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| <Head> |
| <Title>MutableGraph</Title> |
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| |
| |
| <H2><A NAME="sec:MutableGraph"></A> |
| MutableGraph |
| </H2> |
| |
| A MutableGraph can be changed via the addition or removal of |
| edges and vertices. |
| |
| <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 Graph.</TD> |
| </TR> |
| |
| <TR> |
| <TD><tt>g</tt></TD> |
| <TD>An object of type <tt>G</tt>.</TD> |
| </TR> |
| |
| <TR> |
| <TD><tt>e</tt></TD> |
| <TD>An object of type <tt>boost::graph_traits<G>::edge_descriptor</tt>.</TD> |
| </TR> |
| |
| <TR> |
| <TD><tt>u,v</tt></TD> |
| <TD>are objects of type <tt>boost::graph_traits<G>::vertex_descriptor</tt>.</TD> |
| </TR> |
| |
| <TR> |
| <TD><tt>iter</tt></TD> |
| <TD>is an object of type <tt>boost::graph_traits<G>::out_edge_iterator</tt>.</TD> |
| </TR> |
| |
| <TR> |
| <TD><tt>p</tt></TD> |
| <TD>is an object of a type that models <a |
| href="http://www.sgi.com/tech/stl/Predicate.html">Predicate</a> |
| and whose argument type matches the <tt>edge_descriptor</tt> type. |
| </TR> |
| |
| </table> |
| |
| <H3>Valid Expressions</H3> |
| |
| <table border> |
| |
| <tr> |
| <TD><a name="sec:add-edge"><TT>add_edge(u, v, g)</TT></a></TD> |
| <TD> |
| Inserts the edge <i>(u,v)</i> into the graph, and returns an edge |
| descriptor pointing to the new edge. If the graph disallows parallel |
| edges, and the edge <i>(u,v)</i> is already in the graph, then the |
| <tt>bool</tt> flag returned is <tt>false</tt> and the returned edge |
| descriptor points to the already existing edge. Note that for |
| undirected graphs, <i>(u,v)</i> is the same edge as <i>(v,u)</i>, so |
| after a call to the function <tt>add_edge()</tt>, this implies that |
| edge <i>(u,v)</i> will appear in the out-edges of <i>u</i> and |
| <i>(u,v)</i> (or equivalently <i>(v,u)</i>) will appear in the |
| out-edges of <i>v</i>. Put another way, <i>v</i> will be adjacent to |
| <i>u</i> and <i>u</i> will be adjacent to <i>v</i>. |
| <br> |
| Return type: <TT>std::pair<edge_descriptor, bool></TT> |
| </TD> |
| </tr> |
| |
| <tr> |
| <TD><a name="sec:remove_edge"><TT>remove_edge(u, v, g)</TT></a></TD> |
| <TD> |
| Remove the edge <i>(u,v)</i> from the graph. If the |
| graph allows parallel edges this remove all occurrences of |
| <i>(u,v)</i>.<br> |
| Return type: <TT>void</TT><br> |
| Precondition: <i>u</i> and <i>v</i> are vertices in the graph.<br> |
| Postcondition: <i>(u,v)</i> is no longer in the edge set for |
| <TT>g</TT>.<br> |
| </TD> |
| </TR> |
| |
| |
| <tr> |
| <TD><TT>remove_edge(e, g)</TT></TD> |
| <TD>Remove the edge <i>e</i> from the graph.<br> |
| Return type: <TT>void</TT><br> |
| Precondition: <i>e</i> is an edge in the graph.<br> |
| Postcondition: <i>e</i> is no longer in the edge set for <TT>g</TT>. |
| </TD> |
| </TR> |
| |
| <tr> |
| <TD><TT>remove_edge(iter, g)</TT></TD> |
| <TD>Remove the edge pointed to be <tt>iter</tt> from the graph. This |
| expression is only required when the graph also models <a |
| href="./IncidenceGraph.html">IncidenceGraph</a>.<br> |
| Return type: <TT>void</TT><br> |
| Precondition: <tt>*iter</tt> is an edge in the graph.<br> |
| Postcondition: <tt>*iter</tt> is no longer in the edge set for <TT>g</TT>. |
| </TD> |
| </TR> |
| |
| <tr> |
| <TD><TT>remove_edge_if(p, g)</TT></TD> |
| <TD>Remove all the edges from graph <tt>g</tt> for which |
| the predicate <tt>p</tt> returns true.<br> |
| Return type: <TT>void</TT> |
| </TD> |
| </TR> |
| |
| <tr> |
| <TD><TT>remove_out_edge_if(u, p, g)</TT></TD> |
| <TD>Remove all the out-edges of vertex <tt>u</tt> for which the |
| predicate <tt>p</tt> returns true. This expression is only required |
| when the graph also models <a |
| href="./IncidenceGraph.html">IncidenceGraph</a>.<br> |
| Return type: <TT>void</TT> |
| </TD> |
| </TR> |
| |
| <tr> |
| <TD><TT>remove_in_edge_if(u, p, g)</TT></TD> |
| <TD>Remove all the in-edges of vertex <tt>u</tt> for which the |
| predicate <tt>p</tt> returns true. This expression is only required when the |
| graph also models <a |
