doc/groups.dox
author Peter Kovacs <kpeter@inf.elte.hu>
Tue, 15 Mar 2011 19:32:21 +0100
changeset 936 ddd3c0d3d9bf
parent 904 c279b19abc62
child 1002 f63ba40a60f4
permissions -rw-r--r--
Implement the scaling Price Refinement heuristic in CostScaling (#417)
instead of Early Termination.

These two heuristics are similar, but the newer one is faster
and not only makes it possible to skip some epsilon phases, but
it can improve the performance of the other phases, as well.
alpar@209
     1
/* -*- mode: C++; indent-tabs-mode: nil; -*-
alpar@40
     2
 *
alpar@209
     3
 * This file is a part of LEMON, a generic C++ optimization library.
alpar@40
     4
 *
alpar@877
     5
 * Copyright (C) 2003-2010
alpar@40
     6
 * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
alpar@40
     7
 * (Egervary Research Group on Combinatorial Optimization, EGRES).
alpar@40
     8
 *
alpar@40
     9
 * Permission to use, modify and distribute this software is granted
alpar@40
    10
 * provided that this copyright notice appears in all copies. For
alpar@40
    11
 * precise terms see the accompanying LICENSE file.
alpar@40
    12
 *
alpar@40
    13
 * This software is provided "AS IS" with no warranty of any kind,
alpar@40
    14
 * express or implied, and with no claim as to its suitability for any
alpar@40
    15
 * purpose.
alpar@40
    16
 *
alpar@40
    17
 */
alpar@40
    18
kpeter@406
    19
namespace lemon {
kpeter@406
    20
alpar@40
    21
/**
alpar@40
    22
@defgroup datas Data Structures
kpeter@559
    23
This group contains the several data structures implemented in LEMON.
alpar@40
    24
*/
alpar@40
    25
alpar@40
    26
/**
alpar@40
    27
@defgroup graphs Graph Structures
alpar@40
    28
@ingroup datas
alpar@40
    29
\brief Graph structures implemented in LEMON.
alpar@40
    30
alpar@209
    31
The implementation of combinatorial algorithms heavily relies on
alpar@209
    32
efficient graph implementations. LEMON offers data structures which are
alpar@209
    33
planned to be easily used in an experimental phase of implementation studies,
alpar@209
    34
and thereafter the program code can be made efficient by small modifications.
alpar@40
    35
alpar@40
    36
The most efficient implementation of diverse applications require the
alpar@40
    37
usage of different physical graph implementations. These differences
alpar@40
    38
appear in the size of graph we require to handle, memory or time usage
alpar@40
    39
limitations or in the set of operations through which the graph can be
alpar@40
    40
accessed.  LEMON provides several physical graph structures to meet
alpar@40
    41
the diverging requirements of the possible users.  In order to save on
alpar@40
    42
running time or on memory usage, some structures may fail to provide
kpeter@83
    43
some graph features like arc/edge or node deletion.
alpar@40
    44
alpar@209
    45
Alteration of standard containers need a very limited number of
alpar@209
    46
operations, these together satisfy the everyday requirements.
alpar@209
    47
In the case of graph structures, different operations are needed which do
alpar@209
    48
not alter the physical graph, but gives another view. If some nodes or
kpeter@83
    49
arcs have to be hidden or the reverse oriented graph have to be used, then
alpar@209
    50
this is the case. It also may happen that in a flow implementation
alpar@209
    51
the residual graph can be accessed by another algorithm, or a node-set
alpar@209
    52
is to be shrunk for another algorithm.
alpar@209
    53
LEMON also provides a variety of graphs for these requirements called
alpar@209
    54
\ref graph_adaptors "graph adaptors". Adaptors cannot be used alone but only
alpar@209
    55
in conjunction with other graph representations.
alpar@40
    56
alpar@40
    57
You are free to use the graph structure that fit your requirements
alpar@40
    58
the best, most graph algorithms and auxiliary data structures can be used
kpeter@314
    59
with any graph structure.
kpeter@314
    60
kpeter@314
    61
<b>See also:</b> \ref graph_concepts "Graph Structure Concepts".
alpar@40
    62
*/
alpar@40
    63
alpar@40
    64
/**
kpeter@451
    65
@defgroup graph_adaptors Adaptor Classes for Graphs
deba@416
    66
@ingroup graphs
kpeter@451
    67
\brief Adaptor classes for digraphs and graphs
kpeter@451
    68
kpeter@451
    69
This group contains several useful adaptor classes for digraphs and graphs.
deba@416
    70
deba@416
    71
The main parts of LEMON are the different graph structures, generic
kpeter@451
    72
graph algorithms, graph concepts, which couple them, and graph
deba@416
    73
adaptors. While the previous notions are more or less clear, the
deba@416
    74
latter one needs further explanation. Graph adaptors are graph classes
deba@416
    75
which serve for considering graph structures in different ways.
deba@416
    76
deba@416
    77
A short example makes this much clearer.  Suppose that we have an
kpeter@451
    78
instance \c g of a directed graph type, say ListDigraph and an algorithm
deba@416
    79
\code
deba@416
    80
template <typename Digraph>
deba@416
    81
int algorithm(const Digraph&);
deba@416
    82
\endcode
deba@416
    83
is needed to run on the reverse oriented graph.  It may be expensive
deba@416
    84
(in time or in memory usage) to copy \c g with the reversed
deba@416
    85
arcs.  In this case, an adaptor class is used, which (according
kpeter@451
    86
to LEMON \ref concepts::Digraph "digraph concepts") works as a digraph.
