c++ - Boost: Store Pointers to Distributions in Vector -

hi stack exchange experts,

i'm trying collect pointers different statistical distributions provided boost in 1 vector. if distributions derived 1 (virtual) parent class write like

std::vector<parent> v;  boost::math::normal_distribution<double> n; boost::math::students_t_distribution<float> t(4);  boost::math::normal_distribution<double> *p1 = new boost::math::normal_distribution<double>(n); boost::math::students_t_distribution<float> *p2 = new boost::math::students_t_distribution<float>(t); v.push_back(p1); v.push_back(p2); 

and iterate on vector , apply functions etc. dereferenced pointers. since not case don't know how store pointers in 1 place?

so question is, if there way store pointers different template classes in 1 variable/list/vector... (that can handled conveniently std::vector example).

remark example boost pdf density function can applied dereferenced pointers regardless of specific type (so storing them in 1 vector makes sense in cases).

//////////////////////////////////////////////////////////////////////////

i played around different (nice) answers , decided stick boost::variant in conjunction boost::static_visitor. below full application outlined in original question:

#include <boost/math/distributions.hpp> #include <boost/variant.hpp> #include <vector> #include <iostream>  //template based visitor invoke cdf function on distribution class cdf_visitor_generic : public boost::static_visitor<double> {     public:          //constructor handle input arguments      cdf_visitor_generic(const double &x) : _x(x) {}      template <typename t>     double operator()(t &operand) const {     return(boost::math::cdf(operand,_x));     }      private:     double _x; };  //shorten typing typedef boost::variant< boost::math::normal_distribution<double>, boost::math::students_t_distribution<double> > distribution;  int main (int, char*[]) { //example distributions boost::math::normal_distribution<double> s; boost::math::students_t_distribution<double> t(1);  //build variant  distribution v = t;  //example value evaluation double x = 1.96;  //evaluation @ 1 point double y = boost::apply_visitor( cdf_visitor_generic(x),v); std::cout << y << std::endl;   //build vector , apply elements of it: std::vector<distribution> vec_v;  vec_v.push_back(s); vec_v.push_back(t);   (std::vector<distribution>::const_iterator iter = vec_v.begin(); iter != vec_v.end(); ++iter){      //apply cdf dereferenced iterator     double test = boost::apply_visitor( cdf_visitor_generic(x), *iter);     std::cout << test << std::endl; } return 0; } 

the drawback see type of distribution needs explicitly specified (in variant) boost::any adds more freedom.

thank great help!

hank

you can use variant:

std::vector<boost::variant<     boost::math::normal_distribution<double>,     boost::math::students_t_distribution<float> > > v;  boost::math::normal_distribution<double> n; boost::math::students_t_distribution<float> t(4);  v.push_back(n); v.push_back(t); 

i have several answers show how use these elements "polymorphically" (though polymorphism statically compile typeswitching, instead of vtable dispatch). i'll add link or 2 soon.

• generating interface without virtual functions?
• avoid rtti when dealing pairs of objects
• more involved: boost::mpl::fold double parameter abstraction

some of linked answers show "manual" approach type erasure

_{ps. should mention boost::any too, dislike several reasons. shan't recommend purpose.}