/**

 \page getstart How to start using LEMON

 In this page we detail how to start using LEMON, from downloading it to

 your computer, through the steps of installation, to showing a simple

 "Hello World" type program that already uses LEMON. We assume that you

 have a basic knowledge of your operating system and \c C++ programming

 language. The procedure is pretty straightforward, but if you have any

 difficulties don't hesitate to <a href="mailto:etik-ol@cs.elte.hu">ask</a>.

 \section requirementsLEMON Hardware and software requirements

 In LEMON we use C++ templates heavily, thus compilation takes a

 considerable amount of time and memory. So some decent box would be

 advantageous. But otherwise there are no special hardware requirements.

 You will need a recent C++ compiler. Our primary target is the GNU C++

 Compiler (g++), from version 3.3 upwards. We also checked the Intel C++

 Compiler (icc). Microsoft Visual C++ .NET 2003 was also reported to

 work (but not the earlier versions). If you want to develop with LEMON

 under Windows you could consider using Cygwin.

 In this description we will suppose a Linux environment and GNU C++ Compiler.

 \subsection requirementsLP LP solver requirements

 The LEMON LP solver interface can use the GLPK (GNU Linear Programming Kit)

 and CPLEX solvers (was tested with CPLEX 7.5). If you want to use it you will

 need at least one of these. See \ref configureFlags how to enable these at

 compile time.

 \section downloadLEMON How to download LEMON

 You can download LEMON from the LEMON web site:

 http://lemon.cs.elte.hu/download.html .

 There you will find released versions in form of <tt>.tar.gz</tt> files.

 If you want a developer version (for example you want to contribute in

 developing the library LEMON) then you might want to use our Subversion

 repository. This case is not detailed here, so from now on we suppose that

 you downloaded a tar.gz file.

 \section installLEMON How to install LEMON

 In order to install LEMON you have to do the following steps.

 Download the tarball (named <tt>lemon-x.y.z.tar.gz</tt> where \c x,\c y

 and \c z are numbers indicating the version of the library: in our example

 we will have <tt>lemon-0.3.1.tar.gz</tt>) and issue the following

 commands:

 \verbatim

 tar xvzf lemon-0.3.1.tar.gz

 cd lemon-0.3.1

 ./configure

 make

 make check   #(This is optional, but recommended. It runs a bunch of tests.)

 make install

 \endverbatim

 These commands install LEMON under \c /usr/local (you will

 need root privileges to be able to install to that

 directory). If you want to install it to some other place, then

 pass the \c --prefix=DIRECTORY flag to \c ./configure, for example:

 \verbatim

 ./configure --prefix=/home/username/lemon

 \endverbatim

 In what follows we will assume that you were able to install to directory

 \c /usr/local, otherwise some extra care is to be taken to use the

 library.

 We briefly explain these commands below.

 \verbatim

 tar xvzf lemon-0.3.1.tar.gz

 \endverbatim

 This command untars the <tt>tar.gz</tt> file into a directory named <tt>

 lemon-0.3.1</tt>.

 \verbatim

 cd lemon-0.3.1

 \endverbatim

 Enters the directory.

 \verbatim

 ./configure

 \endverbatim

 Does some configuration (creates makefiles etc).

 \verbatim

 make

 \endverbatim

 This command compiles the non-template part of LEMON into

 <b>libemon.a</b> file. It also compiles some benchmark and demo

 programs.

 \verbatim

 make check

 \endverbatim

 This is an optional step: it runs the test programs that we

 developed for LEMON to check whether the library works properly on

 your platform.

 \verbatim

 make install

 \endverbatim

 This will copy the directory structure to its final destination (e.g. to \c

 /usr/local) so that your system can access it. This command should

 be issued as "root", unless you provided a \c --prefix switch to

 the \c configure to install the library in non-default location.

 \subsection configureFlags Configure flags

 You can pass the following flags to \c ./configure (see \c ./configure --help

 for more):

 \verbatim

 --with-glpk[=PREFIX]

 \endverbatim

 Enable GLPK support (default). You should specify the prefix too if you

 installed it to some non-standard location (e.g. your home directory). If

 GLPK is not found, then GLPK support will be disabled.

 \verbatim

 --with-glpk-includedir=DIR

 \endverbatim

 The directory where the GLPK header files are located. This is only useful when

 the GLPK headers and libraries are not under the same prefix (which is

 unlikely).