kpeter@451
    87
The adaptor uses the original digraph structure and digraph operations when
kpeter@451
    88
methods of the reversed oriented graph are called.  This means that the adaptor
kpeter@451
    89
have minor memory usage, and do not perform sophisticated algorithmic
deba@416
    90
actions.  The purpose of it is to give a tool for the cases when a
deba@416
    91
graph have to be used in a specific alteration.  If this alteration is
kpeter@451
    92
obtained by a usual construction like filtering the node or the arc set or
deba@416
    93
considering a new orientation, then an adaptor is worthwhile to use.
deba@416
    94
To come back to the reverse oriented graph, in this situation
deba@416
    95
\code
deba@416
    96
template<typename Digraph> class ReverseDigraph;
deba@416
    97
\endcode
deba@416
    98
template class can be used. The code looks as follows
deba@416
    99
\code
deba@416
   100
ListDigraph g;
kpeter@451
   101
ReverseDigraph<ListDigraph> rg(g);
deba@416
   102
int result = algorithm(rg);
deba@416
   103
\endcode
kpeter@451
   104
During running the algorithm, the original digraph \c g is untouched.
kpeter@451
   105
This techniques give rise to an elegant code, and based on stable
deba@416
   106
graph adaptors, complex algorithms can be implemented easily.
deba@416
   107
kpeter@451
   108
In flow, circulation and matching problems, the residual
deba@416
   109
graph is of particular importance. Combining an adaptor implementing
kpeter@451
   110
this with shortest path algorithms or minimum mean cycle algorithms,
deba@416
   111
a range of weighted and cardinality optimization algorithms can be
deba@416
   112
obtained. For other examples, the interested user is referred to the
deba@416
   113
detailed documentation of particular adaptors.
deba@416
   114
deba@416
   115
The behavior of graph adaptors can be very different. Some of them keep
deba@416
   116
capabilities of the original graph while in other cases this would be
kpeter@451
   117
meaningless. This means that the concepts that they meet depend
kpeter@451
   118
on the graph adaptor, and the wrapped graph.
kpeter@451
   119
For example, if an arc of a reversed digraph is deleted, this is carried
kpeter@451
   120
out by deleting the corresponding arc of the original digraph, thus the
kpeter@451
   121
adaptor modifies the original digraph.
kpeter@451
   122
However in case of a residual digraph, this operation has no sense.
deba@416
   123
deba@416
   124
Let us stand one more example here to simplify your work.
kpeter@451
   125
ReverseDigraph has constructor
deba@416
   126
\code
deba@416
   127
ReverseDigraph(Digraph& digraph);
deba@416
   128
\endcode
kpeter@451
   129
This means that in a situation, when a <tt>const %ListDigraph&</tt>
deba@416
   130
reference to a graph is given, then it have to be instantiated with
kpeter@451
   131
<tt>Digraph=const %ListDigraph</tt>.
deba@416
   132
\code
deba@416
   133
int algorithm1(const ListDigraph& g) {
kpeter@451
   134
  ReverseDigraph<const ListDigraph> rg(g);
deba@416
   135
  return algorithm2(rg);
deba@416
   136
}
deba@416
   137
\endcode
deba@416
   138
*/
deba@416
   139
deba@416
   140
/**
alpar@209
   141
@defgroup maps Maps
alpar@40
   142
@ingroup datas
kpeter@50
   143
\brief Map structures implemented in LEMON.
alpar@40
   144
kpeter@559
   145
This group contains the map structures implemented in LEMON.
kpeter@50
   146
kpeter@314
   147
LEMON provides several special purpose maps and map adaptors that e.g. combine
alpar@40
   148
new maps from existing ones.
kpeter@314
   149
kpeter@314
   150
<b>See also:</b> \ref map_concepts "Map Concepts".
alpar@40
   151
*/
alpar@40
   152
alpar@40
   153
/**
alpar@209
   154
@defgroup graph_maps Graph Maps
alpar@40
   155
@ingroup maps
kpeter@83
   156
\brief Special graph-related maps.
alpar@40
   157
kpeter@559
   158
This group contains maps that are specifically designed to assign
kpeter@406
   159
values to the nodes and arcs/edges of graphs.
kpeter@406
   160
kpeter@406
   161
If you are looking for the standard graph maps (\c NodeMap, \c ArcMap,
kpeter@406
   162
\c EdgeMap), see the \ref graph_concepts "Graph Structure Concepts".
alpar@40
   163
*/
alpar@40
   164
alpar@40
   165
/**
alpar@40
   166
\defgroup map_adaptors Map Adaptors
alpar@40
   167
\ingroup maps
alpar@40
   168
\brief Tools to create new maps from existing ones
alpar@40
   169
kpeter@559
   170
This group contains map adaptors that are used to create "implicit"
kpeter@50
   171
maps from other maps.
alpar@40
   172
kpeter@406
   173
Most of them are \ref concepts::ReadMap "read-only maps".
kpeter@83
   174
They can make arithmetic and logical operations between one or two maps
kpeter@83
   175
(negation, shifting, addition, multiplication, logical 'and', 'or',
kpeter@83
   176
'not' etc.) or e.g. convert a map to another one of different Value type.
alpar@40
   177
kpeter@50
   178
The typical usage of this classes is passing implicit maps to
alpar@40
   179
algorithms.  If a function type algorithm is called then the function
alpar@40
   180
type map adaptors can be used comfortable. For example let's see the
kpeter@314
   181
usage of map adaptors with the \c graphToEps() function.
