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wehub-resource-sync a203934033
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chore: import upstream snapshot with attribution
2026-07-13 13:34:58 +08:00

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Python

# Copyright (c) ModelScope Contributors. All rights reserved.
# Outcome Reward Model (ORM) implementations for GRPO training.
import json
import os
import re
from typing import TYPE_CHECKING, Dict, List, Optional, Union
from swift.infer_engine import InferRequest
if TYPE_CHECKING:
from swift.megatron.arguments import MegatronArguments
from swift.rlhf_trainers import GRPOConfig
class ORM:
"""Base class for synchronous outcome reward models (ORM).
Subclasses should implement the __call__ method to compute rewards.
Example:
class MyReward(ORM):
def __call__(self, completions, **kwargs) -> List[float]:
return [1.0 if len(c) > 100 else 0.0 for c in completions]
"""
def __init__(self, args: Optional[Union['GRPOConfig', 'MegatronArguments']] = None, **kwargs):
self.args = args
def __call__(self, **kwargs) -> List[float]:
raise NotImplementedError
class AsyncORM:
"""Base class for asynchronous outcome reward models (ORM).
Use this for reward functions that involve I/O operations (e.g., API calls,
database queries) that can benefit from async execution.
Async reward functions are executed in parallel using asyncio.gather,
which can significantly speed up reward computation when multiple async
reward functions are used or when the reward function involves network calls.
Example:
class MyAsyncReward(AsyncORM):
async def __call__(self, completions, **kwargs) -> List[float]:
# Use asyncio.gather for parallel execution of all API calls
import asyncio
import aiohttp
async def score_single(session, text):
async with session.post(api_url, json={'text': text}) as resp:
result = await resp.json()
return result['score']
async with aiohttp.ClientSession() as session:
tasks = [score_single(session, c) for c in completions]
rewards = await asyncio.gather(*tasks)
return list(rewards)
"""
def __init__(self, args: Optional[Union['GRPOConfig', 'MegatronArguments']] = None, **kwargs):
self.args = args
async def __call__(self, **kwargs) -> List[float]:
raise NotImplementedError
class MathAccuracy(ORM):
def __init__(self, args=None, **kwargs):
super().__init__(args, **kwargs)
import importlib.util
assert importlib.util.find_spec('math_verify') is not None, (
'The math_verify package is required but not installed. '
"Please install it using 'pip install math_verify'.")
def __call__(self, completions, solution, **kwargs) -> List[float]:
from latex2sympy2_extended import NormalizationConfig
from math_verify import LatexExtractionConfig, parse, verify
rewards = []
for content, sol in zip(completions, solution):
content_match = re.search(r'<answer>(.*?)</answer>', content, re.DOTALL)
content_to_parse = content_match.group(1).strip() if content_match else content
has_answer_tag = content_match is not None
sol_match = re.search(r'<answer>(.*?)</answer>', sol, re.DOTALL)
sol_to_parse = sol_match.group(1).strip() if sol_match else sol
gold_parsed = parse(sol_to_parse, extraction_mode='first_match')
if len(gold_parsed) != 0:
if has_answer_tag:
answer_parsed = parse(content_to_parse, extraction_mode='first_match')
else:
answer_parsed = parse(
content_to_parse,
extraction_config=[
LatexExtractionConfig(
normalization_config=NormalizationConfig(
nits=False,
malformed_operators=False,
basic_latex=True,
boxed=True,
units=True,
),
boxed_match_priority=0,
try_extract_without_anchor=False,
)
],
extraction_mode='first_match',
)
try:
reward = float(verify(gold_parsed, answer_parsed))
except Exception:
reward = 0.0
else:
# If the gold solution is not parseable, we reward 0 to skip this example
reward = 0.0
rewards.append(reward)
return rewards
class Format(ORM):
def __call__(self, completions, **kwargs) -> List[float]:
"""Reward function that checks if the completion has a specific format."""
pattern = r'^<think>.*?</think>\s*<answer>.*?</answer>(?![\s\S])'
matches = [re.match(pattern, content, re.DOTALL | re.MULTILINE) for content in completions]
return [1.0 if match else 0.0 for match in matches]
class ReActFormat(ORM):
def __call__(self, completions, **kwargs) -> List[float]:
"""Reward function that checks if the completion has a specific format."""
