[Boost-users] Using external property map with a mutable boost.graph

From: Jeff Holle (jeff.holle_at_[hidden])
Date: 2004-08-27 16:02:54

I'm using a boost.graph via:
typedef 
boost::adjacency_list<boost::vecS,boost::vecS,boost::bidirectionalS> GraphT;

In my application, I've decided to use external maps.
I have discovered a problem using vertex descriptors as a key of a map.

Basically, in doing a remove_vertex sequence involving vertex descriptors
5, 3, 2, I discovered that the next vertex descriptor produced by 
add_vertex was 4.  At this point the insert into my map failed because 
this element already existed.

Given the mutable nature of vertex descriptors, I don't see how they can
be used as a key in a map.

I'm contemplating two options at this point.

  1.  Switch from map to vector in storing my vertex property externally.
  2.  Switch to internal properties.

My questions are:
  1.  Is the first option viable?  As I see things, vertex descriptors 
are always
       contiguous and in the range (0..num_vertices(graph)].  Is this true?

  2.  Do internal "maps" avoid this type of problem?