#include <triqs/gfs.hpp>
using namespace triqs::gfs;
using triqs::clef::placeholder;
int main() {

 // Cf gf<imfreq> specialisation page for the constructor
 double beta = 10;
 int Nfreq = 100;
 auto g = gf<imfreq>{{beta, Fermion, Nfreq}, {1, 1}};

 // Filling the gf with something...
 placeholder<0> wn_;
 g(wn_) << 1 / (wn_ + 2);
 g(wn_) << 1 / (wn_ + 2 + g(wn_));
}