VinePPO: Accurate Credit Assignment in RL for LLM Mathematical Reasoning
Large language models (LLMs) are increasingly required to solve complex reasoning tasks, like mathematical problems, that involve multiple r… (see more)easoning steps before feedback is received. Effectively identifying and prioritizing key steps by accurately assigning credit to these intermediate steps is essential for enhancing model performance. Proximal Policy Optimization (PPO), a state-of-the-art reinforcement learning algorithm for finetuning LLMs, addresses the credit assignment problem by employing value networks to predict the expected cumulative rewards of intermediate states. In this work, we identify significant limitations with this value estimation method. To address this, we propose \methodname that leverages the flexibility of language environments to compute unbiased Monte Carlo-based estimates of the intermediate values. VinePPO consistently outperforms standard PPO, doing so more efficiently and with lower divergence from the reference model. Our findings underscore the critical importance of accurate credit assignment in LLM post-training and present a simple, yet effective solution.
VinePPO: Accurate Credit Assignment in RL for LLM Mathematical Reasoning
Large language models (LLMs) are increasingly required to solve complex reasoning tasks, like mathematical problems, that involve multiple r… (see more)easoning steps before feedback is received. Effectively identifying and prioritizing key steps by accurately assigning credit to these intermediate steps is essential for enhancing model performance. Proximal Policy Optimization (PPO), a state-of-the-art reinforcement learning algorithm for finetuning LLMs, addresses the credit assignment problem by employing value networks to predict the expected cumulative rewards of intermediate states. In this work, we identify significant limitations with this value estimation method. To address this, we propose \methodname that leverages the flexibility of language environments to compute unbiased Monte Carlo-based estimates of the intermediate values. VinePPO consistently outperforms standard PPO, doing so more efficiently and with lower divergence from the reference model. Our findings underscore the critical importance of accurate credit assignment in LLM post-training and present a simple, yet effective solution.
Visual Writing: Writing by Manipulating Visual Representations of Stories
Zixin Zhao
Fanny Chevalier
We introduce"visual writing", an approach to writing stories by manipulating visuals instead of words. Visual writing relies on editable vis… (see more)ual representations of time, entities, events, and locations to offer representations more suited to specific editing tasks. We propose a taxonomy for these representations and implement a prototype software supporting the visual writing workflow. The system allows writers to edit the story by alternating between modifying the text and manipulating visual representations to edit entities, actions, locations, and order of events. We evaluate this workflow with eight creative writers and find visual writing can help find specific passages, keep track of story elements, specify edits, and explore story variations in a way that encourages creativity.
Visual Writing: Writing by Manipulating Visual Representations of Stories
Zixin Zhao
Fanny Chevalier
We introduce "visual writing", an approach to writing stories by manipulating visuals instead of words. Visual writing relies on editable vi… (see more)sual representations of time, entities, events, and locations to offer representations more suited to specific editing tasks. We propose a taxonomy for these representations and implement a prototype software supporting the visual writing workflow. The system allows writers to edit the story by alternating between modifying the text and manipulating visual representations to edit entities, actions, locations, and order of events. We evaluate this workflow with eight creative writers and find visual writing can help find specific passages, keep track of story elements, specify edits, and explore story variations in a way that encourages creativity.
Differentiation Through Black-Box Quadratic Programming Solvers
Connor W. Magoon
Fengyu Yang
Shahar Kovalsky
Path-filtering in path-integral simulations of open quantum systems using GFlowNets
Jeremy Lackman-Mincoff
Moksh J. Jain
Nikolay Malkin
Lena Simine
Beyond FVD: Enhanced Evaluation Metrics for Video Generation Quality
Ge Ya Luo
Gian Mario Favero
Zhi Hao Luo
Alexia Jolicoeur-Martineau
The Fr\'echet Video Distance (FVD) is a widely adopted metric for evaluating video generation distribution quality. However, its effectivene… (see more)ss relies on critical assumptions. Our analysis reveals three significant limitations: (1) the non-Gaussianity of the Inflated 3D Convnet (I3D) feature space; (2) the insensitivity of I3D features to temporal distortions; (3) the impractical sample sizes required for reliable estimation. These findings undermine FVD's reliability and show that FVD falls short as a standalone metric for video generation evaluation. After extensive analysis of a wide range of metrics and backbone architectures, we propose JEDi, the JEPA Embedding Distance, based on features derived from a Joint Embedding Predictive Architecture, measured using Maximum Mean Discrepancy with polynomial kernel. Our experiments on multiple open-source datasets show clear evidence that it is a superior alternative to the widely used FVD metric, requiring only 16% of the samples to reach its steady value, while increasing alignment with human evaluation by 34%, on average.
