<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>PropertyGraph</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:PropertyGraph"></A> PropertyGraph </H2> A PropertyGraph is a graph that has some property associated with each of the vertices or edges in the graph. As a given graph may have several properties associated with each vertex or edge, a tag is used to identify which property is being accessed. The graph provides a function which returns a property map object. <P> <H3>Refinement of</H3> <a href="./Graph.html">Graph</a> <h3>Notation</h3> <Table> <TR> <TD><tt>G</tt></TD> <TD>A type that is a model of PropertyGraph.</TD> </TR> <TR> <TD><tt>g</tt></TD> <TD>An object of type <tt>G</tt>.</TD> </TR> <TR> <TD><tt>X</tt></TD> <TD>Either the vertex or edge descriptor type for <tt>G</tt>.</TD> </TR> <TR> <TD><tt>x</tt></TD> <TD>An object of type <tt>X</tt>.</TD> </TR> <TR> <TD><tt>Map</tt></TD> <TD>The type <tt>boost::property_map<G, Property>::const_type</tt>.</TD> </TR> <TR> <TD><tt>v</tt></TD> <TD>An object of type <tt>boost::property_traits<Map>::value_type</tt>.</TD> </TR> <TR> <TD><tt>PropertyTag</tt></TD> <TD>A type that models the <a href="./PropertyTag.html">PropertyTag</a> concept.</TD> </TR> <TR> <TD><tt>p</tt></TD> <TD>An object of type <tt>PropertyTag</tt>.</td> </TR> <TR> <TD><tt>pmap</tt></TD> <TD>An object of type <tt>Map</tt>.</td> </TR> </table> <H3>Associated types</H3> <table border> <tr> <td><pre>boost::property_map<G, PropertyTag>::type</pre> The type of the property map for the property specified by <TT>PropertyTag</TT>. This type must be a model of <a href="../../property_map/doc/ReadWritePropertyMap.html">ReadWritePropertyMap</a> with a key type the same as the graph's vertex or edge descriptor type. </td> </tr> <tr> <td><pre>boost::property_map<G, PropertyTag>::const_type</pre> The type of the const property map for the property specified by <TT>PropertyTag</TT>. This type must be a model of <a href="../../property_map/doc/ReadablePropertyMap.html">ReadablePropertyMap</a> with a key type the same as the graph's vertex or edge descriptor type. </td> </tr> </table> <h3>Valid Expressions</h3> <table border> <tr> <td> <TT>get(p, g)</TT> </td> <td> Returns the property map for the property specified by the <tt>PropertyTag</tt> type. The object <tt>p</tt> is only used to carry the type.<br> Return type: <TT>boost::property_map<G, PropertyTag>::type</TT> if <TT>g</TT> is mutable and <br><TT>boost::property_map<G, PropertyTag>::const_type</TT> otherwise. </td> </TR> <tr> <td> <TT>get(p, g, x)</TT> </td> <td> Returns the property value (specified by the <tt>PropertyTag</tt> type) associated with object <tt>x</tt> (a vertex or edge). The object <tt>p</tt> is only used to carry the type. This function is equivalent to:<br> <tt>get(get(p, g), x)</tt><br> Return type: <tt>boost::property_traits<Map>::value_type</tt> </td> </TR> <tr> <td> <TT>put(p, g, x, v)</TT> </td> <td> Set the property (specified by the <tt>PropertyTag</tt> type) associated with object <tt>x</tt> (a vertex or edge) to the value <tt>v</tt>. The object <tt>p</tt> is only used to carry the type. This function is equivalent to:<br> <tt> pmap = get(p, g);<br> put(pmap, x, v) </tt><br> Return type: <TT>void</TT> </td> </TR> </TABLE> <H3>Complexity</H3> The <tt>get()</tt> property map function must be constant time. <H3>Models</H3> <UL> <LI><tt>adjacency_list</tt> with <tt>VertexProperty=property<vertex_distance_t,int,property<vertex_in_degree_t,int> ></tt> and <tt>PropertyTag=vertex_distance_t</tt>.</li> <li><tt>adjacency_list</tt> with <tt>VertexPropertyTag=property<vertex_distance_t,int,property<vertex_in_degree_t,int> ></TT> and <tt>PropertyTag=vertex_in_degree_t</tt>.</li> </UL> <H3>Concept Checking Class</H3> <PRE> template <class Graph, class X, class PropertyTag> struct PropertyGraphConcept { typedef typename property_map<G, PropertyTag>::type Map; typedef typename property_map<G, PropertyTag>::const_type const_Map; void constraints() { function_requires< GraphConcept<G> >(); function_requires< ReadWritePropertyMapConcept<Map, X> >(); function_requires< ReadablePropertyMapConcept<const_Map, X> >(); Map pmap = get(PropertyTag(), g); pval = get(PropertyTag(), g, x); put(PropertyTag(), g, x, pval); ignore_unused_variable_warning(pmap); } void const_constraints(const G& g) { const_Map pmap = get(PropertyTag(), g); pval = get(PropertyTag(), g, x); ignore_unused_variable_warning(pmap); } G g; X x; typename property_traits<Map>::value_type pval; }; </PRE> <h3>See Also</h3> <a href="./property_map.html"><tt>property_map</tt></a> <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>