Bridging Model-Based Optimization and Generative Modeling via Conservative Fine-Tuning of Diffusion Models

Fuente: arXiv
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Main Authors: Uehara, Masatoshi, Zhao, Yulai, Hajiramezanali, Ehsan, Scalia, Gabriele, Eraslan, Gökcen, Lal, Avantika, Levine, Sergey, Biancalani, Tommaso
Format: Preprint
Published: 2024
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author Uehara, Masatoshi
Zhao, Yulai
Hajiramezanali, Ehsan
Scalia, Gabriele
Eraslan, Gökcen
Lal, Avantika
Levine, Sergey
Biancalani, Tommaso
author_facet Uehara, Masatoshi
Zhao, Yulai
Hajiramezanali, Ehsan
Scalia, Gabriele
Eraslan, Gökcen
Lal, Avantika
Levine, Sergey
Biancalani, Tommaso
contents AI-driven design problems, such as DNA/protein sequence design, are commonly tackled from two angles: generative modeling, which efficiently captures the feasible design space (e.g., natural images or biological sequences), and model-based optimization, which utilizes reward models for extrapolation. To combine the strengths of both approaches, we adopt a hybrid method that fine-tunes cutting-edge diffusion models by optimizing reward models through RL. Although prior work has explored similar avenues, they primarily focus on scenarios where accurate reward models are accessible. In contrast, we concentrate on an offline setting where a reward model is unknown, and we must learn from static offline datasets, a common scenario in scientific domains. In offline scenarios, existing approaches tend to suffer from overoptimization, as they may be misled by the reward model in out-of-distribution regions. To address this, we introduce a conservative fine-tuning approach, BRAID, by optimizing a conservative reward model, which includes additional penalization outside of offline data distributions. Through empirical and theoretical analysis, we demonstrate the capability of our approach to outperform the best designs in offline data, leveraging the extrapolation capabilities of reward models while avoiding the generation of invalid designs through pre-trained diffusion models.
format Preprint
id arxiv_https___arxiv_org_abs_2405_19673
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Bridging Model-Based Optimization and Generative Modeling via Conservative Fine-Tuning of Diffusion Models
Uehara, Masatoshi
Zhao, Yulai
Hajiramezanali, Ehsan
Scalia, Gabriele
Eraslan, Gökcen
Lal, Avantika
Levine, Sergey
Biancalani, Tommaso
Machine Learning
Artificial Intelligence
AI-driven design problems, such as DNA/protein sequence design, are commonly tackled from two angles: generative modeling, which efficiently captures the feasible design space (e.g., natural images or biological sequences), and model-based optimization, which utilizes reward models for extrapolation. To combine the strengths of both approaches, we adopt a hybrid method that fine-tunes cutting-edge diffusion models by optimizing reward models through RL. Although prior work has explored similar avenues, they primarily focus on scenarios where accurate reward models are accessible. In contrast, we concentrate on an offline setting where a reward model is unknown, and we must learn from static offline datasets, a common scenario in scientific domains. In offline scenarios, existing approaches tend to suffer from overoptimization, as they may be misled by the reward model in out-of-distribution regions. To address this, we introduce a conservative fine-tuning approach, BRAID, by optimizing a conservative reward model, which includes additional penalization outside of offline data distributions. Through empirical and theoretical analysis, we demonstrate the capability of our approach to outperform the best designs in offline data, leveraging the extrapolation capabilities of reward models while avoiding the generation of invalid designs through pre-trained diffusion models.
title Bridging Model-Based Optimization and Generative Modeling via Conservative Fine-Tuning of Diffusion Models
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2405.19673