Allow ending by local refinement together with live traffic.

During the local refinement phase, two consecutive visits to a bus stop
are not merged if there is negative wait time between them. This avoids
potential infeasibility of the local plan in case the negative wait time
removes too much of available time for deliveries.

python/cfr/json/cfr_json.py

@@ -1017,6 +1017,7 @@ def _recompute_one_transition_start_and_durations(
     transition: Transition,
     start_time: datetime.datetime,
     end_time: datetime.datetime,
+    allow_negative_wait_duration: bool,
 ) -> None:
   """Updates `startTime` and `totalDuration` of one transition.
 
@@ -1029,18 +1030,26 @@ def _recompute_one_transition_start_and_durations(
     transition: The transition to be updated.
     start_time: The requested start time of the transition.
     end_time: The requested end time of the transition.
+    allow_negative_wait_duration: Allow that the time slot betwen start_time and
+      end_time is smaller than the required minimal duration of the transition.
+      When this happens, the function adds a negative wait time so that the
+      total duration of the transition matches the time between the two visits.
 
   Raises:
     ValueError: When sum of the other durations of the transition is greater
-      than the duration between `start_time` and `end_time`.
+      than the duration between `start_time` and `end_time`, and
+      allow_negative_wait_duration is False.
   """
   non_wait_duration = (
       parse_duration_string(transition.get("travelDuration", "0s"))
       + parse_duration_string(transition.get("delayDuration", "0s"))
       + parse_duration_string(transition.get("breakDuration", "0s"))
   )
   required_total_duration = end_time - start_time
-  if non_wait_duration > required_total_duration:
+  if (
+      non_wait_duration > required_total_duration
+      and not allow_negative_wait_duration
+  ):
     raise ValueError(
         f"The minimal duration of the transition ({non_wait_duration}) is"
         f" greater than the available time slot ({required_total_duration})."
@@ -1052,7 +1061,9 @@ def _recompute_one_transition_start_and_durations(
 
 
 def recompute_transition_starts_and_durations(
-    model: ShipmentModel, route: ShipmentRoute
+    model: ShipmentModel,
+    route: ShipmentRoute,
+    allow_negative_wait_duration: bool,
 ) -> None:
   """Recomputes transition start times and wait durations based on visit times.
 
@@ -1064,6 +1075,17 @@ def recompute_transition_starts_and_durations(
     model: The model in which the transition times are recomputed.
     route: The route, for which the transition times are recomputed. Modified in
       place.
+    allow_negative_wait_duration: Allow that the time slot between two visits is
+      shorter than the minimal duration of a transition. The missing time is
+      "fixed" by using a negative wait time. This is the approach taken by the
+      CFR solver when there is a traffic infeasibility; setting this to true
+      allows the computation to proceed also on results computed with live
+      traffic that may have traffic infeasibilities.
+
+  Raises:
+    ValueError: When the time between two visits is shorter than then time
+      required by the transition between them, and allow_negative_wait_duration
+      is False.
   """
   visits = get_visits(route)
   if not visits:
@@ -1079,7 +1101,10 @@ def recompute_transition_starts_and_durations(
       current_visit_start_time = parse_time_string(visit["startTime"])
       transition_in = transitions[transition_index]
       _recompute_one_transition_start_and_durations(
-          transition_in, previous_visit_end_time, current_visit_start_time
+          transition_in,
+          previous_visit_end_time,
+          current_visit_start_time,
+          allow_negative_wait_duration,
       )
 
       visit_duration = get_visit_request_duration(
@@ -1092,6 +1117,7 @@ def recompute_transition_starts_and_durations(
         transitions[-1],
         previous_visit_end_time,
         parse_time_string(route["vehicleEndTime"]),
+        allow_negative_wait_duration,
     )
   except ValueError as err:
     raise ValueError(

python/cfr/json/cfr_json_test.py

@@ -1894,7 +1894,9 @@ def recompute_existing_solution(
 
       if transitions:
         self.assertNotEqual(route, expected_route)
-      cfr_json.recompute_transition_starts_and_durations(model, route)
+      cfr_json.recompute_transition_starts_and_durations(
+          model, route, allow_negative_wait_duration=False
+      )
       self.assertEqual(route, expected_route)
 
