Order Complexity for Ruby Combinatoric Functions

Question

In one of my algorithms I use Ruby's combination and permutation methods. I have to discuss this algorithms complexity. Where could I find information about their complexity/implementation?

I've tried implementing a simple 'hand made' function but the Ruby ones seem to run in near constant time!

Any information about where to look would be much appreciated.

Answer 1

Implementation can be shown on the same pages you linked. Hover your mouse over the name of the combination/permutation methods, and select click to toggle source.

You can view the latest and different versions of source here at the main repo: http://svn.ruby-lang.org/cgi-bin/viewvc.cgi/

You can read the revision history of array.c to see perhaps why/when any changes were made to the combination/permutation methods. http://svn.ruby-lang.org/cgi-bin/viewvc.cgi/trunk/array.c?view=log. This may give you some indication into complexity and design choices made by the developers.

You may even be able to ask certain contributors to the source for reasons as to why they made XYZ change to the method, they may/may not help.