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Andreas Loukas

24 accepted papers

2024

Implicitly Guided Design with PropEn: Match your Data to Follow the Gradient

NeurIPS 2024poster

Across scientific domains, generating new models or optimizing existing ones while meeting specific criteria is crucial. Traditional machine learning frameworks for guided design use a generative model and a surrogate model (discriminator), requiring large datasets. However, real-world scientific ap…

2024

Protein Discovery with Discrete Walk-Jump Sampling

ICLR 2024oral

We resolve difficulties in training and sampling from a discrete generative model by learning a smoothed energy function, sampling from the smoothed data manifold with Langevin Markov chain Monte Carlo (MCMC), and projecting back to the true data manifold with one-step denoising. Our $\textit{Discre…

2023

AbDiffuser: full-atom generation of in-vitro functioning antibodies

NeurIPS 2023spotlight

We introduce AbDiffuser, an equivariant and physics-informed diffusion model for the joint generation of antibody 3D structures and sequences. AbDiffuser is built on top of a new representation of protein structure, relies on a novel architecture for aligned proteins, and utilizes strong diffusion p…

Cited by 52SourcePDFScholar
2023

Infusing Lattice Symmetry Priors in Attention Mechanisms for Sample-Efficient Abstract Geometric Reasoning

ICML 2023poster

The Abstraction and Reasoning Corpus (ARC) (Chollet, 2019) and its most recent language-complete instantiation (LARC) has been postulated as an important step towards general AI. Yet, even state-of-the-art machine learning models struggle to achieve meaningful performance on these problems, falling…

Cited by 6SourcePDFScholar
2023

Towards Understanding and Improving GFlowNet Training

ICML 2023poster

Generative flow networks (GFlowNets) are a family of algorithms that learn a generative policy to sample discrete objects $x$ with non-negative reward $R(x)$. Learning objectives guarantee the GFlowNet samples $x$ from the target distribution $p^*(x) \propto R(x)$ when loss is globally minimized ove…

2022

Neural Set Function Extensions: Learning with Discrete Functions in High Dimensions

NeurIPS 2022accept

Integrating functions on discrete domains into neural networks is key to developing their capability to reason about discrete objects. But, discrete domains are (1) not naturally amenable to gradient-based optimization, and (2) incompatible with deep learning architectures that rely on representatio…

2022

On the generalization of learning algorithms that do not converge

NeurIPS 2022accept

Generalization analyses of deep learning typically assume that the training converges to a fixed point. But, recent results indicate that in practice, the weights of deep neural networks optimized with stochastic gradient descent often oscillate indefinitely. To reduce this discrepancy between theor…

Cited by 15SourcePDFScholar
2022

SPECTRE: Spectral Conditioning Helps to Overcome the Expressivity Limits of One-shot Graph Generators

ICML 2022spotlight

We approach the graph generation problem from a spectral perspective by first generating the dominant parts of the graph Laplacian spectrum and then building a graph matching these eigenvalues and eigenvectors. Spectral conditioning allows for direct modeling of the global and local graph structure…

2021

Attention is not all you need: pure attention loses rank doubly exponentially with depth

ICML 2021oral

Attention-based architectures have become ubiquitous in machine learning. Yet, our understanding of the reasons for their effectiveness remains limited. This work proposes a new way to understand self-attention networks: we show that their output can be decomposed into a sum of smaller terms—or path…

2021

Partition and Code: learning how to compress graphs

NeurIPS 2021poster

Can we use machine learning to compress graph data? The absence of ordering in graphs poses a significant challenge to conventional compression algorithms, limiting their attainable gains as well as their ability to discover relevant patterns. On the other hand, most graph compression approaches rel…

2021

SQALER: Scaling Question Answering by Decoupling Multi-Hop and Logical Reasoning

NeurIPS 2021poster

State-of-the-art approaches to reasoning and question answering over knowledge graphs (KGs) usually scale with the number of edges and can only be applied effectively on small instance-dependent subgraphs. In this paper, we address this issue by showing that multi-hop and more complex logical reason…

Cited by 17SourcePDFScholar
2020

Building powerful and equivariant graph neural networks with structural message-passing

NeurIPS 2020poster

Message-passing has proved to be an effective way to design graph neural networks, as it is able to leverage both permutation equivariance and an inductive bias towards learning local structures in order to achieve good generalization. However, current message-passing architectures have a limited re…

2020

Erdos Goes Neural: an Unsupervised Learning Framework for Combinatorial Optimization on Graphs

NeurIPS 2020oral

Combinatorial optimization (CO) problems are notoriously challenging for neural networks, especially in the absence of labeled instances. This work proposes an unsupervised learning framework for CO problems on graphs that can provide integral solutions of certified quality. Inspired by Erdos' prob…

2020

On the Relationship between Self-Attention and Convolutional Layers

ICLR 2020poster

Recent trends of incorporating attention mechanisms in vision have led researchers to reconsider the supremacy of convolutional layers as a primary building block. Beyond helping CNNs to handle long-range dependencies, Ramachandran et al. (2019) showed that attention can completely replace convoluti…

Cited by 767SourcecodeScholar
2018

Fast Approximate Spectral Clustering for Dynamic Networks

ICML 2018oral

Spectral clustering is a widely studied problem, yet its complexity is prohibitive for dynamic graphs of even modest size. We claim that it is possible to reuse information of past cluster assignments to expedite computation. Our approach builds on a recent idea of sidestepping the main bottleneck o…

2017

Autoregressive moving average graph filters a stable distributed implementation

ICASSP 2017accepted

We present a novel implementation strategy for distributed autoregressive moving average (ARMA) graph filters. Differently from the state of the art implementation, the proposed approach has the following benefits: (i) the designed filter coefficients come with stability guarantees, (ii) the linear…

Cited by 0SourceScholar
2017

Towards stationary time-vertex signal processing

ICASSP 2017accepted

Graph-based methods for signal processing have shown promise for the analysis of data exhibiting irregular structure, such as those found in social, transportation, and sensor networks. Yet, though these systems are often dynamic, state-of-the-art methods for graph signal processing ignore the time…

Cited by 0SourceScholar