Update services/optimizer.py

services/optimizer.py

@@ -1,20 +1,50 @@
 from __future__ import annotations
 from typing import List
-from ortools.constraint_solver import routing_enums_pb2
-from ortools.constraint_solver import pywrapcp
 
-# 単純TSP(開始=0,終了=0)
-def solver_tsp(durations: List[List[float]]) -> List[int]:
+# Try OR-Tools; fallback to a simple nearest-neighbor if unavailable
+try:
+    from ortools.constraint_solver import routing_enums_pb2
+    from ortools.constraint_solver import pywrapcp
+except Exception:  # pragma: no cover
+    routing_enums_pb2 = None
+    pywrapcp = None
+
+
+def solve_tsp(durations: List[List[float]]) -> List[int]:
+    """
+    Solve a single-vehicle TSP with start/end at node 0 on the given duration matrix (seconds).
+    Returns a list of node indices in visiting order, including the final 0 (start=end).
+    Falls back to nearest-neighbor if OR-Tools is not available.
+    """
     n = len(durations)
-    manager = pywrapcp.RoutingIndexManager(n, 1, 0)
+    if n == 0:
+        return []
+    if n == 1:
+        return [0]
+
+    # Fallback: nearest-neighbor tour + return to start
+    if pywrapcp is None:
+        order = [0]
+        remaining = set(range(1, n))
+        cur = 0
+        while remaining:
+            nxt = min(remaining, key=lambda j: durations[cur][j])
+            order.append(nxt)
+            remaining.remove(nxt)
+            cur = nxt
+        order.append(0)
+        return order
+
+    # OR-Tools exact/heuristic solution
+    manager = pywrapcp.RoutingIndexManager(n, 1, 0)  # 1 vehicle, depot=0
     routing = pywrapcp.RoutingModel(manager)
 
     def time_cb(from_index, to_index):
         i = manager.IndexToNode(from_index)
         j = manager.IndexToNode(to_index)
-        return int(durations[i][j])
-    
-    transit_cb_index = routing.TegisterTransitCallback(time_cb)
+        return int(max(0, durations[i][j]))
+
+    transit_cb_index = routing.RegisterTransitCallback(time_cb)
     routing.SetArcCostEvaluatorOfAllVehicles(transit_cb_index)
 
     search_params = pywrapcp.DefaultRoutingSearchParameters()
@@ -23,13 +53,24 @@ def solver_tsp(durations: List[List[float]]) -> List[int]:
     search_params.time_limit.FromSeconds(5)
 
     solution = routing.SolveWithParameters(search_params)
-    if solution is None :
-        return list(range(n))
-    
+    if solution is None:
+        # Fallback if solver fails
+        order = [0]
+        remaining = set(range(1, n))
+        cur = 0
+        while remaining:
+            nxt = min(remaining, key=lambda j: durations[cur][j])
+            order.append(nxt)
+            remaining.remove(nxt)
+            cur = nxt
+        order.append(0)
+        return order
+
+    # Extract route
     index = routing.Start(0)
     order = []
     while not routing.IsEnd(index):
         order.append(manager.IndexToNode(index))
         index = solution.Value(routing.NextVar(index))
-    order.append(manager.IndexToNode(index))
+    order.append(manager.IndexToNode(index))  # return to depot
     return order