AttributeError in Tarjan algorithm about grandalf HOT 1 CLOSED

Hi,
I've patched grandalf to fix the bug in tarjan implementation.
The issue was due to the fact that some parts of the graph remained unvisited
during tarjan algorithm (hence not all vertex had the lowlink
attribute which led to the exception).

Unvisited vertices where those found in cycles that could not be
reached from the
"natural" root nodes (those not having any incoming edges).
Look at the new example in
tests/samples/cycles.dot
which focuses on this particular situation.

Thanks for reporting this!

cheers

Axel

On Wed, Aug 31, 2011 at 12:14 PM, gelim
[email protected]
wrote:

Hi,

displaying  the following DOT graph (http://dl.free.fr/mQEUoqkT9) with masr-graph spits that trace :

$ ./masr-graph -c 3 perms.dot
257 verts, 78 root(s)
using tarjan algorithm to find inverted_edges...
Traceback (most recent call last):
 File "./masr-graph", line 14, in
   app.run(args=sys.argv)
 File "masr/masr/plugins/utils.py", line 8, in wrapper
   plugin.start(func.name,self,**kargs)
 File "masr/masr/plugins/graph/main.py", line 39, in start
   app.session.cg.Draw(1)
 File "masr/masr/plugins/graph/main.py", line 127, in Draw
   L = gr.get_scs_with_feedback(r)
 File "/usr/local/lib/python2.7/dist-packages/grandalf/graphs.py", line 382, in get_scs_with_feedback
   del v.lowlink
AttributeError: lowlink

Any enlightenment is welcome,
Cheers,

Mathieu

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