I have a class MyClass, which operates with some double values beta, stored as a class member, in it's member function g. It sorts them and stores the permutation in the class member std::vector<int> sorted_beta_ind:
double MyClass::g() { // ... sorted_beta_ind.resize(n); for(unsigned int i=0; i<n; ++i) { sorted_beta_ind[i] = i; } std::sort(sorted_beta_ind.begin(), sorted_beta_ind.end(), [this] (const int &a, const int &b) {++op_cmp; return beta[a] > beta[b];}); // ...}Next I want to have several ordered sets of indices in another member function f, which will store the indices in the same order as in sorted_beta_ind. I'm trying to use std::set objects, and as such, I need a comparator. The best solution I figured out is a lambda function
double MyClass::f() { auto ind_comp = [&order = sorted_beta_ind] (const int &a, const int &b) { int pos_a = ~0, pos_b = ~0; for(unsigned int i=0; i<order.size(); ++i) { if(order[i] == a) { pos_a = i; } if(order[i] == b) { pos_b = i; } } return pos_a < pos_b; }; std::set<int, decltype(ind_comp)> d0, d1; // the rest of the function which uses std::union and std::instersection}but on building the project I get
error: use of deleted function ‘MyClass::f()::<lambda(const int&, const int&)>& MyClass::f(int**, int)::<lambda(const int&, const int&)>::operator=(const MyClass::f()::<lambda(const int&, const int&)>&)’Can this approach work or I should try something entirely else?