SFT Supervised Fine Tuning Vs. RAG And Prompt Engineering
Supervised Fine Tuning
Supervised Fine-Tuning (SFT) enables robust models to be customized for specific tasks, domains, and even subtle stylistic differences. Questions about when to utilize SFT and how it stacks up versus alternatives like RAG, in-context learning, and prompt engineering are common among developers.
This article explores the definition of SFT, when to use it, and how it stacks up against other techniques for output optimization.
What is SFT?
Large language model (LLM) development frequently starts with pre-training. The model gains general language comprehension at this stage by reading vast volumes of unlabeled material. Pre-training’s main goal is to give the model a wide range of language understanding abilities. These previously trained LLMs have performed remarkably well on a variety of activities. The performance of this pre-trained model can then be improved for downstream use cases, such summarizing financial papers, that can call for a more in-depth understanding.
Using a task-specific annotated dataset, the pre-trained model is refined to make it suitable for certain use cases. This dataset contains examples of intended outputs (like a summary) correlating to input instances (like an earnings report). The model gains knowledge of how to carry out a particular task by linking inputs with their appropriate outputs. It refer to fine-tuning using an annotated dataset as supervised fine-tuning (SFT).
The main tool for modifying the behavior of the model is its parameters, which are the numerical values that are acquired during training. There are two popular supervised fine-tuning methods, albeit the number of model parameters it update during fine-tuning can vary:
Full fine-tuning: modifies every parameter in the model. However, comprehensive fine-tuning results in greater total costs because it requires more computer resources for both tuning and serving.
Parameter-Efficient Fine-Tuning (PEFT): In order to facilitate quicker and more resource-efficient fine-tuning, a class of techniques known as Parameter-Efficient Fine-Tuning (PEFT) freezes the initial model and only modifies a small number of newly introduced extra parameters. When dealing with huge models or limited computational resources, PEFT is especially helpful.
Although both PEFT and full fine-tuning are supervised learning techniques, they differ in how much parameter updating they carry out, thus one might be better suited for your situation. An example of a PEFT technique is LoRA (Low-Rank Adaptation), which is used in Supervised fine-tuning for Gemini models on Vertex AI.
When should one use supervised fine-tuning?
If you have access to a dataset of well-annotated samples and your objective is to improve the model’s performance on a particular, well-defined task, you should think about utilizing Supervised Fine Tuning. When the task is in line with the initial pre-training data, supervised fine-tuning is very useful for effectively activating and honing the pertinent knowledge that is already contained within the pre-trained model. Here are some situations in which Supervised Fine Tuning excels:
Domain expertise: Give your model specific knowledge to make it an authority on a certain topic, such as finance, law, or medical.
Customize the format: Make your model’s output conform to particular structures or formats.
Task-specific proficiency: Fine-tune the model for certain tasks, including brief summaries.
Edge cases: Boost the model’s capacity to manage particular edge cases or unusual situations.
Behavior Control: Direct the actions of the model, including when to give succinct or thorough answers.
One of SFT’s advantages is that it can produce gains even with a small quantity of excellent training data, which often makes it a more affordable option than complete fine-tuning. Moreover, refined models are typically more user-friendly. Supervised Fine Tuning helps the model become proficient at the job, which minimizes the need for long and intricate cues during inference. This results in decreased expenses and delayed inference.
SFT is an excellent tool for consolidating prior information, but it is not a panacea. In situations where information is dynamic or ever-changing, like when real-time data is involved, it might not be the best option. Let’s go over these additional possibilities as they may be more appropriate in some situations.
LLM Supervised Fine Tuning
Supervised Fine Tuning isn’t necessarily the only or best option for adjusting an LLM’s output, despite its strength. Effective methods for changing the behavior of the model can be found in a number of other approaches, each with advantages and disadvantages.
Prompt engineering is affordable, accessible, and simple to use for controlling outputs. For managing intricate or subtle jobs, it could be less dependable and necessitates experience and trial.
Like prompt engineering, In-Context Learning (ICL) is simple to use and makes use of examples found within the prompt to direct the behavior of the LLM. ICL, sometimes known as few-shot prompting, can be affected by the prompt’s examples and the sequence in which they are given. It might also not generalize well.
In order to increase quality and accuracy, Retrieval Augmented Generation (RAG) gathers pertinent data from Google search and other sources and gives it to the LLM. A strong knowledge base is necessary for this, and the extra step increases complexity and delay.
The capacity of a language model to recognize when external systems are required to respond to a user request and provide structured function calls in order to communicate with these tools and increase their capabilities is known as function calling. It might increase complexity and delay when employed.
Where to start?
You may be asking yourself, “What’s the right path now?” It’s critical to realize that the best course of action is determined by your particular requirements, available resources, and use case goals. These methods can be combined and are not exclusive to one another. Let’s examine a framework that can direct your choice:Image Credit to Google Cloud
If you want to be sure the model can understand the subtleties of your particular domain, you can begin by investigating prompt engineering and few-shot in-context learning. Here, Gemini’s huge context box opens up a world of options. You can experiment using Retrieval Augmented Generation (RAG) and/or Supervised Fine-Tuning (SFT) after you’ve perfected your prompting technique for even more refining. A lot of the most recent methods are shown in this graphic, although generative AI is a rapidly evolving subject.
Supervised Fine-Tuning on Vertex AI with Gemini
When you have a specific objective in mind and have labeled data to assist the model, Supervised Fine-Tuning (SFT) is the best option. Supervised Fine Tuning can be combined with other methods you may already be attempting to create more effective models, which could reduce expenses and speed up response times.
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