Heuristic route fix as a local search move

CHANGELOG.md

@@ -8,6 +8,7 @@
 - Store distance matrices (#956)
 - Default radius of 35km for OSRM snapping (#922)
 - Support for URL path in host (#966)
+- `TSPFix` local search operator (#737)
 
 ### Changed
 

src/algorithms/local_search/local_search.cpp

@@ -24,6 +24,7 @@ All rights reserved (see LICENSE).
 #include "problems/vrptw/operators/route_exchange.h"
 #include "problems/vrptw/operators/route_split.h"
 #include "problems/vrptw/operators/swap_star.h"
+#include "problems/vrptw/operators/tsp_fix.h"
 #include "problems/vrptw/operators/two_opt.h"
 #include "problems/vrptw/operators/unassigned_exchange.h"
 #include "utils/helpers.h"
@@ -47,7 +48,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 LocalSearch<Route,
             UnassignedExchange,
             CrossExchange,
@@ -65,10 +67,11 @@ LocalSearch<Route,
             PDShift,
             RouteExchange,
             SwapStar,
-            RouteSplit>::LocalSearch(const Input& input,
-                                     std::vector<Route>& sol,
-                                     unsigned max_nb_jobs_removal,
-                                     const Timeout& timeout)
+            RouteSplit,
+            TSPFix>::LocalSearch(const Input& input,
+                                 std::vector<Route>& sol,
+                                 unsigned max_nb_jobs_removal,
+                                 const Timeout& timeout)
   : _input(input),
     _nb_vehicles(_input.vehicles.size()),
     _max_nb_jobs_removal(max_nb_jobs_removal),
@@ -131,7 +134,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 void LocalSearch<Route,
                  UnassignedExchange,
                  CrossExchange,
@@ -149,9 +153,9 @@ void LocalSearch<Route,
                  PDShift,
                  RouteExchange,
                  SwapStar,
-                 RouteSplit>::try_job_additions(const std::vector<Index>&
-                                                  routes,
-                                                double regret_coeff) {
+                 RouteSplit,
+                 TSPFix>::try_job_additions(const std::vector<Index>& routes,
+                                            double regret_coeff) {
   bool job_added;
 
   std::vector<std::vector<RouteInsertion>> route_job_insertions;
@@ -325,7 +329,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 void LocalSearch<Route,
                  UnassignedExchange,
                  CrossExchange,
@@ -343,7 +348,8 @@ void LocalSearch<Route,
                  PDShift,
                  RouteExchange,
                  SwapStar,
-                 RouteSplit>::run_ls_step() {
+                 RouteSplit,
+                 TSPFix>::run_ls_step() {
   // Store best move involving a pair of routes.
   std::vector<std::vector<std::unique_ptr<Operator>>> best_ops(_nb_vehicles);
   for (std::size_t v = 0; v < _nb_vehicles; ++v) {
@@ -1104,6 +1110,27 @@ void LocalSearch<Route,
       }
     }
 
+    // TSPFix stuff
+    if (!_input.has_shipments()) {
+      for (const auto& s_t : s_t_pairs) {
+        if (s_t.second != s_t.first or best_priorities[s_t.first] > 0 or
+            !_input.is_good_TSP_candidate(s_t.first) or
+            _sol[s_t.first].size() < 2) {
+          continue;
+        }
+
+#ifdef LOG_LS_OPERATORS
+        ++tried_moves[OperatorName::TSPFix];
+#endif
+        TSPFix op(_input, _sol_state, _sol[s_t.first], s_t.first);
+
+        if (op.gain() > best_gains[s_t.first][s_t.second] and op.is_valid()) {
+          best_gains[s_t.first][s_t.second] = op.gain();
+          best_ops[s_t.first][s_t.second] = std::make_unique<TSPFix>(op);
+        }
+      }
+    }
+
     // IntraExchange stuff
     for (const auto& s_t : s_t_pairs) {
       if (s_t.first != s_t.second or best_priorities[s_t.first] > 0 or
@@ -1838,7 +1865,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 void LocalSearch<Route,
                  UnassignedExchange,
                  CrossExchange,
@@ -1856,7 +1884,8 @@ void LocalSearch<Route,
                  PDShift,
                  RouteExchange,
                  SwapStar,
-                 RouteSplit>::run() {
+                 RouteSplit,
+                 TSPFix>::run() {
   bool try_ls_step = true;
   bool first_step = true;
 
