#!/usr/bin/env python3

# SPDX-FileCopyrightText: Copyright (c) 2026 NVIDIA CORPORATION & AFFILIATES. All rights reserved.

# SPDX-License-Identifier: Apache-2.0

#

# Parse training log for "[LER Validation] Logical error rate: X.XXXXX" and exit 1 if above threshold.

# Used by CI to turn "run and hope it completes" into a real correctness check.

#

# Usage:

# python check_ler_from_log.py <log_file_or_-_for_stdin> [--max-ler 0.1]

import argparse

import re

import sys

from pathlib import Path

# Same pattern as run_one_epoch_ci.py

LER_PATTERN = re.compile(r"\[LER Validation\]\s+Logical error rate:\s+([\d.]+)")

def main():

parser = argparse.ArgumentParser(

description="Check that the last LER in a training log is at or below a threshold."

)

parser.add_argument(

"log",

type=str,

help="Path to log file, or '-' for stdin",

)

parser.add_argument(

"--max-ler",

type=float,

default=0.1,

help="Maximum allowed LER (default: 0.1)",

)

args = parser.parse_args()

if args.log == "-":

content = sys.stdin.read()

else:

path = Path(args.log)

if not path.exists():

print(f"[check_ler_from_log] File not found: {path}", file=sys.stderr)

sys.exit(1)

content = path.read_text()

matches = LER_PATTERN.findall(content)

if not matches:

print(

"[check_ler_from_log] No '[LER Validation] Logical error rate: X.XXXXX' line found.",

file=sys.stderr

)

sys.exit(1)

ler = float(matches[-1])

print(f"[check_ler_from_log] Last LER: {ler:.6f} (max allowed: {args.max_ler})")

if ler > args.max_ler:

print(f"[check_ler_from_log] FAIL: LER {ler} > {args.max_ler}", file=sys.stderr)

sys.exit(1)

print("[check_ler_from_log] PASS.")

sys.exit(0)

if __name__ == "__main__":

main()