Hi, Those interested can already download the preview of Boost.MultiIndex as it'll be shipped in Boost 1.56: https://github.com/boostorg/multi_index/archive/master.zip Full release notes can be read at https://rawgithub.com/boostorg/multi_index/master/doc/release_notes.html#boo... The most important change is a complete reimplementation of the internals of hashed indices, so that erasure of elements is constant-time regardless of the level of occupancy of the internal bucket array (previously, performance degraded as the bucket was being depleted.) A full description of the new data structure as compared with other popular implementations of unordered associative containers is given at: http://bannalia.blogspot.com/2013/10/implementation-of-c-unordered.html http://bannalia.blogspot.com/2013/10/implementation-of-c-unordered_25.html Along with some performance results: http://bannalia.blogspot.com/2013/11/measuring-insertion-times-for-c.html http://bannalia.blogspot.com/2013/11/measuring-insertion-times-for-c_16.html http://bannalia.blogspot.com/2013/11/measuring-erasure-times-for-c-unordered... http://bannalia.blogspot.com/2013/11/measuring-lookup-times-for-c-unordered.... The new data structure has been thoroughly tested but some pre-shipping feedback is always welcome, so if you test this please report back. Thank you, Joaquín M López Muñoz Telefónica Digital ________________________________ Este mensaje se dirige exclusivamente a su destinatario. Puede consultar nuestra política de envío y recepción de correo electrónico en el enlace situado más abajo. This message is intended exclusively for its addressee. We only send and receive email on the basis of the terms set out at: http://www.tid.es/ES/PAGINAS/disclaimer.aspx