Hi Emil, I am trying qvm in a small project that uses complex numbers and have expressions of the kind : cv3 = c1*rv3_1 + c2*rv3_2 (the v3's are vectors, the c's are complex and the r's are real). I wrote it as : cv3 = scalar_cast<complex>(rv3_1)*c1 + scalar_cast<complex>(rv3_2)*c2; but this seems to invoke 6 complex constructors (unnecessarily) I have not tested to see if the constructors will be optimized away, but it seems to me that if : v_traits<vector_scalar_cast_>::scalar_type == complex , bit v_traits<vector_scalar_cast_>::r/ir return real the expression will compile and no complex constructors will be invoked. It seems to me that there is a need for another kind of scalar_cast that just adapts the v_traits<>:scalar_type but leaves the r() and ir() unchanged Another question I have is if there is a reason why vector*scalar works but scalar*vector does not? Thanks in advance, Nikolay PS I can send patches if you'd like.