[Boost-users] How to make multi_index_container work with std::unique_ptr?

Hi All, If the elements of a multi_index_container are std::unique_ptr, it doesn't seem to work because the assignment operator of std::unique_ptr is private. Any way to let it work? If I change unique_ptr to shared_ptr, it works. But I need a good performance. Or is there anyway to work around to get pointer container performance with multi index power? Thanks a lot! Jayden