namin / llm-verified-with-monte-carlo-tree-search

LLM verified with Monte Carlo Tree Search
https://arxiv.org/abs/2402.08147
MIT License
215 stars 26 forks source link

this is cool, thanks. #2

Closed russellballestrini closed 8 months ago

russellballestrini commented 8 months ago

fxhp:

explain monte carlo tree and how it could be used to verify program code that LLMs generate gpt-4

gpt-4-1106-preview:

It seems like there might be a bit of confusion in the question, so let's clarify the concepts and then discuss how they could be related.

Monte Carlo Tree Search (MCTS): Monte Carlo Tree Search is an algorithm used for making decisions in some types of artificial intelligence applications, most notably in games like Go or Chess. The algorithm performs very well in problems with a large search space and is used to find optimal decisions by performing random simulations of the possible outcomes.

The process involves four steps:

Selection: Starting from the root node, the algorithm selects successive child nodes until a leaf node with unexplored children is reached.
Expansion: One or more child nodes are added to expand the tree, depending on the available actions.
Simulation: A simulation is run from the new nodes to a terminal state using a random playout policy.
Backpropagation: The results of the simulation are used to update the information in the nodes along the path from the selected node to the root.

Verification of Program Code Generated by LLMs (like GPT-4): Large Language Models (LLMs) like GPT-4 can generate program code based on the prompts they receive. However, the correctness and reliability of this code need to be verified. Verification typically involves testing the code to ensure it behaves as expected, reviewing the code for potential errors, and sometimes formally verifying the logic of the code.

Using MCTS to Verify Program Code: While MCTS is not a standard method for verifying program code, it could theoretically be adapted for this purpose in a creative way. Here's a speculative approach:

Modeling the Code as a Decision Tree: Treat each branch or decision point in the code as a node in a decision tree. The root node represents the start of the program, and leaf nodes represent different possible outcomes or states the program could end in.

Selection and Expansion: Use MCTS to traverse this decision tree, selecting paths based on some heuristic that estimates the likelihood of bugs or errors.

Simulation: Instead of random playouts, run simulations that represent test cases or input scenarios to see how the code behaves. This could involve using a variety of inputs to test different branches and functions within the code.

Backpropagation: Use the results of these simulations to update the nodes with information about the code's reliability. Nodes that lead to successful outcomes would be strengthened, while those that lead to errors or failures would be noted for further investigation.

Iterative Improvement: By iterating this process, you could potentially identify parts of the code that are more likely to contain errors and require further testing or review.

It's important to note that this is a highly theoretical application of MCTS and not a standard practice in software engineering. Traditional methods of code verification, such as unit testing, integration testing, code reviews, and static analysis, are the prevalent and proven methods for verifying program code. MCTS would likely be inefficient for this purpose compared to these established methods, but exploring such novel applications could be an interesting area for academic research.


fxhp:

gpt-4

LLM verified with Monte Carlo Tree Search

This prototype synthesizes verified code with an LLM.

Using Monte Carlo Tree Search (MCTS), it explores the space of possible generation of a verified program, and it checks at every step that it's on the right track by calling the verifier.

This prototype uses Dafny.

Logs for example runs can be found in the log directory. Scroll to the very end of a log to see a chosen solution. Note that the linked solution is optimal for the problem.

By using this technique, weaker models that might not even know the generated language all that well can compete with stronger models.

We can also reinforce the snippets that succeed positively and that fail negatively through PPO training. The model after PPO can solve the prompts without backtracking! For example, the log for solving the problem fact after PPO training on another problem, opt0. Running

This project relies on GPU access. It has been tested on a multi-GPU machine with two NVIDIA A100s. Setup

Using mamba or equivalently conda:

mamba create --name llm-verified python=3.10 mamba activate llm-verified pip install -r requirements.txt

Execution

Pick an LLM in model.py and a prompt in prompts.py, then:

python run.py

For the PPO trainer (slow!), do:

python run_ppo.py

TODOs

Support other verifiers in addition to Dafny:
    Coq
Support other LLM infrastructures in addition to Hugging Face:
    Ollama
Support test cases.
Design a steerable interaction to give human or tool feedback to the LLM.
Design a reinforcement learning scheme, whereas the LLM learns from trial.
    Evaluate whether the model after PPO suffers degradation for some tasks, even unrelated.
    Force the PPO solution to converge to an optimal known one, using it entirely for training rather than discovery.
Get wandb to work.

