December 2015 - graph-tool - archives.skewed.de

Simple Cycle Finder
by tanzairatier 25 Mar '16

25 Mar '16

Hello all, I'm wondering if anyone can suggest a strategy for finding elementary cycles with Graph-Tool. I'm working also with Network X, and they have a function for this, called simple_cycles(G). That function essentially runs Tarjan's Algorithm to find all strongly connected components, and then detects cycles within each of those components (this approach is called Johnson's Algorithm). I've tried to port the Network X code to Graph-Tool, but there are un-matching parallels in the data structures of both tools. e.g. Graph-Tool prefers to label with property maps. Since I've only begun using Graph-Tool a short while ago, this task is difficult for me. Any help would be appreciated, many thanks in advance. -- 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.

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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

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Edge colors in graphviz_draw
by Yannis Haralambous 28 Dec '15

28 Dec '15

Hi and seasons greetings to everybody! I am displaying graphs with graphviz_draw To obtain a different color for every type of vertex I use argument vcolor=g.vp["typev"] where the vertex property "typev" is of type int, it works just fine My problem is with edge colors: I have an edge property called g.ep["typee"] but it is of type vector<short>, in fact it is a list of three elements and it is the second one that I need to define the color of every edge. I tried ecolor=g.ep["typee"][1] and it didn't worked (this was predictable since one has to apply g.ep["typee"] to an edge first and then take the second element to get an integer). I also tried ecolor=lambda x: g.ep["typee"][x][1] and ecolor=(lambda x: g.ep["typee"][x][1]) none of them worked. How can I obtain what I need? Thanks in advance Yannis -- ------------------------------------------------------- Yannis Haralambous Professor Institut Mines-Télécom, Télécom Bretagne Computer Science Department UMR CNRS 6285 Lab-STICC Technopôle Brest Iroise CS 83818, 29238 Brest Cedex 3, France Email: yannis.haralambous(a)telecom-bretagne.eu Internet: http://perso.telecom-bretagne.eu/yannisharalambous/ ICBM address: 48°21'31.57"N 4°34'16.76"W Twitter: y_haralambous ------------------------------------------------------- ...the ball I threw while playing in the park has not yet reached the ground (Dylan Thomas) Es gab eine Zeit, wo ich nur ungern über Schubert sprechen, nur Nächtens den Bäumen und Sternen von ihm vorerzählen mögen. (Robert Schumann)

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Discussion about new features
by François Kawala 15 Dec '15

15 Dec '15

Hello, I use graph-tool to do some routing tasks over graphs ranging from 1M to 10M edges. To search shortest paths might be quite time consuming. Hence, I wonder if it might be a good idea to try to implement Hierarchical Contractions [1] in graph tool. What is your opinion about it ? Regards, Fran [1] https://en.wikipedia.org/wiki/Contraction_hierarchies

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attacking largest connected component (lcc) by degree
by m jadidi 12 Dec '15

12 Dec '15

Hi, I am trying to implement a function to remove some fraction of high degree nodes based on initial lcc (1% in every step) until the lcc will be destructed completely (size zero). to test my code I am using DBLP coauthor ship network which is already shown that the lcc of the this graph will be destructed after removing 1.5% of high degree nodes. However my code fail to that,. one thing that I am not sure is that when we mask some nodes and then use GraphView(G,vfilt=mask), it does not take of isolated vertices after masking. So I had to check for them manually. thanks for any hint! code is attached. cheers, -- Mohsen

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Save the graph after manipulating in the interactive window
by JBiB 12 Dec '15

12 Dec '15

Hi guys, at first: thanks for your really powerful package. It makes a lot of fun. My question: it is possible to save the graph automatically after manipulating in the interactive mode? I have the problem of networks with a lot of edges and would prefer to built up the network in the interactive window before draw it as a pdf-file. And by the way, I installed the pre-compiled package on a ubuntu machine and found a typo in the the installation documentation ('http://graph-tool.skewedstalling process.de//download#packages'). I think it should be 'add-apt-repository ppa:ubuntu-toolchain-r/test' instead of 'add-apt-repository ppa:ubuntu-tool chain-r/test' Thanks for your great work, Jonathan -- 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.

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