Hi I am trying to extract communities of a graph with the graph_tool.community.minimize_blockmodel_dl function and by following the example on this page: http://graph-tool.skewed.de/static/doc/community.html. Unfortunately, I get an error: Traceback (most recent call last): File "community.py", line 7, in <module> graph_draw(g, pos=g.vp["pos"], vertex_fill_color=b, vertex_shape=b, output="output_blocks_mdl.pdf") File "/usr/lib/python2.7/dist-packages/graph_tool/__init__.py", line 995, in __getitem__ val = self.get_func(self.g, key) File "/usr/lib/python2.7/dist-packages/graph_tool/__init__.py", line 1458, in <lambda> lambda g, k: g.__properties[("v", k)], KeyError: ('v', 'pos') Here is my code: from graph_tool.all import * g = load_graph("graph.dot") b, mdl = minimize_blockmodel_dl(g) graph_draw(g, pos=g.vp["pos"], vertex_fill_color=b, vertex_shape=b, output="output_blocks_mdl.pdf") The dot file looks like this: graph G { 167; 2037; 717; 2169; 166; 669; 2541; 1781; 1424; 167 -- 166; 2037 -- 669; 2037 -- 1424; 717 -- 166; 717 -- 167; 2169 -- 669; 2169 -- 2037; 2541 -- 166; 2541 -- 167; 2541 -- 669; 2541 -- 717; 2541 -- 1781; 2541 -- 2037; } Thnaks for your time. -- View this message in context: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/... Sent from the Main discussion list for the graph-tool project mailing list archive at Nabble.com.