Hi Simon,
thanks for the answer, sorry, I should have included this, it is
apparently not in sessionInfo().
So, this happens on 10.9.4 with R 3.1.1 and also on 10.8.5 with R
3.1.0. And the (10.8) CRAN binary version of igraph unloads cleanly on
both of them.
I am not sure how and why
I just tried on an R version that I compiled myself, and unloading
works fine. \o/
I also tried using the Mavericks build of R, and that works fine, too,
on my Mavericks laptop. \o/
I have no idea why the Snow Leopard R build did not work with my other
Snow Leopard machine, but honestly, I don't