Credits

The montecarlo library is adapted from ImparaAI/monte-carlo-tree-search.
The inspiration comes from Planning with Large Language Models for Code Generation (ICLR 2023).

gpt-4-1106-preview:

The text you've provided outlines a project that integrates Large Language Models (LLMs) with Monte Carlo Tree Search (MCTS) to synthesize and verify code. Here's a breakdown of the key points and how the system works:

Purpose: The system aims to generate verified program code using an LLM, which is then checked for correctness at each step of the generation process using MCTS and a verifier.

Verifier: The prototype uses Dafny, a programming language with built-in support for formal verification. Dafny can mathematically prove the correctness of the code against its specification.

Logs: The system keeps logs of its runs, and the end of each log contains the chosen solution, which is stated to be optimal for the given problem.

Advantages: This approach allows even weaker LLMs, which may not be as proficient in the target programming language, to generate high-quality code by using MCTS to guide the generation process.

Reinforcement Learning: The system uses Proximal Policy Optimization (PPO) to train the model. Successful code snippets are reinforced positively, while failures are reinforced negatively. After PPO training, the model is expected to solve prompts without needing to backtrack.

Hardware Requirements: The project requires GPU access and has been tested on a machine with two NVIDIA A100 GPUs.

Setup and Execution: The setup involves creating a Python environment and installing dependencies. The execution involves running scripts to generate code with the LLM and to train the model with PPO.

TODOs: The project has a list of future improvements, such as supporting additional verifiers like Coq, integrating with other LLM infrastructures, adding test case support, designing interactive feedback mechanisms, and refining the reinforcement learning scheme.

Credits: The project credits include the adaptation of a Monte Carlo library and inspiration from a paper presented at ICLR 2023.

This project represents an innovative approach to code generation and verification, combining the strengths of LLMs in understanding and generating code with the systematic exploration capabilities of MCTS and the formal verification power of tools like Dafny. The use of reinforcement learning through PPO training further enhances the model's ability to learn from its successes and failures, potentially leading to more robust code generation without human intervention.


fxhp:

gpt-4 does the dafny code translate to other programming languages?

gpt-4-1106-preview:

Dafny is a programming language designed to support the formal verification of code. It allows developers to write programs and prove properties about them, such as correctness with respect to a specification. Dafny itself is not intended to be a general-purpose programming language for building software systems; rather, it's a language for proving the correctness of algorithms.

However, Dafny does have the capability to compile its code into other programming languages. As of my last update, Dafny can generate C#, Java, and JavaScript code, among others. This means that you can write and verify your algorithms in Dafny and then compile them into one of these languages to integrate with other systems or to deploy them in a typical runtime environment.

The translation from Dafny to other languages aims to preserve the logical structure and correctness of the verified Dafny code. However, the formal verification guarantees provided by Dafny do not automatically transfer to the generated code. The target language's compiler and runtime system could introduce errors that were not present in the Dafny source code. Therefore, while the Dafny code can be translated into other languages, it is important to maintain a rigorous testing regime for the translated code, especially if the target language or its environment has different semantics that could affect the program's behavior.


fxhp:

gpt-4 can dafny generate python?

gpt-4-1106-preview:

As of my last update, Dafny does not natively support generating Python code directly. Dafny primarily targets C# and Java for code generation, as well as JavaScript and Go to some extent. The focus of Dafny is on formal verification, and the languages it supports for code generation are chosen to align with environments where formal verification is most commonly applied.

However, it is theoretically possible to create a transpiler that takes Dafny-generated C# (or another supported language) and converts it to Python, but this would be an additional layer of complexity and could introduce translation errors. Moreover, such a transpiler would not be able to guarantee that the Python code maintains the same formal guarantees as the original Dafny code, due to differences in language semantics and runtime behavior.

For those looking to integrate Dafny-verified logic into a Python codebase, a more practical approach might be to interface with the generated C# code from Python, using techniques such as inter-process communication or creating a C# library that can be called from Python using a foreign function interface like Python's ctypes or cffi.


fxhp:

gpt-4 can you guess how fast or slow this process is depending on the prompt given? does the monte carlo tree search loop many times?

fxhp (gpt-4-1106-preview):

The speed and efficiency of the process described, which involves using Monte Carlo Tree Search (MCTS) to guide the generation of verified code by a Large Language Model (LLM), can vary significantly depending on several factors:

Complexity of the Prompt: Simpler prompts that require less complex code generation will generally result in faster completion times. Complex prompts that require the generation of intricate algorithms or data structures will take longer, as more potential paths need to be explored and verified.

