:github_url: https://github.com/svenevs/exhale-companion


.. _program_listing_file_netoptim_parametric.hpp:

Program Listing for File parametric.hpp
=======================================

|exhale_lsh| :ref:`Return to documentation for file <file_netoptim_parametric.hpp>` (``netoptim/parametric.hpp``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   // -*- coding: utf-8 -*-
   #pragma once
   
   #include "neg_cycle.hpp" // import negCycleFinder
   // #include <iostream>
   #include <tuple>
   #include <vector>
   
   template <typename Graph, typename T, typename Fn1, typename Fn2,
       typename Container>
   auto max_parametric(const Graph& G, T& r_opt, Fn1&& d, Fn2&& zero_cancel,
       Container&& dist, size_t max_iter = 1000)
   {
       using edge_t = typename Graph::edge_t;
   
       auto get_weight = [&](const edge_t& e) -> T { // int???
           return d(r_opt, e);
       };
   
       auto S = negCycleFinder<Graph>(G);
       auto C_opt = std::vector<edge_t> {}; // should initial outside
   
       auto niter = 0U;
       for (; niter != max_iter; ++niter)
       {
           const auto& C_min =
               S.find_neg_cycle(std::forward<Container>(dist), get_weight);
           if (C_min.empty())
           {
               break;
           }
   
           const auto& r_min = zero_cancel(C_min);
           if (r_min >= r_opt)
           {
               break;
           }
   
           C_opt = C_min;
           r_opt = r_min;
   
           // update ???
           for (auto&& edge : C_opt)
           {
               const auto e = G.end_points(edge);
               dist[e.first] = dist[e.second] - get_weight(edge);
           }
       }
   
       return C_opt;
   }