Emergent Mind

Mastering Diverse Domains through World Models

(2301.04104)
Published Jan 10, 2023 in cs.AI , cs.LG , and stat.ML

Abstract

Developing a general algorithm that learns to solve tasks across a wide range of applications has been a fundamental challenge in artificial intelligence. Although current reinforcement learning algorithms can be readily applied to tasks similar to what they have been developed for, configuring them for new application domains requires significant human expertise and experimentation. We present DreamerV3, a general algorithm that outperforms specialized methods across over 150 diverse tasks, with a single configuration. Dreamer learns a model of the environment and improves its behavior by imagining future scenarios. Robustness techniques based on normalization, balancing, and transformations enable stable learning across domains. Applied out of the box, Dreamer is the first algorithm to collect diamonds in Minecraft from scratch without human data or curricula. This achievement has been posed as a significant challenge in artificial intelligence that requires exploring farsighted strategies from pixels and sparse rewards in an open world. Our work allows solving challenging control problems without extensive experimentation, making reinforcement learning broadly applicable.

Overview

  • DreamerV3 is an advanced RL algorithm designed for generalization across diverse tasks with consistent hyperparameters.

  • The algorithm uses sophisticated neural network-based world models to improve learning from simulated experiences and future outcomes.

  • DreamerV3 demonstrated exceptional performance in the game Minecraft, achieving the notable goal of collecting diamonds without human data.

  • The paper outlines four major contributions of DreamerV3, including versatility, scalability, superior performance, and technological advancements like the symlog function.

  • While successful, there are limitations to DreamerV3's capabilities, indicating the potential for further refinement and research in complex multi-task learning.

Introduction to DreamerV3

Reinforcement learning (RL) has been the driving force behind many AI advancements, enabling computers to autonomously learn complex tasks through interactions with their environment. Leading successes include surpassing human performance in board games like Go and complex video games such as Dota. However, a major obstacle within this field is the capacity of algorithms to generalize - to successfully apply learnt knowledge to novel and varied tasks without extensive tuning. This hurdle becomes pronounced as we transition from simpler applications to more complex, practical settings.

Mastering Diverse Tasks with DreamerV3

Addressing the challenge of generalization in RL, the paper introduces DreamerV3, an RL algorithm that achieves superior performance across a broad spectrum of tasks while maintaining a consistent set of hyperparameters. DreamerV3 employs 'world models' – sophisticated neural networks trained on experiences simulated within an internal model of the world. These world models allow the algorithm to learn from not just past experiences but also imagined future outcomes. DreamerV3 distinguishes itself by scaling effectively with model size, meaning that larger, more powerful models directly improve performance and efficiency, a property not often observed in RL algorithms.

Groundbreaking Results in Minecraft

A standout achievement of DreamerV3 is its performance in Minecraft, a highly intricate and popular video game that has become a benchmark for AI research. DreamerV3, without human data or custom-designed curricula, is the first algorithm of its kind to collect diamonds in Minecraft - an accomplishment that denotes a significant milestone in the AI community. This success underscores the algorithm's ability to handle sparse rewards, need for deep exploration, and the game's open-world nature, all of which mimic real-world challenges.

Contributions and Technological Advancements

The paper underscores four pivotal contributions of DreamerV3:

  1. Introduction of a versatile algorithm capable of mastering various tasks without the need for hyperparameter tuning.
  2. Evidence showing that as DreamerV3's model size increases, so do its performance and data efficiency – monotonically.
  3. Extensive evaluation that establishes DreamerV3 outperforming specialized algorithms across a versatile range of domains.
  4. The revolutionary achievement of collecting diamonds in Minecraft, purely through RL, signifying an important advancement in artificial intelligence.

Technologically, DreamerV3 is underpinned by a trio of neural networks that include the critically important world model, along with the critic and actor components. It accommodates different domains with robust learning objectives, adopting the 'symlog' function to manage quantities across unknown magnitudes effectively. By avoiding the pitfalls of previous models that required crafting domain-specific solutions, DreamerV3 stands as a testimony to the scalability and adaptability of RL algorithms.

Looking Ahead

Despite its success, the researchers acknowledge the limitations of DreamerV3. Its ability to sometimes, but not always, collect diamonds within Minecraft signifies the need for ongoing refinement. Additionally, its dependency on a faster block breaking speed highlights the importance of developing inductive biases for a more natural policy learning.

Concluding, the work on DreamerV3 opens new horizons for applying RL to complex decision-making problems. Further research at larger scales and efforts to enable multi-task across overlapped domains pose promising avenues, buoyed by DreamerV3's establishment as a robust, scalable, and general algorithm in the advancement of AI.

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