Francesco Tudisco

Publications · Keyword

Neural Networks

27 publications with this keyword.

Simplifying Transformer-Based U-Net Neural Physics Simulators

Pietro Sittoni, Francesco Tudisco

Advances in Neural Information Processing Systems (NeurIPS), 2026

U-Net-style architectures are widely adopted for modeling physical systems, as their multiscale structure enables efficient processing of high-resolution data while reflecting the hierarchical structure of many physical phenomena. The most successful U-Net-based neural physics simulators often combine convolutions, …

Low Rank Affine Adversarial Attacks on Image Classifiers

Aizhan Issagali, Catherine F. Higham, Desmond J. Higham, Francesco Tudisco

Springer INdAM Series, 2026

Neural networks for image classification are vulnerable to adversarial attacks; an imperceptible perturbation to an image can cause a change in classification. Standard attack algorithms use explicit or approximate partial derivative information with respect to the input data. Here, we explore the idea of using a less …

Neural-HSS: Hierarchical Semi-Separable Neural PDE Solver

Pietro Sittoni, Emanuele Zangrando, Angelo A. Casulli, Nicola Guglielmi, Francesco Tudisco

International Conference on Machine Learning (ICML), 2026

Deep learning-based methods have shown remarkable effectiveness in solving PDEs, largely due to their ability to enable fast simulations once trained. However, despite the availability of high-performance computing infrastructure, many critical applications remain constrained by the substantial computational costs …

Ambient Physics: Training Neural PDE Solvers with Partial Observations

Harris Abdul Majid, Giannis Daras, Francesco Tudisco, Steven McDonagh

In many scientific contexts, obtaining complete observations of PDE coefficients and solutions proves expensive, hazardous, or unfeasible. Recent diffusion-based approaches can reconstruct fields from incomplete data, yet require fully observed examples during training. We present Ambient Physics, a framework enabling …

Low-Rank Compression of Language Models via Differentiable Rank Selection

Sidhant Sundrani, Francesco Tudisco, Pasquale Minervini

Language Resources and Evaluation Conference (LREC), 2026

Approaches for compressing large-language models using low-rank decomposition have made strides, particularly with the introduction of activation and loss-aware SVD, which improves the trade-off between decomposition rank and downstream task performance. Despite these advancements, a persistent challenge …

Are we measuring oversmoothing in graph neural networks correctly?

Kaicheng Zhang, Piero Deidda, Desmond J. Higham, Francesco Tudisco

International Conference on Learning Representations (ICLR), 2026

Oversmoothing is a fundamental challenge in graph neural networks (GNNs): as the number of layers increases, node embeddings become increasingly similar, and model performance drops sharply. Traditionally, oversmoothing has been quantified using metrics that measure the similarity of neighbouring node features, such as …

Algebraformer: A Neural Approach to Linear Systems

Pietro Sittoni, Francesco Tudisco

NeurIPS Workshop on Machine Learning and the Physical Sciences, 2025

Recent work in deep learning has opened new possibilities for solving classical algorithmic tasks using end-to-end learned models. In this work, we investigate the fundamental task of solving linear systems, particularly those that are ill-conditioned. Existing numerical methods for ill-conditioned systems often …

Stuart-Landau Oscillatory Graph Neural Network

Kaicheng Zhang, David N. Reynolds, Piero Deidda, Francesco Tudisco

The Web Conference (WWW), 2026

Oscillatory Graph Neural Networks (OGNNs) are an emerging class of physics-inspired architectures designed to mitigate oversmoothing and vanishing gradient problems in deep GNNs. In this work, we introduce the Complex-Valued Stuart-Landau Graph Neural Network (SLGNN), a novel architecture grounded in Stuart-Landau …

Test-Time Accuracy-Cost Control in Neural Simulators via Recurrent-Depth

Harris Abdul Majid, Pietro Sittoni, Francesco Tudisco

International Conference on Learning Representations (ICLR), 2026

Accuracy-cost trade-offs are a fundamental aspect of scientific computing. Classical numerical methods inherently offer such a trade-off: increasing resolution, order, or precision typically yields more accurate solutions at higher computational cost. We introduce \textbf{Recurrent-Depth Simulator} (\textbf{RecurrSim}) …

