117 lines
3.6 KiB
HTML
117 lines
3.6 KiB
HTML
<HTML>
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<!-- Copyright 2007 Aaron Windsor
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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: make_connected</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><tt>make_connected</tt></H1>
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<p>
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<pre>
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template <typename Graph, typename VertexIndexMap, typename AddEdgeVisitor>
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make_connected(Graph& g, VertexIndexMap vm, AddEdgeVisitor& vis);
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</pre>
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<p>
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A undirected graph <i>G</i> is connected if, for every pair of vertices
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<i>u,v</i> in <i>G</i>, there is a path from <i>u</i> to <i>v</i>.
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<tt>make_connected</tt> adds the minimum number of edges needed to make the
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input graph connected. The algorithm first identifies all of the
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<a href="./connected_components.html">connected components</a> in the graph,
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then adds edges to connect those components together in a path. For example, if
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a graph contains three connected components <i>A</i>, <i>B</i>, and <i>C</i>,
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<tt>make_connected</tt> will add two edges. The two edges added might consist
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of one connecting a vertex in <i>A</i> with a vertex in <i>B</i> and one
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connecting a vertex in <i>B</i> with a vertex in <i>C</i>.
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<p>
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The default behavior of <tt>make_connected</tt> is to modify the graph
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<tt>g</tt> by calling <tt>add_edge(u,v,g)</tt> for every pair of vertices
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<i>(u,v)</i> where an edge needs to be added to connect <tt>g</tt>. This
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behavior can be overriden by providing a vistor as the <tt>AddEdgeVisitor</tt>
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parameter. The only requirement for an <tt>AddEdgeVisitor</tt> is that it
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define a member function with the following signature:
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<pre>
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template <typename Graph, typename Vertex>
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void visit_vertex_pair(Vertex u, Vertex v, Graph& g);
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</pre>
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This event point can also be used as a hook to update the underlying edge
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index map automatically as edges are added. See the
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documentation for the <a href="./AddEdgeVisitor.html">AddEdgeVisitor</a>
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concept for more information.
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<H3>Where Defined</H3>
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<P>
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<a href="../../../boost/graph/make_connected.hpp">
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<TT>boost/graph/make_connected.hpp</TT>
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</a>
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<h3>Parameters</h3>
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IN/OUT: <tt>Graph& g</tt>
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<blockquote>
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An undirected graph. The graph type must be a model of <a
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href="VertexListGraph.html">Vertex List Graph</a>, <a
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href="IncidenceGraph.html">Incidence Graph</a>, and
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a <a href="MutableGraph.html">Mutable Graph</a><br>
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</blockquote>
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IN: <tt>VertexIndexMap vm</tt>
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<blockquote>
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A <a href="../../property_map/doc/ReadablePropertyMap.html">Readable Property Map
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</a> that maps vertices from <tt>g</tt> to distinct integers in the range
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<tt>[0, num_vertices(g) )</tt><br>
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<b>Default</b>: <tt>get(vertex_index,g)</tt><br>
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</blockquote>
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IN: <tt>AddEdgeVisitor</tt>
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<blockquote>
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A model of <a href="AddEdgeVisitor.html">AddEdgeVisitor
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</a>.<br>
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<b>Default</b>: <tt>default_add_edge_visitor</tt>, a class defines
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<tt>visit_vertex_pair</tt> to dispatch
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its calls to <tt>add_edge</tt>.
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</blockquote>
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<h3>Complexity</h3>
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On a graph with <i>n</i> vertices and <i>m</i> edges, <tt>make_connected</tt>
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runs in time <i>O(n + m)</i>
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<H3>Example</H3>
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<P>
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<a href="../example/make_connected.cpp">
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<TT>../example/make_connected.cpp</TT>
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</a>
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<h3>See Also</h3>
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<a href="planar_graphs.html">Planar Graphs in the Boost Graph Library</a>
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<br>
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<HR>
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Copyright © 2007 Aaron Windsor (<a href="mailto:aaron.windsor@gmail.com">
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aaron.windsor@gmail.com</a>)
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</BODY>
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</HTML>
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