alpar@40
   182
\code
alpar@40
   183
  Color nodeColor(int deg) {
alpar@40
   184
    if (deg >= 2) {
alpar@40
   185
      return Color(0.5, 0.0, 0.5);
alpar@40
   186
    } else if (deg == 1) {
alpar@40
   187
      return Color(1.0, 0.5, 1.0);
alpar@40
   188
    } else {
alpar@40
   189
      return Color(0.0, 0.0, 0.0);
alpar@40
   190
    }
alpar@40
   191
  }
alpar@209
   192
kpeter@83
   193
  Digraph::NodeMap<int> degree_map(graph);
alpar@209
   194
kpeter@314
   195
  graphToEps(graph, "graph.eps")
alpar@40
   196
    .coords(coords).scaleToA4().undirected()
kpeter@83
   197
    .nodeColors(composeMap(functorToMap(nodeColor), degree_map))
alpar@40
   198
    .run();
alpar@209
   199
\endcode
kpeter@83
   200
The \c functorToMap() function makes an \c int to \c Color map from the
kpeter@314
   201
\c nodeColor() function. The \c composeMap() compose the \c degree_map
kpeter@83
   202
and the previously created map. The composed map is a proper function to
kpeter@83
   203
get the color of each node.
alpar@40
   204
alpar@40
   205
The usage with class type algorithms is little bit harder. In this
alpar@40
   206
case the function type map adaptors can not be used, because the
kpeter@50
   207
function map adaptors give back temporary objects.
alpar@40
   208
\code
kpeter@83
   209
  Digraph graph;
kpeter@83
   210
kpeter@83
   211
  typedef Digraph::ArcMap<double> DoubleArcMap;
kpeter@83
   212
  DoubleArcMap length(graph);
kpeter@83
   213
  DoubleArcMap speed(graph);
kpeter@83
   214
kpeter@83
   215
  typedef DivMap<DoubleArcMap, DoubleArcMap> TimeMap;
alpar@40
   216
  TimeMap time(length, speed);
alpar@209
   217
kpeter@83
   218
  Dijkstra<Digraph, TimeMap> dijkstra(graph, time);
alpar@40
   219
  dijkstra.run(source, target);
alpar@40
   220
\endcode
kpeter@83
   221
We have a length map and a maximum speed map on the arcs of a digraph.
kpeter@83
   222
The minimum time to pass the arc can be calculated as the division of
kpeter@83
   223
the two maps which can be done implicitly with the \c DivMap template
alpar@40
   224
class. We use the implicit minimum time map as the length map of the
alpar@40
   225
\c Dijkstra algorithm.
alpar@40
   226
*/
alpar@40
   227
alpar@40
   228
/**
alpar@40
   229
@defgroup paths Path Structures
alpar@40
   230
@ingroup datas
kpeter@318
   231
\brief %Path structures implemented in LEMON.
alpar@40
   232
kpeter@559
   233
This group contains the path structures implemented in LEMON.
alpar@40
   234
kpeter@50
   235
LEMON provides flexible data structures to work with paths.
kpeter@50
   236
All of them have similar interfaces and they can be copied easily with
kpeter@50
   237
assignment operators and copy constructors. This makes it easy and
alpar@40
   238
efficient to have e.g. the Dijkstra algorithm to store its result in
alpar@40
   239
any kind of path structure.
alpar@40
   240
kpeter@710
   241
\sa \ref concepts::Path "Path concept"
kpeter@710
   242
*/
kpeter@710
   243
kpeter@710
   244
/**
kpeter@710
   245
@defgroup heaps Heap Structures
kpeter@710
   246
@ingroup datas
kpeter@710
   247
\brief %Heap structures implemented in LEMON.
kpeter@710
   248
kpeter@710
   249
This group contains the heap structures implemented in LEMON.
kpeter@710
   250
kpeter@710
   251
LEMON provides several heap classes. They are efficient implementations
kpeter@710
   252
of the abstract data type \e priority \e queue. They store items with
kpeter@710
   253
specified values called \e priorities in such a way that finding and
kpeter@710
   254
removing the item with minimum priority are efficient.
kpeter@710
   255
The basic operations are adding and erasing items, changing the priority
kpeter@710
   256
of an item, etc.
kpeter@710
   257
kpeter@710
   258
Heaps are crucial in several algorithms, such as Dijkstra and Prim.
kpeter@710
   259
The heap implementations have the same interface, thus any of them can be
kpeter@710
   260
used easily in such algorithms.
kpeter@710
   261
kpeter@710
   262
\sa \ref concepts::Heap "Heap concept"
kpeter@710
   263
*/
kpeter@710
   264
kpeter@710
   265
/**
alpar@40
   266
@defgroup auxdat Auxiliary Data Structures
alpar@40
   267
@ingroup datas
kpeter@50
   268
\brief Auxiliary data structures implemented in LEMON.
alpar@40
   269
kpeter@559
   270
This group contains some data structures implemented in LEMON in
alpar@40
   271
order to make it easier to implement combinatorial algorithms.
alpar@40
   272
*/
alpar@40
   273
alpar@40
   274
/**
kpeter@714
   275
@defgroup geomdat Geometric Data Structures
kpeter@714
   276
@ingroup auxdat
kpeter@714
   277
\brief Geometric data structures implemented in LEMON.
kpeter@714
   278
kpeter@714
   279
This group contains geometric data structures implemented in LEMON.
kpeter@714
   280
kpeter@714
   281
 - \ref lemon::dim2::Point "dim2::Point" implements a two dimensional
kpeter@714
   282
   vector with the usual operations.