Beyond FVD: Enhanced Evaluation Metrics for Video Generation Quality
Ge Ya Luo
Gian Favero
Zhi Hao Luo
Alexia Jolicoeur-Martineau
The Fr\'echet Video Distance (FVD) is a widely adopted metric for evaluating video generation distribution quality. However, its effectivene… (see more)ss relies on critical assumptions. Our analysis reveals three significant limitations: (1) the non-Gaussianity of the Inflated 3D Convnet (I3D) feature space; (2) the insensitivity of I3D features to temporal distortions; (3) the impractical sample sizes required for reliable estimation. These findings undermine FVD's reliability and show that FVD falls short as a standalone metric for video generation evaluation. After extensive analysis of a wide range of metrics and backbone architectures, we propose JEDi, the JEPA Embedding Distance, based on features derived from a Joint Embedding Predictive Architecture, measured using Maximum Mean Discrepancy with polynomial kernel. Our experiments on multiple open-source datasets show clear evidence that it is a superior alternative to the widely used FVD metric, requiring only 16% of the samples to reach its steady value, while increasing alignment with human evaluation by 34%, on average.
An Effective Theory of Bias Amplification
Arjun Subramonian
Samuel J. Bell
Levent Sagun
Machine learning models may capture and amplify biases present in data, leading to disparate test performance across social groups. To bette… (see more)r understand, evaluate, and mitigate these possible biases, a deeper theoretical understanding of how model design choices and data distribution properties could contribute to bias is needed. In this work, we contribute a precise analytical theory in the context of ridge regression, both with and without random projections, where the former models neural networks in a simplified regime. Our theory offers a unified and rigorous explanation of machine learning bias, providing insights into phenomena such as bias amplification and minority-group bias in various feature and parameter regimes. For example, we demonstrate that there may be an optimal regularization penalty or training time to avoid bias amplification, and there can be fundamental differences in test error between groups that do not vanish with increased parameterization. Importantly, our theoretical predictions align with several empirical observations reported in the literature. We extensively empirically validate our theory on diverse synthetic and semi-synthetic datasets.
Efficient Design-and-Control Automation with Reinforcement Learning and Adaptive Exploration
Jiajun Fan
Hongyao Tang
Michael Przystupa
Mariano Phielipp
Santiago Miret
Seeking good designs is a central goal of many important domains, such as robotics, integrated circuits (IC), medicine, and materials scienc… (see more)e. These design problems are expensive, time-consuming, and traditionally performed by human experts. Moreover, the barriers to domain knowledge make it challenging to propose a universal solution that generalizes to different design problems. In this paper, we propose a new method called Efficient Design and Stable Control (EDiSon) for automatic design and control in different design problems. The key ideas of our method are (1) interactive sequential modeling of the design and control process and (2) adaptive exploration and design replay. To decompose the difficulty of learning design and control as a whole, we leverage sequential modeling for both the design process and control process, with a design policy to generate step-by-step design proposals and a control policy to optimize the objective by operating the design. With deep reinforcement learning (RL), the policies learn to find good designs by maximizing a reward signal that evaluates the quality of designs. Furthermore, we propose an adaptive exploration and replay mechanism based on a design memory that maintains high-quality designs generated so far. By regulating between constructing a design from scratch or replaying a design from memory to refine it, EDiSon balances the trade-off between exploration and exploitation in the design space and stabilizes the learning of the control policy. In the experiments, we evaluate our method in robotic morphology design and Tetris-based design tasks. Our framework has the potential to significantly accelerate the discovery of optimized designs across diverse domains, including automated materials discovery, by improving the exploration in design space while ensuring efficiency.
Efficient Design-and-Control Automation with Reinforcement Learning and Adaptive Exploration
Jiajun Fan
Hongyao Tang
Michael Przystupa
Mariano Phielipp
Santiago Miret
Seeking good designs is a central goal of many important domains, such as robotics, integrated circuits (IC), medicine, and materials scienc… (see more)e. These design problems are expensive, time-consuming, and traditionally performed by human experts. Moreover, the barriers to domain knowledge make it challenging to propose a universal solution that generalizes to different design problems. In this paper, we propose a new method called Efficient Design and Stable Control (EDiSon) for automatic design and control in different design problems. The key ideas of our method are (1) interactive sequential modeling of the design and control process and (2) adaptive exploration and design replay. To decompose the difficulty of learning design and control as a whole, we leverage sequential modeling for both the design process and control process, with a design policy to generate step-by-step design proposals and a control policy to optimize the objective by operating the design. With deep reinforcement learning (RL), the policies learn to find good designs by maximizing a reward signal that evaluates the quality of designs. Furthermore, we propose an adaptive exploration and replay mechanism based on a design memory that maintains high-quality designs generated so far. By regulating between constructing a design from scratch or replaying a design from memory to refine it, EDiSon balances the trade-off between exploration and exploitation in the design space and stabilizes the learning of the control policy. In the experiments, we evaluate our method in robotic morphology design and Tetris-based design tasks. Our framework has the potential to significantly accelerate the discovery of optimized designs across diverse domains, including automated materials discovery, by improving the exploration in design space while ensuring efficiency.
fPLSA: Learning Semantic Structures in Document Collections Using Foundation Models
Weijia Xu
Nebojsa Jojic