August 2014 - graph-tool - archives.skewed.de

What formula is used for std in vertex_average and edge_average?
by VaSa 16 Jul '20

16 Jul '20

I am curious what is being used to calculate the standard deviation of the average in gt.vertex_average and gt.edge_average >>> t2=gt.Graph() >>> t2.add_vertex(2) >>> t2.add_edge(t2.vertex(0), t2.vertex(1)) >>> gt.vertex_average(t2, "in") (0.5, 0.35355339059327373) Now, shouldn't std be σ(n)=sqrt(((0-0.5)^2+(1-0.5)^2)/2)=0.5 ? also q(n-1)=sqrt((0.5^2+0.5^2)/(2-1))~=0.70710 0.3535 is sqrt(2)/4 which happens to be σ(n-1)/2, so it seems there is some relation to that. A little bigger graph. >>> t3=gt.Graph() >>> t3.add_vertex(5) >>> t3.add_edge(t3.vertex(0), t3.vertex(1)) >>> gt.vertex_average(t3, "in") (0.2, 0.17888543819998318) Now, we should have 0,1,0,0,0 series for vertex incoming degree. So Windows calc gives σ(n)=0.4 and σ(n-1)~=0.44721, so where does 0.1788854 come from ? Reason, I am asking because, I have a large graph, where the average looks quite alright but the std makes no sense, as going by the histogram, degree values are quite a bit more distributed than the std would indicate. -- 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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graph-tool can't find Graphviz renderer
by Mikhail Spivakov 07 Apr '16

07 Apr '16

Hello! I've got graphviz installed with python and python27 bindings. However, when I do: graph_draw(ug, vprops={"label": ug.vertex_index}, output="two-nodes.pdf", layout="fdp") I get the following error: graph G { graph [outputorder=edgesfirst, mode=major, overlap=true, ratio=fill, size="5.905512,5.905512", start=3019255687130444316]; node [label="\N", shape=circle, width="0.105", height="0.105", style=filled, color="#2e3436", fillcolor="#a40000"]; edge [arrowsize="0.3", color="#2e3436", penwidth="1.0"]; graph [bb="0,0,425,425"]; 0 [label=0, width="0.47", height="0.47", pos="330,101"]; 1 [label=1, width="0.47", height="0.47", pos="93,324"]; 0 -- 1 [pos="318,113 277,152 147,274 106,312"]; } Error: renderer for pdf is unavailable Out[8]: <PropertyMap object with key type 'Vertex' and value type 'vector<double>', for Graph 0x5ff3f90, at 0x6001290> At the same time, if I save the above dot expression as test1.dot and run the following command from the command line: $ dot -Tpng test1.dot -o graph1.png I get a beautiful graph1.png. Graphviz is installed in a non-standard location as I don't have admin rights. However, the graphviz folder is in LD_LIBRARY_PATH and gv.py is in PYTHONPATH. Would very much appreciate your advice on what else graph-tool might need to find the libraries and/or how to test it better. Many thanks, Mikhail

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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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Help regarding -enable-openMP
by Shubham Bhushan 11 Nov '15

11 Nov '15

Hi I asked earlier as to how utilize the parallel processing in my code. Now I installed it using the precompiled packages for Ubuntu. does that mean I'll have to reinstall it from source using the openmp option in the configure command? Shubham -- http://about.me/shubham.bhushan

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graph-tool graphml and networkx
by tcb 17 Aug '15

17 Aug '15

Hi, I am trying to read the graphml output of graph-tool's graphml using networkx. https://github.com/networkx/networkx/issues/843 Unfortunately this does not work with any of the vector_* type property maps which graph-tool uses. Have you encountered this issue before? It seems the right thing to do might be to extend your graphml to hold the vector_* attributes as detailed: http://graphml.graphdrawing.org/primer/graphml-primer.html#EXT Is there some reason why it was done the way it is? How do you manage read/writing graphml data to other tools? In the meantime, it might be possible to hack some read support for graph-tool's xml into networkx. To this end, could you please advise how to parse the 'key1' data (should be two floats) <node id="n1"> <data key="key0">6</data> <data key="key1">0x1.5c71d0cb8d943p+3, 0x1.70db7f4083655p+3</data> </node> thanks - -- 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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Undefined symbol drawing function
by sasho.j.markov 20 Apr '15

