COIN-OR::LEMON - Graph Library

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1/* -*- mode: C++; indent-tabs-mode: nil; -*-
2 *
3 * This file is a part of LEMON, a generic C++ optimization library.
4 *
5 * Copyright (C) 2003-2009
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
19namespace lemon {
20
21/**
22@defgroup datas Data Structures
23This group describes the several data structures implemented in LEMON.
24*/
25
26/**
27@defgroup graphs Graph Structures
28@ingroup datas
29\brief Graph structures implemented in LEMON.
30
31The implementation of combinatorial algorithms heavily relies on
32efficient graph implementations. LEMON offers data structures which are
33planned to be easily used in an experimental phase of implementation studies,
34and thereafter the program code can be made efficient by small modifications.
35
36The most efficient implementation of diverse applications require the
37usage of different physical graph implementations. These differences
38appear in the size of graph we require to handle, memory or time usage
39limitations or in the set of operations through which the graph can be
40accessed.  LEMON provides several physical graph structures to meet
41the diverging requirements of the possible users.  In order to save on
42running time or on memory usage, some structures may fail to provide
43some graph features like arc/edge or node deletion.
44
45Alteration of standard containers need a very limited number of
46operations, these together satisfy the everyday requirements.
47In the case of graph structures, different operations are needed which do
48not alter the physical graph, but gives another view. If some nodes or
49arcs have to be hidden or the reverse oriented graph have to be used, then
50this is the case. It also may happen that in a flow implementation
51the residual graph can be accessed by another algorithm, or a node-set
52is to be shrunk for another algorithm.
53LEMON also provides a variety of graphs for these requirements called
54\ref graph_adaptors "graph adaptors". Adaptors cannot be used alone but only
55in conjunction with other graph representations.
56
57You are free to use the graph structure that fit your requirements
58the best, most graph algorithms and auxiliary data structures can be used
59with any graph structure.
60
61<b>See also:</b> \ref graph_concepts "Graph Structure Concepts".
62*/
63
64/**
65@defgroup graph_adaptors Adaptor Classes for Graphs
66@ingroup graphs
67\brief Adaptor classes for digraphs and graphs
68
69This group contains several useful adaptor classes for digraphs and graphs.
70
71The main parts of LEMON are the different graph structures, generic
72graph algorithms, graph concepts, which couple them, and graph
73adaptors. While the previous notions are more or less clear, the
74latter one needs further explanation. Graph adaptors are graph classes
75which serve for considering graph structures in different ways.
76
77A short example makes this much clearer.  Suppose that we have an
78instance \c g of a directed graph type, say ListDigraph and an algorithm
79\code
80template <typename Digraph>
81int algorithm(const Digraph&);
82\endcode
83is needed to run on the reverse oriented graph.  It may be expensive
84(in time or in memory usage) to copy \c g with the reversed
85arcs.  In this case, an adaptor class is used, which (according
86to LEMON \ref concepts::Digraph "digraph concepts") works as a digraph.
87The adaptor uses the original digraph structure and digraph operations when
88methods of the reversed oriented graph are called.  This means that the adaptor
89have minor memory usage, and do not perform sophisticated algorithmic
90actions.  The purpose of it is to give a tool for the cases when a
91graph have to be used in a specific alteration.  If this alteration is
92obtained by a usual construction like filtering the node or the arc set or
93considering a new orientation, then an adaptor is worthwhile to use.
94To come back to the reverse oriented graph, in this situation
95\code
96template<typename Digraph> class ReverseDigraph;
97\endcode
98template class can be used. The code looks as follows
99\code
100ListDigraph g;
101ReverseDigraph<ListDigraph> rg(g);
102int result = algorithm(rg);
103\endcode
104During running the algorithm, the original digraph \c g is untouched.
105This techniques give rise to an elegant code, and based on stable
106graph adaptors, complex algorithms can be implemented easily.
107
108In flow, circulation and matching problems, the residual
109graph is of particular importance. Combining an adaptor implementing
110this with shortest path algorithms or minimum mean cycle algorithms,
111a range of weighted and cardinality optimization algorithms can be
112obtained. For other examples, the interested user is referred to the
113detailed documentation of particular adaptors.
