Re: [igraph] Segfault in weighted edge betweenness community detection

[Tamás Nepusz]

Hello, 

Seems to be a bug on our side; I have added a bug report and I am looking into 
this right now. You can follow the issue here:

https://bugs.launchpad.net/igraph/+bug/988480

-- 
T.


On Wednesday, 25 April 2012 at 18:00, R N wrote:

> Hello,
> 
> I'm using igraph-0.6 build 2694-20120421. I'm trying to use the edge
> betweenness community detection
> function with weighted graphs. I tried out a couple of graphs that I
> have, with 1000 vertices and ~2200 edges.
> The function crashes on both of them if edge weights are used, but
> works if the edge weights are not used.
> It seems that it crashes at line 866 of file 'heap.c', in function
> 'igraph_i_2wheap_switch'.
> Is there some (hopefully small) error in igraph or my negligence in using it?
> 
> Here are the crashy graphs:
> http://www.sendspace.com/filegroup/WXCyAHR%2F28xEv21G0LQm8A
> 
> And here is the full proggy that I used.
> 
> ---8<---
> 
> #include <igraph.h>
> #include <string.h>
> #include <stdlib.h>
> 
> int cd_edge_betweenness (igraph_t *g, igraph_vector_t *weights,
> igraph_vector_t *cm, double *Q)
> {
> 
> igraph_vector_t modularity_eb;
> igraph_vector_t eb, edges;
> 
> igraph_vector_init (&modularity_eb, 0);
> igraph_vector_init (&eb, 0);
> igraph_vector_init (&edges, 0);
> 
> igraph_community_edge_betweenness(
> g,
> &edges,
> &eb,
> 0, // merges
> 0, // bridges
> &modularity_eb, // modularity
> cm, //membership
> IGRAPH_UNDIRECTED,
> weights);
> 
> long int i_eb_max_mod = igraph_vector_which_max (&modularity_eb);
> *Q = VECTOR (modularity_eb)[i_eb_max_mod];
> 
> igraph_vector_destroy (&modularity_eb);
> igraph_vector_destroy (&eb);
> igraph_vector_destroy (&edges);
> 
> return 0;
> }
> 
> int main(int argc, char *argv[])
> {
> 
> igraph_t g;
> FILE *ifile, *ofile;
> long int i;
> long int num_vertex, num_edge;
> double Q;
> 
> igraph_vector_t gtypes, vtypes, etypes;
> igraph_strvector_t gnames, vnames, enames;
> 
> if (argc < 3)
> {
> printf ("Usage: %s (IN)in.graphml (OUT)comm_membership_file\n", argv[0]);
> return -1;
> }
> 
> ifile=fopen(argv[1], "r");
> if (ifile == 0)
> {
> printf ("File opening error: %s\n", argv[1]);
> return -1;
> }
> 
> ofile = fopen (argv[2], "w");
> if (ofile == 0)
> {
> printf ("File opening error: %s\n", argv[2]);
> return -1;
> }
> 
> igraph_i_set_attribute_table(&igraph_cattribute_table);
> igraph_read_graph_graphml (&g, ifile, 0);
> fclose(ifile);
> 
> igraph_vector_init(&gtypes, 0);
> igraph_vector_init(&vtypes, 0);
> igraph_vector_init(&etypes, 0);
> igraph_strvector_init(&gnames, 0);
> igraph_strvector_init(&vnames, 0);
> igraph_strvector_init(&enames, 0);
> 
> igraph_cattribute_list(&g, &gnames, &gtypes, &vnames, &vtypes,
> &enames, &etypes);
> 
> num_vertex = igraph_vcount (&g);
> num_edge = igraph_ecount (&g);
> 
> igraph_vector_t weights;
> igraph_vector_t cm; // community membership vector
> 
> igraph_vector_init (&weights, num_edge);
> igraph_vector_init (&cm, num_vertex);
> 
> for (i=0; i < num_edge; i++)
> {
> //printf ("%d: Edge id=%s, weight=%f\n", i, EAS (g, "id", i), EAN
> (g, "weight", i));
> VECTOR(weights) [i] = EAN (&g, "weight", i);
> }
> 
> int ires = cd_edge_betweenness (&g, &weights, &cm, &Q);
> 
> fprintf (ofile, "# modularity: Q=%g\n", Q);
> for (i = 0; i < num_vertex; ++i)
> {
> fprintf (ofile, "%d\t", (int) VECTOR (cm) [i]);
> }
> fprintf (ofile, "\n");
> 
> igraph_vector_destroy (&weights);
> igraph_vector_destroy (&cm);
> 
> igraph_vector_destroy (&gtypes);
> igraph_vector_destroy (&vtypes);
> igraph_vector_destroy (&etypes);
> igraph_strvector_destroy (&gnames);
> igraph_strvector_destroy (&vnames);
> igraph_strvector_destroy (&enames);
> 
> igraph_destroy(&g);
> 
> return 0;
> }
> 
> _______________________________________________
> igraph-help mailing list
> address@hidden (mailto:address@hidden)
> https://lists.nongnu.org/mailman/listinfo/igraph-help