Greetings, Tiago! I am trying to use the multiprocess module in Python to accelerate my simulations. Specifically, I use the following code to parallelly calculate k-shortest paths for a set of node pairs, self.valid_paths[v] = pool.map(lambda x: gt.all_shortest_paths(self.g,source = v_index, target = x),[self.g.vertex_index[c] for c in self.Cloudlet]), where self.Cloudlet is a predefined node list. However, python reports the pickling issues self.valid_paths[v] = pool.map(lambda x: gt.all_shortest_paths(self.g,source = v_index, target = x),[self.g.vertex_index[c] for c in self.Cloudlet]) File "/home/percy/anaconda2/lib/python2.7/site-packages/multiprocess/pool.py", line 251, in map return self.map_async(func, iterable, chunksize).get() File "/home/percy/anaconda2/lib/python2.7/site-packages/multiprocess/pool.py", line 567, in get raise self._value RuntimeError: Pickling of "graph_tool.libgraph_tool_core.Vertex" instances is not enabled (http://www.boost.org/libs/python/doc/v2/pickle.html) Is there anything I am missing? My OS is 16.04, python 2.7.14, graph-tool is from Ostrokach's Anaconda. Thanks for your reply Best, Percy -- Sent from: http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com/