114
115The behavior of graph adaptors can be very different. Some of them keep
116capabilities of the original graph while in other cases this would be
117meaningless. This means that the concepts that they meet depend
118on the graph adaptor, and the wrapped graph.
119For example, if an arc of a reversed digraph is deleted, this is carried
120out by deleting the corresponding arc of the original digraph, thus the
121adaptor modifies the original digraph.
122However in case of a residual digraph, this operation has no sense.
123
124Let us stand one more example here to simplify your work.
125ReverseDigraph has constructor
126\code
127ReverseDigraph(Digraph& digraph);
128\endcode
129This means that in a situation, when a <tt>const %ListDigraph&</tt>
130reference to a graph is given, then it have to be instantiated with
131<tt>Digraph=const %ListDigraph</tt>.
132\code
133int algorithm1(const ListDigraph& g) {
134  ReverseDigraph<const ListDigraph> rg(g);
135  return algorithm2(rg);
136}
137\endcode
138*/
139
140/**
141@defgroup semi_adaptors Semi-Adaptor Classes for Graphs
142@ingroup graphs
143\brief Graph types between real graphs and graph adaptors.
144
145This group describes some graph types between real graphs and graph adaptors.
146These classes wrap graphs to give new functionality as the adaptors do it.
147On the other hand they are not light-weight structures as the adaptors.
148*/
149
150/**
151@defgroup maps Maps
152@ingroup datas
153\brief Map structures implemented in LEMON.
154
155This group describes the map structures implemented in LEMON.
156
157LEMON provides several special purpose maps and map adaptors that e.g. combine
158new maps from existing ones.
159
160<b>See also:</b> \ref map_concepts "Map Concepts".
161*/
162
163/**
164@defgroup graph_maps Graph Maps
165@ingroup maps
166\brief Special graph-related maps.
167
168This group describes maps that are specifically designed to assign
169values to the nodes and arcs/edges of graphs.
170
171If you are looking for the standard graph maps (\c NodeMap, \c ArcMap,
172\c EdgeMap), see the \ref graph_concepts "Graph Structure Concepts".
173*/
174
175/**
176\defgroup map_adaptors Map Adaptors
177\ingroup maps
178\brief Tools to create new maps from existing ones
179
180This group describes map adaptors that are used to create "implicit"
181maps from other maps.
182
183Most of them are \ref concepts::ReadMap "read-only maps".
184They can make arithmetic and logical operations between one or two maps
185(negation, shifting, addition, multiplication, logical 'and', 'or',
186'not' etc.) or e.g. convert a map to another one of different Value type.
187
188The typical usage of this classes is passing implicit maps to
189algorithms.  If a function type algorithm is called then the function
190type map adaptors can be used comfortable. For example let's see the
191usage of map adaptors with the \c graphToEps() function.
192\code
193  Color nodeColor(int deg) {
194    if (deg >= 2) {
195      return Color(0.5, 0.0, 0.5);
196    } else if (deg == 1) {
197      return Color(1.0, 0.5, 1.0);
198    } else {
199      return Color(0.0, 0.0, 0.0);
200    }
201  }
202
203  Digraph::NodeMap<int> degree_map(graph);
204
205  graphToEps(graph, "graph.eps")
206    .coords(coords).scaleToA4().undirected()
207    .nodeColors(composeMap(functorToMap(nodeColor), degree_map))
208    .run();
209\endcode
210The \c functorToMap() function makes an \c int to \c Color map from the
211\c nodeColor() function. The \c composeMap() compose the \c degree_map
212and the previously created map. The composed map is a proper function to
213get the color of each node.
214
215The usage with class type algorithms is little bit harder. In this
216case the function type map adaptors can not be used, because the
217function map adaptors give back temporary objects.
