graph-tool October 2011

graph-tool@skewed.de

2 participants
3 discussions

Segmentation fault using shortest_distance
by Juan Manuel Tirado 20 Mar '16

20 Mar '16

Hi Tiago, I am trying to calculate the shortest distances of a graph after applying a filter. I have a code that looks like this: g=gt.load_graph("myGraph.xml",format="xml") #for later use distances = gt.shortest_distance(g) #extract the components of the graph comp = g.label_components(g) #This splits the graph in several components #I want to calculate the shortest distances #for the component 2 for example filtering = g.new_vertex_property("boolean") for v in g.vertices(): if comp[v]==2: filtering[v]=True else: filtering[v]=False #set the vertex filter g.set_vertex_filter(filtering) distances_comp=gt.shortest_distance(g) The last line of code rises a segmentation fault. I have plotted the graph with the filtered graph and its correct, also I can calculate the local_clustering_coefficient without problems. Am I doing something wrong? Is there any other way to filter the graph and calculate the shortest distances? Is this a bug? Thanks so much, Juan

5 9

Parallel Processing
by Derek Ditch 21 Nov '13

21 Nov '13

I want to use graph-tool using the multiprocessing library in Python 2.6. I keep running into issues though with trying to share a full graph object. I can store the graph in a multiprocessing.Namespace, but it doesn't keep the dicts of properties. Example: def initNS( ns ): _g = Graph( directed = False) ns.graph = _g ns.edge_properties = { 'genres': _g.new_edge_property("vector<string>"), 'movieid': _g.new_edge_property("int"), } ns.vertex_properties = { 'personid': _g.new_vertex_property("int32_t") } """ Build property maps for edges and vertices to hold our data The graph vertices represent actors whereas movies represent edges """ # Edges _g.edge_properties["genres"] = ns.edge_properties['genres'] _g.edge_properties["movieid"] = ns.edge_properties['movieid'] # Vertices _g.vertex_properties["personid"] = ns.vertex_properties['personid'] ns.graph = _g ########## This initializes 'ns', which is a multiprocessing.Namespace. The problem is that for example, ns.edge_properties[ * ] tells me that the type isn't pickle-able. I tried to just skip that and use the _g.edge_properties to access it, but those dicts aren't carried over to the different process in the pool. Presumably b/c they aren't pickle-able. Any thoughts about how to fix this? (For those interested, I'm attempting to use the IMDbPy library to do some graph analysis on the relationships among actors and movies. Each process has it's own db connection and trying to populate the graph with actor and movie information in parallel since it's a pretty large and dense graph. Somewhere in the neighborhood of 250,000+ vertices for just a depth of three relationships) Thanks, -- Derek

3 7

Problem saving the graph
by Giuseppe Profiti 11 Oct '11

11 Oct '11

Hi, I encountered a strange problem. While saving a graph from a script, the generated file is mostly )or completely) composed by "NUL" characters. This happens with both dot and xml.gz outputs. The script correclty prints the number of edges and vertices. The properties list is also correct and the labels of the vertices are correctly stored in memory andd printed on screen. The only output to the file is a huge number of NUL and, in the dot case, some of the edges. The error happens after building the graph from a data file (with a custom script) and also after loading (in the interactive console) graphs previously saved in xml.gz format with graph_tool. I cannot reproduce the error via interactive console creating a graph with 2 nodes, 1 edge and no properties. OS is ubuntu and graph_tool version is 2.2.15-1 Everything worked just fine until past week. Thanks in advance for the help, Giuseppe

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graph-tool October 2011