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Frederic Koehler

19 accepted papers

2024

Inferring Dynamic Networks from Marginals with Iterative Proportional Fitting

ICML 2024poster

A common network inference problem, arising from real-world data constraints, is how to infer a dynamic network from its time-aggregated adjacency matrix and time-varying marginals (i.e., row and column sums). Prior approaches to this problem have repurposed the classic iterative proportional fittin…

2024

Sampling Multimodal Distributions with the Vanilla Score: Benefits of Data-Based Initialization

ICLR 2024poster

There is a long history, as well as a recent explosion of interest, in statistical and generative modeling approaches based on \emph{score functions} --- derivatives of the log-likelihood of a distribution. In seminal works, Hyv\"arinen proposed vanilla score matching as a way to learn distributions…

Cited by 11SourcePDFScholar
2023

Statistical Efficiency of Score Matching: The View from Isoperimetry

ICLR 2023top-5%

Deep generative models parametrized up to a normalizing constant (e.g. energy-based models) are difficult to train by maximizing the likelihood of the data because the likelihood and/or gradients thereof cannot be explicitly or efficiently written down. Score matching is a training method, whereby i…

Cited by 65SourcePDFScholar
2022

A Non-Asymptotic Moreau Envelope Theory for High-Dimensional Generalized Linear Models

NeurIPS 2022accept

We prove a new generalization bound that shows for any class of linear predictors in Gaussian space, the Rademacher complexity of the class and the training error under any continuous loss $\ell$ can control the test error under all Moreau envelopes of the loss $\ell$ . We use our finite-sample boun…

2022

Lower Bounds on Randomly Preconditioned Lasso via Robust Sparse Designs

NeurIPS 2022accept

Sparse linear regression with ill-conditioned Gaussian random covariates is widely believed to exhibit a statistical/computational gap, but there is surprisingly little formal evidence for this belief. Recent work has shown that, for certain covariance matrices, the broad class of Preconditioned Las…

Cited by 5SourcePDFScholar
2022

Variational autoencoders in the presence of low-dimensional data: landscape and implicit bias

ICLR 2022poster

Variational Autoencoders (VAEs) are one of the most commonly used generative models, particularly for image data. A prominent difficulty in training VAEs is data that is supported on a lower dimensional manifold. Recent work by Dai and Wipf (2020) proposes a two-stage training algorithm for VAEs, ba…

2021

Multidimensional Scaling: Approximation and Complexity

ICML 2021spotlight

Metric Multidimensional scaling (MDS) is a classical method for generating meaningful (non-linear) low-dimensional embeddings of high-dimensional data. MDS has a long history in the statistics, machine learning, and graph drawing communities. In particular, the Kamada-Kawai force-directed graph draw…

Cited by 17SourcePDFScholar
2021

Representational aspects of depth and conditioning in normalizing flows

ICML 2021spotlight

Normalizing flows are among the most popular paradigms in generative modeling, especially for images, primarily because we can efficiently evaluate the likelihood of a data point. This is desirable both for evaluating the fit of a model, and for ease of training, as maximizing the likelihood can be…

Cited by 40SourcePDFScholar
2021

Uniform Convergence of Interpolators: Gaussian Width, Norm Bounds and Benign Overfitting

NeurIPS 2021oral

We consider interpolation learning in high-dimensional linear regression with Gaussian data, and prove a generic uniform convergence guarantee on the generalization error of interpolators in an arbitrary hypothesis class in terms of the class’s Gaussian width. Applying the generic bound to Euclidea…

Cited by 80SourcePDFScholar
2020

Classification Under Misspecification: Halfspaces, Generalized Linear Models, and Evolvability

NeurIPS 2020spotlight

In this paper, we revisit the problem of distribution-independently learning halfspaces under Massart noise with rate $\eta$. Recent work resolved a long-standing problem in this model of efficiently learning to error $\eta + \epsilon$ for any $\epsilon > 0$, by giving an improper learner that parti…

2020

Learning Some Popular Gaussian Graphical Models without Condition Number Bounds

NeurIPS 2020spotlight

Gaussian Graphical Models (GGMs) have wide-ranging applications in machine learning and the natural and social sciences. In most of the settings in which they are applied, the number of observed samples is much smaller than the dimension and they are assumed to be sparse. While there are a variety o…

Cited by 31SourcePDFScholar
2019

The Comparative Power of ReLU Networks and Polynomial Kernels in the Presence of Sparse Latent Structure

ICLR 2019poster

There has been a large amount of interest, both in the past and particularly recently, into the relative advantage of different families of universal function approximators, for instance neural networks, polynomials, rational functions, etc. However, current research has focused almost exclusively o…

Cited by 8SourcePDFScholar
2017

Information Theoretic Properties of Markov Random Fields, and their Algorithmic Applications

NeurIPS 2017poster

Markov random fields are a popular model for high-dimensional probability distributions. Over the years, many mathematical, statistical and algorithmic problems on them have been studied. Until recently, the only known algorithms for provably learning them relied on exhaustive search, correlation de…

Cited by 83SourcePDFScholar
2016

Provable Algorithms for Inference in Topic Models

ICML 2016poster

Recently, there has been considerable progress on designing algorithms with provable guarantees —typically using linear algebraic methods—for parameter learning in latent variable models. Designing provable algorithms for inference has proved more difficult. Here we take a first step towards provabl…