218\code
219  Digraph graph;
220
221  typedef Digraph::ArcMap<double> DoubleArcMap;
222  DoubleArcMap length(graph);
223  DoubleArcMap speed(graph);
224
225  typedef DivMap<DoubleArcMap, DoubleArcMap> TimeMap;
226  TimeMap time(length, speed);
227
228  Dijkstra<Digraph, TimeMap> dijkstra(graph, time);
229  dijkstra.run(source, target);
230\endcode
231We have a length map and a maximum speed map on the arcs of a digraph.
232The minimum time to pass the arc can be calculated as the division of
233the two maps which can be done implicitly with the \c DivMap template
234class. We use the implicit minimum time map as the length map of the
235\c Dijkstra algorithm.
236*/
237
238/**
239@defgroup matrices Matrices
240@ingroup datas
241\brief Two dimensional data storages implemented in LEMON.
242
243This group describes two dimensional data storages implemented in LEMON.
244*/
245
246/**
247@defgroup paths Path Structures
248@ingroup datas
249\brief %Path structures implemented in LEMON.
250
251This group describes the path structures implemented in LEMON.
252
253LEMON provides flexible data structures to work with paths.
254All of them have similar interfaces and they can be copied easily with
255assignment operators and copy constructors. This makes it easy and
256efficient to have e.g. the Dijkstra algorithm to store its result in
257any kind of path structure.
258
259\sa lemon::concepts::Path
260*/
261
262/**
263@defgroup auxdat Auxiliary Data Structures
264@ingroup datas
265\brief Auxiliary data structures implemented in LEMON.
266
267This group describes some data structures implemented in LEMON in
268order to make it easier to implement combinatorial algorithms.
269*/
270
271/**
272@defgroup algs Algorithms
273\brief This group describes the several algorithms
274implemented in LEMON.
275
276This group describes the several algorithms
277implemented in LEMON.
278*/
279
280/**
281@defgroup search Graph Search
282@ingroup algs
283\brief Common graph search algorithms.
284
285This group describes the common graph search algorithms, namely
286\e breadth-first \e search (BFS) and \e depth-first \e search (DFS).
287*/
288
289/**
290@defgroup shortest_path Shortest Path Algorithms
291@ingroup algs
292\brief Algorithms for finding shortest paths.
293
294This group describes the algorithms for finding shortest paths in digraphs.
295
296 - \ref Dijkstra algorithm for finding shortest paths from a source node
297   when all arc lengths are non-negative.
298 - \ref BellmanFord "Bellman-Ford" algorithm for finding shortest paths
299   from a source node when arc lenghts can be either positive or negative,
300   but the digraph should not contain directed cycles with negative total
301   length.
302 - \ref FloydWarshall "Floyd-Warshall" and \ref Johnson "Johnson" algorithms
303   for solving the \e all-pairs \e shortest \e paths \e problem when arc
304   lenghts can be either positive or negative, but the digraph should
305   not contain directed cycles with negative total length.
306 - \ref Suurballe A successive shortest path algorithm for finding
307   arc-disjoint paths between two nodes having minimum total length.
308*/
309
310/**
311@defgroup max_flow Maximum Flow Algorithms
312@ingroup algs
313\brief Algorithms for finding maximum flows.
314
315This group describes the algorithms for finding maximum flows and
316feasible circulations.
317
318The \e maximum \e flow \e problem is to find a flow of maximum value between
319a single source and a single target. Formally, there is a \f$G=(V,A)\f$
320digraph, a \f$cap:A\rightarrow\mathbf{R}^+_0\f$ capacity function and
321\f$s, t \in V\f$ source and target nodes.
322A maximum flow is an \f$f:A\rightarrow\mathbf{R}^+_0\f$ solution of the
323following optimization problem.
324
325\f[ \max\sum_{a\in\delta_{out}(s)}f(a) - \sum_{a\in\delta_{in}(s)}f(a) \f]
326\f[ \sum_{a\in\delta_{out}(v)} f(a) = \sum_{a\in\delta_{in}(v)} f(a)
327    \qquad \forall v\in V\setminus\{s,t\} \f]
328\f[ 0 \leq f(a) \leq cap(a) \qquad \forall a\in A \f]
329
330LEMON contains several algorithms for solving maximum flow problems:
331- \ref EdmondsKarp Edmonds-Karp algorithm.
