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Controlling Output Length in Language Models

A new framework helps language models generate precise responses.

Seoha Song, Junhyun Lee, Hyeonmok Ko

― 6 min read


AI Output Length Control AI Output Length Control response length. New methods improve how AI manages
Table of Contents

Language models have come a long way and are quite popular these days. They can write stories, answer questions, and help with various tasks. However, one challenge remains: controlling how long their responses are. Imagine asking a language model to summarize a book, and it gives you a 10-page essay instead. That wouldn’t be ideal, would it?

In this article, we’ll explore a new Framework designed to make language models better at managing the length of their outputs. This framework allows these models to be more precise when generating content, making them more useful for everyday tasks.

The Problem

Controlling how long a response should be is important. For example, in a news app, users expect concise summaries that fit within a limited space. Similarly, a voice assistant might need to adapt its responses based on how much information a user wants. The challenge here is that most large language models, despite being smart, struggle to keep track of how many words they are producing.

Long outputs can lead to confusion and frustration. If you ask for a short summary and get a lengthy description, it can be overwhelming. Therefore, finding a way to control Output Length is crucial for improving user experience.

Finding a Solution

Researchers have been trying different methods to help language models say just the right amount. For example, some have suggested feeding the model information about the desired length during training. Others have experimented with various techniques to give the models hints about how long their answers should be.

Despite these efforts, most existing methods focus on smaller models and aren’t practical for larger models with billions of parameters. This is a bit like trying to fit a square peg into a round hole.

Introducing the Framework

Here comes our new hero: a framework designed to help language models manage output length more efficiently. This framework uses special Tokens that pop up at different intervals during the generation process. Think of these tokens like road signs for the model, guiding it along the way and helping it stay on track.

When the model is generating text, these special tokens keep it informed about how much longer it should be writing. By including this information, the framework helps control the output length without sacrificing the quality of the content.

Training the Model

To teach the model how to handle output length, researchers created a special Training Dataset. This dataset includes regular appearances of the special tokens, which provide hints about the target length. It's like giving the model a cheat sheet, making it easier for it to learn how to stay within the desired word count.

The training process involves feeding the model various examples containing the special tokens. As the model learns, it becomes better at predicting how long its outputs should be. Researchers found that this method was effective across various large language models, regardless of the specific technical details of how each one handles positional encoding.

Testing the Framework

Once the model was trained, it was time to see how well it performed. The researchers put the model to the test using different datasets and tasks. They looked for two main things: how accurately the model could meet the target length and the overall quality of the text it generated.

The results were promising. The model showed a significant reduction in the difference between its output length and the target length. In other words, it became much better at hitting the word count that was specified. Additionally, it maintained a high standard in terms of content quality. This means users could expect coherent and readable responses that were still concise.

Real-Life Applications

The ability to control output length has real-world benefits. For example, imagine an app that summarizes articles. Users could request summaries of different lengths based on their needs. A busy professional might want a quick 50-word summary, while a student might prefer a more detailed 200-word version. With this framework, the language model can adapt its responses accordingly.

Similarly, voice assistants could tune their responses to fit user preferences. Asking for "the weather" could yield a short answer, while a request for "more details" could result in a more elaborate response. This flexibility makes the technology more user-friendly and effective.

The Importance of Accuracy

While generating text is one thing, doing so accurately is another. Language models are known for sometimes drifting off-topic or not quite sticking to the required output length. With the new framework, the accuracy of length predictions improved remarkably. This means users are less likely to receive text that goes off on a tangent or becomes overly verbose.

The framework enhances the model's ability to understand the general idea of length control without requiring the model to memorize exact numbers from its training. This gives it a more natural approach to generating text.

What Makes It Special

One of the key attributes of this framework is its simplicity. By integrating special tokens into the training dataset, it allows models to learn about length control without needing a complete overhaul. This means that language models that are already trained can still benefit from this new approach.

In a way, it’s like adding a simple add-on to a classic car. The car remains the same on the outside, but it gets a few modern features that enhance performance without changing its core identity.

Versatility Across Models

The framework has shown versatility and adaptability. It works with various types of language models, regardless of their specific architectures. Whether one uses rotary positional embedding or learned embeddings, the framework can still assist in regulating output length effectively.

This means that many different organizations and developers can adopt this technology without needing to make major changes to their existing models. It's as if a new tool was introduced to a workshop, compatible with many tools already on the shelf.

The Road Ahead

As language models continue to evolve, the ability to control output length will only become more relevant. As we see more applications in storytelling, customer service, content generation, and more, having a reliable way to manage output will be essential for ensuring user satisfaction.

Furthermore, advancements in this field could inspire further innovations in how models learn and adapt to user needs. For instance, researchers might explore ways to allow users to personalize output length preferences, tailoring responses according to individual tastes.

Conclusion

In conclusion, controlling the length of output in language models is a significant stride towards improving the overall user experience. The introduction of this framework offers a promising solution that maintains high quality while providing accurate length predictions.

As technology moves forward, users can expect more refined interactions with language models that understand not only what to say but also how much to say. With this newfound ability, our digital assistants might finally learn that sometimes, less truly is more.

Original Source

Title: Hansel: Output Length Controlling Framework for Large Language Models

Abstract: Despite the great success of large language models (LLMs), efficiently controlling the length of the output sequence still remains a challenge. In this paper, we propose Hansel, an efficient framework for length control in LLMs without affecting its generation ability. Hansel utilizes periodically outputted hidden special tokens to keep track of the remaining target length of the output sequence. Together with techniques to avoid abrupt termination of the output, this seemingly simple method proved to be efficient and versatile, while not harming the coherency and fluency of the generated text. The framework can be applied to any pre-trained LLMs during the finetuning stage of the model, regardless of its original positional encoding method. We demonstrate this by finetuning four different LLMs with Hansel and show that the mean absolute error of the output sequence decreases significantly in every model and dataset compared to the prompt-based length control finetuning. Moreover, the framework showed a substantially improved ability to extrapolate to target lengths unseen during finetuning, such as long dialog responses or extremely short summaries. This indicates that the model learns the general means of length control, rather than learning to match output lengths to those seen during training.

Authors: Seoha Song, Junhyun Lee, Hyeonmok Ko

Last Update: Dec 18, 2024

Language: English

Source URL: https://arxiv.org/abs/2412.14033

Source PDF: https://arxiv.org/pdf/2412.14033

Licence: https://creativecommons.org/licenses/by/4.0/

Changes: This summary was created with assistance from AI and may have inaccuracies. For accurate information, please refer to the original source documents linked here.

Thank you to arxiv for use of its open access interoperability.

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