20 Apr '15

Hi New to the graph-tool. Build it from src on Fedora 16 (64) . Built with cairomm enabled . Try to run as per the quick start , however when executing graph_draw(g, vertex_text=g.vertex_index, vertex_font_size=18, ... output_size=(200, 200), output="two-nodes.pdf") i get undefined symbol _ZN5Cairo7ContextC1EP6_cairob However the symbol above is defined in : libcairomm-1.0.so see below nm command results nm /usr/local/lib/libcairomm-1.0.so | grep -i _ZN5Cairo7ContextC1EP6_cairob 0000000000014b90 T _ZN5Cairo7ContextC1EP6_cairob Interestingly the library libgraph_tool_draw.so has indeed have the undefined symbol U _ZN5Cairo7ContextC1EP6_cairob but does not depend on the cairomm libarary - see the ldd output . unless the library is dynamically load i do not understand why Any advise appreciated- regards Sasho ldd /usr/local/lib/python2.7/site-packages/graph_tool/draw/libgraph_tool_draw.so linux-vdso.so.1 => (0x00007fffc46da000) libstdc++.so.6 => /usr/lib64/libstdc++.so.6 (0x00007f99fd6cd000) libpython2.7.so.1.0 => /usr/lib64/libpython2.7.so.1.0 (0x00007f99fd30e000) libboost_iostreams.so.1.49.0 => /usr/local/lib/libboost_iostreams.so.1.49.0 (0x00007f99fd0f6000) libboost_python.so.1.49.0 => /usr/local/lib/libboost_python.so.1.49.0 (0x00007f99fceaa000) libboost_regex.so.1.49.0 => /usr/local/lib/libboost_regex.so.1.49.0 (0x00007f99fcbc8000) libCGAL.so.9 => /usr/local/lib/libCGAL.so.9 (0x00007f99fc9a5000) libexpat.so.0 => /usr/local/lib/libexpat.so.0 (0x00007f99fc77c000) libbz2.so.1 => /lib64/libbz2.so.1 (0x00007f99fc54d000) libm.so.6 => /lib64/libm.so.6 (0x00007f99fc2c9000) libc.so.6 => /lib64/libc.so.6 (0x00007f99fbf11000) libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f99fbcfb000) /lib64/ld-linux-x86-64.so.2 (0x00000030cea00000) libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f99fbadf000) libdl.so.2 => /lib64/libdl.so.2 (0x00007f99fb8db000) libutil.so.1 => /lib64/libutil.so.1 (0x00007f99fb6d7000) libz.so.1 => /lib64/libz.so.1 (0x00007f99fb4c0000) librt.so.1 => /lib64/librt.so.1 (0x00007f99fb2b8000) libgmpxx.so.4 => /usr/lib64/libgmpxx.so.4 (0x00007f99fb0b3000) libboost_thread.so.1.49.0 => /usr/local/lib/libboost_thread.so.1.49.0 (0x00007f99fae98000) libgmp.so.3 => /usr/lib64/libgmp.so.3 (0x00007f99fac41000) -- 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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Edge filter
by Flavien Lambert 03 Sep '14

03 Sep '14

Dear all, could you tell me what I am doing wrong in the following script, trying to filter an edge? Best, F. bug.py: import graph_tool as gt _g = gt.Graph() _g.add_vertex(2) _g.add_edge(0,1) print _g _p = _g.new_edge_property('int') for _e in _g.edges() : _p[_e] = 0 _g.set_edge_filter(_p) print _g [Flavien@localhost Downloads]$ python bug.py <Graph object, directed, with 2 vertices and 1 edge at 0x256b990> Traceback (most recent call last): File "bug.py", line 11, in <module> print _g File "/usr/lib/python2.7/site-packages/graph_tool/__init__.py", line 1272, in __repr__ n = self.num_vertices() File "/usr/lib/python2.7/site-packages/graph_tool/__init__.py", line 2048, in num_vertices return self.__graph.GetNumberOfVertices() RuntimeError: Vertex filter is active but edge filter is not. This is a bug.

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Graph id
by Flavien Lambert 25 Aug '14

25 Aug '14

Hi guys, could you tell me the name of the graph id internal property? For vertices and edges, they are _graphml_vertex_id and _graphml_edge_id but for the whole graph... Best, F.

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Efficient property map handling
by Dominik 21 Aug '14

21 Aug '14

Hi, I am working with a lot of vertex property maps that amongst others need to be initialized. Here is a simple example: I am profiling it with: time python2.7 -m cProfile -o stats test_pmap_speed.py then draw the callgraph with gprof2dot -f pstats stats | dot -Tpdf -o output.pdf Here is an example: output.pdf <http://main-discussion-list-for-the-graph-tool-project.982480.n3.nabble.com…> There seems to be a constant overhead associated with accessing the property maps. Fortunately, it appears to be independent of the number of vertices. It contributes quite significantly to the runtime of my tool. The initialization is an example, but in general, I also need to copy one map to another one, e.g. map.a = map1.a, where map1 belongs to the graph Sv, map belongs to S, and Sv is a GraphView of S. Alright, after the context, here comes my question: how can I efficiently (i.e. fast) initialize the maps, copy the maps, etc.? Also, creating a new map seems to take quite long. I am not working with big graphs, but with a lot of maps. I have seen gt.inline, however there is practically no documentation. Could that be a way to speed this up, and if so, how can I learn about the usage? Thanks! -- 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 with multiple graphs
by tmramalho 19 Aug '14

19 Aug '14

Creating multiple graphs in a loop, I get a segmentation fault on mac os x (using macports version) after 6 iterations. Example code to replicate bug import numpy as np import graph_tool as gt for i in xrange(255): edges = np.random.random_integers(0, 20, (2,20)) g = gt.Graph() g.add_edge_list(edges) print i Any ideas what might be causing this? Thanks -- 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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