[Lemon-commits] [lemon_svn] alpar: r2206 - hugo/trunk/doc
Lemon SVN
svn at lemon.cs.elte.hu
Mon Nov 6 20:50:55 CET 2006
Author: alpar
Date: Wed Sep 14 12:00:43 2005
New Revision: 2206
Modified:
hugo/trunk/doc/graph_orientation.dox
Log:
Better doc.
Modified: hugo/trunk/doc/graph_orientation.dox
==============================================================================
--- hugo/trunk/doc/graph_orientation.dox (original)
+++ hugo/trunk/doc/graph_orientation.dox Wed Sep 14 12:00:43 2005
@@ -6,7 +6,28 @@
\brief Graph orientation with lower bound requirement on the
in-degree of the nodes.
+This demo shows an adaptation of the well-known "preflow push" algorithm to
+a simple graph orientation problem.
+The input of the problem is a(n undirected) graph and an integer value
+<i>f(n)</i> assigned to each node \e n. The task is to find an orientation
+of the edges for which the number of edge arriving to each node \e n is at
+least least <i>f(n)</i>.
+
+In fact, the algorithm reads a directed graph and computes a set of edges to
+be reversed in order to achieve the in-degree requirement.
+This input is given using
+\ref graph-io-page ".lgf (Lemon Graph Format)" file. It should contain
+three node maps. The one called "f" contains the in-degree requirements, while
+"coordinate_x" and "coordinate_y" indicate the position of the nodes. These
+latter ones are used to generate the output, which is a <tt>.eps</tt> file.
+
+
+\section go-alg-dec The C++ source file
+
+Here you find how to solve the problem above using lemon.
+
+\subsection go-alg-head Headers and convenience typedefs
First we include some important headers.
@@ -36,6 +57,8 @@
\skip typedef
\until InEdgeIt
+\subsection go-alg-main The main() function
+
Well, we are ready to start <tt>main()</tt>.
\skip main
\until {
@@ -47,7 +70,7 @@
\until }
Now, we read a graph \c g, and a map \c f containing
-the in-deg requirements from a \ref graph-io-page ".lgf" (Lemon Graph Format)
+the in-deg requirements from a \ref graph-io-page ".lgf (Lemon Graph Format)"
file. To generate the output picture, we also read the node titles (\c id) and
coordinates (\c coords).
So, first we create the graph
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