Nonlinear Joint Spectral Radius

Piero Deidda, Nicola Guglielmi, Francesco Tudisco

We introduce a nonlinear extension of the joint spectral radius (JSR) for switched discrete-time dynamical systems. The classical JSR characterizes the exponential growth rate of linear switched systems, but its extension to nonlinear systems has remained an open problem. Our approach builds on the framework of …

Graph-Convolutional-Beta-VAE for Synthetic Abdominal Aortic Aneurysm Generation

Francesco Fabbri, Martino Andrea Scarpolini, Angelo Iollo, Francesco Viola, Francesco Tudisco

Medical & Biological Engineering & Computing, vol. 64, pp. 827–845, 2026

Synthetic data generation plays a crucial role in medical research by mitigating privacy concerns and enabling large-scale patient data analysis. This study presents a beta-Variational Autoencoder Graph Convolutional Neural Network framework for generating synthetic Abdominal Aorta Aneurysms (AAA). Using a small …

Approximation properties of neural ODEs

Arturo De Marinis, Davide Murari, Elena Celledoni, Nicola Guglielmi, Brynjulf Owren, Francesco Tudisco

We study the approximation properties of neural ordinary differential equations (neural ODEs) in the space of continuous functions. Since a neural ODE requires input and output dimensions to be the same, while input and output dimensions of a continuous function are generally different, we need to embed an input into …

Improving the robustness of neural ODEs with minimal weight perturbation

Arturo De Marinis, Nicola Guglielmi, Stefano Sicilia, Francesco Tudisco

We propose a method to enhance the stability of a neural ordinary differential equation (neural ODE) by reducing the maximum error growth subsequent to a perturbation of the initial value. Since the stability depends on the logarithmic norm of the Jacobian matrix associated with the neural ODE, we control the …

A Low-Rank Perspective on Oversmoothing in Graph Neural Networks

Kaicheng Zhang, Piero Deidda, Desmond J. Higham, Francesco Tudisco

AAAI Conference on Artificial Intelligence (AAAI), Workshop on Connecting Low-Rank Representations in AI, 2025

Oversmoothing is a fundamental challenge in graph neural networks (GNNs): as the number of layers increases, node embeddings become increasingly similar, and model performance drops sharply. Traditionally, oversmoothing has been quantified using metrics that measure the similarity of neighbouring node features, such as …

dEBORA: Efficient Bilevel Optimization-based low-Rank Adaptation

Emanuele Zangrando, Sara Venturini, Francesco Rinaldi, Francesco Tudisco

International Conference on Learning Representations (ICLR), 2025

Low-rank adaptation methods are a popular approach for parameter-efficient fine-tuning of large-scale neural networks. However, selecting the optimal rank for each layer remains a challenging problem that significantly affects both performance and efficiency. In this paper, we introduce a novel bilevel optimization …

GeoLoRA: Geometric integration for parameter efficient fine-tuning

Steffen Schotthöfer, Emanuele Zangrando, Gianluca Ceruti, Francesco Tudisco, Jonas Kusch

International Conference on Learning Representations (ICLR), 2025

Low-Rank Adaptation (LoRA) has become a widely used method for parameter-efficient fine-tuning of large-scale, pre-trained neural networks. However, LoRA and its extensions face several challenges, including the need for rank adaptivity, robustness, and computational efficiency during the fine-tuning process. We …

Low-Rank Adversarial PGD Attack

Dayana Savostianova, Emanuele Zangrando, Francesco Tudisco

Adversarial attacks on deep neural network models have seen rapid development and are extensively used to study the stability of these networks. Among various adversarial strategies, Projected Gradient Descent (PGD) is a widely adopted method in computer vision due to its effectiveness and quick implementation, making …

Geometry-aware training of factorized layers in tensor Tucker format

Emanuele Zangrando, Steffen Schotthöfer, Jonas Kusch, Gianluca Ceruti, Francesco Tudisco

Advances in Neural Information Processing Systems (NeurIPS), 2024

Reducing parameter redundancies in neural network architectures is crucial for achieving feasible computational and memory requirements during training and inference phases. Given its easy implementation and flexibility, one promising approach is layer factorization, which reshapes weight tensors into a matrix format …

