/**

 @defgroup datas Data Structures

 This group describes the several graph structures implemented in LEMON.

 */

 /**

 @defgroup graphs Graph Structures

 @ingroup datas

 \brief Graph structures implemented in LEMON.

 The implementation of combinatorial algorithms heavily relies on 

 efficient graph implementations. LEMON offers data structures which are 

 planned to be easily used in an experimental phase of implementation studies, 

 and thereafter the program code can be made efficient by small modifications. 

 The most efficient implementation of diverse applications require the usage of different physical graph implementations. These differences appear in the size of 

 graph we require to handle, memory or time usage limitations or in 

 the set of operations through which the graph can be accessed. 

 LEMON provides several physical graph structures to meet the 

 diverging requirements of the possible users. 

 In order to save on running time or on memory usage, some structures may 

 fail to provide some graph features like edge or node deletion.

 Alteration of standard containers need a very limited number of 

 operations, these together satisfy the everyday requirements. 

 In the case of graph strutures, different operations are needed which do 

 not alter the physical graph, but gives another view. If some nodes or 

 edges have to be hidden or the reverse oriented graph have to be used, then 

 this is the case. It also may happen that in a flow implemenation 

 the residual graph can be accessed by another algorithm, or a node-set 

 is to be shrunk for another algorithm. 

 LEMON also provides a variety of graphs for these requirements called 

 \ref graph_adaptors "graph adaptors". Adaptors cannot be used alone but only 

 in conjunction with other graph representation. 

 You are free to use the graph structure that fit your requirements

 the best, most graph algorithms and auxiliary data structures can be used

 with any graph structures. 

 */

 /**

 @defgroup semi_adaptors Semi-Adaptors Classes for Graphs

 @ingroup graphs

 \brief Graph types between real graphs and graph adaptors.

 Graph types between real graphs and graph adaptors. These classes

 wrap graphs to give new functionality as the adaptors do it. But the

 other way they are not light-weigth structures as the adaptors.

 */

 /**

 @defgroup maps Maps 

 @ingroup datas

 \brief Some special purpose map to make life easier.

 LEMON provides several special maps that e.g. combine

 new maps from existing ones.

 */

 /**

 @defgroup graph_maps Graph Maps 

 @ingroup maps

 \brief Special Graph-Related Maps.

 These maps are specifically designed to assign values to the nodes and edges of

 graphs.

 */

 /**

 \defgroup map_adaptors Map Adaptors

 \ingroup maps

 \brief Tools to create new maps from existing ones

 Map adaptors are used to create "implicit" maps from other maps.

 Most of them are \ref lemon::concept::ReadMap "ReadMap"s. They can

 make arithmetic oprerations between one or two maps (negation, scalig,

 addition, multiplication etc.) or e.g. convert a map to another one

 of different Value type.

 */

 /**

 @defgroup auxdat Auxiliary Data Structures

 @ingroup datas

 \brief Some data structures implemented in LEMON.

 This group describes the data structures implemented in LEMON in

 order to make it easier to implement combinatorial algorithms.

 */

 /**

 @defgroup graphbits Tools to Make It Easier to Make Graphs

 @ingroup auxdat

 \brief Tools to Make It Easier to Make Graphs.

 This group describes the tools that makes it easier to make graphs and

 the maps that dynamically update with the graph changes.

 */

 /**

 @defgroup galgs Graph Algorithms

 \brief This group describes the several graph algorithms

 implemented in LEMON.

 This group describes the several graph algorithms

 implemented in LEMON.

 */

 /**

 @defgroup gutils General Graph Utilities

 @ingroup galgs

 \brief This group describes some simple general graph utilities.

 This group describes some simple general graph utilities.

 */

 /**

 @defgroup gen_opt_group General Optimization Tools

 \brief This group describes some general optimization frameworks

 implemented in LEMON.

 \brief This group describes some general optimization frameworks

 implemented in LEMON.

 */

 /**

 @defgroup flowalgs Path and Flow Algorithms

 @ingroup galgs

 \brief This group describes the algorithms

 for finding paths and flows in graphs.

 */

 /**

 @defgroup topology Topology related algorithms

 @ingroup galgs

 \brief This group describes the algorithms

 for discover the topology of the graphs.

 */

 /**

 @defgroup exceptions Exceptions

 This group contains the exceptions thrown by LEMON library

 */

 /**

 @defgroup misc Miscellaneous Tools

 Here you can find several useful tools for development,

 debugging and testing.

 */

 /**

 @defgroup timecount Time measuring and Counting

 @ingroup misc

 Here you can find simple tools for measuring the performance

 of algorithms.

 */

 /**

 @defgroup io_group Input-Output

 Here you can find tools for imporing and exporting graphs and graph related

 data

 */

 /**

 @defgroup section_io Section readers and writers

 @ingroup io_group

 \brief Section readers and writers for lemon Input-Output.

 Here you can find which section readers and writers can attach to

 the LemonReader and LemonWriter.

 */

 /**

 @defgroup item_io Item Readers and Writers

 @ingroup io_group

 \brief Item readers and writers for lemon Input-Output.

 The Input-Output classes can handle more data type by example

 as map or attribute value. Each of these should be written and

 read some way. The module make possible to do this.  

 */

 /**

 @defgroup concept Concepts

 \brief Skeleton classes and concept checking classes

 This group describes the data/algorithm skeletons and concept checking

 classes implemented in LEMON.

 One aim of these classes is to make it easier to check if a certain

 class or template function is correctly implemented.

 The other (sometimes even more important) aim is to document the concepts.

 */

 /**

 @defgroup graph_concepts Graph Structure Concepts

 @ingroup concept

 \brief Skeleton and concept checking classes for graph structures

 This group contains the skeletons and concept checking classes of LEMON's

 graph structures and helper classes used to implement these.

 */

 /* --- Unused group

 @defgroup experimental Experimental Structures and Algorithms

 This group contains some Experimental structures and algorithms.

 The stuff here is subject to change.

 */

 /**

 \anchor demoprograms

 @defgroup demos Demo programs

 Some demo programs are listed here. Their full source codes can be found in

 the \c demo subdirectory of the source tree.

 The standard compilation procedure (<tt>./configure;make</tt>) will compile

 them, as well. 

 */