Re: [Boost-bugs] [Boost C++ Libraries] #3506: Graph's Tour / Dijkstra's parent nodes

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #3506: Graph's Tour / Dijkstra's parent nodes
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2009-10-04 12:46:37

#3506: Graph's Tour / Dijkstra's parent nodes
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  Reporter:  JDKunkMailing@…          |       Owner:  asutton       
      Type:  Bugs                     |      Status:  closed        
 Milestone:  Boost 1.41.0             |   Component:  graph         
   Version:  Boost 1.40.0             |    Severity:  Not Applicable
Resolution:  fixed                    |    Keywords:                
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Changes (by JDKunkMailing@…):

  * severity:  Problem => Not Applicable

Comment:

 Replying to [comment:2 jewillco]:
 > This does appear to be a bug in the example -- there is a special
 null_vertex() value that is used to mark invalid vertices.  I changed the
 code to use that, but it is probably not a good idea to look at the
 predecessor of the start vertex anyway.  I do not believe the visitor ever
 sets the predecessor since it never has an edge coming in that is
 discovering the start vertex.

 I discovered that if a parent does not exist, it does not set anything to
 the property map. Therefore, algorithms (maybe just dijkstra) will not
 change an element if there is nothing to set it to. I recommend that all
 users should place default values into the analysis from algorithms, but
 this is just good application programming practice.

-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/3506#comment:3>
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