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- Copyright (c) Jeremy Siek, Lie-Quan Lee, and Andrew Lumsdaine 2000
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- Distributed under the Boost Software License, Version 1.0.
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- <Head>
- <Title>Boost Graph Library: predecessor_recorder</Title>
- <BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b"
- ALINK="#ff0000">
- <IMG SRC="../../../boost.png"
- ALT="C++ Boost" width="277" height="86">
- <BR Clear>
- <H1>
- <pre>
- predecessor_recorder<PredecessorMap, EventTag>
- </pre>
- </H1>
- This is an <a href="./EventVisitor.html">EventVisitor</a> that records
- the predecessor (or parent) of a vertex in a predecessor property
- map. This is particularly useful in graph search algorithms where
- recording the predecessors is an efficient way to encode the search
- tree that was traversed during the search. The predecessor recorder is
- typically used with the <tt>on_tree_edge</tt> or
- <tt>on_relax_edge</tt> events and cannot be used with vertex events.
- <p>
- <tt>predecessor_recorder</tt> can be used with graph algorithms by
- wrapping it with an algorithm-specific adaptor, such as <a
- href="./bfs_visitor.html"><tt>bfs_visitor</tt></a> and <a
- href="./dfs_visitor.html"><tt>dfs_visitor</tt></a>. Also, this event
- visitor can be combined with other event visitors using
- <tt>std::pair</tt> to form an EventVisitorList.
- <p>
- Algorithms such as Dijkstra's and breadth-first search will not assign
- a predecessor to the source vertex (which is the root of the search
- tree). It is often useful to initialize the source vertex's
- predecessor to itself, thereby identifying the root vertex as the only
- vertex which is its own parent. When using an algorithm like
- depth-first search that creates a forest (multiple search trees) it
- is useful to initialize the predecessor of every vertex to itself. This
- way all the root nodes can be distinguished.
- <h3>Example</h3>
- See the example for <a href="./bfs_visitor.html"><tt>bfs_visitor</tt></a>.
- <h3>Model of</h3>
- <a href="./EventVisitor.html">EventVisitor</a>
- <H3>Where Defined</H3>
- <P>
- <a href="../../../boost/graph/visitors.hpp">
- <TT>boost/graph/visitors.hpp</TT></a>
- <H3>Template Parameters</H3>
- <P>
- <TABLE border>
- <TR>
- <th>Parameter</th><th>Description</th><th>Default</th>
- </tr>
- <TR><TD><TT>PredecessorMap</TT></TD>
- <TD>
- A <a
- href="../../property_map/doc/WritablePropertyMap.html">WritablePropertyMap</a>
- where the key type and the value type are the vertex descriptor type
- of the graph.
- </TD>
- <TD> </TD>
- </TR>
- <TR><TD><TT>EventTag</TT></TD>
- <TD>
- The tag to specify when the <tt>predecessor_recorder</tt> should be
- applied during the graph algorithm. <tt>EventTag</tt> must be an
- edge event.
- </TD>
- <TD> </TD>
- </TR>
- </table>
- <H2>Associated Types</H2>
- <table border>
- <tr>
- <th>Type</th><th>Description</th>
- </tr>
- <tr>
- <td><tt>predecessor_recorder::event_filter</tt></td>
- <td>
- This will be the same type as the template parameter <tt>EventTag</tt>.
- </td>
- </tr>
- </table>
- <h3>Member Functions</h3>
- <p>
- <table border>
- <tr>
- <th>Member</th><th>Description</th>
- </tr>
- <tr>
- <td><tt>
- predecessor_recorder(PredecessorMap pa);
- </tt></td>
- <td>
- Construct a predecessor recorder object with predecessor property map
- <tt>pa</tt>.
- </td>
- </tr>
- <tr>
- <td><tt>
- template <class Edge, class Graph><br>
- void operator()(Edge e, const Graph& g);
- </tt></td>
- <td>
- Given edge <i>e = (u,v)</i>, this records <i>u</i> as the
- predecessor (or parent) of <i>v</i>.
- </td>
- </tr>
- </table>
- <h3>Non-Member Functions</h3>
- <table border>
- <tr>
- <th>Function</th><th>Description</th>
- </tr>
- <tr><td><tt>
- template <class PredecessorMap, class Tag><br>
- predecessor_recorder<PredecessorMap, Tag> <br>
- record_predecessors(PredecessorMap pa, Tag);
- </tt></td><td>
- A convenient way to create a <tt>predecessor_recorder</tt>.
- </td></tr>
- </table>
- <h3>See Also</h3>
- <a href="./visitor_concepts.html">Visitor concepts</a>
- <p>
- The following are other event visitors: <a
- <a href="./distance_recorder.html"><tt>distance_recorder</tt></a>,
- <a href="./time_stamper.html"><tt>time_stamper</tt></a>,
- and <a href="./property_writer.html"><tt>property_writer</tt></a>.
- <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>)<br>
- <A HREF="http://www.boost.org/people/liequan_lee.htm">Lie-Quan Lee</A>, Indiana University (<A HREF="mailto:llee@cs.indiana.edu">llee@cs.indiana.edu</A>)<br>
- <A HREF="https://homes.cs.washington.edu/~al75">Andrew Lumsdaine</A>,
- Indiana University (<A
- HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>)
- </TD></TR></TABLE>
- </BODY>
- </HTML>
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