id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
5659	The closed_plus structure should accept a custom infinity value.	Thomas Sewell <thomas.sewell@…>	Jeremiah Willcock	"I'm trying to run dijkstra_shortest_paths with a custom distance type (my graph supports two metrics, I want to find the length in metric A of the shortest paths according to metric B).

I've been struggling to understand why I was getting dependencies on MyDistType(int). It turns out that overloading + on MyDistType is only half the story. The default combine operator for distances comes from closed_plus, which assumes an infinity value can be constructed by std::numeric_limits<D>::max(). This function seems to degrade to trying the constructor T(n) for some int n (probably INT_MAX) if it isn't a known numeric type, leading to bizarre errors (buried under piles of template goop).

This patch gives instances of closed_plus a parameter to store the custom infinity value, defaulting to the one from std::numeric_limits. It also passes the correct default value in dijkstra_shortest_paths. I haven't checked whether any of the other algorithms that use closed_plus can potentially have non-standard infinity values.

Hope you agree this is an improvement.

Yours,
    Thomas."	Bugs	closed	To Be Determined	graph	Boost 1.46.1	Problem	fixed