145 lines
4.5 KiB
HTML
145 lines
4.5 KiB
HTML
<HTML>
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<!--
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Copyright (c) Jeremy Siek 2000
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Distributed under the Boost Software License, Version 1.0.
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(See accompanying file LICENSE_1_0.txt or copy at
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http://www.boost.org/LICENSE_1_0.txt)
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-->
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<Head>
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<Title>Boost Graph Library: Depth-First Visit</Title>
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<BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
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ALINK="#ff0000">
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<IMG SRC="../../../boost.png"
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ALT="C++ Boost" width="277" height="86">
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<BR Clear>
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<H2><A NAME="sec:dfs"></A>
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<img src="figs/python.gif" alt="(Python)"/>
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<TT>depth_first_visit</TT>
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</H2>
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<P>
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<PRE>
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template <class <a href="./IncidenceGraph.html">IncidenceGraph</a>, class <a href="./DFSVisitor.html">DFSVisitor</a>, class ColorMap>
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void depth_first_visit(IncidenceGraph& g,
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typename graph_traits<IncidenceGraph>::vertex_descriptor s,
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DFSVisitor& vis, ColorMap color)
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template <class <a href="./IncidenceGraph.html">IncidenceGraph</a>, class <a href="./DFSVisitor.html">DFSVisitor</a>, class ColorMap,
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class TerminatorFunc>
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void depth_first_visit(IncidenceGraph& g,
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typename graph_traits<IncidenceGraph>::vertex_descriptor s,
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DFSVisitor& vis, ColorMap color, TerminatorFunc func = TerminatorFunc())
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</PRE>
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<P>
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This function visits all of the vertices in the same connected
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component as the source vertex <tt>s</tt>, using the <a
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href="./graph_theory_review.html#sec:dfs-algorithm">depth-first
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pattern</a>. The main purpose of the function is for the
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implementation of <TT>depth_first_search()</TT> though sometimes it is
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useful on its own.
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<p>
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The <tt>DFSVisitor</tt> supplied by the user determines what
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actions are taken at each event-point within the algorithm.
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<p>
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The <tt>ColorMap</tt> is used by the algorithm to keep track
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of which vertices have been visited.
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<p>The second variant can be used, for example, to find all marked vertices
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reachable from a start vertex by a path which does not contain any another
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marked vertices.
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<P>
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<h3>Where Defined:</h3>
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<a href="../../../boost/graph/depth_first_search.hpp"><TT>boost/graph/depth_first_search.hpp</TT></a>
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<h3>Parameters</h3>
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IN <tt>IncidenceGraph& g</tt>
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<blockquote>
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A directed or undirected graph. The graph's type must be a model of
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<a href="./IncidenceGraph.html">Incidence Graph</a>.<br>
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<b>Python</b>: The parameter is named <tt>graph</tt>.
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</blockquote>
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IN: <tt>vertex_descriptor s</tt>
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<blockquote>
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The source vertex from which to start the search.<br>
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<b>Python</b>: The parameter is named <tt>root_vertex</tt>.
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</blockquote>
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IN: <tt>DFSVisitor visitor</tt>
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<blockquote>
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A visitor object that is invoked inside the algorithm at the
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event-points specified by the <a href="./DFSVisitor.html">DFS
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Visitor</a> concept. The visitor object is passed by value <a
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href="#1">[1]</a>.<br>
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<b>Python</b>: The parameter should be an object that derives from
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the <a href="DFSVisitor.html#python"><tt>DFSVisitor</tt></a> type of
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the graph.
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</blockquote>
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UTIL: <tt>ColorMap color</tt>
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<blockquote>
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This is used by the algorithm to keep track of its progress through
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the graph. The type <tt>ColorMap</tt> must be a model of <a
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href="../../property_map/doc/ReadWritePropertyMap.html">Read/Write
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Property Map</a> and its key type must be the graph's vertex
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descriptor type and the value type of the color map map must model
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<a href="./ColorValue.html">Color Value</a>.<br>
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<b>Python</b>: The color map must be a <tt>vertex_color_map</tt> for
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the graph.
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</blockquote>
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IN: <tt>TerminatorFunc func</tt>
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<blockquote>
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A function object callable with two parameters - the descriptor of
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vertex and the graph instance - and returning bool. The call is made
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immediately after call to 'discover_vertex' visitor
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event. If <tt>true</tt> is returned, the out edges of the vertex are
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not examined, as if they don't exist.<br>
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<b>Python</b>: Unsupported parameter.
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</blockquote>
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<P>
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<h3>Complexity</h3>
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Time complexity is <i>O(E)</i>.
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<h3>Notes</h3>
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<p><a name="1">[1]</a>
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Since the visitor parameter is passed by value, if your visitor
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contains state then any changes to the state during the algorithm
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will be made to a copy of the visitor object, not the visitor object
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passed in. Therefore you may want the visitor to hold this state by
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pointer or reference.
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<br>
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<HR>
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<TABLE>
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<TR valign=top>
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<TD nowrap>Copyright © 2000-2001</TD><TD>
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<A HREF="http://www.boost.org/people/jeremy_siek.htm">Jeremy Siek</A>, Indiana University (<A HREF="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</A>)
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</TD></TR></TABLE>
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</BODY>
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</HTML>
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