source: lemon-0.x/doc/quicktour.dox @ 1178:3c176c65d33b

/**

\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:

- 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.

 \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 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 assume that the graph is already given in the memory):

\code

\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.
*/