Create optimizer.py

services/optimizer.py

@@ -0,0 +1,68 @@
+from __future__ import annotations
+from typing import List
+from ortools.constraint_solver import pywrapcp, routing_enums_pb2
+
+def solve_tsp(time_matrix: List[List[float]]) -> List[int]:
+    """
+    OSRMのduration行列（秒）を入力に、0番ノード（Start）発→全訪問→Start戻りの巡回順序を返す。
+    OR-Toolsで解けない場合は貪欲法でフォールバックします。
+    返り値例: [0, 3, 2, 1, 0]
+    """
+    n = len(time_matrix) if time_matrix else 0
+    if n <= 1:
+        return list(range(n))
+
+    # 行列のサニタイズ（Noneや欠損を大値に、対角は0、int秒へ）
+    BIG = 10**9
+    matrix: List[List[int]] = []
+    for i in range(n):
+        row_i = []
+        for j in range(n):
+            try:
+                v = time_matrix[i][j]
+                v = float(v) if v is not None else BIG
+            except Exception:
+                v = BIG
+            if i == j:
+                v = 0.0
+            row_i.append(int(max(0, round(v))))
+        matrix.append(row_i)
+
+    # OR-Tools セットアップ
+    manager = pywrapcp.RoutingIndexManager(n, 1, 0)  # depot=0
+    routing = pywrapcp.RoutingModel(manager)
+
+    def transit_cb(from_index, to_index):
+        i = manager.IndexToNode(from_index)
+        j = manager.IndexToNode(to_index)
+        return matrix[i][j]
+
+    transit_idx = routing.RegisterTransitCallback(transit_cb)
+    routing.SetArcCostEvaluatorOfAllVehicles(transit_idx)
+
+    params = pywrapcp.DefaultRoutingSearchParameters()
+    params.first_solution_strategy = routing_enums_pb2.FirstSolutionStrategy.PATH_CHEAPEST_ARC
+    params.local_search_metaheuristic = routing_enums_pb2.LocalSearchMetaheuristic.GUIDED_LOCAL_SEARCH
+    params.time_limit.FromSeconds(1)  # 1秒で切り上げ（HF Spaces向けに軽量）
+
+    solution = routing.SolveWithParameters(params)
+    if solution:
+        index = routing.Start(0)
+        order: List[int] = []
+        while not routing.IsEnd(index):
+            order.append(manager.IndexToNode(index))
+            index = solution.Value(routing.NextVar(index))
+        order.append(manager.IndexToNode(index))  # 最後にdepot(0)へ戻る
+        return order
+
+    # フォールバック：近傍貪欲
+    unvisited = set(range(1, n))
+    order = [0]
+    cur = 0
+    while unvisited:
+        nxt = min(unvisited, key=lambda j: matrix[cur][j])
+        order.append(nxt)
+        unvisited.remove(nxt)
+        cur = nxt
+    order.append(0)
+    return order