I am looking for an expert opinion on what the fastest combination generator is. I am currently facing a problem of generating a huge combinations (k elements out of n) and as it stands now, the running time of my program will take more than three years. My current implementation uses the Algorithm R (see Knuth's book pre-fascicle 3a), a revolving-door algorithm.
If anyone knows a better/faster way of enumerating combinations, please let me know. Many thanks.