Re: [Boost-users] BGL python: dijkstra_shortest_paths

From: John Reid (j.reid_at_[hidden])
Date: 2007-04-27 04:10:36

ping - is absolutely no one interested in this problem?

John.

John Reid wrote:
> ping
> 
> This looks like a bug in the BGL python bindings.
> 
> John.
> 
> John Reid wrote:
> 
>>Hi,
>>
>>I can't seem to use dijkstra_shortest_paths as I think I should via the 
>>python bindings. It works fine when I pass a weight_map and 
>>predecessor_map. What I want to do is to pass a predecessor_map and a 
>>distance_map. Unfortunately boost.python can't convert the arguments.
>>
>>I'm using a bgl that says bgl.__version__ = '1.0' although I haven't 
>>updated it from SVN recently.
>>
>>
>>
>>This works:
>>import boost.graph as bgl
>>graph = bgl.Graph()
>>a = graph.add_vertex()
>>b = graph.add_vertex()
>>e = graph.add_edge(a, b)
>>weights = graph.add_edge_property('integer')
>>weights[e] = 5
>>predecessors = graph.add_vertex_property('vertex')
>>bgl.dijkstra_shortest_paths(
>>         graph,
>>         a,
>>         predecessor_map = predecessors,
>>         weight_map = weights
>>)
>>
>>
>>
>>
>>This doesn't work:
>>import boost.graph as bgl
>>graph = bgl.Graph()
>>a = graph.add_vertex()
>>b = graph.add_vertex()
>>e = graph.add_edge(a, b)
>>distances = graph.add_edge_property('float')
>>predecessors = graph.add_vertex_property('vertex')
>>bgl.dijkstra_shortest_paths(
>>         graph,
>>         a,
>>         predecessor_map = predecessors,
>>         distance_map = distances
>>)
>>
>>
>>
>>
>>
>>This is the error I get:
>><class 'Boost.Python.ArgumentError'>: Python argument types in
>>     boost.graph._graph.dijkstra_shortest_paths(Graph, Vertex)
>>did not match C++ signature:
>>     dijkstra_shortest_paths(class 
>>boost::graph::python::basic_graph<struct boost
>>::bidirectionalS> graph, struct 
>>boost::graph::python::basic_descriptor<void *,st
>>ruct boost::bidirectionalS> root_vertex, class 
>>boost::vector_property_map<struct
>>  boost::graph::python::basic_descriptor<void *,struct 
>>boost::bidirectionalS>,str
>>uct boost::graph::python::basic_index_map<struct 
>>boost::graph::python::basic_des
>>criptor<void *,struct boost::bidirectionalS>,struct 
>>boost::adj_list_vertex_prope
>>rty_map<class boost::adjacency_list<struct boost::listS,struct 
>>boost::listS,stru
>>ct boost::bidirectionalS,struct boost::property<enum 
>>boost::vertex_index_t,unsig
>>ned int,struct boost::no_property>,struct boost::property<enum 
>>boost::edge_index
>>_t,unsigned int,struct boost::no_property>,struct 
>>boost::no_property,struct boos
>>t::listS>,unsigned int,unsigned int const &,enum boost::vertex_index_t> 
>> > > * pr
>>edecessor_map=None, class boost::vector_property_map<float,struct 
>>boost::graph::
>>python::basic_index_map<struct 
>>boost::graph::python::basic_descriptor<void *,str
>>uct boost::bidirectionalS>,struct 
>>boost::adj_list_vertex_property_map<class boos
>>t::adjacency_list<struct boost::listS,struct boost::listS,struct 
>>boost::bidirect
>>ionalS,struct boost::property<enum boost::vertex_index_t,unsigned 
>>int,struct boo
>>st::no_property>,struct boost::property<enum 
>>boost::edge_index_t,unsigned int,st
>>ruct boost::no_property>,struct boost::no_property,struct 
>>boost::listS>,unsigned
>>  int,unsigned int const &,enum boost::vertex_index_t> > > * 
>>distance_map=None, c
>>lass boost::vector_property_map<float,struct 
>>boost::graph::python::basic_index_m
>>ap<struct boost::graph::python::basic_descriptor<class 
>>boost::detail::edge_desc_
>>impl<struct boost::bidirectional_tag,void *>,struct 
>>boost::bidirectionalS>,struc
>>t boost::adj_list_edge_property_map<struct 
>>boost::bidirectional_tag,unsigned int
>>,unsigned int const &,void *,struct boost::property<enum 
>>boost::edge_index_t,uns
>>igned int,struct boost::no_property> const ,enum boost::edge_index_t> > 
>> > {lvalu
>>e} weight_map, class boost::python::api::object visitor=None, class 
>>boost::vecto
>>r_property_map<enum boost::default_color_type,struct 
>>boost::graph::python::basic
>>_index_map<struct boost::graph::python::basic_descriptor<void *,struct 
>>boost::bi
>>directionalS>,struct boost::adj_list_vertex_property_map<class 
>>boost::adjacency_
>>list<struct boost::listS,struct boost::listS,struct 
>>boost::bidirectionalS,struct
>>  boost::property<enum boost::vertex_index_t,unsigned int,struct 
>>boost::no_proper
>>ty>,struct boost::property<enum boost::edge_index_t,unsigned int,struct 
>>boost::n
>>o_property>,struct boost::no_property,struct boost::listS>,unsigned 
>>int,unsigned
>>  int const &,enum boost::vertex_index_t> > > * color_map=None)
>>     dijkstra_shortest_paths(class 
>>boost::graph::python::basic_graph<struct boost
>>::undirectedS> graph, struct boost::graph::python::basic_descriptor<void 
>>*,struc
