DSPy programming LMs

DSPy programming LMs.md

DSPy is the framework for programming—rather than prompting—language models. It allows you to iterate fast on building modular AI systems and offers algorithms for optimizing their prompts and weights, whether you're building simple classifiers, sophisticated RAG pipelines, or Agent loops.

DSPy stands for Declarative Self-improving Python. Instead of brittle prompts, you write compositional Python code and use DSPy to teach your LM to deliver high-quality outputs.

This lecture excerpt by Omar Khattab introduces Compound AI Systems, a modular approach to building AI systems using Large Language Models (LLMs) as components. The presentation highlights the limitations of monolithic LLMs, emphasizing the advantages of Compound AI Systems in terms of improved reliability, controllability, transparency, and efficiency. Khattab then details DSPy, a framework for creating these modular systems by expressing them as programs with natural-language-typed modules, and discusses methods for optimizing these programs, including instruction and demonstration optimization techniques. Finally, the presentation showcases experimental results and concludes that modularity, rather than simply larger LLMs, is key to advancing AI.

DSPy is superior to traditional prompting engineering for several reasons. Traditional prompting engineering is based on monolithic language models where users input a prompt into a language model as a black box and hope that the system outputs the desired response. DSPy on the other hand uses a modular approach where language models act as components that specialize in particular roles within a larger program. This modular approach has several advantages over traditional prompting methods. Here is a list of those advantages:

• Quality: DSPy offers a more reliable composition of better-scoped language model capabilities. By breaking down a task into smaller modules, language models can focus on specific aspects of the task, leading to improved overall performance. For example, in a multi-hop retrieval-augmented generation task, one module could focus on generating search queries, while another focuses on synthesizing information from retrieved contexts.
• Control: DSPy allows for iterative improvements and grounding through external tools. Developers have greater control over the system's architecture, enabling faster iteration and the ability to build systems that individual language models cannot achieve. For instance, a developer could add a fact-checking module to a pipeline, enhancing the system's reliability without needing to retrain the entire model.
• Transparency: DSPy provides debugging capabilities and user-facing attribution. By inspecting the trace of system behavior, developers can understand why a system generated specific information, facilitating debugging and improvement. If a system makes a mistake, it's easier to pinpoint the source of the error and rectify it.
• Efficiency: DSPy enables the use of smaller language models by offloading knowledge and control flow. Instead of requiring a monolithic language model to possess knowledge on all topics, DSPy distributes the workload across specialized modules. This leads to more efficient systems, as smaller, more focused language models can be used effectively.
• Inference-Time Scaling: DSPy enables systematic searches for better outputs at inference time. By using strategies like reflection and solution ranking, DSPy can spend more compute at test time to explore various solution paths and improve performance. This is exemplified by systems like AlphaCodium, which iteratively generates, ranks, and refines code solutions.

In contrast, traditional prompting methods suffer from several limitations.

• First, they lack modularity, making it difficult to control, debug, and improve the resulting systems.
• Second, they heavily rely on trial-and-error to coax language models into desired behaviors, often leading to lengthy and non-generalizable prompts.
• Third, traditional prompts implicitly couple various roles, hindering portability across different tasks, language models, and objectives.

DSPy addresses these limitations by offering a more structured, modular, and transparent approach to building compound AI systems. By abstracting away prompting details and enabling optimization through programming paradigms, DSPy empowers developers to create more robust, efficient, and adaptable AI systems.

A canonical example that demonstrates how DSPy works is multi-hop retrieval-augmented generation (RAG). In this example, the goal is to answer a complex question that requires retrieving information from multiple sources.

Traditional approaches would input the entire question into a monolithic language model, hoping it could synthesize an answer from its internal knowledge. This method often fails because it requires the model to retain vast amounts of knowledge and understand complex reasoning patterns.

