[igraph] Question about vector

[zhengjun chen]

Hi,

I have a problem with vector data type. After using community structure detection algorithm, I got the membership of vertices. This information is written into file.

Then I want to calculate the modularity for this community division. 

So I extract membership information from the file, and assign them to a vector. The code is in the following:  

     

     int member[12000] ;

     ..........

     for(j=0; j<nodes; j++)  // nodes is the number of nodes in the graph

     {

       igraph_vector_set( &membership, j, (double) member [j] );  // member array stores the membership of vertices

       printf( "%f\n", (double)VECTOR(membership)[j] );

     }

     igraph_modularity( &graph, &membership, &modu, NULL );

The vector membership is initialized correctly. But when running  igraph_modularity() function, it reports the following errors:

*** glibc detected *** ./modularity: malloc(): memory corruption (fast): 0x08084318 ***

======= Backtrace: =========

/lib/i686/nosegneg/libc.so.6[0x45dbfc6e]

/lib/i686/nosegneg/libc.so.6(__libc_calloc+0x94)[0x45dc0874]

/usr/local/lib/libigraph.so.0(igraph_vector_init+0x33)[0xeb1143]

/usr/local/lib/libigraph.so.0(igraph_modularity+0x5f)[0xf0600f]

./modularity[0x8048980]

/lib/i686/nosegneg/libc.so.6(__libc_start_main+0xdc)[0x45d6ddec]

./modularity[0x8048691]

So, I am a bit confused. Where is wrong?

--
Thanks
zhengjun

Graduate research assistant
Dept of Computer Science and Engineering
Lehigh University