kpeter@714
   283
 - \ref lemon::dim2::Box "dim2::Box" can be used to determine the
kpeter@714
   284
   rectangular bounding box of a set of \ref lemon::dim2::Point
kpeter@714
   285
   "dim2::Point"'s.
kpeter@714
   286
*/
kpeter@714
   287
kpeter@714
   288
/**
kpeter@714
   289
@defgroup matrices Matrices
kpeter@714
   290
@ingroup auxdat
kpeter@714
   291
\brief Two dimensional data storages implemented in LEMON.
kpeter@714
   292
kpeter@714
   293
This group contains two dimensional data storages implemented in LEMON.
kpeter@714
   294
*/
kpeter@714
   295
kpeter@714
   296
/**
alpar@40
   297
@defgroup algs Algorithms
kpeter@559
   298
\brief This group contains the several algorithms
alpar@40
   299
implemented in LEMON.
alpar@40
   300
kpeter@559
   301
This group contains the several algorithms
alpar@40
   302
implemented in LEMON.
alpar@40
   303
*/
alpar@40
   304
alpar@40
   305
/**
alpar@40
   306
@defgroup search Graph Search
alpar@40
   307
@ingroup algs
kpeter@50
   308
\brief Common graph search algorithms.
alpar@40
   309
kpeter@559
   310
This group contains the common graph search algorithms, namely
kpeter@755
   311
\e breadth-first \e search (BFS) and \e depth-first \e search (DFS)
kpeter@755
   312
\ref clrs01algorithms.
alpar@40
   313
*/
alpar@40
   314
alpar@40
   315
/**
kpeter@314
   316
@defgroup shortest_path Shortest Path Algorithms
alpar@40
   317
@ingroup algs
kpeter@50
   318
\brief Algorithms for finding shortest paths.
alpar@40
   319
kpeter@755
   320
This group contains the algorithms for finding shortest paths in digraphs
kpeter@755
   321
\ref clrs01algorithms.
kpeter@406
   322
kpeter@406
   323
 - \ref Dijkstra algorithm for finding shortest paths from a source node
kpeter@406
   324
   when all arc lengths are non-negative.
kpeter@406
   325
 - \ref BellmanFord "Bellman-Ford" algorithm for finding shortest paths
kpeter@406
   326
   from a source node when arc lenghts can be either positive or negative,
kpeter@406
   327
   but the digraph should not contain directed cycles with negative total
kpeter@406
   328
   length.
kpeter@406
   329
 - \ref FloydWarshall "Floyd-Warshall" and \ref Johnson "Johnson" algorithms
kpeter@406
   330
   for solving the \e all-pairs \e shortest \e paths \e problem when arc
kpeter@406
   331
   lenghts can be either positive or negative, but the digraph should
kpeter@406
   332
   not contain directed cycles with negative total length.
kpeter@406
   333
 - \ref Suurballe A successive shortest path algorithm for finding
kpeter@406
   334
   arc-disjoint paths between two nodes having minimum total length.
alpar@40
   335
*/
alpar@40
   336
alpar@209
   337
/**
kpeter@714
   338
@defgroup spantree Minimum Spanning Tree Algorithms
kpeter@714
   339
@ingroup algs
kpeter@714
   340
\brief Algorithms for finding minimum cost spanning trees and arborescences.
kpeter@714
   341
kpeter@714
   342
This group contains the algorithms for finding minimum cost spanning
kpeter@755
   343
trees and arborescences \ref clrs01algorithms.
kpeter@714
   344
*/
kpeter@714
   345
kpeter@714
   346
/**
kpeter@314
   347
@defgroup max_flow Maximum Flow Algorithms
alpar@209
   348
@ingroup algs
kpeter@50
   349
\brief Algorithms for finding maximum flows.
alpar@40
   350
kpeter@559
   351
This group contains the algorithms for finding maximum flows and
kpeter@755
   352
feasible circulations \ref clrs01algorithms, \ref amo93networkflows.
alpar@40
   353
kpeter@406
   354
The \e maximum \e flow \e problem is to find a flow of maximum value between
kpeter@406
   355
a single source and a single target. Formally, there is a \f$G=(V,A)\f$
kpeter@609
   356
digraph, a \f$cap: A\rightarrow\mathbf{R}^+_0\f$ capacity function and
kpeter@406
   357
\f$s, t \in V\f$ source and target nodes.
kpeter@609
   358
A maximum flow is an \f$f: A\rightarrow\mathbf{R}^+_0\f$ solution of the
kpeter@406
   359
following optimization problem.
alpar@40
   360
kpeter@609
   361
\f[ \max\sum_{sv\in A} f(sv) - \sum_{vs\in A} f(vs) \f]
kpeter@609
   362
\f[ \sum_{uv\in A} f(uv) = \sum_{vu\in A} f(vu)
kpeter@609
   363
    \quad \forall u\in V\setminus\{s,t\} \f]
kpeter@609
   364
\f[ 0 \leq f(uv) \leq cap(uv) \quad \forall uv\in A \f]
alpar@40
   365
kpeter@50
   366
LEMON contains several algorithms for solving maximum flow problems:
kpeter@755
   367
- \ref EdmondsKarp Edmonds-Karp algorithm
kpeter@755
   368
  \ref edmondskarp72theoretical.
kpeter@755
   369
- \ref Preflow Goldberg-Tarjan's preflow push-relabel algorithm
kpeter@755
   370
  \ref goldberg88newapproach.
kpeter@755
   371
- \ref DinitzSleatorTarjan Dinitz's blocking flow algorithm with dynamic trees
kpeter@755
   372
  \ref dinic70algorithm, \ref sleator83dynamic.
