Merge branch 'dev'

Author: Romain MONTAGNÉ

docs/vrp_variants.rst

@@ -192,6 +192,8 @@ where each item of the list is the maximum load per vehicle type. For example, i
 Note how the dimensions of ``load_capacity`` and ``cost`` are consistent: each list must have as many items as vehicle types, and the
 order of the items of the ``load_capacity`` list is consistent with the order of the ``cost`` list on every edge of the graph.
 
+Once the problem is solved, the type of vehicle per route can be queried with ``prob.best_routes_type``.  
+
 
 VRP options
 ~~~~~~~~~~~
@@ -254,7 +256,20 @@ will add to the total travel cost each time a node is dropped. For example, if t
 	>>> prob.drop_penalty = 1000
 	
 This problem is sometimes referred to as the `capacitated profitable tour problem` or the `prize collecting tour problem.`
+
+Minimizing the global time span
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+It is possible to modify the objective function in order to solve a min-max problem. More specifically, the total time span can be minimized
+by setting the ``minimize_global_span`` to ``True``. Of course this assumes edges have a ``time`` argument:
+
+.. code-block:: python
+
+	>>> prob.minimize_global_span = True
 	
+.. note::
+
+   This may lead to poor computation times.
 
 Other VRPs
 ~~~~~~~~~~

examples/cvrp_drop.py

@@ -17,14 +17,20 @@
 
 if __name__ == "__main__":
 
-    prob = VehicleRoutingProblem(G,
-                                 load_capacity=15,
-                                 drop_penalty=1000,
-                                 num_vehicles=4)
-    prob.solve()
+    prob = VehicleRoutingProblem(G, load_capacity=15, drop_penalty=1000, num_vehicles=4)
+    prob.solve(
+        preassignments=[  # locking these routes should yield prob.best_value == 7936
+            # [9, 14, 16],
+            # [12, 11, 4, 3, 1],
+            # [7, 13],
+            # [8, 10, 2, 5],
+        ],
+    )
     print(prob.best_value)
     print(prob.best_routes)
     print(prob.best_routes_cost)
     print(prob.best_routes_load)
     print(prob.node_load)
-    assert prob.best_value == 7548
+    assert prob.best_value == 8096
+
+    # why doesn't vrpy find 7936 ?

tests/test_issue110.py

@@ -0,0 +1,19 @@
+from networkx import DiGraph
+from vrpy import VehicleRoutingProblem
+
+
+class TestIssue110:
+    def setup(self):
+        G = DiGraph()
+        G.add_edge("Source", 1, cost=[1, 2])
+        G.add_edge("Source", 2, cost=[2, 4])
+        G.add_edge(1, "Sink", cost=[0, 0])
+        G.add_edge(2, "Sink", cost=[2, 4])
+        G.add_edge(1, 2, cost=[1, 2])
+        G.nodes[1]["demand"] = 13
+        G.nodes[2]["demand"] = 13
+        self.prob = VehicleRoutingProblem(G, mixed_fleet=True, load_capacity=[10, 15])
+
+    def test_node_load(self):
+        self.prob.solve()
+        assert self.prob.best_routes_type == {1: 1, 2: 1}

tests/test_toy.py

@@ -7,7 +7,6 @@
 
 
 class TestsToy:
-
     def setup(self):
         """
         Creates a toy graph.
@@ -58,10 +57,7 @@ def test_cspy_stops_capacity_duration(self):
         """Tests column generation procedure on toy graph
         with stop, capacity and duration constraints
         """
-        prob = VehicleRoutingProblem(self.G,
-                                     num_stops=3,
-                                     load_capacity=10,
-                                     duration=62)
+        prob = VehicleRoutingProblem(self.G, num_stops=3, load_capacity=10, duration=62)
         prob.solve(exact=False)
         assert prob.best_value == 85
         assert set(prob.best_routes_duration.values()) == {41, 62}
@@ -82,8 +78,7 @@ def test_cspy_stops_time_windows(self):
         assert prob.arrival_time[1]["Sink"] in [41, 62]
 
     def test_cspy_schedule(self):
-        """Tests if final schedule is time-window feasible
-        """
+        """Tests if final schedule is time-window feasible"""
         prob = VehicleRoutingProblem(
             self.G,
             num_stops=3,
@@ -93,13 +88,13 @@ def test_cspy_schedule(self):
         # Check departure times
         for k1, v1 in prob.departure_time.items():
             for k2, v2 in v1.items():
-                assert (self.G.nodes[k2]["lower"] <= v2)
-                assert (v2 <= self.G.nodes[k2]["upper"])
+                assert self.G.nodes[k2]["lower"] <= v2
+                assert v2 <= self.G.nodes[k2]["upper"]
         # Check arrival times
         for k1, v1 in prob.arrival_time.items():
             for k2, v2 in v1.items():
-                assert (self.G.nodes[k2]["lower"] <= v2)
-                assert (v2 <= self.G.nodes[k2]["upper"])
+                assert self.G.nodes[k2]["lower"] <= v2
+                assert v2 <= self.G.nodes[k2]["upper"]
 
