Levels of Complexity: RAG Applications¶

This post comprehensive guide to understanding and implementing RAG applications across different levels of complexity. Whether you're a beginner eager to learn the basics or an experienced developer looking to deepen your expertise, you'll find valuable insights and practical knowledge to help you on your journey. Let's embark on this exciting exploration together and unlock the full potential of RAG applications.

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Level 1: The Basics¶

Welcome to the foundational level of RAG applications! Here, we'll start with the basics, laying the groundwork for your journey into the realm of Retrieval-Augmented Generation. This level is designed to introduce you to the core concepts and techniques essential for working with RAG models. By the end of this section, you'll have a solid understanding of how to traverse file systems for text generation, chunk and batch text for processing, and interact with embedding APIs. Let's dive in and explore the exciting capabilities of RAG applications together!

1. Recursively traverse the file system to generate text.
2. Utilize a generator for text chunking.
3. Employ a generator to batch requests and asynchronously send them to an embedding API.
4. Store data in LanceDB.
5. Implement a CLI for querying, embedding questions, yielding text chunks, and generating responses.

Processing Pipeline¶

from dataclasses import dataclass
from typing import Iterable, List
import asyncio

sem = asyncio.Semaphore(10)

class TextChunk(BaseModel):
    id: int
    text: str
    embedding: np.array
    filename: str
    uuid: str = Field(default_factory=uuid.uuid4)

def flatmap(f, items):
    for item in items:
        for subitem in f(item):
            yield subitem

def get_texts():
    for file in files:
        yield TextChunk(
            text=file.read(),
            embedding=None,
            filename=file.name
        )

def chunk_text(items:Iterable[TextChunk], window_size: int, overlap: int=0):
    for i in range(0, len(items), window_size-overlap):
        yield TextChunk(
            text = items[i:i+window_size],
            embedding = None,
            filename = items[i].filename
        )

def batched(iterable, n=1):
    l = len(iterable)
    for ndx in range(0, l, n):
        yield iterable[ndx:min(ndx + n, l)]

def embed_batch(chunks: List[TextChunk]) -> List[TextChunk]:
    texts = [chunk.text for chunk in chunks]
    resp = embedding_api( # this is just the openai call
        texts=texts
    )
    for chunk, embedding in zip(chunks, resp):
        chunk.embedding = embedding
        yield chunks

def save_batch(chunks: List[TextChunk]):
    for chunk in chunks:
        db.insert(chunk)

if __name__ == "__main__":
    # This is the CLI
    texts = get_texts()
    chunks = flatmap(chunk_text, texts)
    batched_chunks = batched(chunks, 10)
    for chunks in tqdm(batched_chunks):
        chunk_with_embedding = embed_batch(chunks)
        save_batch(chunk_with_embedding)

Search Pipeline¶

def search(question: str) -> List[TextChunk]:
    embeddings = embedding_api(texts=[question])
    results = db.search(question)
    return results

if __name__ == "__main__":
    question = input("Ask a question: ")
    results = search(question)
    for chunk in results:
        print(chunk.text)

Answer Pipeline¶

def answer(question: str, results: List[TextChunk]) -> str:
    return client.chat.completions.create(
        model="gpt-3.5-turbo",
        stream=False,
        messages=[
            {"role": "system", "content": "You are a helpful assistant."},
            {"role": "user", "content": prompt(question, results)}
        ]
    )

if __name__ == "__main__":
    question = input("Ask a question: ")
    results = search(question)
    response = answer(question, results)
    for chunk in response:
        print(chunk.text, end="")

Level 2: More Structured Processing¶

Here we delve deeper into the world of Retrieval-Augmented Generation (RAG) applications. This level is designed for those who have grasped the basics and are ready to explore more advanced techniques and optimizations. Here, we focus on enhancing the efficiency and effectiveness of our RAG applications through better asynchronous programming, improved chunking strategies, and robust retry mechanisms in processing pipelines.

In the search pipeline, we introduce sophisticated methods such as better ranking algorithms, query expansion and rewriting, and executing parallel queries to elevate the quality and relevance of search results.

Furthermore, the answering pipeline is refined to provide more structured and informative responses, including citing specific text chunks and employing a streaming response model for better interaction.