@@ -1945,7 +1974,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 std::array<OperatorStats, OperatorName::MAX>
 LocalSearch<Route,
             UnassignedExchange,
@@ -1964,7 +1994,8 @@ LocalSearch<Route,
             PDShift,
             RouteExchange,
             SwapStar,
-            RouteSplit>::get_stats() const {
+            RouteSplit,
+            TSPFix>::get_stats() const {
   std::array<OperatorStats, OperatorName::MAX> stats;
   for (auto op = 0; op < OperatorName::MAX; ++op) {
     stats[op] = OperatorStats(tried_moves.at(op), applied_moves.at(op));
@@ -1991,7 +2022,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 Eval LocalSearch<Route,
                  UnassignedExchange,
                  CrossExchange,
@@ -2009,7 +2041,8 @@ Eval LocalSearch<Route,
                  PDShift,
                  RouteExchange,
                  SwapStar,
-                 RouteSplit>::job_route_cost(Index v_target, Index v, Index r) {
+                 RouteSplit,
+                 TSPFix>::job_route_cost(Index v_target, Index v, Index r) {
   assert(v != v_target);
 
   Eval eval = NO_EVAL;
@@ -2062,7 +2095,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 Eval LocalSearch<Route,
                  UnassignedExchange,
                  CrossExchange,
@@ -2080,7 +2114,8 @@ Eval LocalSearch<Route,
                  PDShift,
                  RouteExchange,
                  SwapStar,
-                 RouteSplit>::relocate_cost_lower_bound(Index v, Index r) {
+                 RouteSplit,
+                 TSPFix>::relocate_cost_lower_bound(Index v, Index r) {
   Eval best_bound = NO_EVAL;
 
   for (std::size_t other_v = 0; other_v < _sol.size(); ++other_v) {
@@ -2112,7 +2147,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 Eval LocalSearch<Route,
                  UnassignedExchange,
                  CrossExchange,
@@ -2130,9 +2166,10 @@ Eval LocalSearch<Route,
                  PDShift,
                  RouteExchange,
                  SwapStar,
-                 RouteSplit>::relocate_cost_lower_bound(Index v,
-                                                        Index r1,
-                                                        Index r2) {
+                 RouteSplit,
+                 TSPFix>::relocate_cost_lower_bound(Index v,
+                                                    Index r1,
+                                                    Index r2) {
   Eval best_bound = NO_EVAL;
 
   for (std::size_t other_v = 0; other_v < _sol.size(); ++other_v) {
@@ -2166,7 +2203,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 void LocalSearch<Route,
                  UnassignedExchange,
                  CrossExchange,
@@ -2184,7 +2222,8 @@ void LocalSearch<Route,
                  PDShift,
                  RouteExchange,
                  SwapStar,
-                 RouteSplit>::remove_from_routes() {
+                 RouteSplit,
+                 TSPFix>::remove_from_routes() {
   // Store nearest job from and to any job in any route for constant
   // time access down the line.
   for (std::size_t v1 = 0; v1 < _nb_vehicles; ++v1) {
@@ -2321,7 +2360,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 utils::SolutionIndicators<Route> LocalSearch<Route,
                                              UnassignedExchange,
                                              CrossExchange,
@@ -2339,7 +2379,8 @@ utils::SolutionIndicators<Route> LocalSearch<Route,
                                              PDShift,
                                              RouteExchange,
                                              SwapStar,
-                                             RouteSplit>::indicators() const {
+                                             RouteSplit,
+                                             TSPFix>::indicators() const {
   return _best_sol_indicators;
 }
 