| href="./BidirectionalGraph.html">BidirectionalGraph</a>.<br> |
| Return type: <TT>void</TT> |
| </TD> |
| </TR> |
| |
| |
| <tr> |
| <TD><a name="sec:add-vertex"><TT>add_vertex(g)</TT></a></TD> |
| <TD> |
| Add a new vertex to the graph. The <TT>vertex_descriptor</TT> for the |
| new vertex is returned.<br> |
| Return type: <TT>vertex_descriptor</TT> |
| </TD> |
| </TR> |
| |
| |
| <tr> |
| <TD><TT>clear_vertex(u, g)</TT></TD> |
| <TD> |
| Remove all edges to and from vertex <tt>u</tt> from the graph.<br> |
| Return type: <TT>void</TT><br> |
| Precondition: <tt>u</tt> is a valid vertex descriptor of <TT>g</TT>.<br> |
| Postcondition: <tt>u</tt> does not appear as a source or target of |
| any edge in <TT>g</TT>. |
| </TD> |
| </TR> |
| |
| <tr> |
| <TD><a name="sec:remove-vertex"><TT>remove_vertex(u, g)</TT></a></TD> |
| <TD> |
| Remove <i>u</i> from the vertex set of the graph. Note that undefined |
| behavior may result if there are edges remaining in the graph who's |
| target is <i>u</i>. Typically the <TT>clear_vertex()</TT> function |
| should be called first.<br> |
| Return type: <TT>void</TT><br> |
| Precondition: <TT>u</TT> is a valid vertex descriptor of <TT>g</TT>.<br> |
| Postcondition: <TT>num_vertices(g)</TT> is one less, <TT>u</TT> |
| no longer appears in the vertex set of the graph and it |
| is no longer a valid vertex descriptor. |
| </TD> |
| </TR> |
| </TABLE> |
| |
| <P> |
| </LI> |
| </UL> |
| |
| <P> |
| |
| <H3>Complexity Guarantees</H3> |
| |
| <P> |
| |
| <UL> |
| <LI>Edge insertion must be either amortized constant time or it |
| can be <i>O(log(E/V))</i> if the insertion also checks to |
| prevent the addition of parallel edges (which is a ``feature'' of |
| some graph types). |
| </LI> |
| <LI>Edge removal is guaranteed to be <i>O(E)</i>.</LI> |
| <LI>Vertex insertion is guaranteed to be amortized constant time.</LI> |
| <LI>Clearing a vertex is <i>O(E + V)</i>.</LI> |
| <LI>Vertex removal is <i>O(E + V)</i>.</LI> |
| </UL> |
| |
| <H3>Models</H3> |
| |
| <UL> |
| <LI><TT>adjacency_list</TT> |
| </LI> |
| </UL> |
| |
| |
| <H3>Concept Checking Class</H3> |
| |
| <PRE> |
| template <class G> |
| struct MutableGraphConcept |
| { |
| typedef typename boost::graph_traits<G>::edge_descriptor edge_descriptor; |
| void constraints() { |
| v = add_vertex(g); |
| clear_vertex(v, g); |
| remove_vertex(v, g); |
| e_b = add_edge(u, v, g); |
| remove_edge(u, v, g); |
| remove_edge(e, g); |
| } |
| G g; |
| edge_descriptor e; |
| std::pair<edge_descriptor, bool> e_b; |
| typename boost::graph_traits<G>::vertex_descriptor u, v; |
| typename boost::graph_traits<G>::out_edge_iterator iter; |
| }; |
| |
| template <class edge_descriptor> |
| struct dummy_edge_predicate { |
| bool operator()(const edge_descriptor& e) const { |
| return false; |
| } |
| }; |
| |
| template <class G> |
| struct MutableIncidenceGraphConcept |
| { |
| void constraints() { |
| function_requires< MutableGraph<G> >(); |
| remove_edge(iter, g); |
| remove_out_edge_if(u, p, g); |
| } |
| G g; |
| typedef typename boost::graph_traits<G>::edge_descriptor edge_descriptor; |
| dummy_edge_predicate<edge_descriptor> p; |
| typename boost::graph_traits<G>::vertex_descriptor u; |
| typename boost::graph_traits<G>::out_edge_iterator iter; |
| }; |
| |
| template <class G> |
| struct MutableBidirectionalGraphConcept |
| { |
| void constraints() { |
| function_requires< MutableIncidenceGraph<G> >(); |
| remove_in_edge_if(u, p, g); |
| } |
| G g; |
| typedef typename boost::graph_traits<G>::edge_descriptor edge_descriptor; |
| dummy_edge_predicate<edge_descriptor> p; |
| typename boost::graph_traits<G>::vertex_descriptor u; |
| }; |
| |
| template <class G> |
| struct MutableEdgeListGraphConcept |
| { |
| void constraints() { |
| function_requires< MutableGraph<G> >(); |
| remove_edge_if(p, g); |
| } |
| G g; |
| typedef typename boost::graph_traits<G>::edge_descriptor edge_descriptor; |
| dummy_edge_predicate<edge_descriptor> p; |
| }; |
| </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> |
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