 \verbatim

 --with-glpk-libdir=DIR

 \endverbatim

 The directory where the GLPK libraries are located. This is only useful when

 the GLPK headers and libraries are not under the same prefix (which is

 unlikely).

 \verbatim

 --without-glpk

 \endverbatim

 Disable GLPK support.

 \verbatim

 --with-cplex[=PREFIX]

 \endverbatim

 Enable CPLEX support (default). You should specify the prefix too if you

 installed it to some non-standard location (e.g. \c /opt/ilog/cplex75). If

 CPLEX is not found, then CPLEX support will be disabled.

 \verbatim

 --with-cplex-includedir=DIR

 \endverbatim

 The directory where the CPLEX header files are located. This is only useful

 when the CPLEX headers and libraries are not under the same prefix.

 \verbatim

 --with-cplex-libdir=DIR

 \endverbatim

 The directory where the CPLEX libraries are located. This is only useful when

 the CPLEX headers and libraries are not under the same prefix.

 \verbatim

 --without-cplex

 \endverbatim

 Disable CPLEX support.

 \section svnCheckout How to checkout LEMON form our Subversion repository

 You can obtain the latest version of LEMON from our Subversion repository. To

 do this issue the following command:

 \verbatim

 svn co https://lemon.cs.elte.hu/svn/hugo/trunk lemon

 \endverbatim

 Use "lemon" as username, the password is empty.

 \section svnCompile How to compile the source from the repository

 You can compile the code from the repository similarly to the packaged version,

 but you will need to run \c ./bootstrap before \c ./configure. See \c

 ./bootstrap \c --help for options. For bootstrapping you will need the

 following tools:

  - <a href="http://www.gnu.org/software/automake/">automake</a> (1.7 or newer)

  - <a href="http://www.gnu.org/software/autoconf/">autoconf</a> (2.59 or newer)

  - <a href="http://www.gnu.org/software/libtool/">libtool</a>

  - <a href="http://pkgconfig.freedesktop.org/">pkgconfig</a>

 To generate the documentation, run \c make \c doc. You will need

 <a href="http://www.doxygen.org/">Doxygen</a> for this.

 You can pass the \c --enable-doc=full flag to \c ./configure to generate the

 internal documentation too.

 If you pass the \c --disable-doc flag to \c ./configure then the documentation

 won't be installed, when you run \c make \c install (this speeds things up a

 bit).

 \section helloworld My first program using LEMON

 If you have installed LEMON on your system you can paste the

 following code segment into a file (you can find it as \c

 demo/hello_lemon.cc in the LEMON package) to have a first working

 program that uses library LEMON.

 \dontinclude hello_lemon.cc

 \skip include

 \until }

 First let us briefly explain how this program works.

 ListGraph is one of LEMON's graph classes. It is based on linked lists,

 therefore iterating throuh its edges and nodes is fast.

 After some convenience typedefs we create a graph and add three nodes to it.

 Then we add edges to it to form a complete graph.

 Then we iterate through all nodes of the graph. We use a constructor of the

 node iterator to initialize it to the first node. The operator++ is used to

 step to the next node. Using operator++ on the iterator pointing to the last

 node invalidates the iterator i.e. sets its value to

 \ref lemon::INVALID "INVALID". This is what we exploit in the stop condition.

 We can also iterate through all edges of the graph very similarly. The 

 \c target and

 \c source member functions can be used to access the endpoints of an edge.

 If your installation of LEMON into directory \c /usr/local was

 successful, then it is very easy to compile this program with the

 following command (the argument <tt>-lemon</tt> tells the compiler

 that we are using the installed library LEMON):

 \verbatim

 g++ hello_lemon.cc -o hello_lemon -lemon

 \endverbatim

 As a result you will get the exacutable \c hello_lemon in

 this directory that you can run by the command 

 \verbatim

 ./hello_lemon

 \endverbatim

 If everything has gone well then the previous code fragment prints

 out the following:

 \verbatim

 Nodes: 2 1 0

 Edges: (0,2) (1,2) (0,1) (2,1) (1,0) (2,0)

 \endverbatim

 Congratulations!

 If you want to see more features, go to the

 \ref quicktour "Quick Tour to LEMON",

 if you want to see see some demo programs then go to our 

 \ref demoprograms "Demo Programs" page! 

 */