Processing¶

1. Better Asyncio
2. Better Chunking
3. Better Retries

Search¶

1. Better Ranking (Cohere)
2. Query Expansion / Rewriting
3. Parallel Queries

class SearchQuery(BaseModel):
    semantic_search: str

def extract_query(question: str) -> Iterable[SearchQuery]:
    return client.completions.create(
        model="gpt-3.5-turbo",
        messages=[
            {
                "role": "system",
                "content": "Extract a query"
            },
            {
                "role": "user",
                "content": question
            }
        ],
        response_model=Iterable[SearchQuery]
    )

def search(search: Iterable[SearchQuery]) -> List[TextChunk]:
    with LanceDB() as db:
        results = db.search(search)
        return results


def rerank(question: str, results: List[TextChunk]) -> List[TextChunk]:
    return cohere_api(
        question=question,
        texts=[chunk.text for chunk in results]
    )

if __name__ == "__main__":
    question = input("Ask a question: ")
    search_query = extract_query(question)
    results = search(search_query)
    ranked_results = rerank(question, results)
    for chunk in ranked_results:
        print(chunk.text)

Answering¶

1. Citating specific text chunks
2. Streaming Response Model for better structure.

class MultiPartResponse(BaseModel):
    response: str
    followups: List[str]
    sources: List[int]

def answer(question: str, results: List[TextChunk]) -> Iterable[MultiPartResponse]:
    return client.chat.completions.create(
        model="gpt-3.5-turbo",
        stream=True,
        response_model=instructor.Partial[MultiPartResponse]
        messages=[
            {"role": "system", "content": "You are a helpful assistant."},
            {"role": "user", "content": prompt(question, results)}
        ]
    )

if __name__ == "__main__":
    from rich.console import Console

    question = input("Ask a question: ")

    search_query = extract_query(question)
    results = search(search_query)
    results = rerank(question, results)
    response = answer(question, results)

    console = Console()
    for chunk in response:
        console.clear()
        console.print(chunk.dump_model_json())

Level 3: Observability¶

At Level 3, the focus shifts towards the critical practice of observability. This stage emphasizes the importance of implementing comprehensive logging mechanisms to monitor and measure the multifaceted performance of your application. Establishing robust observability allows you to swiftly pinpoint and address any bottlenecks or issues, ensuring optimal functionality. Below, we outline several key types of logs that are instrumental in achieving this goal.

Expanding on Wide Event Tracking¶

Wide event tracking

• Do it wide

Log how the queries are being rewritten¶

1. When addressing a complaint we should quickly understand if the query was written correctly

example: once we found that for queries with "latest" the dates it was selecting was literally the current date, we were able to quickly fix the issue by including few shot examples that consider latest to be 1 week or more.

1. Training a model

We can also use all the positive examples to figure out how to train a model that does query expansion better.

Log the citations¶

By logging the citations, we can quickly understand if the model is citing the correct information, what text chunks are popular, review and understand if the model is citing the correct information. and also potentially build a model in the future that can understand what text chunks are more important.

There's a couple ways you can do this. For example, when you cite something, you can include not only what was shown to the language model, but also what was cited. If something was shown as a language model but was not cited, we can include this as part of the dataset.

Log mean cosine scores and reranker scores¶

By attaching this little metadata, we will be able to very cheaply identify queries that may be performing poorly.

Here you might see "oh clearly i can't answer questions about file modification" thats not even in my index.

Log user level metadata for the search¶

By including other group information information, we can quickly identify if a certain group is having a bad experience

Examples could be

1. Organization ID
2. User ID
3. User Role
4. Signup Date
5. Device Type
6. Geo Location
7. Language

This could help you understand a lot of different things about how your application is being used. Maybe people on a different device are asking shorter queries and they are performing poorly. Or maybe when a new organization signed up, the types of questions they were asking were being served poorly by the language model. In the future we'll talk about other metrics, but just by implementing the mean cosine score and the free ranker score, you get these things for free without any additional work.

Just by building up some simple dashboards that are grouped by these attributes and look at the average scores, you can learn a lot. My recommendation is to review these things during stand-up once a week, look at some examples, and figure out what we could do to improve our system. When we see poor scores, we can look at the query and the rewritten query and try to understand what exactly is going on.

Have Users¶

By this point you should definitely be having users. You've already set yourself for success by understanding queries, rewriting them, and monitoring how users are actually using your system. The next couple of steps will be around improving specific metrics and also different ways of doing that.

Level 4: Evaluations¶

Evaluations at this stage are crucial for understanding the performance and effectiveness of our systems. Primarily, we are dealing with two distinct systems: the search system and the question answering (QA) system. It's common to see a lot of focus on evaluating the QA system, given its direct interaction with the end-user's queries. However, it's equally important to not overlook the search system. The search system acts as the backbone, fetching relevant information upon which the QA system builds its answers. A comprehensive evaluation strategy should include both systems, assessing them individually and how well they integrate and complement each other in providing accurate, relevant answers to the user's queries.

