Search Results for author: Alexander Tong

Found 27 papers, 14 papers with code

Iterated Denoising Energy Matching for Sampling from Boltzmann Densities

1 code implementation9 Feb 2024 Tara Akhound-Sadegh, Jarrid Rector-Brooks, Avishek Joey Bose, Sarthak Mittal, Pablo Lemos, Cheng-Hao Liu, Marcin Sendera, Siamak Ravanbakhsh, Gauthier Gidel, Yoshua Bengio, Nikolay Malkin, Alexander Tong

Efficiently generating statistically independent samples from an unnormalized probability distribution, such as equilibrium samples of many-body systems, is a foundational problem in science.

Denoising Efficient Exploration

Assessing Neural Network Representations During Training Using Noise-Resilient Diffusion Spectral Entropy

no code implementations4 Dec 2023 Danqi Liao, Chen Liu, Benjamin W. Christensen, Alexander Tong, Guillaume Huguet, Guy Wolf, Maximilian Nickel, Ian Adelstein, Smita Krishnaswamy

Entropy and mutual information in neural networks provide rich information on the learning process, but they have proven difficult to compute reliably in high dimensions.

A Computational Framework for Solving Wasserstein Lagrangian Flows

1 code implementation16 Oct 2023 Kirill Neklyudov, Rob Brekelmans, Alexander Tong, Lazar Atanackovic, Qiang Liu, Alireza Makhzani

The dynamical formulation of the optimal transport can be extended through various choices of the underlying geometry ($\textit{kinetic energy}$), and the regularization of density paths ($\textit{potential energy}$).

Causal Inference in Gene Regulatory Networks with GFlowNet: Towards Scalability in Large Systems

no code implementations5 Oct 2023 Trang Nguyen, Alexander Tong, Kanika Madan, Yoshua Bengio, Dianbo Liu

Understanding causal relationships within Gene Regulatory Networks (GRNs) is essential for unraveling the gene interactions in cellular processes.

Causal Discovery Causal Inference

Simulation-free Schrödinger bridges via score and flow matching

1 code implementation7 Jul 2023 Alexander Tong, Nikolay Malkin, Kilian Fatras, Lazar Atanackovic, Yanlei Zhang, Guillaume Huguet, Guy Wolf, Yoshua Bengio

We present simulation-free score and flow matching ([SF]$^2$M), a simulation-free objective for inferring stochastic dynamics given unpaired samples drawn from arbitrary source and target distributions.

Graph Fourier MMD for Signals on Graphs

no code implementations5 Jun 2023 Samuel Leone, Aarthi Venkat, Guillaume Huguet, Alexander Tong, Guy Wolf, Smita Krishnaswamy

GFMMD is defined via an optimal witness function that is both smooth on the graph and maximizes difference in expectation between the pair of distributions on the graph.

Neural FIM for learning Fisher Information Metrics from point cloud data

1 code implementation1 Jun 2023 Oluwadamilola Fasina, Guillaume Huguet, Alexander Tong, Yanlei Zhang, Guy Wolf, Maximilian Nickel, Ian Adelstein, Smita Krishnaswamy

Although data diffusion embeddings are ubiquitous in unsupervised learning and have proven to be a viable technique for uncovering the underlying intrinsic geometry of data, diffusion embeddings are inherently limited due to their discrete nature.

A Heat Diffusion Perspective on Geodesic Preserving Dimensionality Reduction

1 code implementation NeurIPS 2023 Guillaume Huguet, Alexander Tong, Edward De Brouwer, Yanlei Zhang, Guy Wolf, Ian Adelstein, Smita Krishnaswamy

Finally, we show that parameters of our more general method can be configured to give results similar to PHATE (a state-of-the-art diffusion based manifold learning method) as well as SNE (an attraction/repulsion neighborhood based method that forms the basis of t-SNE).

Denoising Dimensionality Reduction +1

DynGFN: Towards Bayesian Inference of Gene Regulatory Networks with GFlowNets

1 code implementation NeurIPS 2023 Lazar Atanackovic, Alexander Tong, Bo wang, Leo J. Lee, Yoshua Bengio, Jason Hartford

In this paper we leverage the fact that it is possible to estimate the "velocity" of gene expression with RNA velocity techniques to develop an approach that addresses both challenges.

Bayesian Inference Causal Discovery

Improving and generalizing flow-based generative models with minibatch optimal transport

2 code implementations1 Feb 2023 Alexander Tong, Kilian Fatras, Nikolay Malkin, Guillaume Huguet, Yanlei Zhang, Jarrid Rector-Brooks, Guy Wolf, Yoshua Bengio

CFM features a stable regression objective like that used to train the stochastic flow in diffusion models but enjoys the efficient inference of deterministic flow models.

Learnable Filters for Geometric Scattering Modules

no code implementations15 Aug 2022 Alexander Tong, Frederik Wenkel, Dhananjay Bhaskar, Kincaid MacDonald, Jackson Grady, Michael Perlmutter, Smita Krishnaswamy, Guy Wolf

We propose a new graph neural network (GNN) module, based on relaxations of recently proposed geometric scattering transforms, which consist of a cascade of graph wavelet filters.