     ###############
     # subsolve lp #
@@ -151,13 +146,13 @@ def test_LP_schedule(self):
         # Check departure times
         for k1, v1 in prob.departure_time.items():
             for k2, v2 in v1.items():
-                assert (self.G.nodes[k2]["lower"] <= v2)
-                assert (v2 <= self.G.nodes[k2]["upper"])
+                assert self.G.nodes[k2]["lower"] <= v2
+                assert v2 <= self.G.nodes[k2]["upper"]
         # Check arrival times
         for k1, v1 in prob.arrival_time.items():
             for k2, v2 in v1.items():
-                assert (self.G.nodes[k2]["lower"] <= v2)
-                assert (v2 <= self.G.nodes[k2]["upper"])
+                assert self.G.nodes[k2]["lower"] <= v2
+                assert v2 <= self.G.nodes[k2]["upper"]
 
     def test_LP_stops_elementarity(self):
         """Tests column generation procedure on toy graph"""
@@ -188,11 +183,9 @@ def test_clarke_wright(self):
     #########
 
     def test_all(self):
-        prob = VehicleRoutingProblem(self.G,
-                                     num_stops=3,
-                                     time_windows=True,
-                                     duration=63,
-                                     load_capacity=10)
+        prob = VehicleRoutingProblem(
+            self.G, num_stops=3, time_windows=True, duration=63, load_capacity=10
+        )
         prob.solve(cspy=False)
         lp_best = prob.best_value
         prob.solve(cspy=True)
@@ -217,9 +210,7 @@ def test_knapsack(self):
 
     def test_pricing_strategies(self):
         sol = []
-        for strategy in [
-                "Exact", "BestPaths", "BestEdges1", "BestEdges2", "Hyper"
-        ]:
+        for strategy in ["Exact", "BestPaths", "BestEdges1", "BestEdges2", "Hyper"]:
             prob = VehicleRoutingProblem(self.G, num_stops=4)
             prob.solve(pricing_strategy=strategy)
             sol.append(prob.best_value)
@@ -294,22 +285,25 @@ def test_fixed_cost(self):
         assert set(prob.best_routes_cost.values()) == {30 + 100, 40 + 100}
 
     def test_drop_nodes(self):
-        prob = VehicleRoutingProblem(self.G,
-                                     num_stops=3,
-                                     num_vehicles=1,
-                                     drop_penalty=100)
+        prob = VehicleRoutingProblem(
+            self.G, num_stops=3, num_vehicles=1, drop_penalty=100
+        )
         prob.solve()
         assert prob.best_value == 240
         assert prob.best_routes == {1: ["Source", 1, 2, 3, "Sink"]}
 
     def test_num_vehicles_use_all(self):
-        prob = VehicleRoutingProblem(self.G,
-                                     num_stops=3,
-                                     num_vehicles=2,
-                                     use_all_vehicles=True,
-                                     drop_penalty=100)
+        prob = VehicleRoutingProblem(
+            self.G, num_stops=3, num_vehicles=2, use_all_vehicles=True, drop_penalty=100
+        )
         prob.solve()
         assert len(prob.best_routes) == 2
+        prob.num_vehicles = 3
+        prob.solve()
+        assert len(prob.best_routes) == 3
+        prob.num_vehicles = 4
+        prob.solve()
+        assert len(prob.best_routes) == 4
 
     def test_periodic(self):
         self.G.nodes[2]["frequency"] = 2
@@ -322,10 +316,7 @@ def test_periodic(self):
                 frequency += 1
         assert frequency == 2
         assert prob.schedule[0] in [[1], [1, 2]]
-        prob = VehicleRoutingProblem(self.G,
-                                     num_stops=2,
-                                     periodic=2,
-                                     num_vehicles=1)
+        prob = VehicleRoutingProblem(self.G, num_stops=2, periodic=2, num_vehicles=1)
         prob.solve()
         assert prob.schedule == {}
 

vrpy/master_solve_pulp.py

@@ -46,6 +46,7 @@ def solve(self, relax, time_limit):
         logger.debug("master problem relax %s" % relax)
         logger.debug("Status: %s" % pulp.LpStatus[self.prob.status])
         logger.debug("Objective: %s" % pulp.value(self.prob.objective))
+        # self.prob.writeLP("master.lp")
 
         if pulp.LpStatus[self.prob.status] != "Optimal":
             raise Exception("problem " + str(pulp.LpStatus[self.prob.status]))
@@ -194,8 +195,6 @@ def _solve(self, relax: bool, time_limit: Optional[int]):
                 if "artificial_bound_" in var.name:
                     var.upBound = 0
                     var.lowBound = 0
-            # self.prob.writeLP("master.lp")
-            # print(self.prob)
         # Solve with appropriate solver
         if self.solver == "cbc":
             self.prob.solve(
@@ -210,7 +209,8 @@ def _solve(self, relax: bool, time_limit: Optional[int]):
                 pulp.CPLEX_CMD(
                     msg=False,
                     timeLimit=time_limit,
-                    options=["set lpmethod 4", "set barrier crossover -1"],
+                    # options=["set lpmethod 4", "set barrier crossover -1"], # set barrier crossover -1 is deprecated
+                    options=["set lpmethod 4", "set solutiontype 2"],
                 )
             )
         elif self.solver == "gurobi":
@@ -360,7 +360,7 @@ def _add_drop_variables(self):
         drop[v] takes value 1 if and only if node v is dropped.
         """
         for node in self.G.nodes():
-            if self.G.nodes[node]["demand"] > 0 and node != "Source":
+            if node not in ["Source", "Sink"]:
                 self.drop[node] = pulp.LpVariable(
                     "drop_%s" % node,
                     lowBound=0,

vrpy/masterproblem.py

@@ -7,7 +7,7 @@ class _MasterProblemBase:
         routes (list): Current routes/variables/columns.
         drop_penalty (int, optional): Value of penalty if node is dropped. Defaults to None.
         num_vehicles (int, optional): Maximum number of vehicles. Defaults to None.
-        use_all_vehicles (bool, optional): True if all vehicles specified by num_vehicles should be used. Defaults to False
+        use_all_vehicles (bool, optional): True if all vehicles specified by num_vehicles should be used. Defaults to False.
         periodic (bool, optional): True if vertices are to be visited periodically. Defaults to False.
         minimize_global_span (bool, optional): True if global span (maximum distance) is minimized. Defaults to False.
         solver (str): Name of solver to use.