On Fri, 21 May 2010, Eric Fowler wrote:
Thank you. I can now compile with an std::vector<> as my queue, and the default color map.
Named parameters should also allow you to use the built-in color map generation; you weren't using them before so that's why I told you to just add that argument explicitly.
In looking at the Dijkstra example, I see it is using a boost::mutable_queue<>, which has the primary feature of being able to dynamically change the sorting criterion. This is exciting but not something I need.
It's not dynamically changing, or are you referring to update()? That just lets you update the sort key of an element without removing and reinserting it.
Turning my attention to boost::queue<>, I am trying to see how to place my own sorting criteria. It looks like I need to define a class encapsulating my data (or deriving from the class that holds my data), and to define the usual ordering operators (<,>,==, etc) within that class. I would then declare an object of type boost::queue<MyClass> and go from there.
Is that the "cheapest" way to get a priority queue with a custom sort order?
boost::queue<> is unsorted, so you cannot use a sort order with it. Are you sure your problem is not just shortest paths with custom compare and/or combine operators? That is the easiest way: dijkstra_shortest_paths sets up the queue, color map, and such for you. Otherwise, look at the code in dijkstra_shortest_paths that I pointed out and use one of the queues instantiated there. Note that Dijkstra's algorithm does use a custom < operator in its priority queue in the mutable_queue variant (in order to use indirect_cmp and the user's comparison operator which is not necessarily < either). -- Jeremiah Willcock