@@ -2360,7 +2401,8 @@ template class LocalSearch<TWRoute,
                            vrptw::PDShift,
                            vrptw::RouteExchange,
                            vrptw::SwapStar,
-                           vrptw::RouteSplit>;
+                           vrptw::RouteSplit,
+                           vrptw::TSPFix>;
 
 template class LocalSearch<RawRoute,
                            cvrp::UnassignedExchange,
@@ -2379,6 +2421,7 @@ template class LocalSearch<RawRoute,
                            cvrp::PDShift,
                            cvrp::RouteExchange,
                            cvrp::SwapStar,
-                           cvrp::RouteSplit>;
+                           cvrp::RouteSplit,
+                           cvrp::TSPFix>;
 
 } // namespace vroom::ls

src/algorithms/local_search/local_search.h

@@ -32,7 +32,8 @@ template <class Route,
           class PDShift,
           class RouteExchange,
           class SwapStar,
-          class RouteSplit>
+          class RouteSplit,
+          class TSPFix>
 class LocalSearch {
 private:
   const Input& _input;

src/problems/cvrp/cvrp.cpp

@@ -25,6 +25,7 @@ All rights reserved (see LICENSE).
 #include "problems/cvrp/operators/route_exchange.h"
 #include "problems/cvrp/operators/route_split.h"
 #include "problems/cvrp/operators/swap_star.h"
+#include "problems/cvrp/operators/tsp_fix.h"
 #include "problems/cvrp/operators/two_opt.h"
 #include "problems/cvrp/operators/unassigned_exchange.h"
 #include "problems/tsp/tsp.h"
@@ -51,7 +52,8 @@ using LocalSearch = ls::LocalSearch<RawRoute,
                                     cvrp::PDShift,
                                     cvrp::RouteExchange,
                                     cvrp::SwapStar,
-                                    cvrp::RouteSplit>;
+                                    cvrp::RouteSplit,
+                                    cvrp::TSPFix>;
 } // namespace cvrp
 
 const std::vector<HeuristicParameters> CVRP::homogeneous_parameters =

src/problems/cvrp/operators/tsp_fix.cpp

@@ -0,0 +1,75 @@
+/*
+
+This file is part of VROOM.
+
+Copyright (c) 2015-2022, Julien Coupey.
+All rights reserved (see LICENSE).
+
+*/
+
+#include "problems/cvrp/operators/tsp_fix.h"
+#include "problems/tsp/tsp.h"
+
+namespace vroom::cvrp {
+
+TSPFix::TSPFix(const Input& input,
+               const utils::SolutionState& sol_state,
+               RawRoute& s_route,
+               Index s_vehicle)
+  // Use dummy 0 values for unused ranks.
+  : Operator(OperatorName::TSPFix,
+             input,
+             sol_state,
+             s_route,
+             s_vehicle,
+             0,
+             s_route,
+             s_vehicle,
+             0),
+    _s_delivery(source.load_at_step(0)) {
+  assert(s_route.size() >= 2);
+}
+
+void TSPFix::compute_gain() {
+  std::vector<Index> jobs = s_route;
+  TSP tsp(_input, std::move(jobs), s_vehicle);
+  tsp_route = tsp.raw_solve(1, Timeout());
+
+  s_gain = _sol_state.route_evals[s_vehicle] -
+           utils::route_eval_for_vehicle(_input, s_vehicle, tsp_route);
+  stored_gain = s_gain;
+  gain_computed = true;
+}
+
+bool TSPFix::is_valid() {
+  bool valid = is_valid_for_source_max_travel_time();
+
+  if (valid) {
+    RawRoute route(_input, s_vehicle, _input.zero_amount().size());
+
+    valid = route.is_valid_addition_for_capacity_inclusion(_input,
+                                                           _s_delivery,
+                                                           tsp_route.begin(),
+                                                           tsp_route.end(),
+                                                           0,
+                                                           0);
+  }
+
+  return valid;
+}
+
+void TSPFix::apply() {
+  s_route = std::move(tsp_route);
+
+  source.update_amounts(_input);
+}
+
+std::vector<Index> TSPFix::addition_candidates() const {
+  return {s_vehicle};
+}
+
+std::vector<Index> TSPFix::update_candidates() const {
+  return {s_vehicle};
+}
+
+} // namespace vroom::cvrp