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