   def test_moderate_local(self):
@@ -1929,7 +1931,58 @@ def test_insufficient_time(self):
         ],
     }
     with self.assertRaisesRegex(ValueError, "minimal duration"):
-      cfr_json.recompute_transition_starts_and_durations(model, route)
+      cfr_json.recompute_transition_starts_and_durations(
+          model, route, allow_negative_wait_duration=False
+      )
+
+  def test_insufficient_time_allow_negative_duration(self):
+    model: cfr_json.ShipmentModel = {
+        "shipments": [{"deliveries": [{"duration": "120s"}]}],
+    }
+    route: cfr_json.ShipmentRoute = {
+        "vehicleIndex": 0,
+        "vehicleStartTime": "2024-01-15T10:00:00Z",
+        "vehicleEndTime": "2024-01-15T11:00:00z",
+        "visits": [{
+            "shipmentIndex": 0,
+            "visitRequestIndex": 0,
+            "isPickup": False,
+            "startTime": "2024-01-15T10:10:00Z",
+        }],
+        "transitions": [
+            {},
+            {"breakDuration": "1800s", "travelDuration": "1200s"},
+        ],
+    }
+    expected_route: cfr_json.ShipmentRoute = {
+        "transitions": [
+            {
+                "startTime": "2024-01-15T10:00:00Z",
+                "totalDuration": "600s",
+                "waitDuration": "600s",
+            },
+            {
+                "breakDuration": "1800s",
+                "startTime": "2024-01-15T10:12:00Z",
+                "totalDuration": "2880s",
+                "travelDuration": "1200s",
+                "waitDuration": "-120s",
+            },
+        ],
+        "vehicleEndTime": "2024-01-15T11:00:00z",
+        "vehicleIndex": 0,
+        "vehicleStartTime": "2024-01-15T10:00:00Z",
+        "visits": [{
+            "isPickup": False,
+            "shipmentIndex": 0,
+            "startTime": "2024-01-15T10:10:00Z",
+            "visitRequestIndex": 0,
+        }],
+    }
+    cfr_json.recompute_transition_starts_and_durations(
+        model, route, allow_negative_wait_duration=True
+    )
+    self.assertEqual(route, expected_route)
 
 
 class UpdateTimeStringTest(unittest.TestCase):
@@ -2006,6 +2059,11 @@ def test_fractions(self):
         "0.5s",
     )
 
+  def test_negative_time(self):
+    self.assertEqual(
+        cfr_json.as_duration_string(datetime.timedelta(seconds=-100)), "-100s"
+    )
+
 
 class EncodePolylineTest(unittest.TestCase):
   """Tests for encode_polyline."""

python/cfr/testdata/small/expected_integrated_global_response_with_traffic_infeasibility.json

