Hi all, As the subject says, I'm trying to create a vector of histograms. This needs to be a member variable of a class so I need to get the types right in the declaration. I keep getting type conversion errors when I pass the axis to the constructor, so I'm trying a non-vector example. Here's the base code: using UU = boost::histogram::unlimited_storage<std::allocator<double> >; using AA = std::tuple<boost::histogram::axis::variable<double> >; AA ax; boost::histogram::histogram<AA, UU> histo; histo = boost::histogram::histogram(ax); //this has a conversion problem The error on VS 2017 is: error C2440: '<function-style-cast>': cannot convert from 'boost::histogram::axis::variable<double,boost::use_default,boost::use_defau lt,std::allocator<_Ty>>' to 'boost::histogram::histogram<boost::histogram::axis::variable<double,boost:: use_default,boost::use_default,std::allocator<_Ty>>,boost::histogram::defaul t_storage>' with [ _Ty=double ] note: No constructor could take the source type, or constructor overload resolution was ambiguous I can see that the types are different, but no matter what I do with the template arguments of the axis type I still get that error. Can anyone help? Damien