On 16 Nov 2015, at 17:16, abdelghani ALIDRA <alidrandco@yahoo.fr> wrote:Hi everybody,I was discussing with Thibault about the performance of some methods defined on sets ( actually quite slow for big collections, mainly union: and intersection: ) and we were wondering if there is any implementation of some BitField-like class to speed up these operations? May be in an external project?Abdelghani