Depth and Breadth of the Search Tree: The number of possible code paths (branches) and the depth of the tree (how many steps are needed to reach a solution) will affect the number of iterations MCTS needs to perform. A larger search space will result in more iterations and a longer search time.

Performance of the Verifier: The speed at which the verifier (e.g., Dafny) can verify the generated code snippets will also impact the overall process. If verification is slow, it will bottleneck the MCTS loop.

Quality of the LLM: A more capable LLM might generate more accurate code snippets on the first try, reducing the number of MCTS iterations needed. Conversely, a weaker LLM might require more iterations to find a correct solution.

Efficiency of the MCTS Implementation: The specific implementation of MCTS, including how well it's optimized and how it balances exploration versus exploitation, will influence the number of iterations and the time taken.

Computational Resources: The availability of computational resources, especially GPU power for both the LLM and the MCTS process, will affect the speed of the process. More powerful hardware can perform more iterations in less time.

Reinforcement Learning: If the system uses reinforcement learning (like PPO) to improve the LLM, the initial training will take additional time. However, once trained, the LLM may generate correct code more quickly, reducing the number of MCTS iterations needed.

In general, MCTS can loop many times, especially for complex problems. Each iteration involves selecting a path through the tree, expanding the tree with new nodes, simulating the outcome of those nodes, and then backpropagating the results. The number of iterations can range from a few to many thousands, depending on the complexity of the problem and the factors mentioned above.

Without specific details about the prompt, the LLM, and the MCTS implementation, it's difficult to provide a precise estimate of the speed of the process. However, it's safe to say that for non-trivial problems, the process could be quite computationally intensive and time-consuming.


fxhp:

gpt-4 could you provide a dafny hello world and fizzbuzz?

fxhp (gpt-4-1106-preview):

Certainly! Below are examples of a "Hello, World!" program and a FizzBuzz implementation in Dafny.

Hello, World! in Dafny:

method Main() { print "Hello, World!\n"; }

In Dafny, the print statement is used to output text to the console. The Main method is the entry point of the program, similar to many other programming languages.

FizzBuzz in Dafny:


method FizzBuzz(n: nat) {
    var i: nat := 1;
    while i <= n
        invariant 1 <= i <= n+1
    {
        if i % 15 == 0 {
            print "FizzBuzz\n";
        } else if i % 3 == 0 {
            print "Fizz\n";
        } else if i % 5 == 0 {
            print "Buzz\n";
        } else {
            print i, "\n";
        }
        i := i + 1;
    }
}

method Main() {
    FizzBuzz(100);
}

In this FizzBuzz implementation, we define a method FizzBuzz that takes a natural number n and prints the numbers from 1 to n. For multiples of 3, it prints "Fizz"; for multiples of 5, it prints "Buzz"; and for multiples of both 3 and 5, it prints "FizzBuzz". For all other numbers, it prints the number itself.

The Main method calls FizzBuzz with 100 as an argument to demonstrate the function.

Please note that Dafny is primarily used for formal verification, and these examples do not include any verification properties or proofs. In a typical Dafny program, you would also specify preconditions, postconditions, and invariants to formally verify the correctness of the code.


fxhp:

gpt-4 oh given that code, it seems like I can read dafny for the most part. the while look is different and the variable types such as nat which I guess is natural number?

fxhp (gpt-4-1106-preview):

Yes, you're correct. Dafny's syntax is designed to be readable and familiar to those who have experience with C-like programming languages, although it includes additional constructs for formal verification.

The nat type in Dafny stands for "natural number," which includes all non-negative integers (0, 1, 2, ...). This is different from many programming languages that don't have a distinct type for natural numbers and instead use general integer types that include negative values.

The while loop in Dafny can look a bit different because it often includes an invariant clause. Invariants are conditions that must hold true before and after each iteration of the loop, and they are used to prove properties about the loop for verification purposes. Here's a breakdown of the loop structure:

while i <= n // Loop condition
    invariant 1 <= i <= n+1 // Loop invariant
{
    // Loop body
}

The invariant clause in this example states that i will always be between 1 and n+1 during the execution of the loop. This is a simple invariant, but in more complex algorithms, invariants can be crucial for proving that the loop behaves correctly.

Understanding these additional verification constructs is key to writing and verifying code in Dafny.