kpeter@755
   373
- \ref GoldbergTarjan !Preflow push-relabel algorithm with dynamic trees
kpeter@755
   374
  \ref goldberg88newapproach, \ref sleator83dynamic.
alpar@40
   375
kpeter@755
   376
In most cases the \ref Preflow algorithm provides the
kpeter@406
   377
fastest method for computing a maximum flow. All implementations
kpeter@651
   378
also provide functions to query the minimum cut, which is the dual
kpeter@651
   379
problem of maximum flow.
kpeter@651
   380
deba@869
   381
\ref Circulation is a preflow push-relabel algorithm implemented directly
kpeter@651
   382
for finding feasible circulations, which is a somewhat different problem,
kpeter@651
   383
but it is strongly related to maximum flow.
kpeter@651
   384
For more information, see \ref Circulation.
alpar@40
   385
*/
alpar@40
   386
alpar@40
   387
/**
kpeter@663
   388
@defgroup min_cost_flow_algs Minimum Cost Flow Algorithms
alpar@40
   389
@ingroup algs
alpar@40
   390
kpeter@50
   391
\brief Algorithms for finding minimum cost flows and circulations.
alpar@40
   392
kpeter@609
   393
This group contains the algorithms for finding minimum cost flows and
kpeter@755
   394
circulations \ref amo93networkflows. For more information about this
kpeter@755
   395
problem and its dual solution, see \ref min_cost_flow
kpeter@755
   396
"Minimum Cost Flow Problem".
kpeter@406
   397
kpeter@663
   398
LEMON contains several algorithms for this problem.
kpeter@609
   399
 - \ref NetworkSimplex Primal Network Simplex algorithm with various
kpeter@755
   400
   pivot strategies \ref dantzig63linearprog, \ref kellyoneill91netsimplex.
kpeter@813
   401
 - \ref CostScaling Cost Scaling algorithm based on push/augment and
kpeter@813
   402
   relabel operations \ref goldberg90approximation, \ref goldberg97efficient,
kpeter@755
   403
   \ref bunnagel98efficient.
kpeter@813
   404
 - \ref CapacityScaling Capacity Scaling algorithm based on the successive
kpeter@813
   405
   shortest path method \ref edmondskarp72theoretical.
kpeter@813
   406
 - \ref CycleCanceling Cycle-Canceling algorithms, two of which are
kpeter@813
   407
   strongly polynomial \ref klein67primal, \ref goldberg89cyclecanceling.
kpeter@609
   408
kpeter@919
   409
In general, \ref NetworkSimplex and \ref CostScaling are the most efficient
kpeter@919
   410
implementations, but the other two algorithms could be faster in special cases.
kpeter@609
   411
For example, if the total supply and/or capacities are rather small,
kpeter@919
   412
\ref CapacityScaling is usually the fastest algorithm (without effective scaling).
alpar@40
   413
*/
alpar@40
   414
alpar@40
   415
/**
kpeter@314
   416
@defgroup min_cut Minimum Cut Algorithms
alpar@209
   417
@ingroup algs
alpar@40
   418
kpeter@50
   419
\brief Algorithms for finding minimum cut in graphs.
alpar@40
   420
kpeter@559
   421
This group contains the algorithms for finding minimum cut in graphs.
alpar@40
   422
kpeter@406
   423
The \e minimum \e cut \e problem is to find a non-empty and non-complete
kpeter@406
   424
\f$X\f$ subset of the nodes with minimum overall capacity on
kpeter@406
   425
outgoing arcs. Formally, there is a \f$G=(V,A)\f$ digraph, a
kpeter@406
   426
\f$cap: A\rightarrow\mathbf{R}^+_0\f$ capacity function. The minimum
kpeter@50
   427
cut is the \f$X\f$ solution of the next optimization problem:
alpar@40
   428
alpar@210
   429
\f[ \min_{X \subset V, X\not\in \{\emptyset, V\}}
kpeter@713
   430
    \sum_{uv\in A: u\in X, v\not\in X}cap(uv) \f]
alpar@40
   431
kpeter@50
   432
LEMON contains several algorithms related to minimum cut problems:
alpar@40
   433
kpeter@406
   434
- \ref HaoOrlin "Hao-Orlin algorithm" for calculating minimum cut
kpeter@406
   435
  in directed graphs.
kpeter@406
   436
- \ref NagamochiIbaraki "Nagamochi-Ibaraki algorithm" for
kpeter@406
   437
  calculating minimum cut in undirected graphs.
kpeter@559
   438
- \ref GomoryHu "Gomory-Hu tree computation" for calculating
kpeter@406
   439
  all-pairs minimum cut in undirected graphs.
alpar@40
   440
alpar@40
   441
If you want to find minimum cut just between two distinict nodes,
kpeter@406
   442
see the \ref max_flow "maximum flow problem".
alpar@40
   443
*/
alpar@40
   444
alpar@40
   445
/**
kpeter@768
   446
@defgroup min_mean_cycle Minimum Mean Cycle Algorithms
alpar@40
   447
@ingroup algs
kpeter@768
   448
\brief Algorithms for finding minimum mean cycles.
alpar@40
   449
kpeter@771
   450
This group contains the algorithms for finding minimum mean cycles
kpeter@771
   451
\ref clrs01algorithms, \ref amo93networkflows.
alpar@40
   452
kpeter@768
   453
The \e minimum \e mean \e cycle \e problem is to find a directed cycle
kpeter@768
   454
of minimum mean length (cost) in a digraph.
