If std::for_each is acceptable then the following works. Or do you specifically need std::transform? ////////////////////// #include <algorithm> #include <vector> #include <iostream> #include <boost/spirit/include/phoenix_core.hpp> #include <boost/spirit/include/phoenix_operator.hpp> #include <boost/spirit/include/phoenix_bind.hpp> struct point { double _prob; double _x; }; point make_point(double prob, double x) { point const p = { prob, x }; return p; } int main() { namespace phx = boost::phoenix; using namespace phx::arg_names; typedef std::vector<point> points_t; points_t points; points.push_back(make_point(1., 5.)); points.push_back(make_point(2., 6.)); points.push_back(make_point(3., 7.)); points.push_back(make_point(4., 8.)); std::for_each( points.begin(), points.end(), phx::bind(&point::_prob, _1) *= 2. ); for (points_t::const_iterator i = points.begin(), i_end = points.end(); i != i_end; ++i) std::cout << i->_prob << ' ' << i->_x << std::endl; return 0; }