#include <triqs/arrays.hpp>
#include <triqs/arrays/make_immutable_array.hpp>
using triqs::arrays::array;
using triqs::arrays::range;
using triqs::clef::placeholder;
int main() {
 placeholder<0> i_;
 placeholder<1> j_;

 auto a = make_immutable_array(1.0 / (2 + i_ + j_), i_ = range(0, 2), j_ = range(0, 2));

 std::cout << "a = " << a << std::endl;
 std::cout << "a = " << array<double, 2>(a) << std::endl;

 // or if you prefer using a lambda...
 auto b = make_immutable_array([](int i, int j) { return i - j; }, range(0, 2), range(0, 2));

 std::cout << "b = " << b << std::endl;
 std::cout << "b = " << array<double, 2>(b) << std::endl;
}