pattern = r'^<think>.*?</think>\s*Action:.*?Action Input:.*?$'
matches = [re.match(pattern, content, re.DOTALL | re.MULTILINE) for content in completions]
return [1.0 if match else 0.0 for match in matches]
class CosineReward(ORM):
# https://arxiv.org/abs/2502.03373
def __init__(self, args: Optional[Union['GRPOConfig', 'MegatronArguments']] = None, accuracy_orm=None):
super().__init__(args)
self.min_len_value_wrong = args.cosine_min_len_value_wrong
self.max_len_value_wrong = args.cosine_max_len_value_wrong
self.min_len_value_correct = args.cosine_min_len_value_correct
self.max_len_value_correct = args.cosine_max_len_value_correct
self.max_len = args.cosine_max_len
self.accuracy_orm = accuracy_orm or MathAccuracy()
@staticmethod
def cosfn(t, T, min_value, max_value):
import math
return max_value - (max_value - min_value) * (1 - math.cos(t * math.pi / T)) / 2
def __call__(self, completions, solution, **kwargs) -> List[float]:
acc_rewards = self.accuracy_orm(completions, solution, **kwargs)
response_token_ids = kwargs.get('response_token_ids')
rewards = []
for ids, acc_reward in zip(response_token_ids, acc_rewards):
is_correct = acc_reward >= 1.
if is_correct:
# Swap min/max for correct answers
min_value = self.max_len_value_correct
max_value = self.min_len_value_correct
else:
min_value = self.max_len_value_wrong
max_value = self.min_len_value_wrong
gen_len = len(ids)
reward = self.cosfn(gen_len, self.max_len, min_value, max_value)
rewards.append(reward)
return rewards
class RepetitionPenalty(ORM):
# https://arxiv.org/abs/2502.03373
def __init__(self, args: Optional[Union['GRPOConfig', 'MegatronArguments']] = None, **kwargs):
super().__init__(args)
self.ngram_size = args.repetition_n_grams
self.max_penalty = args.repetition_max_penalty
@staticmethod
def zipngram(text: str, ngram_size: int):
words = text.lower().split()
return zip(*[words[i:] for i in range(ngram_size)])
def __call__(self, completions, **kwargs) -> List[float]:
"""
reward function the penalizes repetitions
Args:
completions: List of model completions
"""
rewards = []
for completion in completions:
if completion == '':
rewards.append(0.0)
continue
if len(completion.split()) < self.ngram_size:
rewards.append(0.0)
continue
ngrams = set()
total = 0
for ng in self.zipngram(completion, self.ngram_size):
ngrams.add(ng)
total += 1
scaling = 1 - len(ngrams) / total
reward = scaling * self.max_penalty
rewards.append(reward)
return rewards
class SoftOverlong(ORM):
def __init__(self, args: Optional[Union['GRPOConfig', 'MegatronArguments']] = None, **kwargs):
super().__init__(args)
assert args.soft_cache_length < args.soft_max_length
self.soft_max_length = args.soft_max_length
self.soft_cache_length = args.soft_cache_length
def __call__(self, completions, **kwargs) -> List[float]:
rewards = []
response_token_ids = kwargs.get('response_token_ids')
for ids in response_token_ids:
completion_length = len(ids)
expected_len = self.soft_max_length - self.soft_cache_length
exceed_len = completion_length - expected_len
rewards.append(min(-exceed_len / self.soft_cache_length, 0))
return rewards
class ReactORM(ORM):
@staticmethod
def evaluate_action_reward(action_pred: list, action_ref: list, cand_list: list, ref_list: list):
f1 = []
for i in range(len(action_pred)):
ref_action = action_ref[i]
pred_action = action_pred[i]
ref_input = ref_list[i]
cand_input = cand_list[i]
ref_is_json = False
try:
ref_input_json = json.loads(ref_input)
ref_is_json = True
except Exception:
ref_input_json = ref_input
cand_is_json = False
try:
cand_input_json = json.loads(cand_input)
cand_is_json = True
except Exception:
cand_input_json = cand_input
if ref_action != pred_action or (ref_is_json ^ cand_is_json):
f1.append(0)
elif not ref_is_json and not cand_is_json:
rougel = ReactORM.evaluate_rougel([ref_input_json], [cand_input_json])
if rougel is None or rougel < 10:
f1.append(0)
elif 10 <= rougel < 20:
f1.append(0.1)
else:
f1.append(1)
else:
if not isinstance(ref_input_json, dict) or not isinstance(cand_input_json, dict):
# This cannot be happen, but:
# line 62, in evaluate_action_reward
# for k, v in ref_input_json.items():
# AttributeError: 'str' object has no attribute 'items'
# print(f'>>>>>>ref_input_json: {ref_input_json}, cand_input_json: {cand_input_json}')
f1.append(0)
continue
half_match = 0
full_match = 0
if ref_input_json == {}:
if cand_input_json == {}:
f1.append(1)
else:
f1.append(0)
else:
for k, v in ref_input_json.items():
if k in cand_input_json.keys():
if cand_input_json[k] == v:
full_match += 1
else:
half_match += 1
recall = (0.5 * half_match + full_match) / (len(ref_input_json) + 1e-30)
precision = (0.5 * half_match + full_match) / (len(cand_input_json) + 1e-30)
try:
