Den 04-01-2011 19:56, Howard Hinnant skrev:
On Jan 4, 2011, at 12:00 PM, Thorsten Ottosen wrote:
Den 04-01-2011 04:40, Howard Hinnant skrev:
Warming this up for tr2:
http://home.roadrunner.com/~hinnant/combinations.html
Comments welcome. Real world use welcome.
I'm curious: Which algorithms of his do you use? And for what ballpark ranges of r (distance[first, middle)) and N (distance(first, last))?
I can see that I have only used next_combination(), and in my case I needed to call it for all possible sizes of combinations, so I call next_combination() inside a for loop. I have no predetermined bound on N, it depends on my models, but can range from 10 to 30 to even more, although such N usually become intractable. So I haven' used all of Herve's interface, although I think they could be useful at some point. The thing is, once you need one of these functions, then it's soo nice to find one implemented and tested. In general, I believe there are much more efficient ways to visit all combinations (*) than using the swap-based algorithms provided by Herve, but they give me a fast solution I can use to unit-test other more complicated approached (at least for small N). -Thorsten (*) I have a paper lying around somewhere .... don't have time to find it ... something along "subset enumeration trees" or something