[boost] [graph] strange behaviour of relax

Subject: [boost] [graph] strange behaviour of relax
From: Jan Hudec (bulb_at_[hidden])
Date: 2012-10-22 16:10:12

Hello All,

Writing special variant of dijkstra's algorithm I wanted to reuse the `relax`
function (from boost/graph/relax.hpp) that is used by
dijkstra_shortest_paths_no_color_map. And I've notices what I think is
mismatch in behaviour between relax and dijkstra_shortest_paths_no_color_map.

When the graph is not oriented, the relax function will consider decreasing
distance of either target (obiously) or source. However it returns the same
true in both cases, so the caller does not know which vertex was updated and
the dijkstra_shortest_paths_no_color_map does not expect having to update the
source at all. It shouldn't happen, but than why is that condition there?

It appears to me that one or the other is wrong. But I don't know the code
well enough to tell which.

Regards,
Jan

-- 
						 Jan 'Bulb' Hudec <bulb_at_[hidden]>