f1.append((2 * recall * precision) / (recall + precision))
except Exception:
f1.append(0.0)
if f1[0] == 1.0:
return True
else:
return False
@staticmethod
def parse_action(text):
if 'Action Input:' in text:
input_idx = text.rindex('Action Input:')
action_input = text[input_idx + len('Action Input:'):].strip()
else:
action_input = '{}'
if 'Action:' in text:
action_idx = text.rindex('Action:')
action = text[action_idx + len('Action:'):].strip()
if 'Action Input:' in action:
input_idx = action.index('Action Input:')
action = action[:input_idx].strip()
else:
action = 'none'
return action, action_input
@staticmethod
def parse_output(text):
action, action_input = ReactORM.parse_action(text)
return action, action_input
def __call__(self, infer_requests: List[Union['InferRequest', Dict]], solution: List[str], **kwargs) -> List[float]:
rewards = []
if not isinstance(infer_requests[0], str):
predictions = [request['messages'][-1]['content'] for request in infer_requests]
else:
predictions = infer_requests
for prediction, ground_truth in zip(predictions, solution):
if prediction.endswith('Observation:'):
prediction = prediction[:prediction.index('Observation:')].strip()
action_ref = []
action_input_ref = []
action_pred = []
action_input_pred = []
reference = ground_truth
prediction = prediction.replace('<|endoftext|>', '').replace('<|im_end|>', '').strip()
ref_action, ref_input = ReactORM.parse_output(reference)
pred_action, pred_input = ReactORM.parse_output(prediction)
action_ref.append(ref_action)
action_input_ref.append(ref_input)
if pred_action is None:
action_pred.append('none')
else:
action_pred.append(pred_action)
if pred_input is None:
action_input_pred.append('{}')
else:
action_input_pred.append(pred_input)
reward = ReactORM.evaluate_action_reward(action_pred, action_ref, action_input_pred, action_input_ref)
rewards.append(float(reward))
return rewards
@staticmethod
def evaluate_rougel(cand_list: list, ref_list: list):
if len(ref_list) == 0:
return None
try:
from rouge import Rouge
rouge = Rouge()
rouge_score = rouge.get_scores(hyps=cand_list, refs=ref_list, avg=True)
rougel = rouge_score['rouge-l']['f']
return rougel
except Exception:
return None
class MathORM(ORM):
def __init__(self, args=None, **kwargs):
super().__init__(args)
from transformers.utils import strtobool
self.use_opencompass = strtobool(os.environ.get('USE_OPENCOMPASS_EVALUATOR', 'False'))
if self.use_opencompass:
from opencompass.datasets.math import MATHEvaluator
self.evaluator = MATHEvaluator()
@staticmethod
def check_terminate(answers: Union[str, List[str]]) -> List[bool]:
if isinstance(answers, str):
answers = [answers]
results = []
for answer in answers:
results.append('\\boxed' in answer)
return results
@staticmethod
def extract_boxed_result(text):
pattern = r'\\boxed{([^}]*)}'
match = re.search(pattern, text)
if match:
return match.group(1).strip()
else:
return text
@staticmethod
def clean_latex(latex_str):
latex_str = re.sub(r'\\\(|\\\)|\\\[|\\]', '', latex_str)
latex_str = latex_str.replace('}}', '}').replace('{', '').replace('}', '')
return latex_str.strip()
@staticmethod
def parse_expression(latex_str):
from sympy import simplify
from sympy.parsing.latex import parse_latex
try:
expr = parse_latex(latex_str)
return simplify(expr)
except Exception:
return None
@staticmethod
def compare_consecutive(first, second):
cleaned_list = [MathORM.clean_latex(latex) for latex in [first, second]]
parsed_exprs = [MathORM.parse_expression(latex) for latex in cleaned_list]
if hasattr(parsed_exprs[0], 'equals') and hasattr(parsed_exprs[1], 'equals'):
value = parsed_exprs[0].equals(parsed_exprs[1])
else:
value = parsed_exprs[0] == parsed_exprs[1]
if value is None:
value = False
return value
def __call__(self, infer_requests: List[Union['InferRequest', Dict]], ground_truths: List[str],
**kwargs) -> List[float]:
rewards = []
predictions = [request.messages[-1]['content'] for request in infer_requests]
for prediction, ground_truth in zip(predictions, ground_truths):
if '# Answer' in prediction:
prediction = prediction.split('# Answer')[1]
if '# Answer' in ground_truth:
ground_truth = ground_truth.split('# Answer')[1]
prediction = prediction.strip()
ground_truth = ground_truth.strip()
prediction = MathORM.extract_boxed_result(prediction)
ground_truth = MathORM.extract_boxed_result(ground_truth)
if self.use_opencompass:
reward = self.evaluator.is_equiv(prediction, ground_truth)
else:
reward = MathORM.compare_consecutive(prediction, ground_truth)
rewards.append(float(reward))
return rewards
orms = {
'toolbench': ReactORM,
'math': MathORM,
'accuracy': MathAccuracy,
'format': Format,
'react_format': ReActFormat,
'cosine': CosineReward,
'repetition': RepetitionPenalty,
'soft_overlong': SoftOverlong,
}