Hi, I'm trying to get a grip on what it means when I have a random access index in a multi_index_container. I have no mental model for what data structure you're actually creating, which makes it difficult to evaluate multi-index vs. hand-rolling my own container. If I was doing this myself, I'd use a combination of these two: hash_map<key, value> deque<hash_map<key, value>::pointer> because I need to maintain an LRU cache of what has been put in the map (i.e. I need O(1) push_back and pop_front). MultiIndex only lets me use sequenced<> which it implies essentially has the properties of list<hash_map<key, value>::iterator>... although I can imagine you could save a lot by using the same nodes for the hash_map and the list. Do you do that? Regardless, I could still save roughly one pointer per node with my deque. I'd think about trying to modify MultiIndex to let it do random access with deques, but I can't make head or tail of the implementation code used for random access. Could someone clarify what's going on in there? -- Dave Abrahams BoostPro Computing http://www.boostpro.com