DSPy provides a more structured solution. Here's how a multi-hop RAG system is built using DSPy:

1. Define Modules: The system is broken down into smaller, manageable modules. For multi-hop RAG, two key modules are:

   • generate_query: This module takes the question and any existing context as input and outputs a search query.
   • generate_answer: This module takes the retrieved contexts and the original question as input and produces a final answer.

2. Specify Program Logic: The forward method of a DSPy module defines the program's execution flow. In this case, the forward method would:

   • Initialize an empty context list.
   • Loop for a predetermined number of hops (e.g., two).
   • In each hop, call generate_query to get a search query.
   • Retrieve relevant passages using the generated query and append them to the context.
   • Finally, call generate_answer with the accumulated context and the original question to produce the final answer.

3. Optimize the System: The initial modules, defined using natural language signatures, need to be translated into effective prompts for the underlying language model. DSPy offers various optimization strategies, such as:

   • Bootstrap Few-Shot: Automatically generate example input-output pairs for each module by executing a basic version of the program and selecting successful trajectories based on a predefined metric. These examples are then included in the prompts to guide the language model.
   • MIPRO (Multi-prompt Instruction Proposal Optimizer): Use a language model to propose candidate instructions and demonstrations for each module, leveraging information about the task, dataset, and program structure. MIPRO employs Bayesian optimization to efficiently search the space of possible combinations, evaluating their performance on a small validation set and refining the prompts iteratively.

4. Evaluate and Iterate: The optimized DSPy program is then evaluated on a test set. The modular nature of DSPy allows developers to easily modify or add modules to improve the system's performance. For example, a fact-checking module could be incorporated to verify the generated answer against retrieved sources, further enhancing the system's reliability.

In essence, DSPy transforms the problem of prompt engineering into a programming task. Developers can define a modular system, specify its behavior using natural language, and rely on optimization techniques to generate effective prompts for the language models. This approach offers greater control, transparency, and efficiency compared to traditional monolithic prompting methods.

The multi-hop RAG example highlights the benefits of DSPy: it demonstrates the decomposition of a complex task into simpler modules, the use of natural language signatures to define module behavior, and the application of optimization techniques to automatically improve prompt quality.

Building a language model-based agent system to automatically analyze compiler optimization reports and edit input code is an innovative application of language models. DSPy can significantly enhance your system's capabilities. Here's how you can apply DSPy to your current system:

1. Modularize with DSPy Modules:

Instead of relying on simple prompting, decompose your system's functionality into distinct DSPy modules:

• analyze_report Module: This module takes the compiler optimization report as input and outputs a structured analysis, identifying potential optimizations and their suggested implementations.
• apply_optimization Module: This module takes the analysis from analyze_report and the original code as input. It outputs the modified code with the suggested optimizations applied.
• validate_code Module: This module takes the optimized code as input and determines if it compiles successfully and passes all tests. It outputs a boolean value (True for success, False otherwise) and any relevant error messages.
• fix_code Module: This module takes the optimized code, the validation result from validate_code, and any error messages as input. It attempts to rectify compilation errors or test failures, outputting the revised code.

2. Define Program Logic with forward Method:

The forward method of your main DSPy module orchestrates the interaction between these modules:

• It receives the compiler optimization report and the original code as input.
• It iterates up to 10 times or until validate_code returns True.
• In each iteration:
  • Call analyze_report to analyze the report.
  • Call apply_optimization to modify the code.
  • Call validate_code to check for compilation and test success.
  • If validate_code returns False, call fix_code to attempt repairs.
• Finally, output the optimized code.

3. Optimize Modules with DSPy Techniques:

DSPy provides various optimization methods to enhance the effectiveness of your modules. Apply these techniques to improve their performance:

• Bootstrap Few-Shot: Generate example input-output pairs for each module by executing initial versions and selecting successful trajectories. Include these examples in the prompts to guide the language models.
• MIPRO: Utilize MIPRO's capabilities to propose candidate instructions and demonstrations for each module. Leverage information about the task, dataset, and program structure for better grounding.