kpeter@768
   455
The mean length of a cycle is the average length of its arcs, i.e. the
kpeter@768
   456
ratio between the total length of the cycle and the number of arcs on it.
alpar@40
   457
kpeter@768
   458
This problem has an important connection to \e conservative \e length
kpeter@768
   459
\e functions, too. A length function on the arcs of a digraph is called
kpeter@768
   460
conservative if and only if there is no directed cycle of negative total
kpeter@768
   461
length. For an arbitrary length function, the negative of the minimum
kpeter@768
   462
cycle mean is the smallest \f$\epsilon\f$ value so that increasing the
kpeter@768
   463
arc lengths uniformly by \f$\epsilon\f$ results in a conservative length
kpeter@768
   464
function.
alpar@40
   465
kpeter@768
   466
LEMON contains three algorithms for solving the minimum mean cycle problem:
kpeter@879
   467
- \ref KarpMmc Karp's original algorithm \ref amo93networkflows,
kpeter@771
   468
  \ref dasdan98minmeancycle.
kpeter@879
   469
- \ref HartmannOrlinMmc Hartmann-Orlin's algorithm, which is an improved
kpeter@771
   470
  version of Karp's algorithm \ref dasdan98minmeancycle.
kpeter@879
   471
- \ref HowardMmc Howard's policy iteration algorithm
kpeter@771
   472
  \ref dasdan98minmeancycle.
alpar@40
   473
kpeter@919
   474
In practice, the \ref HowardMmc "Howard" algorithm turned out to be by far the
kpeter@879
   475
most efficient one, though the best known theoretical bound on its running
kpeter@879
   476
time is exponential.
kpeter@879
   477
Both \ref KarpMmc "Karp" and \ref HartmannOrlinMmc "Hartmann-Orlin" algorithms
kpeter@879
   478
run in time O(ne) and use space O(n<sup>2</sup>+e), but the latter one is
kpeter@879
   479
typically faster due to the applied early termination scheme.
alpar@40
   480
*/
alpar@40
   481
alpar@40
   482
/**
kpeter@314
   483
@defgroup matching Matching Algorithms
alpar@40
   484
@ingroup algs
kpeter@50
   485
\brief Algorithms for finding matchings in graphs and bipartite graphs.
alpar@40
   486
kpeter@590
   487
This group contains the algorithms for calculating
alpar@40
   488
matchings in graphs and bipartite graphs. The general matching problem is
kpeter@590
   489
finding a subset of the edges for which each node has at most one incident
kpeter@590
   490
edge.
alpar@209
   491
alpar@40
   492
There are several different algorithms for calculate matchings in
alpar@40
   493
graphs.  The matching problems in bipartite graphs are generally
alpar@40
   494
easier than in general graphs. The goal of the matching optimization
kpeter@406
   495
can be finding maximum cardinality, maximum weight or minimum cost
alpar@40
   496
matching. The search can be constrained to find perfect or
alpar@40
   497
maximum cardinality matching.
alpar@40
   498
kpeter@406
   499
The matching algorithms implemented in LEMON:
kpeter@406
   500
- \ref MaxBipartiteMatching Hopcroft-Karp augmenting path algorithm
kpeter@406
   501
  for calculating maximum cardinality matching in bipartite graphs.
kpeter@406
   502
- \ref PrBipartiteMatching Push-relabel algorithm
kpeter@406
   503
  for calculating maximum cardinality matching in bipartite graphs.
kpeter@406
   504
- \ref MaxWeightedBipartiteMatching
kpeter@406
   505
  Successive shortest path algorithm for calculating maximum weighted
kpeter@406
   506
  matching and maximum weighted bipartite matching in bipartite graphs.
kpeter@406
   507
- \ref MinCostMaxBipartiteMatching
kpeter@406
   508
  Successive shortest path algorithm for calculating minimum cost maximum
kpeter@406
   509
  matching in bipartite graphs.
kpeter@406
   510
- \ref MaxMatching Edmond's blossom shrinking algorithm for calculating
kpeter@406
   511
  maximum cardinality matching in general graphs.
kpeter@406
   512
- \ref MaxWeightedMatching Edmond's blossom shrinking algorithm for calculating
kpeter@406
   513
  maximum weighted matching in general graphs.
kpeter@406
   514
- \ref MaxWeightedPerfectMatching
kpeter@406
   515
  Edmond's blossom shrinking algorithm for calculating maximum weighted
kpeter@406
   516
  perfect matching in general graphs.
deba@869
   517
- \ref MaxFractionalMatching Push-relabel algorithm for calculating
deba@869
   518
  maximum cardinality fractional matching in general graphs.
deba@869
   519
- \ref MaxWeightedFractionalMatching Augmenting path algorithm for calculating
deba@869
   520
  maximum weighted fractional matching in general graphs.
deba@869
   521
- \ref MaxWeightedPerfectFractionalMatching
deba@869
   522
  Augmenting path algorithm for calculating maximum weighted
deba@869
   523
  perfect fractional matching in general graphs.
alpar@40
   524
alpar@865
   525
\image html matching.png
alpar@873
   526
\image latex matching.eps "Min Cost Perfect Matching" width=\textwidth
alpar@40
   527
*/
alpar@40
   528
alpar@40
   529
/**
kpeter@714
   530
@defgroup graph_properties Connectivity and Other Graph Properties
alpar@40
   531
@ingroup algs
kpeter@714
   532
\brief Algorithms for discovering the graph properties
alpar@40
   533
kpeter@714
   534
This group contains the algorithms for discovering the graph properties
kpeter@714
   535
like connectivity, bipartiteness, euler property, simplicity etc.
