Re: [igraph] python betweenness and closeness normalization

[Tamás Nepusz]

> I took your advice and checked by trying something (e.g. a star graph) in 
> both R and Python. The defaults are different for each version of igraph. It 
> appears that in python the closeness has default normalized=TRUE , while 
> betweenness has default normalized=FALSE. In R, the defaults are both 
> normalized=FALSE.

Ah, this is sort of because of “historical reasons”. The R interface has had 
the ability to normalize scores for a long time (as far as I know), but the 
normalization was implemented in R code, so the Python interface could not have 
used it. Some time around 0.6 (can’t remember), the normalization for the 
closeness centrality was moved down to the C layer. At that point, I added a 
“normalized” argument to Graph.closeness with a default value of True (for sake 
of compatibility with earlier versions that have also used normalization since 
the C core provided normalized values). So, yes, you are right, this is not 
logical. However, switching the default value from True to False in Python 
could break existing code for others who have relied on this behaviour so I 
guess this is here to stay for now :(

T.