baseline

project/q2/cases.py

@@ -0,0 +1,37 @@
+"""问题二算例：随机首次示向度（全向源）。"""
+
+from __future__ import annotations
+
+import math
+import random
+
+from mcm26b.config import ProblemConfig
+
+
+def random_case(seed: int, config: ProblemConfig | None = None) -> dict:
+    """随机检测点 s 与示向度 θ：默认让真源与读数一致（误差 ±1° 内）。"""
+    config = config or ProblemConfig()
+    rng = random.Random(seed)
+    radius = config.field.omega_radius_m
+    # 检测点可在目标域内或域外；这里取域内，符合题目常规场景
+    angle_s = rng.uniform(0, 2 * math.pi)
+    distance_s = radius * math.sqrt(rng.random()) * 0.9
+    station = (distance_s * math.cos(angle_s), distance_s * math.sin(angle_s))
+    # 真源与检测点距离落在 [60, 1500) 且仍在 Ω 内
+    while True:
+        bearing_true = rng.uniform(0, 2 * math.pi)
+        source_distance = rng.uniform(60, config.field.r_eff_max_m - 1)
+        target = (station[0] + source_distance * math.cos(bearing_true),
+                  station[1] + source_distance * math.sin(bearing_true))
+        if math.hypot(*target) <= radius:
+            break
+    error = math.radians(rng.uniform(-0.95, 0.95))
+    bearing_deg = math.degrees(bearing_true + error) % 360.0
+    return {"id": f"q2-{seed}", "station": [round(station[0], 2), round(station[1], 2)],
+            "bearing_deg": round(bearing_deg, 2), "half_angle_deg": 1.0,
+            "true_source": [round(target[0], 2), round(target[1], 2)]}
+
+
+def random_cases(count: int, base_seed: int = 4200,
+                 config: ProblemConfig | None = None) -> list[dict]:
+    return [random_case(base_seed + index, config) for index in range(count)]