72 lines
2.6 KiB
Python
72 lines
2.6 KiB
Python
"""问题二基线实现：两个朴素但常见的对照。
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- ``candidate_perp``：沿首次示向度垂直方向、距检测点约 1000 m 取点。
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这是"尽量把交会角做成 90°"的教科书启发式，**但它忽略接收距离保证**：
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真源可能落在首次角域的远端（≤1500 m），此时第二点距离可超过 1000 m，
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第二次测量直接 ``no_signal``，几何收益落空。
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- ``candidate_mec``：退到候选集最小包围圆圆心。它确实落在保证接收盘内
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（ρ≤1000 时），但交会角可能接近 0°、后验几乎不收缩，代表"最保守"一端。
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"""
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from __future__ import annotations
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import math
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from mcm26b.config import ProblemConfig
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from mcm26b.planner import safe_disk_radius
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from project.common import Method, problem_config
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from project.q2.region import first_bearing_region
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PERP = Method(
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key="baseline_perp",
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name="垂直 1000 m 最大交会角",
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kind="baseline",
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note="忽略接收保证的几何启发式",
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)
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MEC = Method(
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key="baseline_mec",
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name="候选集 MEC 圆心",
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kind="baseline",
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note="保证接收但交会角最差的保守基线",
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)
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METHODS = (PERP, MEC)
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def _region(case: dict, config: ProblemConfig):
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return first_bearing_region(case, config)
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def candidate_perp(case: dict, config: ProblemConfig | None = None) -> dict:
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config = config or problem_config()
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region = _region(case, config)
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station = (case["station"][0], case["station"][1])
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theta = math.radians(case["bearing_deg"] + 90.0)
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distance = config.field.r_eff_min_m
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position = (station[0] + distance * math.cos(theta),
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station[1] + distance * math.sin(theta))
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return {
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"method": PERP.key,
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"position": [round(position[0], 4), round(position[1], 4)],
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"worst_posterior_radius_m": None, # 由 compare 统一评估
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"move_cost_s": None,
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"safe_disk_radius_m": safe_disk_radius(region, config),
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"initial_radius_m": region.mec()[1],
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"reason": "沿首次示向度法向 1000 m 取 90° 交会点",
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}
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def candidate_mec(case: dict, config: ProblemConfig | None = None) -> dict:
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config = config or problem_config()
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region = _region(case, config)
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center, radius = region.mec()
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return {
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"method": MEC.key,
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"position": [round(center[0], 4), round(center[1], 4)],
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"worst_posterior_radius_m": None,
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"move_cost_s": None,
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"safe_disk_radius_m": safe_disk_radius(region, config),
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"initial_radius_m": radius,
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"reason": "取候选集最小包围圆圆心，保证接收但交会角可能最差",
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}
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