[igraph] Re: betweenness and degree correlation

[Tamas Nepusz]

Hi Yong,

Are you sure you are using the patched igraph version (the one that  
uses a long double to count the number of shortest paths)? If so, can  
you check how many bytes does a long double use on your platform?  
(It's 16 bytes on mine, both on OS X and on openSuSE). You can use the  
following program:

#include <stdio.h>
int main(int argc, char* argv[]) {
  printf("%d\n", sizeof(long double));
  return 0;
}

--
Tamas

On 2009.06.23., at 18:55, Yong Zou wrote:

> Hi Tamas,
>
> Here is my result: 1189955308309381376.000000, vertex 433
>
> I did in the following way (exactly the same way as we discussed  
> last time):
> igraph_read_graph_edgelist(&graph, f_edge, 0, IGRAPH_UNDIRECTED);
> igraph_betweenness(&graph, &result, igraph_vss_all(),  
> IGRAPH_UNDIRECTED);
>
> What's wrong here?
>
> Thanks,
> Yong
>
> On Tue, Jun 23, 2009 at 6:03 PM, Tamas Nepusz<address@hidden> wrote:
> > Hi Yong,
> >
> > > For the betweenness centrality, it seems very easy to have overflow
> > > now for my other network. Please have a look at my attachment (edge
> > > list), which has only 1000 nodes. But I really want to analyze the  
> > > BC
> > > for this network.
> > The betweenness calculation seems fine for me for this network; i.e.,
> > the maximum betweenness is 3641.928 and the minimum is zero. What are
> > your results?
> >
> > > Another problem is about the degree-degree correlation, namely, I  
> > > want
> > > to calculate something P(k'|k) which is so called assortativity
> > > coefficient. But I'm sorry I couldn't find it somewhere from igraph.
> > This is not implemented directly in igraph, but it's fairly simple  
> > (at
> > least if you are thinking about the assortativity coefficient as  
> > defined
> > by Newman). This is calculated in Python as follows:
> >
> > http://snipplr.com/view/9914/calculating-assortativity-coefficient-in-igraph/
> >
> > I guess it's not too complicated to translate this back to C.
> >
> > --
> > Tamas