332- \ref Preflow Goldberg-Tarjan's preflow push-relabel algorithm.
333- \ref DinitzSleatorTarjan Dinitz's blocking flow algorithm with dynamic trees.
334- \ref GoldbergTarjan Preflow push-relabel algorithm with dynamic trees.
335
336In most cases the \ref Preflow "Preflow" algorithm provides the
337fastest method for computing a maximum flow. All implementations
338provides functions to also query the minimum cut, which is the dual
339problem of the maximum flow.
340*/
341
342/**
343@defgroup min_cost_flow Minimum Cost Flow Algorithms
344@ingroup algs
345
346\brief Algorithms for finding minimum cost flows and circulations.
347
348This group describes the algorithms for finding minimum cost flows and
349circulations.
350
351The \e minimum \e cost \e flow \e problem is to find a feasible flow of
352minimum total cost from a set of supply nodes to a set of demand nodes
353in a network with capacity constraints and arc costs.
354Formally, let \f$G=(V,A)\f$ be a digraph,
355\f$lower, upper: A\rightarrow\mathbf{Z}^+_0\f$ denote the lower and
356upper bounds for the flow values on the arcs,
357\f$cost: A\rightarrow\mathbf{Z}^+_0\f$ denotes the cost per unit flow
358on the arcs, and
359\f$supply: V\rightarrow\mathbf{Z}\f$ denotes the supply/demand values
360of the nodes.
361A minimum cost flow is an \f$f:A\rightarrow\mathbf{R}^+_0\f$ solution of
362the following optimization problem.
363
364\f[ \min\sum_{a\in A} f(a) cost(a) \f]
365\f[ \sum_{a\in\delta_{out}(v)} f(a) - \sum_{a\in\delta_{in}(v)} f(a) =
366    supply(v) \qquad \forall v\in V \f]
367\f[ lower(a) \leq f(a) \leq upper(a) \qquad \forall a\in A \f]
368
369LEMON contains several algorithms for solving minimum cost flow problems:
370 - \ref CycleCanceling Cycle-canceling algorithms.
371 - \ref CapacityScaling Successive shortest path algorithm with optional
372   capacity scaling.
373 - \ref CostScaling Push-relabel and augment-relabel algorithms based on
374   cost scaling.
375 - \ref NetworkSimplex Primal network simplex algorithm with various
376   pivot strategies.
377*/
378
379/**
380@defgroup min_cut Minimum Cut Algorithms
381@ingroup algs
382
383\brief Algorithms for finding minimum cut in graphs.
384
385This group describes the algorithms for finding minimum cut in graphs.
386
387The \e minimum \e cut \e problem is to find a non-empty and non-complete
388\f$X\f$ subset of the nodes with minimum overall capacity on
389outgoing arcs. Formally, there is a \f$G=(V,A)\f$ digraph, a
390\f$cap: A\rightarrow\mathbf{R}^+_0\f$ capacity function. The minimum
391cut is the \f$X\f$ solution of the next optimization problem:
392
393\f[ \min_{X \subset V, X\not\in \{\emptyset, V\}}
394    \sum_{uv\in A, u\in X, v\not\in X}cap(uv) \f]
395
396LEMON contains several algorithms related to minimum cut problems:
397
398- \ref HaoOrlin "Hao-Orlin algorithm" for calculating minimum cut
399  in directed graphs.
400- \ref NagamochiIbaraki "Nagamochi-Ibaraki algorithm" for
401  calculating minimum cut in undirected graphs.
402- \ref GomoryHuTree "Gomory-Hu tree computation" for calculating
403  all-pairs minimum cut in undirected graphs.
404
405If you want to find minimum cut just between two distinict nodes,
406see the \ref max_flow "maximum flow problem".
407*/
408
409/**
410@defgroup graph_prop Connectivity and Other Graph Properties
411@ingroup algs
412\brief Algorithms for discovering the graph properties
413
414This group describes the algorithms for discovering the graph properties
415like connectivity, bipartiteness, euler property, simplicity etc.
