The only reason why i want to use compression in my index is for perfomance reasons..that was my thougths untill now but it seems that i wasnt right..:(..since with the vec function i can decode 3000000 doc ids in 2 seconds and 10 milion in 6 secs!!!)
Lets forget the Elias code..and use only the vec , unpack V* and w* to benchmark..and finaly to found the winner...