kpeter@714
   536
kpeter@714
   537
\image html connected_components.png
kpeter@714
   538
\image latex connected_components.eps "Connected components" width=\textwidth
kpeter@714
   539
*/
kpeter@714
   540
kpeter@714
   541
/**
kpeter@919
   542
@defgroup planar Planar Embedding and Drawing
kpeter@714
   543
@ingroup algs
kpeter@714
   544
\brief Algorithms for planarity checking, embedding and drawing
kpeter@714
   545
kpeter@714
   546
This group contains the algorithms for planarity checking,
kpeter@714
   547
embedding and drawing.
kpeter@714
   548
kpeter@714
   549
\image html planar.png
kpeter@714
   550
\image latex planar.eps "Plane graph" width=\textwidth
kpeter@714
   551
*/
kpeter@714
   552
kpeter@714
   553
/**
kpeter@904
   554
@defgroup approx_algs Approximation Algorithms
kpeter@714
   555
@ingroup algs
kpeter@714
   556
\brief Approximation algorithms.
kpeter@714
   557
kpeter@714
   558
This group contains the approximation and heuristic algorithms
kpeter@714
   559
implemented in LEMON.
kpeter@904
   560
kpeter@904
   561
<b>Maximum Clique Problem</b>
kpeter@904
   562
  - \ref GrossoLocatelliPullanMc An efficient heuristic algorithm of
kpeter@904
   563
    Grosso, Locatelli, and Pullan.
alpar@40
   564
*/
alpar@40
   565
alpar@40
   566
/**
kpeter@314
   567
@defgroup auxalg Auxiliary Algorithms
alpar@40
   568
@ingroup algs
kpeter@50
   569
\brief Auxiliary algorithms implemented in LEMON.
alpar@40
   570
kpeter@559
   571
This group contains some algorithms implemented in LEMON
kpeter@50
   572
in order to make it easier to implement complex algorithms.
alpar@40
   573
*/
alpar@40
   574
alpar@40
   575
/**
alpar@40
   576
@defgroup gen_opt_group General Optimization Tools
kpeter@559
   577
\brief This group contains some general optimization frameworks
alpar@40
   578
implemented in LEMON.
alpar@40
   579
kpeter@559
   580
This group contains some general optimization frameworks
alpar@40
   581
implemented in LEMON.
alpar@40
   582
*/
alpar@40
   583
alpar@40
   584
/**
kpeter@755
   585
@defgroup lp_group LP and MIP Solvers
alpar@40
   586
@ingroup gen_opt_group
kpeter@755
   587
\brief LP and MIP solver interfaces for LEMON.
alpar@40
   588
kpeter@755
   589
This group contains LP and MIP solver interfaces for LEMON.
kpeter@755
   590
Various LP solvers could be used in the same manner with this
kpeter@755
   591
high-level interface.
kpeter@755
   592
kpeter@755
   593
The currently supported solvers are \ref glpk, \ref clp, \ref cbc,
kpeter@755
   594
\ref cplex, \ref soplex.
alpar@40
   595
*/
alpar@40
   596
alpar@209
   597
/**
kpeter@314
   598
@defgroup lp_utils Tools for Lp and Mip Solvers
alpar@40
   599
@ingroup lp_group
kpeter@50
   600
\brief Helper tools to the Lp and Mip solvers.
alpar@40
   601
alpar@40
   602
This group adds some helper tools to general optimization framework
alpar@40
   603
implemented in LEMON.
alpar@40
   604
*/
alpar@40
   605
alpar@40
   606
/**
alpar@40
   607
@defgroup metah Metaheuristics
alpar@40
   608
@ingroup gen_opt_group
alpar@40
   609
\brief Metaheuristics for LEMON library.
alpar@40
   610
kpeter@559
   611
This group contains some metaheuristic optimization tools.
alpar@40
   612
*/
alpar@40
   613
alpar@40
   614
/**
alpar@209
   615
@defgroup utils Tools and Utilities
kpeter@50
   616
\brief Tools and utilities for programming in LEMON
alpar@40
   617
kpeter@50
   618
Tools and utilities for programming in LEMON.
alpar@40
   619
*/
alpar@40
   620
alpar@40
   621
/**
alpar@40
   622
@defgroup gutils Basic Graph Utilities
alpar@40
   623
@ingroup utils
kpeter@50
   624
\brief Simple basic graph utilities.
alpar@40
   625
kpeter@559
   626
This group contains some simple basic graph utilities.
alpar@40
   627
*/
alpar@40
   628
alpar@40
   629
/**
alpar@40
   630
@defgroup misc Miscellaneous Tools
alpar@40
   631
@ingroup utils
kpeter@50
   632
\brief Tools for development, debugging and testing.
kpeter@50
   633
kpeter@559
   634
This group contains several useful tools for development,
alpar@40
   635
debugging and testing.
alpar@40
   636
*/
alpar@40
   637
alpar@40
   638
/**
kpeter@314
   639
@defgroup timecount Time Measuring and Counting
alpar@40
   640
@ingroup misc
kpeter@50
   641
\brief Simple tools for measuring the performance of algorithms.
kpeter@50
   642
kpeter@559
   643
This group contains simple tools for measuring the performance
alpar@40
   644
of algorithms.
alpar@40
   645
*/
alpar@40
   646
alpar@40
   647
/**
alpar@40
   648
@defgroup exceptions Exceptions
alpar@40
   649
@ingroup utils
kpeter@50
   650
\brief Exceptions defined in LEMON.
kpeter@50
   651
kpeter@559
   652
This group contains the exceptions defined in LEMON.
