/**

 \page quicktour Quick Tour to LEMON

 Let us first answer the question <b>"What do I want to use LEMON for?"

 </b>. 

 LEMON is a C++ library, so you can use it if you want to write C++ 

 programs. What kind of tasks does the library LEMON help to solve? 

 It helps to write programs that solve optimization problems that arise

 frequently when <b>designing and testing certain networks</b>, for example

 in telecommunication, computer networks, and other areas that I cannot

 think of now. A very natural way of modelling these networks is by means

 of a <b> graph</b> (we will always mean a directed graph by that). 

 So if you want to write a program that works with 

 graphs then you might find it useful to use our library LEMON.

 Some examples are the following (you will find links next to the code fragments that help to download full demo programs):

 - First we give two examples that show how to instantiate a graph. The

 first one shows the methods that add nodes and edges, but one will

 usually use the second way which reads a graph from a stream (file).

 -# The following code fragment shows how to fill a graph with data. It creates a complete graph on 4 nodes. The type Listgraph is one of the LEMON graph types: the typedefs in the beginning are for convenience and we will supppose them later as well.

  \code

   typedef ListGraph Graph;

   typedef Graph::Edge Edge;

   typedef Graph::InEdgeIt InEdgeIt;

   typedef Graph::OutEdgeIt OutEdgeIt;

   typedef Graph::EdgeIt EdgeIt;

   typedef Graph::Node Node;

   typedef Graph::NodeIt NodeIt;

   Graph g;

   for (int i = 0; i < 3; i++)

     g.addNode();

   for (NodeIt i(g); i!=INVALID; ++i)

     for (NodeIt j(g); j!=INVALID; ++j)

       if (i != j) g.addEdge(i, j);

  \endcode 

 If you want to read more on the LEMON graph structures and concepts, read the page about \ref graphs "graphs". 

 -# The following code shows how to read a graph from a stream (e.g. a file). LEMON supports the DIMACS file format: it can read a graph instance from a file 

 in that format (find the documentation of the format on the web). 

 \code

 Graph g;

 std::ifstream f("graph.dim");

 readDimacs(f, g);

 \endcode

 One can also store network (graph+capacity on the edges) instances and other things in DIMACS format: to see the details read the documentation of the \ref dimacs.h "Dimacs file format reader".

 - If you want to solve some transportation problems in a network then 

 you will want to find shortest paths between nodes of a graph. This is 

 usually solved using Dijkstra's algorithm. A utility

 that solves this is  the \ref lemon::Dijkstra "LEMON Dijkstra class".

 A simple program using the \ref lemon::Dijkstra "LEMON Dijkstra class" is

 as follows (we do not include the part that instantiates the graph and the length function):

 \code

   typedef Graph::EdgeMap<int> LengthMap;

   Graph G;

   Node s, t;

   LengthMap cap(G);

 	...

   Dijkstra<Graph, LengthMap> 

 	dijkstra_test(G, cap);

   dijkstra_test.run(s);

 \endcode

 - If you want to design a network and want to minimize the total length

 of wires then you might be looking for a <b>minimum spanning tree</b> in

 an undirected graph. This can be found using the Kruskal algorithm: the 

 class \ref lemon::Kruskal "LEMON Kruskal class" does this job for you.

 The following code fragment shows an example:

 \code

 \endcode

 Some more detailed introduction can be obtained by following the links 

 below:

 \ref graphs "Graph structures"

 play a central role in LEMON, so if you are new to the library,

 you probably should start \ref graphs "here".

 (You can also find that page along with others under

 <a class="el" href="pages.html"> Related Pages </a>.)

 If you are 

 interested in data structures and algorithms in more details, then

 you should browse the reference manual part of the documentation.

 Section <a class="el" href="modules.html"> Modules </a>

  is a good starting point for this.

 */