Emergent Mind

Large Language Model Guided Tree-of-Thought

(2305.08291)
Published May 15, 2023 in cs.AI , cs.CL , cs.CV , cs.LG , and cs.NE

Abstract

In this paper, we introduce the Tree-of-Thought (ToT) framework, a novel approach aimed at improving the problem-solving capabilities of auto-regressive LLMs. The ToT technique is inspired by the human mind's approach for solving complex reasoning tasks through trial and error. In this process, the human mind explores the solution space through a tree-like thought process, allowing for backtracking when necessary. To implement ToT as a software system, we augment an LLM with additional modules including a prompter agent, a checker module, a memory module, and a ToT controller. In order to solve a given problem, these modules engage in a multi-round conversation with the LLM. The memory module records the conversation and state history of the problem solving process, which allows the system to backtrack to the previous steps of the thought-process and explore other directions from there. To verify the effectiveness of the proposed technique, we implemented a ToT-based solver for the Sudoku Puzzle. Experimental results show that the ToT framework can significantly increase the success rate of Sudoku puzzle solving. Our implementation of the ToT-based Sudoku solver is available on GitHub: \url{https://github.com/jieyilong/tree-of-thought-puzzle-solver}.

Strategy for Tree-of-Trees (ToT) search.

Overview

  • Theta Labs, Inc. introduces the Tree-of-Thought (ToT) framework to enhance LLMs like GPT-4 for better long-range reasoning and problem-solving through a tree-like exploration strategy.

  • The ToT framework consists of a Prompter Agent, Checker Module, Memory Module, and ToT Controller to enable iterative exploration, error correction, and logical consistency in problem-solving.

  • Applied to solving Sudoku puzzles, the ToT framework demonstrated superior performance over conventional LLM approaches by effectively employing iterative refinement and backtracking mechanisms.

  • The study acknowledges limitations in the current ToT framework and proposes future enhancements including employing neural network-based components and reinforcement learning techniques for more generalizable problem-solving capabilities.

Large Language Model Guided Tree-of-Thought for Enhanced Problem-Solving

Introduction

LLMs such as GPT-4 have showcased remarkable capabilities across diverse tasks. However, their efficacy in "long-range" reasoning, necessitating extensive planning and exploration, remains limited. Conventional auto-regressive models often struggle with complex problem-solving that requires iterative refinement and error correction. In light of these challenges, Theta Labs, Inc. introduces the Tree-of-Thought (ToT) framework. This innovative approach enhances LLMs with a "tree-like" exploration strategy, akin to human problem-solving processes, enabling iterative exploration and backtracking which considerably improves solution accuracy, particularly in "long-range" reasoning tasks.

System Architecture and Components

The ToT framework is implemented as a composite software system augmenting standard LLM operations with several key modules. Central to its architecture are:

  • Prompter Agent: Responsible for initiating and guiding the conversation with the LLM towards generating intermediary problem-solving steps.
  • Checker Module: Validates the correctness of the intermediate solutions produced by the LLM, ensuring logical consistency throughout the problem-solving process.
  • Memory Module: Maintains a record of the ongoing conversation and intermediary steps, facilitating backtracking and iterative refinement.
  • ToT Controller: Manages the overall flow of the ToT search strategy, including initiating backtracking when necessary to explore alternative solution paths or correct errors.

This modular design enables the ToT framework to effectively simulate a tree-like exploration of solution spaces, akin to human cognitive processes when approaching complex problem-solving tasks.

Problem Solving and Evaluation

The efficacy of the ToT framework is demonstrated through its application to solving Sudoku puzzles, a domain where "long-range" reasoning and iterative solution refinement are critical. Comparative assessments between the ToT-based solver and conventional LLM approaches (zero-shot, one-shot, and few-shot solvers) show a marked improvement in success rates across different puzzle sizes, underscored by:

  • A significant enhancement in solving 3x3, 4x4, and 5x5 Sudoku puzzles with success rates indicating a robust improvement, particularly in cases requiring extensive logical reasoning and iterative exploration.
  • The ability to effectively recover from incorrect solution paths through the backtracking mechanism, showcasing an advanced level of "long-range" reasoning capability not present in standard LLM operations.

Limitations and Future Directions

The current implementation of the ToT framework, while effective, faces limitations due to the reliance on rule-based components for validation and control. The adaptation of this framework to a broader spectrum of problem-solving tasks is contingent on the development of more generalizable checker modules and advanced neural network-based ToT controllers.

Further research will explore the integration of neural network-based components for more dynamic and adaptable problem-solving strategies. Additionally, the potential for employing reinforcement learning techniques, akin to the "self-play" methodologies seen in AI research, presents an exciting avenue for enabling LLMs and their augmentations to "think outside the box," inventing novel strategies beyond those found in their training corpora.

Conclusion

The Tree-of-Thought framework marks a substantial step forward in enhancing the problem-solving capabilities of LLMs. By simulating a more human-like, iterative approach to exploring solution spaces, the ToT framework significantly improves upon the existing limitations of LLMs in "long-range" reasoning tasks. Future developments in this area promise to unlock even more sophisticated cognitive capabilities, edging closer to the real-world application of artificial general intelligence in complex problem-solving domains.

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