[graph-tool] Cannot access vertices of a GraphView

17 Dec 2012

      Dear experts,

when I build a GraphView, I cannot access the vertices of an edge. Here 
is a minimal example:

import graph_tool as gt
import graph_tool.topology as gtt

G = gt.Graph(directed=False)

G.add_vertex(4)

for s,t in [(0,1), (2,3), (0,2)]:
     G.add_edge(G.vertex(s), G.vertex(t))

match, is_maximal = gtt.max_cardinality_matching(G)

GV = gt.GraphView(G, efilt=match)

for edge in GV.edges():
     source = GV.vertex_index(edge.source())
     print(source)

I get the following error message:

Traceback (most recent call last):
   File "gt_test.py", line 16, in <module>
     source = GV.vertex_index(edge.source())
...
...
   File "/usr/lib/python2.7/site-packages/graph_tool/__init__.py", line 
181, in _type_alias
     raise ValueError("invalid property value type: " + type_name)
ValueError: invalid property value type: unsigned long

Any idea what's wrong here, and more importantly: how to fix it?

Best regards,

Daniel

-- 
Daniel Müllner
Stanford University
Department of Mathematics
450 Serra Mall, Building 380
Stanford, CA 94305
USA
e-mail: muellner@math.stanford.edu
http://math.stanford.edu/~muellner