Just a quick update on the status of Nbody. I discovered that the hanging that people were experiencing were due to the Newton Raphson root finding algorithm which would get stuck in an infinite loop. After looking for why this occurred for sometime, I decided to switch to a bisection method which is insured not to get stuck.
The slow nature of the initialization of the plummer was found to be an error in the calculation of one of the limits of integration in a crucial integral that was being calculated. What a time it was finding that! With that limit fixed, it seems that the initialization takes a few seconds!
I am currently unit testing the code and hopefully should get a lovely new version in a couple of weeks.