On Tue, 16 Apr 2013, The Maschine wrote:

Hi all,

I've been reading around the list (Ill post examples below) but I dont really know how to implement the thing below.

I want the search to be able to stop based on some "value" or "result of a function". For example, every node has a "length" value in a custom "struct VertexProperties".

How is it possible for dijkstra_shortest_paths to only consider nodes that are inside a radius from the source? Everything else should be considered as 'unconnected'.

I have checked a couple of posts form the list but I dont know what do really do. (function property map, exceptions in visitors etc) http://thread.gmane.org/gmane.comp.lib.boost.user/54392/focus=54397 http://thread.gmane.org/gmane.comp.lib.boost.user/72072/focus=72074 http://thread.gmane.org/gmane.comp.lib.boost.user/73358/focus=73384

I havent found any example or source online that deals with something similar.

Any ideas? code example or tutorials?

Best, Tasos

my graph for example: struct VertexProperties { double m_length; int m_ref; };

typedef double Weight; typedef boost::property<boost::edge_weight_t, double> EdgeWeightProperty; typedef boost::adjacency_list<boost::vecS, boost::vecS, boost::undirectedS, VertexProperties, EdgeWeightProperty> unGraph;

Here's the basic idea (not tested); use this as your Dijkstra visitor, and change the part labeled "threshold" to your threshold computation: struct threshold_visitor: boost::default_dijkstra_visitor { double threshold; threshold_visitor(double threshold): threshold(threshold) {} struct hit_threshold {}; void examine_vertex(vertex_descriptor v, const unGraph& g) { if (get(&VertexProperties::m_ref, g, v) > threshold) throw hit_threshold(); } }; Remember to wrap your call to Dijkstra's algorithm in a try-catch block for threshold_visitor::hit_threshold. -- Jeremiah Willcock