alpar@40
   653
*/
alpar@40
   654
alpar@40
   655
/**
alpar@40
   656
@defgroup io_group Input-Output
kpeter@50
   657
\brief Graph Input-Output methods
alpar@40
   658
kpeter@559
   659
This group contains the tools for importing and exporting graphs
kpeter@314
   660
and graph related data. Now it supports the \ref lgf-format
kpeter@314
   661
"LEMON Graph Format", the \c DIMACS format and the encapsulated
kpeter@314
   662
postscript (EPS) format.
alpar@40
   663
*/
alpar@40
   664
alpar@40
   665
/**
kpeter@351
   666
@defgroup lemon_io LEMON Graph Format
alpar@40
   667
@ingroup io_group
kpeter@314
   668
\brief Reading and writing LEMON Graph Format.
alpar@40
   669
kpeter@559
   670
This group contains methods for reading and writing
ladanyi@236
   671
\ref lgf-format "LEMON Graph Format".
alpar@40
   672
*/
alpar@40
   673
alpar@40
   674
/**
kpeter@314
   675
@defgroup eps_io Postscript Exporting
alpar@40
   676
@ingroup io_group
alpar@40
   677
\brief General \c EPS drawer and graph exporter
alpar@40
   678
kpeter@559
   679
This group contains general \c EPS drawing methods and special
alpar@209
   680
graph exporting tools.
alpar@40
   681
*/
alpar@40
   682
alpar@40
   683
/**
kpeter@714
   684
@defgroup dimacs_group DIMACS Format
kpeter@388
   685
@ingroup io_group
kpeter@388
   686
\brief Read and write files in DIMACS format
kpeter@388
   687
kpeter@388
   688
Tools to read a digraph from or write it to a file in DIMACS format data.
kpeter@388
   689
*/
kpeter@388
   690
kpeter@388
   691
/**
kpeter@351
   692
@defgroup nauty_group NAUTY Format
kpeter@351
   693
@ingroup io_group
kpeter@351
   694
\brief Read \e Nauty format
kpeter@388
   695
kpeter@351
   696
Tool to read graphs from \e Nauty format data.
kpeter@351
   697
*/
kpeter@351
   698
kpeter@351
   699
/**
alpar@40
   700
@defgroup concept Concepts
alpar@40
   701
\brief Skeleton classes and concept checking classes
alpar@40
   702
kpeter@559
   703
This group contains the data/algorithm skeletons and concept checking
alpar@40
   704
classes implemented in LEMON.
alpar@40
   705
alpar@40
   706
The purpose of the classes in this group is fourfold.
alpar@209
   707
kpeter@318
   708
- These classes contain the documentations of the %concepts. In order
alpar@40
   709
  to avoid document multiplications, an implementation of a concept
alpar@40
   710
  simply refers to the corresponding concept class.
alpar@40
   711
alpar@40
   712
- These classes declare every functions, <tt>typedef</tt>s etc. an
kpeter@318
   713
  implementation of the %concepts should provide, however completely
alpar@40
   714
  without implementations and real data structures behind the
alpar@40
   715
  interface. On the other hand they should provide nothing else. All
alpar@40
   716
  the algorithms working on a data structure meeting a certain concept
alpar@40
   717
  should compile with these classes. (Though it will not run properly,
alpar@40
   718
  of course.) In this way it is easily to check if an algorithm
alpar@40
   719
  doesn't use any extra feature of a certain implementation.
alpar@40
   720
alpar@40
   721
- The concept descriptor classes also provide a <em>checker class</em>
kpeter@50
   722
  that makes it possible to check whether a certain implementation of a
alpar@40
   723
  concept indeed provides all the required features.
alpar@40
   724
alpar@40
   725
- Finally, They can serve as a skeleton of a new implementation of a concept.
alpar@40
   726
*/
alpar@40
   727
alpar@40
   728
/**
alpar@40
   729
@defgroup graph_concepts Graph Structure Concepts
alpar@40
   730
@ingroup concept
alpar@40
   731
\brief Skeleton and concept checking classes for graph structures
alpar@40
   732
kpeter@735
   733
This group contains the skeletons and concept checking classes of
kpeter@735
   734
graph structures.
alpar@40
   735
*/
alpar@40
   736
kpeter@314
   737
/**
kpeter@314
   738
@defgroup map_concepts Map Concepts
kpeter@314
   739
@ingroup concept
kpeter@314
   740
\brief Skeleton and concept checking classes for maps
kpeter@314
   741
kpeter@559
   742
This group contains the skeletons and concept checking classes of maps.
alpar@40
   743
*/
alpar@40
   744
alpar@40
   745
/**
kpeter@714
   746
@defgroup tools Standalone Utility Applications
kpeter@714
   747
kpeter@714
   748
Some utility applications are listed here.
kpeter@714
   749
kpeter@714
   750
The standard compilation procedure (<tt>./configure;make</tt>) will compile
kpeter@714
   751
them, as well.
kpeter@714
   752
*/
kpeter@714
   753
kpeter@714
   754
/**
alpar@40
   755
\anchor demoprograms
alpar@40
   756
kpeter@406
   757
@defgroup demos Demo Programs
alpar@40
   758
alpar@40
   759
Some demo programs are listed here. Their full source codes can be found in
alpar@40
   760
the \c demo subdirectory of the source tree.
alpar@40
   761
ladanyi@564
   762
In order to compile them, use the <tt>make demo</tt> or the
ladanyi@564
   763
<tt>make check</tt> commands.
alpar@40
   764
*/
alpar@40
   765
kpeter@406
   766
}