Benefits of Applying DSPy:

By adopting DSPy, you gain several advantages:

• Modularity: Separating functionalities into modules enhances control, debugging, and improvement. You can isolate and refine individual components without affecting the entire system.
• Transparency: DSPy's structure enables tracing the execution flow and understanding each module's decisions. This improves debugging, error analysis, and overall system comprehension.
• Iterative Improvement: Modules can be individually optimized and refined, allowing for systematic improvement of the overall system's performance.
• Generalizability: DSPy promotes defining modules using natural language signatures, abstracting away specific prompting details. This enhances portability across different language models and tasks.

By transitioning your system from simple prompting to a DSPy-based framework, you unlock greater control, transparency, and optimization capabilities. This modular, structured approach leads to a more robust and efficient system for automated compiler optimization report analysis and code modification.

MIPRO, which stands for Multi-prompt Instruction Proposal Optimizer, is a sophisticated technique within the DSPy framework designed to automatically optimize the instructions and demonstrations used in language model (LM) programs. MIPRO leverages the power of LMs themselves to propose and refine these crucial components, leading to improved performance and adaptability in complex AI pipelines.

Here's a breakdown of MIPRO's key aspects and how it works:

• Goal: MIPRO aims to discover the most effective instructions and few-shot examples for each module within a DSPy program, thereby maximizing a predefined performance metric.

• Motivation: Traditionally, crafting prompts for LMs involved significant manual effort and experimentation. MIPRO automates this process, reducing the reliance on hand-crafted prompts and enabling more systematic and efficient optimization.

• Approach: MIPRO employs a three-step process:

  1. Bootstrap Task Demonstrations: MIPRO begins by generating potential demonstrations for each module. It does this by running a basic version of the program on a training set and collecting successful execution traces. These traces serve as candidate demonstrations, illustrating desirable input-output pairs for each module.

  2. Propose Instruction Candidates: MIPRO utilizes a dedicated LM program, often referred to as a "proposer LM," to generate candidate instructions for each module. This proposer LM leverages a variety of grounding techniques to generate relevant and diverse instructions. These techniques include:

     • Dataset Summaries: Analyzing the training dataset to extract key characteristics and insights.
     • Program Summaries: Examining the DSPy program's code to understand its structure and intended behavior.
     • Bootstrapped Demonstrations: Utilizing the previously generated demonstrations to infer desirable instructions.
     • External Tips and Guidelines: Incorporating predefined instructions or guidelines from existing prompting literature.

  3. Jointly Tune with Bayesian Optimization: Having generated candidate instructions and demonstrations, MIPRO employs Bayesian optimization to efficiently search for the optimal combination. This involves:

     • Constructing a Surrogate Model: A probabilistic model that predicts the performance of the DSPy program based on the chosen instructions and demonstrations.
     • Iterative Evaluation and Refinement: Evaluating a small set of candidate combinations on a validation set, updating the surrogate model based on the observed performance, and selecting the next set of candidates to evaluate based on the model's predictions.

• Key Features:

  • Automated Prompt Optimization: MIPRO automates the process of discovering effective instructions and demonstrations, relieving developers from manual prompt engineering.
  • Grounding and Contextualization: MIPRO utilizes various sources of information, including the dataset, the program's structure, and external knowledge, to generate contextually relevant instructions.
  • Efficient Search: Bayesian optimization enables MIPRO to explore the space of possible prompt configurations effectively, minimizing the number of evaluations required to find optimal solutions.

• Benefits:

  • Improved Performance: MIPRO consistently leads to significant performance gains compared to basic prompting techniques and even surpasses expert-written prompts in some cases.
  • Adaptability and Portability: By abstracting away specific prompting details, MIPRO facilitates the adaptation of DSPy programs to different LMs, tasks, and datasets.

In conclusion, MIPRO is a powerful tool within DSPy that empowers developers to create more effective and adaptable LM programs by automatically optimizing their prompt components. By leveraging LMs' abilities to understand language, code, and data, MIPRO simplifies the development process and unlocks greater performance potential in compound AI systems.