def cosine_scaled_reward(completions, solution, **kwargs):
        """Reward function that scales based on completion length using a cosine schedule.

        Shorter correct solutions are rewarded more than longer ones.
        Longer incorrect solutions are penalized less than shorter ones.

        Args:
            completions: List of model completions
            solution: List of ground truth solutions

        This function is parameterized by the following arguments:
            min_value_wrong: Minimum reward for wrong answers
            max_value_wrong: Maximum reward for wrong answers
            min_value_correct: Minimum reward for correct answers
            max_value_correct: Maximum reward for correct answers
            max_len: Maximum length for scaling
        """
        contents = [completion[0]["content"] for completion in completions]
        rewards = []

        for content, sol in zip(contents, solution):
            gold_parsed = parse(
                sol,
                extraction_mode="first_match",
                extraction_config=[LatexExtractionConfig()],
            )
            if len(gold_parsed) == 0:
                rewards.append(1.0)  # Skip unparseable examples
                print("Failed to parse gold solution: ", sol)
                continue

            answer_parsed = parse(
                content,
                extraction_config=[
                    LatexExtractionConfig(
                        normalization_config=NormalizationConfig(
                            nits=False,
                            malformed_operators=False,
                            basic_latex=True,
                            equations=True,
                            boxed=True,
                            units=True,
                        ),
                        boxed_match_priority=0,
                        try_extract_without_anchor=False,
                    )
                ],
                extraction_mode="first_match",
            )

            is_correct = verify(answer_parsed, gold_parsed)
            gen_len = len(content)

            # Apply cosine scaling based on length
            progress = gen_len / max_len
            cosine = math.cos(progress * math.pi)

            if is_correct:
                min_value = min_value_correct
                max_value = max_value_correct
            else:
                # Swap min/max for incorrect answers
                min_value = max_value_wrong
                max_value = min_value_wrong

            reward = min_value + 0.5 * (max_value - min_value) * (1.0 + cosine)
            rewards.append(float(reward))

        return rewards
Reward function that scales based on completion length using a cosine schedule.

        Shorter correct solutions are rewarded more than longer ones.
        Longer incorrect solutions are penalized less than shorter ones.

        Args:
            completions: List of model completions
            solution: List of ground truth solutions

        This function is parameterized by the following arguments:
            min_value_wrong: Minimum reward for wrong answers
            max_value_wrong: Maximum reward for wrong answers
            min_value_correct: Minimum reward for correct answers
            max_value_correct: Maximum reward for correct answers
            max_len: Maximum length for scaling
        
src/open_r1/rewards.py