[boost] [Math] Adding prime sieves - design discussion

Just a heads up, that Boost.Math has an open PR for adding prime sieves, and there is an ongoing design discussion on interface etc.  If anyone has any strong feelings on the matter, usage requirements etc, then comments would be most welcome.  See https://github.com/boostorg/math/pull/400. Many thanks, John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus