COIN-OR::LEMON - Graph Library

source: lemon-0.x/src/lemon/smart_graph.h @ 974:785062a83f8e

Last change on this file since 974:785062a83f8e was 974:785062a83f8e, checked in by Alpar Juttner, 15 years ago

Changes in doc.

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1/* -*- C++ -*-
2 * src/lemon/smart_graph.h - Part of LEMON, a generic C++ optimization library
3 *
4 * Copyright (C) 2004 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
31#include <lemon/idmappable_graph_extender.h>
32
33#include <lemon/iterable_graph_extender.h>
34
35#include <lemon/alteration_observer_registry.h>
36#include <lemon/default_map.h>
37
38
39#include <lemon/graph_utils.h>
40
41
42namespace lemon {
43
44  /// \addtogroup graphs
45  /// @{
46
47  class SmartGraph;
48  ///Base of SmartGraph
49
50  ///Base of SmartGraph
51  ///
52  class SmartGraphBase {
53
54    friend class SmatGraph;
55
56  protected:
57    struct NodeT
58    {
59      int first_in,first_out;     
60      NodeT() : first_in(-1), first_out(-1) {}
61    };
62    struct EdgeT
63    {
64      int head, tail, next_in, next_out;     
65      //FIXME: is this necessary?
66      EdgeT() : next_in(-1), next_out(-1) {} 
67    };
68
69    std::vector<NodeT> nodes;
70
71    std::vector<EdgeT> edges;
72   
73   
74  public:
75
76    typedef SmartGraphBase Graph;
77
78    class Node;
79    class Edge;
80
81   
82  public:
83
84    SmartGraphBase() : nodes(), edges() { }
85    SmartGraphBase(const SmartGraphBase &_g) : nodes(_g.nodes), edges(_g.edges) { }
86   
87    ///Number of nodes.
88    int nodeNum() const { return nodes.size(); }
89    ///Number of edges.
90    int edgeNum() const { return edges.size(); }
91
92    /// Maximum node ID.
93   
94    /// Maximum node ID.
95    ///\sa id(Node)
96    int maxNodeId() const { return nodes.size()-1; }
97    /// Maximum edge ID.
98   
99    /// Maximum edge ID.
100    ///\sa id(Edge)
101    int maxEdgeId() const { return edges.size()-1; }
102
103    Node tail(Edge e) const { return edges[e.n].tail; }
104    Node head(Edge e) const { return edges[e.n].head; }
105
106    /// Node ID.
107   
108    /// The ID of a valid Node is a nonnegative integer not greater than
109    /// \ref maxNodeId(). The range of the ID's is not surely continuous
110    /// and the greatest node ID can be actually less then \ref maxNodeId().
111    ///
112    /// The ID of the \ref INVALID node is -1.
113    ///\return The ID of the node \c v.
114    static int id(Node v) { return v.n; }
115    /// Edge ID.
116   
117    /// The ID of a valid Edge is a nonnegative integer not greater than
118    /// \ref maxEdgeId(). The range of the ID's is not surely continuous
119    /// and the greatest edge ID can be actually less then \ref maxEdgeId().
120    ///
121    /// The ID of the \ref INVALID edge is -1.
122    ///\return The ID of the edge \c e.
123    static int id(Edge e) { return e.n; }
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].tail=u.n; edges[e.n].head=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].tail!=v.n) e = edges[e].next_out;
218      prev.n=e;
219      return prev;
220    }
221
222  };
223
224  typedef AlterableGraphExtender<SmartGraphBase> AlterableSmartGraphBase;
225  typedef IterableGraphExtender<AlterableSmartGraphBase> IterableSmartGraphBase;
226  typedef IdMappableGraphExtender<IterableSmartGraphBase> IdMappableSmartGraphBase;
227  typedef DefaultMappableGraphExtender<IdMappableSmartGraphBase> MappableSmartGraphBase;
228  typedef ExtendableGraphExtender<MappableSmartGraphBase> ExtendableSmartGraphBase;
229  typedef ClearableGraphExtender<ExtendableSmartGraphBase> ClearableSmartGraphBase;
230
