kpeter@3: /* -*- mode: C++; indent-tabs-mode: nil; -*-
kpeter@3:  *
kpeter@3:  * This file is a part of LEMON, a generic C++ optimization library.
kpeter@3:  *
kpeter@3:  * Copyright (C) 2003-2008
kpeter@3:  * Egervary Jeno Kombinatorikus Optimalizalasi Kutatocsoport
kpeter@3:  * (Egervary Research Group on Combinatorial Optimization, EGRES).
kpeter@3:  *
kpeter@3:  * Permission to use, modify and distribute this software is granted
kpeter@3:  * provided that this copyright notice appears in all copies. For
kpeter@3:  * precise terms see the accompanying LICENSE file.
kpeter@3:  *
kpeter@3:  * This software is provided "AS IS" with no warranty of any kind,
kpeter@3:  * express or implied, and with no claim as to its suitability for any
kpeter@3:  * purpose.
kpeter@3:  *
kpeter@3:  */
kpeter@3: 
kpeter@3: /**
alpar@10: [PAGE]hello_lemon[PAGE] Compile Your First Code
kpeter@6: 
kpeter@6: If you have installed LEMON on your system you can paste the following
kpeter@6: code segment into a file called <tt>hello_lemon.cc</tt> to have a first
kpeter@6: working program that uses LEMON.
kpeter@6: 
kpeter@6: \dontinclude hello_lemon.cc
kpeter@6: \skip #include
kpeter@6: \until }
kpeter@6: 
kpeter@6: First let us briefly explain how this example program works.
kpeter@9: (The used notions will be discussed in detail in the following sections.)
kpeter@6: 
kpeter@6: After some convenience typedefs we create a directed graph (\e digraph)
kpeter@6: and add some nodes and arcs to it.
kpeter@6: ListDigraph is one of the digraph classes implemented in LEMON.
kpeter@6: It is based on linked lists, therefore iterating through its nodes and
kpeter@6: arcs is fast.
kpeter@6: 
kpeter@6: Then we iterate through all nodes of the digraph and print their unique
kpeter@6: IDs. We use a constructor of the node iterator to initialize it to the
kpeter@6: first node.
kpeter@6: The <tt>operator++</tt> is used to step to the next node. After the last
kpeter@6: node the iterator becomes invalid (i.e. it is set to \c INVALID).
kpeter@6: This is what we exploit in the stop condition.
kpeter@6: We iterate through all arcs of the digraph very similarly and print the
kpeter@6: IDs of their source (tail) and target (head) nodes using the \c source()
kpeter@6: and \c target() member functions.
kpeter@6: 
kpeter@6: After that we create an arc map, which is actually a mapping that assigns
kpeter@6: an \c int value (length) to each arc, and we set this value for each arc.
kpeter@6: Finally we iterate through all arcs again and print their lengths.
kpeter@6: 
kpeter@9: Now let us compile this simple example program.
kpeter@6: 
alpar@10: [SEC]hello_lemon_system[SEC] If LEMON is Installed System-Wide
kpeter@6: 
kpeter@9: If LEMON is installed system-wide (into directory \c /usr/local),
kpeter@9: then it is very easy to compile this program with the
kpeter@6: following command (the argument <tt>-lemon</tt> tells the compiler
kpeter@6: that we are using the installed LEMON):
kpeter@6: 
kpeter@6: \verbatim
kpeter@9: g++ -lemon hello_lemon.cc -o hello_lemon
kpeter@6: \endverbatim
kpeter@6: 
kpeter@6: As a result you will get the exacutable \c hello_lemon in the current
kpeter@6: directory, which you can run by the following command.
kpeter@6: 
kpeter@6: \verbatim
kpeter@6: ./hello_lemon
kpeter@6: \endverbatim
kpeter@6: 
alpar@10: [SEC]hello_lemon_user[SEC] If LEMON is Installed User-Local
kpeter@6: 
kpeter@6: Compiling the code is a bit more difficult if you installed LEMON
kpeter@6: user-local into a directory (e.g. <tt>~/lemon</tt>) or if you just
kpeter@6: skipped the step <tt>make install</tt>.
kpeter@6: You have to issue a command like this.
kpeter@6: 
kpeter@6: \verbatim
kpeter@9: g++ -lemon -I ~/lemon -L ~/lemon/lemon/.libs hello_lemon.cc -o hello_lemon
kpeter@6: \endverbatim
kpeter@6: 
kpeter@6: If everything has gone well, then our program prints out the followings.
kpeter@6: 
kpeter@6: \verbatim
kpeter@6: Hello World!
kpeter@6: This is LEMON library here. We have a direceted graph.
kpeter@6: 
kpeter@6: Nodes: 3 2 1 0
kpeter@6: Arcs: (2,3) (1,3) (1,2) (0,2) (0,1)
kpeter@6: 
kpeter@6: There is a map on the arcs (length):
kpeter@6: 
kpeter@6: length(2,3)=10
kpeter@6: length(1,3)=25
kpeter@6: length(1,2)=5
kpeter@6: length(0,2)=20
kpeter@6: length(0,1)=10
kpeter@6: \endverbatim
kpeter@6: 
kpeter@6: You may note that iterating through the nodes and arcs is done in the
kpeter@6: reverse order compared to the creating order (the IDs are in decreasing
kpeter@6: order).
kpeter@6: This is due to implementation aspects, that may differ at other graph
kpeter@6: types, moreover it may be changed in the next releases.
kpeter@6: Thus you should not exploit this method in any way, you should not
kpeter@6: suppose anything about the iteration order.
kpeter@6: 
kpeter@6: If you managed to compile and run this example code without any problems,
kpeter@6: you can go on reading this tutorial to get to know more features and tools
kpeter@6: of LEMON.
kpeter@6: Otherwise if you encountered problems that you did not manage to solve,
kpeter@6: do not hesitate to
kpeter@6: <a href="mailto:lemon-user@lemon.cs.elte.hu"><b>contact us</b></a>.
kpeter@6: 
alpar@10: [TRAILER]
kpeter@3: */