Descriptive Graph Classification

Manifold Interpolating Optimal-Transport Flows for Trajectory Inference

no code implementations29 Jun 2022 Guillaume Huguet, D. S. Magruder, Alexander Tong, Oluwadamilola Fasina, Manik Kuchroo, Guy Wolf, Smita Krishnaswamy

In GAE the latent space distance between points is regularized to match a novel multiscale geodesic distance on the data manifold that we define.

Time-inhomogeneous diffusion geometry and topology

no code implementations28 Mar 2022 Guillaume Huguet, Alexander Tong, Bastian Rieck, Jessie Huang, Manik Kuchroo, Matthew Hirn, Guy Wolf, Smita Krishnaswamy

From a geometric perspective, we obtain convergence bounds based on the smallest transition probability and the radius of the data, whereas from a spectral perspective, our bounds are based on the eigenspectrum of the diffusion kernel.

Clustering Denoising +1

MURAL: An Unsupervised Random Forest-Based Embedding for Electronic Health Record Data

1 code implementation19 Nov 2021 Michal Gerasimiuk, Dennis Shung, Alexander Tong, Adrian Stanley, Michael Schultz, Jeffrey Ngu, Loren Laine, Guy Wolf, Smita Krishnaswamy

In particular, in EHR data, some variables are {\em missing not at random (MNAR)} but deliberately not collected and thus are a source of information.

Dimensionality Reduction

Embedding Signals on Knowledge Graphs with Unbalanced Diffusion Earth Mover's Distance

no code implementations26 Jul 2021 Alexander Tong, Guillaume Huguet, Dennis Shung, Amine Natik, Manik Kuchroo, Guillaume Lajoie, Guy Wolf, Smita Krishnaswamy

We propose to compare and organize such datasets of graph signals by using an earth mover's distance (EMD) with a geodesic cost over the underlying graph.

Knowledge Graph Embedding Knowledge Graphs

Diffusion Earth Mover's Distance and Distribution Embeddings

1 code implementation25 Feb 2021 Alexander Tong, Guillaume Huguet, Amine Natik, Kincaid MacDonald, Manik Kuchroo, Ronald Coifman, Guy Wolf, Smita Krishnaswamy

Here, Diffusion EMD can derive distances between patients on the manifold of cells at least two orders of magnitude faster than equally accurate methods.

Multimodal Data Visualization and Denoising with Integrated Diffusion

no code implementations12 Feb 2021 Manik Kuchroo, Abhinav Godavarthi, Alexander Tong, Guy Wolf, Smita Krishnaswamy

We propose a method called integrated diffusion for combining multimodal datasets, or data gathered via several different measurements on the same system, to create a joint data diffusion operator.

Clustering Data Visualization +1

Data-Driven Learning of Geometric Scattering Networks

no code implementations6 Oct 2020 Alexander Tong, Frederik Wenkel, Kincaid MacDonald, Smita Krishnaswamy, Guy Wolf

We propose a new graph neural network (GNN) module, based on relaxations of recently proposed geometric scattering transforms, which consist of a cascade of graph wavelet filters.

Descriptive Graph Classification

Uncovering the Folding Landscape of RNA Secondary Structure with Deep Graph Embeddings

2 code implementations12 Jun 2020 Egbert Castro, Andrew Benz, Alexander Tong, Guy Wolf, Smita Krishnaswamy

We propose a geometric scattering autoencoder (GSAE) network for learning such graph embeddings.

TrajectoryNet: A Dynamic Optimal Transport Network for Modeling Cellular Dynamics

2 code implementations ICML 2020 Alexander Tong, Jessie Huang, Guy Wolf, David van Dijk, Smita Krishnaswamy

To address this issue, we establish a link between continuous normalizing flows and dynamic optimal transport, that allows us to model the expected paths of points over time.

Understanding Graph Neural Networks with Generalized Geometric Scattering Transforms

1 code implementation14 Nov 2019 Michael Perlmutter, Alexander Tong, Feng Gao, Guy Wolf, Matthew Hirn

As a result, the proposed construction unifies and extends known theoretical results for many of the existing graph scattering architectures.

Fixing Bias in Reconstruction-based Anomaly Detection with Lipschitz Discriminators

no code implementations26 May 2019 Alexander Tong, Guy Wolf, Smita Krishnaswamy

We show that this procedure successfully detects unseen anomalies with guarantees on those that have a certain Wasserstein distance from the data or corrupted training set.

Anomaly Detection

Graph Spectral Regularization For Neural Network Interpretability

no code implementations ICLR 2019 Alexander Tong, David van Dijk, Jay Stanley, Guy Wolf, Smita Krishnaswamy

First, we show a synthetic example that the graph-structured layer can reveal topological features of the data.

Interpretable Neuron Structuring with Graph Spectral Regularization

1 code implementation ICLR 2019 Alexander Tong, David van Dijk, Jay S. Stanley III, Matthew Amodio, Kristina Yim, Rebecca Muhle, James Noonan, Guy Wolf, Smita Krishnaswamy

Taking inspiration from spatial organization and localization of neuron activations in biological networks, we use a graph Laplacian penalty to structure the activations within a layer.

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