Subhomogeneous Deep Equilibrium Models

Pietro Sittoni, Francesco Tudisco

International Conference on Machine Learning (ICML), 2024

Implicit-depth neural networks have grown as powerful alternatives to traditional networks in various applications in recent years. However, these models often lack guarantees of existence and uniqueness, raising stability, performance, and reproducibility issues. In this paper, we present a new analysis of the …

Solaris: A Foundation Model for the Sun

Harris Abdul Majid, Pietro Sittoni, Francesco Tudisco

NeurIPS Workshop on Foundation Models for Science, 2024

Foundation models have demonstrated remarkable success across various scientific domains, motivating our exploration of their potential in solar physics. In this paper, we present Solaris, the first foundation model for forecasting the Sun’s atmosphere. We leverage 13 years of full-disk, multi-wavelength solar imagery …

Mixture of Neural Operators: Incorporating Historical Information for Longer Rollouts

Harris Abdul Majid, Francesco Tudisco

ICLR Workshop on AI4DifferentialEquations in Science, 2024

Traditional numerical solvers for time-dependent partial differential equations (PDEs) notoriously require high computational resources and necessitate recomputation when faced with new problem parameters. In recent years, neural surrogates have shown great potential to overcome these limitations. However, it has been …

Contractivity of neural ODEs: an eigenvalue optimization problem

Nicola Guglielmi, Arturo De Marinis, Anton Savostianov, Francesco Tudisco

Mathematics of Computation, vol. 95, pp. 293–319, 2026

We propose a novel methodology to solve a key eigenvalue optimization problem which arises in the contractivity analysis of neural ODEs. When looking at contractivity properties of a one layer weight-tied neural ODE $\dot{u}(t)=σ(Au(t)+b)$ (with $u,b \in {\mathbb R}^n$, $A$ is a given $n \times n$ matrix, $σ: {\mathbb …

Provable Emergence of Deep Neural Collapse and Low-Rank Bias in $L^2$-Regularized Nonlinear Networks

Emanuele Zangrando, Piero Deidda, Simone Brugiapaglia, Nicola Guglielmi, Francesco Tudisco

Transactions on Machine Learning Research (TMLR), 2026

Recent work in deep learning has shown strong empirical and theoretical evidence of an implicit low-rank bias: weight matrices in deep networks tend to be approximately low-rank. Moreover, removing relatively small singular values during training, or from available trained models, may significantly reduce model size …

Learning the effective order of a hypergraph dynamical system

Leonie Neuhäuser, Michael Scholkemper, Francesco Tudisco, Michael T. Schaub

Science Advances, 2024

Dynamical systems on hypergraphs can display a rich set of behaviours not observable for systems with pairwise interactions. Given a distributed dynamical system with a putative hypergraph structure, an interesting question is thus how much of this hypergraph structure is actually necessary to faithfully replicate the …

Robust low-rank training via approximate orthonormal constraints

Dayana Savostianova, Emanuele Zangrando, Gianluca Ceruti, Francesco Tudisco

Advances in Neural Information Processing Systems (NeurIPS), 2023

With the growth of model and data sizes, a broad effort has been made to design pruning techniques that reduce the resource demand of deep learning pipelines, while retaining model performance. In order to reduce both inference and training costs, a prominent line of work uses low-rank matrix factorizations to …

Low-rank lottery tickets: finding efficient low-rank neural networks via matrix differential equations

Steffen Schotthöfer, Emanuele Zangrando, Jonas Kusch, Gianluca Ceruti, Francesco Tudisco

Advances in Neural Information Processing Systems (NeurIPS), 2022

Neural networks have achieved tremendous success in a large variety of applications. However, their memory footprint and computational demand can render them impractical in application settings with limited hardware or energy resources. In this work, we propose a novel algorithm to find efficient low-rank subnetworks. …

Learning the right layers: a data-driven layer-aggregation strategy for semi-supervised learning on multilayer graphs

Sara Venturini, Andrea Cristofari, Francesco Rinaldi, Francesco Tudisco

International Conference on Machine Learning (ICML), 2023

Clustering (or community detection) on multilayer graphs poses several additional complications with respect to standard graphs as different layers may be characterized by different structures and types of information. One of the major challenges is to establish the extent to which each layer contributes to the cluster …