Evaluating the Search System¶

The aim here is to enhance our focus on key metrics such as precision and recall at various levels (K). With the comprehensive logging of all citation data, we have a solid foundation to employ a language model for an in-depth evaluation of the search system's efficacy.

For instances where the dataset might be limited, turning to synthetic data is a practical approach. This method involves selecting random text chunks or documents and then prompting a language model to generate questions that these texts could answer. This process is crucial for verifying the search system's ability to accurately identify and retrieve the text chunks responsible for generating these questions.

def test():
    text_chunk = sample_text_chunk()
    questions = ask_ai(f"generate questions that could be ansered by {text_chunk.text}")
    for question in questions:
        search_results = search(question)

    return {
        "recall@5": (1 if text_chunk in search_results[:5] else 0),
        ...
    }

average_recall = sum(test() for _ in range(n)) / n

Your code shouldn't actually look like this, but this generally captures the idea that we can synthetically generate questions and use them as part of our evaluation. You can try to be creative. But ultimately it will be a function of how well you can actually write a generation prompt.

Evaluating the Answering System¶

This is a lot trickier, but often times people will use a framework like, I guess, to evaluate the questions. Here I recommend spending some more time building out a data set that actually has answers.

def test():
    text_chunk = sample_text_chunks(n=...)
    question, answer = ask_ai(f"generate questions and answers for {text_chunk.text}")

    ai_answer = rag_app(question)
    return ask_ai(f"for the question {question} is the answer {ai_answer} correct given that {answer} is the correct answer?")

Evaluating the Answering System: Feedback¶

It's also good to build in feedback mechanisms in order to get better scores. I recommend building a thumbs up, thumbs down rating system rather than a five star rating system. I won't go into details right now, but this is something I strongly recommend.

The purpose of synethic data¶

The purpose of synthetic data is to help you quickly get some metrics out. It will help you build out this evaluation pipeline in hopes that as you get more users and more real questions, you'll be able to understand where we're performing well and where we're performing poorly using the suite of tests that we have. Precision, recall, mean ranking scores, etc.

Level 5: Understanding Short comings¶

At this point you should be able to have a data set that is extremely diverse using both the synthetic data and production data. We should also have a suite of scores that we can use to evaluate the quality of our answers.

Now we can do a bunch of different things to understand how we're doing by doing exploratory data analysis. We can look at the mean ranking score and reranker score and see if there are any patterns. We can look at the citations and see if there are any patterns. We can look at the user feedback and see if there are any patterns. We can look at the sources and see if there are any patterns. We can look at the queries and see if there are any patterns.

Clustering Queries¶

We can use clustering to understand if there are any patterns in the queries. We can use clustering to understand if there are any patterns in the citations. We can use clustering to understand if there are any patterns in the sources. We can use clustering to understand if there are any patterns in the user feedback.

We'll go into more depth later, but the general idea is we can also introduce cluster topics. I find that there's usually two different kinds of clutches that we detect.

1. Topics
2. Capabilities

Topics are captured by the nature of the text chunks and the queries. Capabilities are captured by the nature of the sources or additional metadata that we have.

Capabilites could be more like:

1. Questions that ask about document metadata "who modified the file last"
2. Quyestions that require summarzation of a document "what are the main points of this document"
3. Questions that required timeline information "what happened in the last 3 months"
4. Questions that compare and contrast "what are the differences between these two documents"

There are all things you'll likely find as you cluster and explore the datasets.

Upcoming Topics¶

As we continue to explore the depths of RAG applications, the following areas will be addressed in subsequent levels, each designed to enhance the complexity and functionality of your RAG systems:

Level 6: Advanced Data Handling¶

• Finding Segments and Routing: Techniques for identifying and directing data segments efficiently.
• Processing Tables: Strategies for interpreting and manipulating tabular data.
• Processing Images: Methods for incorporating image data into RAG applications.

Level 7: Query Enhancement¶

• Building Up Timeline Queries: Crafting queries that span across different timeframes for dynamic data analysis.
• Adding Additional Metadata: Leveraging metadata to enrich query context and improve response accuracy.

Level 8: Summarization Techniques¶

• Summarization and Summary Indices: Developing concise summaries from extensive datasets to aid quick insights.

Level 9: Outcome Modeling¶

• Modeling Business Outcomes: Applying RAG techniques to predict and model business outcomes, facilitating strategic decision-making.