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

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   9 <Head>
  10 <Title>Boost Graph Library: Depth-First Visit</Title>
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  17
  18 <H2><A NAME="sec:dfs"></A>
  19 <img src="figs/python.gif" alt="(Python)"/>
  20 <TT>depth_first_visit</TT>
  21 </H2>
  22
  23
  24 <P>
  25 <PRE>
  26 template &lt;class <a href="./IncidenceGraph.html">IncidenceGraph</a>, class <a href="./DFSVisitor.html">DFSVisitor</a>, class ColorMap&gt;
  27 void depth_first_visit(IncidenceGraph& g,
  28   typename graph_traits&lt;IncidenceGraph&gt;::vertex_descriptor s,
  29   DFSVisitor&amp; vis, ColorMap color)
  30
  31 template &lt;class <a href="./IncidenceGraph.html">IncidenceGraph</a>, class <a href="./DFSVisitor.html">DFSVisitor</a>, class ColorMap,
  32           class TerminatorFunc&gt;
  33 void depth_first_visit(IncidenceGraph& g,
  34   typename graph_traits&lt;IncidenceGraph&gt;::vertex_descriptor s,
  35   DFSVisitor&amp; vis, ColorMap color, TerminatorFunc func = TerminatorFunc())
  36 </PRE>
  37
  38 <P>
  39 This function visits all of the vertices in the same connected
  40 component as the source vertex <tt>s</tt>, using the <a
  41 href="./graph_theory_review.html#sec:dfs-algorithm">depth-first
  42 pattern</a>. The main purpose of the function is for the
  43 implementation of <TT>depth_first_search()</TT> though sometimes it is
  44 useful on its own.
  45
  46 <p>
  47 The <tt>DFSVisitor</tt> supplied by the user determines what
  48 actions are taken at each event-point within the algorithm.
  49
  50 <p>
  51 The <tt>ColorMap</tt> is used by the algorithm to keep track
  52 of which vertices have been visited.
  53
  54 <p>The second variant can be used, for example, to find all marked vertices
  55 reachable from a start vertex by a path which does not contain any another
  56 marked vertices.
  57
  58
  59 <P>
  60
  61 <h3>Where Defined:</h3>
  62
  63 <a href="../../../boost/graph/depth_first_search.hpp"><TT>boost/graph/depth_first_search.hpp</TT></a>
  64
  65
  66 <h3>Parameters</h3>
  67
  68 IN <tt>IncidenceGraph&amp; g</tt>
  69 <blockquote>
  70 A directed or undirected graph. The graph's type must be a model of
  71 <a href="./IncidenceGraph.html">Incidence Graph</a>.<br>
  72
  73 <b>Python</b>: The parameter is named <tt>graph</tt>.
  74 </blockquote>
  75
  76 IN: <tt>vertex_descriptor s</tt>
  77 <blockquote>
  78   The source vertex from which to start the search.<br>
  79
  80   <b>Python</b>: The parameter is named <tt>root_vertex</tt>.
  81 </blockquote>
  82
  83 IN: <tt>DFSVisitor visitor</tt>
  84 <blockquote>
  85   A visitor object that is invoked inside the algorithm at the
  86   event-points specified by the <a href="./DFSVisitor.html">DFS
  87   Visitor</a> concept. The visitor object is passed by value <a
  88   href="#1">[1]</a>.<br>
  89
  90   <b>Python</b>: The parameter should be an object that derives from
  91   the <a href="DFSVisitor.html#python"><tt>DFSVisitor</tt></a> type of
  92   the graph.
  93 </blockquote>
  94
  95 UTIL: <tt>ColorMap color</tt>
  96 <blockquote>
  97   This is used by the algorithm to keep track of its progress through
  98   the graph. The type <tt>ColorMap</tt> must be a model of <a
  99   href="../../property_map/doc/ReadWritePropertyMap.html">Read/Write
 100   Property Map</a> and its key type must be the graph's vertex
 101   descriptor type and the value type of the color map map must model
 102   <a href="./ColorValue.html">Color Value</a>.<br>
 103
 104   <b>Python</b>: The color map must be a <tt>vertex_color_map</tt> for
 105   the graph.
 106 </blockquote>
 107
 108 IN: <tt>TerminatorFunc func</tt>
 109 <blockquote>
 110 A function object callable with two parameters - the descriptor of
 111 vertex and the graph instance - and returning bool. The call is made
 112 immediately after call to 'discover_vertex' visitor
 113 event. If <tt>true</tt> is returned, the out edges of the vertex are
 114 not examined, as if they don't exist.<br>
 115
 116   <b>Python</b>: Unsupported parameter.
 117 </blockquote>
 118 <P>
 119
 120 <h3>Complexity</h3>
 121
 122 Time complexity is <i>O(E)</i>.
 123
 124
 125 <h3>Notes</h3>
 126
 127 <p><a name="1">[1]</a>
 128   Since the visitor parameter is passed by value, if your visitor
 129   contains state then any changes to the state during the algorithm
 130   will be made to a copy of the visitor object, not the visitor object
 131   passed in. Therefore you may want the visitor to hold this state by
 132   pointer or reference.
 133
 134
 135 <br>
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 137 <TABLE>
 138 <TR valign=top>
 139 <TD nowrap>Copyright &copy; 2000-2001</TD><TD>
 140 <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>)
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