393
394  ///A smart undirected graph class.
395
396  ///This is a simple and fast undirected graph implementation.
397  ///It is also quite memory efficient, but at the price
398  ///that <b> it does support only limited (only stack-like)
399  ///node and edge deletions</b>.
400  ///Except from this it conforms to
401  ///the \ref concept::UndirGraph "UndirGraph" concept.
402  ///\sa concept::UndirGraph.
403  ///
404  ///\todo SnapShot hasn't been implemented yet.
405  ///
406  class UndirSmartGraph : public UndirSmartGraphBase {
407  };
408
409 
410  /// @} 
411} //namespace lemon
412
413
414#endif //LEMON_SMART_GRAPH_H
Note: See TracBrowser for help on using the repository browser.