ceph/src/boost/libs/graph/doc/make_connected.html

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  10 <Title>Boost Graph Library: make_connected</Title>
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  18 <H1><tt>make_connected</tt></H1>
  19
  20 <p>
  21
  22 <pre>
  23 template &lt;typename Graph, typename VertexIndexMap, typename AddEdgeVisitor&gt;
  24 make_connected(Graph& g, VertexIndexMap vm, AddEdgeVisitor& vis);
  25 </pre>
  26
  27 <p>
  28
  29 A undirected graph <i>G</i> is connected if, for every pair of vertices
  30 <i>u,v</i> in <i>G</i>, there is a path from <i>u</i> to <i>v</i>.
  31 <tt>make_connected</tt> adds the minimum number of edges needed to make the
  32 input graph connected. The algorithm first identifies all of the
  33 <a href="./connected_components.html">connected components</a> in the graph,
  34 then adds edges to connect those components together in a path. For example, if
  35 a graph contains three connected components <i>A</i>, <i>B</i>, and <i>C</i>,
  36 <tt>make_connected</tt> will add two edges. The two edges added might consist
  37 of one connecting a vertex in <i>A</i> with a vertex in <i>B</i> and one
  38 connecting a vertex in <i>B</i> with a vertex in <i>C</i>.
  39 <p>
  40 The default behavior of <tt>make_connected</tt> is to modify the graph
  41 <tt>g</tt> by calling <tt>add_edge(u,v,g)</tt> for every pair of vertices
  42 <i>(u,v)</i> where an edge needs to be added to connect <tt>g</tt>. This
  43 behavior can be overriden by providing a vistor as the <tt>AddEdgeVisitor</tt>
  44 parameter. The only requirement for an <tt>AddEdgeVisitor</tt> is that it
  45 define a member function with the following signature:
  46 <pre>
  47 template &lt;typename Graph, typename Vertex&gt;
  48 void visit_vertex_pair(Vertex u, Vertex v, Graph& g);
  49 </pre>
  50 This event point can also be used as a hook to update the underlying edge
  51 index map automatically as edges are added. See the
  52 documentation for the <a href="./AddEdgeVisitor.html">AddEdgeVisitor</a>
  53 concept for more information.
  54
  55
  56 <H3>Where Defined</H3>
  57
  58 <P>
  59 <a href="../../../boost/graph/make_connected.hpp">
  60 <TT>boost/graph/make_connected.hpp</TT>
  61 </a>
  62
  63 <h3>Parameters</h3>
  64
  65 IN/OUT: <tt>Graph&amp; g</tt>
  66
  67 <blockquote>
  68 An undirected graph. The graph type must be a model of <a
  69 href="VertexListGraph.html">Vertex List Graph</a>, <a
  70 href="IncidenceGraph.html">Incidence Graph</a>, and
  71 a <a href="MutableGraph.html">Mutable Graph</a><br>
  72 </blockquote>
  73
  74 IN: <tt>VertexIndexMap vm</tt>
  75
  76 <blockquote>
  77 A <a href="../../property_map/doc/ReadablePropertyMap.html">Readable Property Map
  78 </a> that maps vertices from <tt>g</tt> to distinct integers in the range
  79 <tt>[0, num_vertices(g) )</tt><br>
  80 <b>Default</b>: <tt>get(vertex_index,g)</tt><br>
  81 </blockquote>
  82
  83 IN: <tt>AddEdgeVisitor</tt>
  84
  85 <blockquote>
  86 A model of <a href="AddEdgeVisitor.html">AddEdgeVisitor
  87 </a>.<br>
  88 <b>Default</b>: <tt>default_add_edge_visitor</tt>, a class defines
  89 <tt>visit_vertex_pair</tt> to dispatch
  90 its calls to <tt>add_edge</tt>.
  91 </blockquote>
  92
  93
  94
  95 <h3>Complexity</h3>
  96
  97 On a graph with <i>n</i> vertices and <i>m</i> edges, <tt>make_connected</tt>
  98 runs in time <i>O(n + m)</i>
  99
 100 <H3>Example</H3>
 101
 102 <P>
 103 <a href="../example/make_connected.cpp">
 104 <TT>../example/make_connected.cpp</TT>
 105 </a>
 106
 107 <h3>See Also</h3>
 108
 109 <a href="planar_graphs.html">Planar Graphs in the Boost Graph Library</a>
 110
 111 <br>
 112 <HR>
 113 Copyright &copy; 2007 Aaron Windsor (<a href="mailto:aaron.windsor@gmail.com">
 114 aaron.windsor@gmail.com</a>)
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