nan egde betweenness values

Hi,
I am computing a centrality.betweenness for a graph with weight equal to an
edge property map of type double. Some of the resulting edge betweenness
values are nan. The graph in question is connected so am unsure why a nan
value is occurring. I would be delighted to hear any suggestions.
Regards,
Padraig

Without a concrete example, it is hard to say what is going on. Maybe
you have some weights with value zero?

Cheers,
Tiago