222 lines
5.4 KiB
HTML
222 lines
5.4 KiB
HTML
<HTML>
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<!--
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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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(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: Edge List Class</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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<H1><A NAME="sec:edge-list-class"></A>
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<PRE>
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edge_list<EdgeIterator, ValueType, DiffType>
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</PRE>
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</H1>
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<P>
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The <TT>edge_list</TT> class is an adaptor that turns a pair of edge
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iterators into a class that models <TT>EdgeListGraph</TT>. The
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<TT>value_type</TT> of the edge iterator must be a <TT>std::pair</TT> (or
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at least have <TT>first</TT> and <TT>second</TT> members). The
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<TT>first_type</TT> and <TT>second_type</TT> of the pair must be the
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same and they will be used for the graph's <TT>vertex_descriptor</TT>.
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The <TT>ValueType</TT> and <TT>DiffType</TT> template parameters are only
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needed if your compiler does not support partial
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specialization. Otherwise they default to the correct types.
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<P>
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<H3>Example</H3>
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<P>
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Applying the Bellman-Ford shortest paths algorithm to an
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<TT>edge_list</TT>.
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<P>
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<PRE>
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enum { u, v, x, y, z, N };
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char name[] = { 'u', 'v', 'x', 'y', 'z' };
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typedef std::pair<int,int> E;
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E edges[] = { E(u,y), E(u,x), E(u,v),
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E(v,u),
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E(x,y), E(x,v),
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E(y,v), E(y,z),
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E(z,u), E(z,x) };
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int weight[] = { -4, 8, 5,
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-2,
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9, -3,
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7, 2,
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6, 7 };
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typedef boost::edge_list<E*> Graph;
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Graph g(edges, edges + sizeof(edges) / sizeof(E));
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std::vector<int> distance(N, std::numeric_limits<short>::max());
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std::vector<int> parent(N,-1);
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distance[z] = 0;
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parent[z] = z;
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bool r = boost::bellman_ford_shortest_paths(g, int(N), weight,
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distance.begin(),
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parent.begin());
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if (r)
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for (int i = 0; i < N; ++i)
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std::cout << name[i] << ": " << distance[i]
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<< " " << name[parent[i]] << std::endl;
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else
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std::cout << "negative cycle" << std::endl;
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</PRE>
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The output is the distance from the root and the parent
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of each vertex in the shortest paths tree.
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<PRE>
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u: 2 v
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v: 4 x
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x: 7 z
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y: -2 u
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z: 0 z
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</PRE>
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<P>
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<p>
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<H3>Where Defined</H3>
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<a href="../../../boost/graph/edge_list.hpp"><TT>boost/graph/edge_list.hpp</TT></a>
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<P>
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<H3>Template Parameters</H3>
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<P>
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<TABLE border>
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<TR>
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<th>Parameter</th><th>Description</th>
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</tr>
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<TR><TD><TT>EdgeIterator</TT></TD> <TD>Must be model of <a
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href="http://www.boost.org/sgi/stl/InputIterator.html">InputIterator</a>
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who's <TT>value_type</TT> must be a pair of vertex descriptors.</TD>
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</TR>
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<TR><TD><TT>ValueType</TT></TD>
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<TD>The <TT>value_type</TT> of the <TT>EdgeIterator</TT>.<br>
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Default: <TT>std::iterator_traits<EdgeIterator>::value_type</TT></TD>
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</TR>
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<TR><TD><TT>DiffType</TT></TD>
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<TD>The <TT>difference_type</TT> of the <TT>EdgeIterator</TT>.<br>
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Default: <TT>std::iterator_traits<EdgeIterator>::difference_type</TT></TD>
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</TR>
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</TABLE>
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<P>
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<H3>Model of</H3>
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<a href="./EdgeListGraph.html">EdgeListGraph</a>
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<P>
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<H3>Associated Types</H3>
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<hr>
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<tt>boost::graph_traits<edge_list>::vertex_descriptor</tt>
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<br><br>
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The type for the vertex descriptors associated with the
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<TT>edge_list</TT>. This will be the same type as
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<TT>std::iterator_traits<EdgeIterator>::value_type::first_type</TT>.
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<hr>
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<tt>
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boost::graph_traits<edge_list>::edge_descriptor
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</tt>
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<br><br>
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The type for the edge descriptors associated with the
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<TT>edge_list</TT>.
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<hr>
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<tt>
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boost::graph_traits<edge_list>::edge_iterator
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</tt>
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<br><br>
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The type for the iterators returned by <TT>edges()</TT>. The iterator
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category of the <TT>edge_iterator</TT> will be the same as that of the
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<TT>EdgeIterator</TT>.
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<hr>
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<h3>Member Functions</h3>
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<hr>
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<tt>
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edge_list(EdgeIterator first, EdgeIterator last)
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</tt>
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<br><br>
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Creates a graph object with <TT>n</TT> vertices and with the
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edges specified in the edge list given by the range <TT>[first,last)</TT>.
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<hr>
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<H3>Non-Member Functions</H3>
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<hr>
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<tt>
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std::pair<edge_iterator, edge_iterator><br>
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edges(const edge_list& g)
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</tt>
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<br><br>
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Returns an iterator-range providing access to the edge set of graph <TT>g</TT>.
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<hr>
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<tt>
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vertex_descriptor<br>
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source(edge_descriptor e, const edge_list& g)
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</tt>
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<br><br>
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Returns the source vertex of edge <TT>e</TT>.
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<hr>
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<tt>
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vertex_descriptor<br>
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target(edge_descriptor e, const edge_list& g)
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</tt>
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<br><br>
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Returns the target vertex of edge <TT>e</TT>.
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<hr>
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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>,
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Indiana University (<A
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HREF="mailto:jsiek@osl.iu.edu">jsiek@osl.iu.edu</A>)<br>
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<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>
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<A HREF="https://homes.cs.washington.edu/~al75">Andrew Lumsdaine</A>,
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Indiana University (<A
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HREF="mailto:lums@osl.iu.edu">lums@osl.iu.edu</A>)
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</TD></TR></TABLE>
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