]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | <HTML> |
2 | <!-- | |
3 | Copyright (c) Jeremy Siek 2000 | |
4 | ||
5 | Distributed under the Boost Software License, Version 1.0. | |
6 | (See accompanying file LICENSE_1_0.txt or copy at | |
7 | http://www.boost.org/LICENSE_1_0.txt) | |
8 | --> | |
9 | <Head> | |
10 | <Title>Boost Graph Library: Depth-First Visit</Title> | |
11 | <BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" | |
12 | ALINK="#ff0000"> | |
13 | <IMG SRC="../../../boost.png" | |
14 | ALT="C++ Boost" width="277" height="86"> | |
15 | ||
16 | <BR Clear> | |
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 <class <a href="./IncidenceGraph.html">IncidenceGraph</a>, class <a href="./DFSVisitor.html">DFSVisitor</a>, class ColorMap> | |
27 | void depth_first_visit(IncidenceGraph& g, | |
28 | typename graph_traits<IncidenceGraph>::vertex_descriptor s, | |
29 | DFSVisitor& vis, ColorMap color) | |
30 | ||
31 | template <class <a href="./IncidenceGraph.html">IncidenceGraph</a>, class <a href="./DFSVisitor.html">DFSVisitor</a>, class ColorMap, | |
32 | class TerminatorFunc> | |
33 | void depth_first_visit(IncidenceGraph& g, | |
34 | typename graph_traits<IncidenceGraph>::vertex_descriptor s, | |
35 | DFSVisitor& 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& 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> | |
136 | <HR> | |
137 | <TABLE> | |
138 | <TR valign=top> | |
139 | <TD nowrap>Copyright © 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>) | |
141 | </TD></TR></TABLE> | |
142 | ||
143 | </BODY> | |
144 | </HTML> |