[igraph] R igraph is comiled?

[M. Okuda]

Dear Sirs/Madams,

I use R igraph, especially the "cluster_spinglass" and "cluster_infomap"
functions.
Are these functions compiled or just R scripts?
To compare the processing speed of these methods with the compiled other
clustering methods,
I would like to know what condition R igraph works on.

Truly yours,

M. Okuda