Boost Graph Library documentation unclear
I've been trying to use the Boost Graph Library. For the most part I'm working it out. However, I'm finding the documentation annoyingly decentralized....it isn't interlinked enough, at the very least. Too hard to go from "how do I use X" to "oh, here's the documentation on X." Took me half an hour just to find *something* on the add_edge function (turns out it's on the Concepts page?), and what's there *barely* qualifies as a prototype, much less a proper man page. My current question is regarding properties. Some of the algorithms specify the "edge_weight" property as if it's something all edges have, and the vertex_index property as if it's something all vecS-specified graphs have. Yet I can't find any documentation explicitly confirming this, and my compiler seems to disagree in any case. http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/kruskal_min_spanning_tre... Can something be done about the state of the documentation, and is there a comprehensive list of default properties available somewhere (together with how those are replaced or supplemented when user properties are introduced)?
I've been trying to use the Boost Graph Library. For the most part I'm working it out. However, I'm finding the documentation annoyingly decentralized....it isn't interlinked enough, at the very least. Too hard to go from "how do I use X" to "oh, here's the documentation on X." Took me half an hour just to find *something* on the add_edge function (turns out it's on the Concepts page?), and what's there *barely* qualifies as a prototype, much less a proper man page.
Concepts are similar "STL Concepts" ( http://www.sgi.com/tech/stl/table_of_contents.html). They classify and describe the operations available to /all/ graph data structures (e.g., adjacency_list or matrix), which is why it might seem to barely qualify as a prototype.
My current question is regarding properties. Some of the algorithms specify the "edge_weight" property as if it's something all edges have, and the vertex_index property as if it's something all vecS-specified graphs have. Yet I can't find any documentation explicitly confirming this, and my compiler seems to disagree in any case.
http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/kruskal_min_spanning_tre...
No edges are weighted by default. The easiest way to weight a graph is to used bundled properties ( http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/bundles.html) and create a property_map over a member pointer. Currently, only adjacency_list<OEL, vecS, D, VP, EP, GP, EL> has a vertex_index property by default. The OEL, D, etc. are just placeholders for any template argument. Can something be done about the state of the documentation, and is there a
comprehensive list of default properties available somewhere (together with how those are replaced or supplemented when user properties are introduced)?
I'm currently rewriting the documentation, but that won't be ready until 1.40 at the earliest. Andrew Sutton andrew.n.sutton@gmail.com
Well, my code looks like typedef boost::adjacency_list< boost::listS, boost::vecS, boost::undirectedS, RegionProperties, EdgeProperties> Graph; template <typename Graph> struct edge_off { edge_off(): G(NULL) { } edge_off(const Graph &G) : m_G(&G) { } template <typename Edge> bool operator()(const Edge& e) const { return !(*G)[e].on; } const Graph *G; }; .... Graph G; .... filtered_graph<Graph, edge_off<Graph> > G_off_edges(G, edge_off<Graph>(G)); for (tie(ei, ei_end) = edges(G_off_edges); ei != ei_end; ++ei) { size_t v1 = G_off_edges[source(*ei,G_off_edges)].vertex_index; size_t v2 = G_off_edges[target(*ei,G_off_edges)].vertex_index; .... } And I'm getting compiler errors that vertex_index is not a member of my class RegionProperties. I suppose this means that filtered_graph hides the vertex_index attribute of the underlying graph, even though I'm not filtering the vertexes at all? Can I use the returns of source and target as *if* they were indexes? Also, do source and target refer to the two different ends of an undirected edge? That's another thing I wasn't sure about from the docs. Seemed reasonable, but I wish it were stated.
I've been trying to use the Boost Graph Library. For the most part I'm working it out. However, I'm finding the documentation annoyingly decentralized....it isn't interlinked enough, at the very least. Too hard to go from "how do I use X" to "oh, here's the documentation on X." Took me half an hour just to find *something* on the add_edge function (turns out it's on the Concepts page?), and what's there *barely* qualifies as a prototype, much less a proper man page.
Concepts are similar "STL Concepts" ( http://www.sgi.com/tech/stl/table_of_contents.html). They classify and describe the operations available to /all/ graph data structures (e.g., adjacency_list or matrix), which is why it might seem to barely qualify as a prototype.
My current question is regarding properties. Some of the algorithms specify the "edge_weight" property as if it's something all edges have, and the vertex_index property as if it's something all vecS-specified graphs have. Yet I can't find any documentation explicitly confirming this, and my compiler seems to disagree in any case.
http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/kruskal_min_spanning_tre...
No edges are weighted by default. The easiest way to weight a graph is to used bundled properties ( http://www.boost.org/doc/libs/1_38_0/libs/graph/doc/bundles.html) and create a property_map over a member pointer. Currently, only adjacency_list<OEL, vecS, D, VP, EP, GP, EL> has a vertex_index property by default. The OEL, D, etc. are just placeholders for any template argument. Can something be done about the state of the documentation, and is there a
comprehensive list of default properties available somewhere (together with how those are replaced or supplemented when user properties are introduced)?
I'm currently rewriting the documentation, but that won't be ready until 1.40 at the earliest. Andrew Sutton andrew.n.sutton@gmail.com _______________________________________________ Boost-users mailing list Boost-users@lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users
And I'm getting compiler errors that vertex_index is not a member of my class RegionProperties. I suppose this means that filtered_graph hides the vertex_index attribute of the underlying graph, even though I'm not filtering the vertexes at all? Can I use the returns of source and target as *if* they were indexes?
It's not a member of your class. It's a member of the vertex stored by the graph, which is only accessible via the get() accessor. You could write, for example: typedef property_map<Graph, vertex_index_t>::type IndexMap; IndexMap indices = get(vertex_index, g); ... size_t v1 = get(indices, source(*ei, g)); size_t v2 = get(indices, target(*ei, g)); Also, do source and target refer to the two different ends of an undirected
edge? That's another thing I wasn't sure about from the docs. Seemed reasonable, but I wish it were stated.
Yes. It's written somewhere in the documentation, but it isn't obvious, and I forget where exactly. Andrew Sutton andrew.n.sutton@gmail.com
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