416
417\image html edge_biconnected_components.png
418\image latex edge_biconnected_components.eps "bi-edge-connected components" width=\textwidth
419*/
420
421/**
422@defgroup planar Planarity Embedding and Drawing
423@ingroup algs
424\brief Algorithms for planarity checking, embedding and drawing
425
426This group describes the algorithms for planarity checking,
427embedding and drawing.
428
429\image html planar.png
430\image latex planar.eps "Plane graph" width=\textwidth
431*/
432
433/**
434@defgroup matching Matching Algorithms
435@ingroup algs
436\brief Algorithms for finding matchings in graphs and bipartite graphs.
437
438This group contains algorithm objects and functions to calculate
439matchings in graphs and bipartite graphs. The general matching problem is
440finding a subset of the arcs which does not shares common endpoints.
441
442There are several different algorithms for calculate matchings in
443graphs.  The matching problems in bipartite graphs are generally
444easier than in general graphs. The goal of the matching optimization
445can be finding maximum cardinality, maximum weight or minimum cost
446matching. The search can be constrained to find perfect or
447maximum cardinality matching.
448
449The matching algorithms implemented in LEMON:
450- \ref MaxBipartiteMatching Hopcroft-Karp augmenting path algorithm
451  for calculating maximum cardinality matching in bipartite graphs.
452- \ref PrBipartiteMatching Push-relabel algorithm
453  for calculating maximum cardinality matching in bipartite graphs.
454- \ref MaxWeightedBipartiteMatching
455  Successive shortest path algorithm for calculating maximum weighted
456  matching and maximum weighted bipartite matching in bipartite graphs.
457- \ref MinCostMaxBipartiteMatching
458  Successive shortest path algorithm for calculating minimum cost maximum
459  matching in bipartite graphs.
460- \ref MaxMatching Edmond's blossom shrinking algorithm for calculating
461  maximum cardinality matching in general graphs.
462- \ref MaxWeightedMatching Edmond's blossom shrinking algorithm for calculating
463  maximum weighted matching in general graphs.
464- \ref MaxWeightedPerfectMatching
465  Edmond's blossom shrinking algorithm for calculating maximum weighted
466  perfect matching in general graphs.
467
468\image html bipartite_matching.png
469\image latex bipartite_matching.eps "Bipartite Matching" width=\textwidth
470*/
471
472/**
473@defgroup spantree Minimum Spanning Tree Algorithms
474@ingroup algs
475\brief Algorithms for finding a minimum cost spanning tree in a graph.
476
477This group describes the algorithms for finding a minimum cost spanning
478tree in a graph.
479*/
480
481/**
482@defgroup auxalg Auxiliary Algorithms
483@ingroup algs
484\brief Auxiliary algorithms implemented in LEMON.
485
486This group describes some algorithms implemented in LEMON
487in order to make it easier to implement complex algorithms.
488*/
489
490/**
491@defgroup approx Approximation Algorithms
492@ingroup algs
493\brief Approximation algorithms.
494
495This group describes the approximation and heuristic algorithms
496implemented in LEMON.
497*/
498
499/**
500@defgroup gen_opt_group General Optimization Tools
501\brief This group describes some general optimization frameworks
502implemented in LEMON.
503
504This group describes some general optimization frameworks
505implemented in LEMON.
506*/
507
508/**
509@defgroup lp_group Lp and Mip Solvers
510@ingroup gen_opt_group
511\brief Lp and Mip solver interfaces for LEMON.
512
513This group describes Lp and Mip solver interfaces for LEMON. The
514various LP solvers could be used in the same manner with this
515interface.
516*/
517
518/**
519@defgroup lp_utils Tools for Lp and Mip Solvers
520@ingroup lp_group
521\brief Helper tools to the Lp and Mip solvers.
522
523This group adds some helper tools to general optimization framework
524implemented in LEMON.
525*/
526
527/**
528@defgroup metah Metaheuristics
529@ingroup gen_opt_group
530\brief Metaheuristics for LEMON library.
531
532This group describes some metaheuristic optimization tools.
533*/
534
535/**
536@defgroup utils Tools and Utilities
537\brief Tools and utilities for programming in LEMON
538
539Tools and utilities for programming in LEMON.
