railsim-arena / source /rail_core /reference.py
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RailSimEnv for OpenEnv Arena: tasks, submission, source
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"""A task's reference: the proven optimum, the floor, the lazy policies' costs and rewards, and the real outcome.
Nothing here is shown to the agent.
"""
from __future__ import annotations
from pathlib import Path
from .baselines import POLICIES
from .check import evaluate
from .model import Task, plan_to_list
from .reward import score
from .solve import floor_parts, optimal_plan
def add_reference(task: Task, time_limit: float = 90.0, workers: int = 4, extend: int = 2) -> dict:
hints = {}
for name in ("greedy", "greedy_fast"):
try:
hints[name] = POLICIES[name](task)
except Exception as e: # a baseline that crashes is a bug, but must not stop a build
hints[name] = None
task.reference.setdefault("errors", []).append(f"{name}: {type(e).__name__}: {e}")
best_hint = None
for name, p in hints.items():
if p is None:
continue
r = evaluate(task, p)
if r.feasible and (best_hint is None or r.cost < best_hint[1]):
best_hint = (p, r.cost)
floor, parts = floor_parts(task)
sol = optimal_plan(task, time_limit=time_limit, workers=workers, hint=best_hint[0] if best_hint else None,
unit_floor=parts)
if sol.plan is None:
raise ValueError(f"{task.task_id}: no feasible plan found ({sol.status})")
floor = min(floor, sol.bound)
# large windows: warm-start from the best plan and give the proof more time, while the gap is closable
limit, spent = time_limit, sol.seconds
for _ in range(extend):
gap = (sol.cost - sol.bound) / (sol.cost - floor + task.rule("gap_k"))
if sol.optimal or gap <= 0.01 or gap > 0.3: # close enough to finish, or hopeless
break
limit *= 2
nxt = optimal_plan(task, time_limit=limit, workers=workers, hint=sol.plan, unit_floor=parts)
spent += nxt.seconds
if nxt.plan is not None and (nxt.cost, -nxt.bound) <= (sol.cost, -sol.bound):
sol = nxt
elif nxt.plan is not None:
sol = type(sol)(sol.plan, sol.cost, max(sol.bound, nxt.bound), sol.optimal, sol.status, sol.seconds)
floor = min(floor, sol.bound)
ref = task.reference
ref.update(optimal_cost=sol.cost, optimal_plan=plan_to_list(sol.plan), proven_optimal=sol.optimal,
lower_bound=sol.bound, floor_cost=floor, solver_seconds=round(spent, 1), solver=sol.status)
score_baselines(task, hints)
if "real" in ref:
rr = ref["real"]
rew, _ = score(rr["cost"], True, 1.0, sol.cost, floor, gap_k)
rr["reward_if_legal"] = round(rew, 4)
return ref
def score_baselines(task: Task, hints: dict | None = None) -> None:
"""The lazy policies' feasibility, cost, reward and rule breaks, against the stored optimum and floor."""
ref = task.reference
if hints is None:
hints = {}
for name in ("greedy", "greedy_fast"):
try:
hints[name] = POLICIES[name](task)
except Exception as e:
hints[name] = None
ref.setdefault("errors", []).append(f"{name}: {type(e).__name__}: {e}")
gap_k = task.rule("gap_k")
for name, p in [("naive", POLICIES["naive"](task))] + list(hints.items()):
if p is None:
ref[f"{name}_feasible"] = False
ref[f"{name}_reward"] = 0.0
continue
r = evaluate(task, p)
clean = sum(1 for x in r.runs if not x.problems) / max(1, len(r.runs))
rew, _ = score(r.cost, r.feasible, clean, ref["optimal_cost"], ref["floor_cost"], gap_k)
ref[f"{name}_feasible"] = r.feasible
ref[f"{name}_cost"] = r.cost
ref[f"{name}_reward"] = round(rew, 4)
ref[f"{name}_violations"] = len(r.violations)
BASELINE_KEYS = [f"{n}_{k}" for n in ("naive", "greedy", "greedy_fast") for k in ("feasible", "cost", "reward",
"violations")]
def refresh_baselines(pack_dir: Path) -> list[str]:
"""Re-score the lazy policies of every task in a pack (after a baseline fix), without re-solving. Rewrites the
pack only if something changed; returns the ids of the tasks that changed."""
import json
from .build import write_pack
from .hardness import features
from .pack import _read
tasks, manifest = _read(pack_dir)
raw = [t.to_dict() for t in tasks]
changed = []
for t, d in zip(tasks, raw):
before = {k: t.reference.get(k) for k in BASELINE_KEYS}
t.reference.pop("errors", None)
score_baselines(t)
if {k: t.reference.get(k) for k in BASELINE_KEYS} != before or "errors" in d["reference"]:
t.reference["hardness"] = features(t)
d["reference"] = t.reference
changed.append(t.task_id)
if changed:
log = [json.loads(x) for x in (pack_dir / "build_log.jsonl").read_text().splitlines()]
for st in log:
for t in tasks:
if st.get("task_id") == t.task_id and "hardness" in st:
st["hardness"] = t.reference["hardness"]
std = {"name", "split", "tasks", "file", "tiers", "sha256", "candidates", "days", "proven_optimal", "runs",
"source"}
write_pack(pack_dir, raw, log, manifest["split"], {k: v for k, v in manifest.items() if k not in std})
return changed
if __name__ == "__main__":
import argparse
ap = argparse.ArgumentParser(description="re-score the lazy policies stored in task packs")
ap.add_argument("packs", nargs="+")
for pack in ap.parse_args().packs:
print(pack, refresh_baselines(Path(pack)))