231  ///A smart graph class.
232
233  ///This is a simple and fast graph implementation.
234  ///It is also quite memory efficient, but at the price
235  ///that <b> it does support only limited (only stack-like)
236  ///node and edge deletions</b>.
237  ///It conforms to
238  ///the \ref concept::ExtendableGraph "ExtendableGraph" concept.
239  ///\sa concept::ExtendableGraph.
240  ///
241  ///\todo Some member functions could be \c static.
242  ///
243  ///\author Alpar Juttner
244  class SmartGraph :public ClearableSmartGraphBase {
245  public:
246    /// Finds an edge between two nodes.
247   
248    /// Finds an edge from node \c u to node \c v.
249    ///
250    /// If \c prev is \ref INVALID (this is the default value), then
251    /// it finds the first edge from \c u to \c v. Otherwise it looks for
252    /// the next edge from \c u to \c v after \c prev.
253    /// \return The found edge or \ref INVALID if there is no such an edge.
254    ///
255    /// Thus you can iterate through each edge from \c u to \c v as it follows.
256    /// \code
257    /// for(Edge e=G.findEdge(u,v);e!=INVALID;e=G.findEdge(u,v,e)) {
258    ///   ...
259    /// }
260    /// \endcode
261    /// \todo Possibly it should be a global function.
262    Edge findEdge(Node u,Node v, Edge prev = INVALID)
263    {
264      return _findEdge(u,v,prev);
265    }
266   
267    ///Internal data structure to store snapshots
268   
269    ///\ingroup graphs
270    ///\sa makeSnapShot()
271    ///\sa rollBack()
272    struct SnapShot
273    {
274      unsigned int node_num;
275      unsigned int edge_num;
276    };
277   
278    ///Make a snapshot of the graph.
279
280    ///Make a snapshot of the graph.
281    ///
282    ///The newly added nodes and edges can be removed using the
283    ///rollBack() function.
284    ///
285    ///\return An stucture SnapShot describing the pesent state of the
286    ///graph.
287    ///\note After you rolled back to a state, you cannot roll "back" to
288    ///a later state, in other word you cannot add again the edges deleted
289    ///by rollBack().
290    ///\todo This function might be called saveState() or getState().
291    SnapShot makeSnapShot()
292    {
293      SnapShot s;
294      s.node_num=nodes.size();
295      s.edge_num=edges.size();
296      return s;
297    }
298   
299    ///Undo the changes until a snapshot.
300
301    ///Undo the changes until a snapshot created by makeSnapShot().
302    ///
303    ///\param s an internal stucture given back by makeSnapShot()
304    ///\note After you rolled back to a state, you cannot "roll forward" to
305    ///a later state, in other word you cannot add again the edges deleted
306    ///by rollBack().
307    ///
308    ///\todo This function might be called undo().
309   
310    void rollBack(const SnapShot &s)
311    {
312      while(s.edge_num>edges.size()) {
313        edge_observers.erase(Edge(edges.size()-1));
314        nodes[edges.back().head].first_in=edges.back().next_in;
315        nodes[edges.back().tail].first_out=edges.back().next_out;
316        edges.pop_back();
317      }
318      //nodes.resize(s.nodes_num);
319      while(s.node_num>nodes.size()) {
320        node_observers.erase(Node(nodes.size()-1));
321        nodes.pop_back();
322      }
323    }
324  };
325 
326  template <>
327  int countNodes<SmartGraph>(const SmartGraph& graph) {
328    return graph.nodeNum();
329  }
330
331  template <>
332  int countEdges<SmartGraph>(const SmartGraph& graph) {
333    return graph.edgeNum();
334  }
335
336  /// @} 
337} //namespace lemon
338
339
340
341
342#endif //LEMON_SMART_GRAPH_H
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