@@ -0,0 +1,152 @@
+{
+  "requestLabel": "my_little_model/refined_global",
+  "routes": [
+    {
+      "hasTrafficInfeasibilities": false,
+      "metrics": {
+        "breakDuration": "0s",
+        "delayDuration": "360s",
+        "performedMandatoryShipmentCount": 3,
+        "performedShipmentCount": 3,
+        "totalDuration": "28800s",
+        "travelDistanceMeters": 2404,
+        "travelDuration": "815s",
+        "visitDuration": "1775s",
+        "waitDuration": "25850s"
+      },
+      "routeTotalCost": 1582.404,
+      "transitions": [
+        {
+          "startTime": "2023-08-11T08:00:00Z",
+          "totalDuration": "421s",
+          "travelDistanceMeters": 1249,
+          "travelDuration": "421s",
+          "vehicleLoads": {
+            "ore": { "amount": "1" },
+            "wood": { "amount": "5" }
+          },
+          "waitDuration": "0s"
+        },
+        {
+          "startTime": "2023-08-11T08:09:31Z",
+          "totalDuration": "20503s",
+          "travelDistanceMeters": 719,
+          "travelDuration": "238s",
+          "vehicleLoads": {
+            "ore": { "amount": "1" },
+            "wood": { "amount": "5" }
+          },
+          "waitDuration": "20265s"
+        },
+        {
+          "delayDuration": "180s",
+          "startTime": "2023-08-11T14:10:50Z",
+          "totalDuration": "1802s",
+          "travelDuration": "0s",
+          "vehicleLoads": {
+            "ore": { "amount": "1" },
+            "wood": { "amount": "5" }
+          },
+          "waitDuration": "1622s"
+        },
+        {
+          "delayDuration": "180s",
+          "startTime": "2023-08-11T14:48:21Z",
+          "totalDuration": "4299s",
+          "travelDistanceMeters": 436,
+          "travelDuration": "156s",
+          "vehicleLoads": { "ore": {}, "wood": {} },
+          "waitDuration": "3963s"
+        }
+      ],
+      "travelSteps": [
+        { "distanceMeters": 1249, "duration": "421s" },
+        { "distanceMeters": 719, "duration": "238s" },
+        { "distanceMeters": 0, "duration": "0s" },
+        { "distanceMeters": 436, "duration": "156s" }
+      ],
+      "vehicleEndTime": "2023-08-11T16:00:00Z",
+      "vehicleIndex": 0,
+      "vehicleLabel": "V001",
+      "vehicleStartTime": "2023-08-11T08:00:00Z",
+      "visits": [
+        {
+          "detour": "56s",
+          "isPickup": false,
+          "shipmentIndex": 0,
+          "shipmentLabel": "s:8 S009",
+          "startTime": "2023-08-11T08:07:01Z"
+        },
+        {
+          "detour": "20574s",
+          "isPickup": false,
+          "shipmentIndex": 1,
+          "shipmentLabel": "p:0 S001,S004,S003,S002",
+          "startTime": "2023-08-11T13:51:14Z"
+        },
+        {
+          "detour": "23372s",
+          "isPickup": false,
+          "shipmentIndex": 2,
+          "shipmentLabel": "p:1 S007",
+          "startTime": "2023-08-11T14:40:52Z"
+        }
+      ]
+    },
+    {
+      "hasTrafficInfeasibilities": true,
+      "metrics": {
+        "breakDuration": "0s",
+        "delayDuration": "360s",
+        "performedMandatoryShipmentCount": 1,
+        "performedShipmentCount": 1,
+        "totalDuration": "43200s",
+        "travelDistanceMeters": 1988,
+        "travelDuration": "722s",
+        "visitDuration": "750s",
+        "waitDuration": "41368s"
+      },
+      "routeTotalCost": 1721.988,
+      "transitions": [
+        {
+          "delayDuration": "180s",
+          "startTime": "2023-08-11T08:00:00Z",
+          "totalDuration": "653s",
+          "travelDistanceMeters": 1552,
+          "travelDuration": "573s",
+          "waitDuration": "-100s",
+          "vehicleLoads": {
+            "ore": { "amount": "2" },
+            "wheat": { "amount": "3" }
+          }
+        },
+        {
+          "delayDuration": "180s",
+          "startTime": "2023-08-11T08:23:23Z",
+          "totalDuration": "41797s",
+          "travelDistanceMeters": 436,
+          "travelDuration": "149s",
+          "vehicleLoads": { "ore": {}, "wheat": {} },
+          "waitDuration": "41468s"
+        }
+      ],
+      "travelSteps": [
+        { "distanceMeters": 1552, "duration": "573s" },
+        { "distanceMeters": 436, "duration": "149s" }
+      ],
+      "vehicleEndTime": "2023-08-11T20:00:00Z",
+      "vehicleIndex": 1,
+      "vehicleLabel": "V002",
+      "vehicleStartTime": "2023-08-11T08:00:00Z",
+      "visits": [
+        {
+          "detour": "0s",
+          "isPickup": false,
+          "shipmentIndex": 3,
+          "shipmentLabel": "p:2 S006,S008,S005",
+          "startTime": "2023-08-11T08:10:53Z"
+        }
+      ]
+    }
+  ]
+}