540*/
541
542/**
543@defgroup gutils Basic Graph Utilities
544@ingroup utils
545\brief Simple basic graph utilities.
546
547This group describes some simple basic graph utilities.
548*/
549
550/**
551@defgroup misc Miscellaneous Tools
552@ingroup utils
553\brief Tools for development, debugging and testing.
554
555This group describes several useful tools for development,
556debugging and testing.
557*/
558
559/**
560@defgroup timecount Time Measuring and Counting
561@ingroup misc
562\brief Simple tools for measuring the performance of algorithms.
563
564This group describes simple tools for measuring the performance
565of algorithms.
566*/
567
568/**
569@defgroup exceptions Exceptions
570@ingroup utils
571\brief Exceptions defined in LEMON.
572
573This group describes the exceptions defined in LEMON.
574*/
575
576/**
577@defgroup io_group Input-Output
578\brief Graph Input-Output methods
579
580This group describes the tools for importing and exporting graphs
581and graph related data. Now it supports the \ref lgf-format
582"LEMON Graph Format", the \c DIMACS format and the encapsulated
583postscript (EPS) format.
584*/
585
586/**
587@defgroup lemon_io LEMON Graph Format
588@ingroup io_group
589\brief Reading and writing LEMON Graph Format.
590
591This group describes methods for reading and writing
592\ref lgf-format "LEMON Graph Format".
593*/
594
595/**
596@defgroup eps_io Postscript Exporting
597@ingroup io_group
598\brief General \c EPS drawer and graph exporter
599
600This group describes general \c EPS drawing methods and special
601graph exporting tools.
602*/
603
604/**
605@defgroup dimacs_group DIMACS format
606@ingroup io_group
607\brief Read and write files in DIMACS format
608
609Tools to read a digraph from or write it to a file in DIMACS format data.
610*/
611
612/**
613@defgroup nauty_group NAUTY Format
614@ingroup io_group
615\brief Read \e Nauty format
616
617Tool to read graphs from \e Nauty format data.
618*/
619
620/**
621@defgroup concept Concepts
622\brief Skeleton classes and concept checking classes
623
624This group describes the data/algorithm skeletons and concept checking
625classes implemented in LEMON.
626
627The purpose of the classes in this group is fourfold.
628
629- These classes contain the documentations of the %concepts. In order
630  to avoid document multiplications, an implementation of a concept
631  simply refers to the corresponding concept class.
632
633- These classes declare every functions, <tt>typedef</tt>s etc. an
634  implementation of the %concepts should provide, however completely
635  without implementations and real data structures behind the
636  interface. On the other hand they should provide nothing else. All
637  the algorithms working on a data structure meeting a certain concept
638  should compile with these classes. (Though it will not run properly,
639  of course.) In this way it is easily to check if an algorithm
640  doesn't use any extra feature of a certain implementation.
641
642- The concept descriptor classes also provide a <em>checker class</em>
643  that makes it possible to check whether a certain implementation of a
644  concept indeed provides all the required features.
645
646- Finally, They can serve as a skeleton of a new implementation of a concept.
647*/
648
649/**
650@defgroup graph_concepts Graph Structure Concepts
651@ingroup concept
652\brief Skeleton and concept checking classes for graph structures
653
654This group describes the skeletons and concept checking classes of LEMON's
655graph structures and helper classes used to implement these.
656*/
657
658/**
659@defgroup map_concepts Map Concepts
660@ingroup concept
661\brief Skeleton and concept checking classes for maps
662
663This group describes the skeletons and concept checking classes of maps.
664*/
665
666/**
667\anchor demoprograms
668
669@defgroup demos Demo Programs
670
671Some demo programs are listed here. Their full source codes can be found in
672the \c demo subdirectory of the source tree.
673
674It order to compile them, use <tt>--enable-demo</tt> configure option when
675build the library.
676*/
677
678/**
679@defgroup tools Standalone Utility Applications
680
681Some utility applications are listed here.
682
683The standard compilation procedure (<tt>./configure;make</tt>) will compile
684them, as well.
685*/
686
687}
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