>>t boost::undirectedS> root_vertex, class 
>>boost::vector_property_map<struct boost
>>::graph::python::basic_descriptor<void *,struct 
>>boost::undirectedS>,struct boost
>>::graph::python::basic_index_map<struct 
>>boost::graph::python::basic_descriptor<v
>>oid *,struct boost::undirectedS>,struct 
>>boost::adj_list_vertex_property_map<clas
>>s boost::adjacency_list<struct boost::listS,struct boost::listS,struct 
>>boost::un
>>directedS,struct boost::property<enum boost::vertex_index_t,unsigned 
>>int,struct
>>boost::no_property>,struct boost::property<enum 
>>boost::edge_index_t,unsigned int
>>,struct boost::no_property>,struct boost::no_property,struct 
>>boost::listS>,unsig
>>ned int,unsigned int const &,enum boost::vertex_index_t> > > * 
>>predecessor_map=N
>>one, class boost::vector_property_map<float,struct 
>>boost::graph::python::basic_i
>>ndex_map<struct boost::graph::python::basic_descriptor<void *,struct 
>>boost::undi
>>rectedS>,struct boost::adj_list_vertex_property_map<class 
>>boost::adjacency_list<
>>struct boost::listS,struct boost::listS,struct boost::undirectedS,struct 
>>boost::
>>property<enum boost::vertex_index_t,unsigned int,struct 
>>boost::no_property>,stru
>>ct boost::property<enum boost::edge_index_t,unsigned int,struct 
>>boost::no_proper
>>ty>,struct boost::no_property,struct boost::listS>,unsigned int,unsigned 
>>int con
>>st &,enum boost::vertex_index_t> > > * distance_map=None, class 
>>boost::vector_pr
>>operty_map<float,struct boost::graph::python::basic_index_map<struct 
>>boost::grap
>>h::python::basic_descriptor<class boost::detail::edge_desc_impl<struct 
>>boost::un
>>directed_tag,void *>,struct boost::undirectedS>,struct 
>>boost::adj_list_edge_prop
>>erty_map<struct boost::undirected_tag,unsigned int,unsigned int const 
>>&,void *,s
>>truct boost::property<enum boost::edge_index_t,unsigned int,struct 
>>boost::no_pro
>>perty> const ,enum boost::edge_index_t> > > {lvalue} weight_map, class 
>>boost::py
>>thon::api::object visitor=None, class boost::vector_property_map<enum 
>>boost::def
>>ault_color_type,struct boost::graph::python::basic_index_map<struct 
>>boost::graph
>>::python::basic_descriptor<void *,struct boost::undirectedS>,struct 
>>boost::adj_l
>>ist_vertex_property_map<class boost::adjacency_list<struct 
>>boost::listS,struct b
>>oost::listS,struct boost::undirectedS,struct boost::property<enum 
>>boost::vertex_
>>index_t,unsigned int,struct boost::no_property>,struct 
>>boost::property<enum boos
>>t::edge_index_t,unsigned int,struct boost::no_property>,struct 
>>boost::no_propert
>>y,struct boost::listS>,unsigned int,unsigned int const &,enum 
>>boost::vertex_inde
>>x_t> > > * color_map=None)
>>
>>
>>
>>
>>For reference here is the docstring bgl gives me:
>>Type:           function
>>Base Class:     <type 'builtin_function_or_method'>
>>String Form:    <Boost.Python.function object at 0x04AEE940>
>>Namespace:      Interactive
>>Docstring:
>>     dijkstra_shortest_paths(graph, root_vertex, predecessor_map = None,
>>                         distance_map = None, weight_map = None,
>>                         visitor = None)
>>
>>Computes the shortest paths from the root vertex to every other vertex
>>in a graph.
>>
>>Parameters:
>>   graph            the graph on which to compute shortest paths will
>>                    run. It may be either a directed or undirected graph.
>>
>>   root_vertex      the starting vertex for the shortest-path search.
>>
>>   predecessor_map  a vertex -> vertex map that stores the predecessor of
>>                    each vertex in the shortest paths tree. From a given
>>                    vertex, one can follow the predecessor_map back to
>>                    the root_vertex to reconstruct the shortest path.
>>
>>   distance_map     a vertex -> float map that stores the distance from
>>                    the root_vertex to each vertex in the tree. A
>>                    distance of infinity in this property map indicates
>>                    that the vertex is unreachable from the root_vertex.
>>
>>   weight_map       an edge -> float map that stores the weight of each
>>                    edge in the graph. Negative edge weights are not
>>                    permitted. If no weight map is provided, each edge
>>                    will be assumed to have a weight of 1.0.
>>
>>   visitor          a visitor that will receive events as the
>>                    shortest-paths computation progresses. Typically this
>>                    visitor should be derived from
>>                    boost.graph.dijkstra_visitor.
>>
>>See also:
>>   bellman_ford_shortest_paths
>>   dag_shortest_paths
>>   dijkstra_visitor
>>
>>Complete C++ documentation is available at:
>>   http://www.boost.org/libs/graph/doc/dijkstra_shortest_paths.html
>>
>>
>>
>>Any help appreciated,
>>John.