[igraph] C/igraph: How to handle weighted graphs?

[Szabolcs Horvát]

Dear All,

What is the proper way to handle weighted graphs with C/igraph?

It appears that most (all?) functions that use weights take the
weights as a separate argument (and ignore them if passed NULL).  But
weights can also be stored inside the graph, as a graph attribute. Is
there any reason, other than perhaps convenience, why I should store
the weights as a graph attribute instead of a separate vector?  Do any
functions automatically use the weights stored in the graph itself?

I am working on an igraph interface for Mathematica.  I am asking this
question to make sure the choice I make will work well with all
functions, including the ones I haven't looked at yet.

Szabolcs