<HTML> <!-- Copyright (c) Jeremy Siek 2000 Distributed under the Boost Software License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) --> <Head> <Title>AdjacencyMatrix</Title> <BODY BGCOLOR="#ffffff" LINK="#0000ee" TEXT="#000000" VLINK="#551a8b" ALINK="#ff0000"> <IMG SRC="../../../boost.png" ALT="C++ Boost" width="277" height="86"> <BR Clear> <H2><A NAME="concept:AdjacencyMatrix"></A> AdjacencyMatrix </H2> <P> The AdjacencyMatrix concept refines <a href="./Graph.html">Graph</a> concept and adds the requirement for efficient access to any edge in the graph given the source and target vertices. No Boost Graph Library algorithms currently use this concept. However there are algorithms not yet implemented such as Floyd-Warshall that would require this concept. <H3>Refinement of</H3> <a href="./Graph.html">Graph</a> <H3>Associated Types</H3> <Table border> <tr> <td><tt>boost::graph_traits<G>::traversal_category</tt><br><br> This tag type must be convertible to <tt>adjacency_matrix_tag</tt>. </td> </tr> </table> <H3>Valid Expressions</H3> <table border> <tr> <th>Name</th><th>Expression</th><th>Return Type</th><th>Description</th> </tr> <tr> <td>Direct Edge Access</td> <TD><TT>edge(u,v,g)</TT></TD> <TD><TT>std::pair<edge_descriptor, bool></TT></TD> <TD> Returns a pair consisting of a flag saying whether there exists an edge between <TT>u</TT> and <TT>v</TT> in graph <TT>g</TT>, and consisting of the edge descriptor if the edge was found. </TD> </TR> </TABLE> <H3>Complexity guarantees</H3> The <TT>edge()</TT> function must return in constant time. <H3>Models</H3> <a href="./adjacency_matrix.html"><tt>adjacency_matrix</tt></a> <H3>Concept Checking Class</H3> <PRE> template <class G> struct AdjacencyMatrix { typedef typename boost::graph_traits<G>::edge_descriptor edge_descriptor; void constraints() { p = edge(u, v, g); } typename boost::graph_traits<G>::vertex_descriptor u, v; std::pair<bool, edge_descriptor> p; G g; }; </PRE> <br> <HR> <TABLE> <TR valign=top> <TD nowrap>Copyright © 2000-2001</TD><TD> <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>) </TD></TR></TABLE> </BODY> </HTML>