[igraph] Weighted graphs in Python interface

[Jonathan Donges]

Hi igraphers!

I've some questions about weighted networks in igraph:

1. Working with the Python interface, I would like to generate a  
directed weighted graph (without multiple edges and self-loops) from  
an adjacency matrix, where the elements of the matrix store the weight  
if an edge exists and are otherwise zero. The matrix is a numpy array  
or list of lists. How can this be achieved in a most direct way?

2. I would like to calculate shortest path related measures including  
the weights, i.e. the length of a path should be defined by the sum of  
the edge weights on the way. Particularly, I am interested in average  
path length, vertex betweenness centrality and vertex closeness  
centrality using edge weights. The weights are all positive in my  
application. Is this implemented yet in iGraph? Maybe in some  
developement version? If not, do you have suggestions for other fast  
libraries implementing these features?

Thank you so much for your help in advance!

Jonathan Donges
University of Potsdam, Germany