Search Results for author: Lars Ruthotto

Found 31 papers, 23 papers with code

PyHySCO: GPU-Enabled Susceptibility Artifact Distortion Correction in Seconds

1 code implementation15 Mar 2024 Abigail Julian, Lars Ruthotto

Over the past decade, reversed Gradient Polarity (RGP) methods have become a popular approach for correcting susceptibility artifacts in Echo-Planar Imaging (EPI).

Differential Equations for Continuous-Time Deep Learning

no code implementations8 Jan 2024 Lars Ruthotto

This short, self-contained article seeks to introduce and survey continuous-time deep learning approaches that are based on neural ordinary differential equations (neural ODEs).

Learning Control Policies of Hodgkin-Huxley Neuronal Dynamics

1 code implementation13 Nov 2023 Malvern Madondo, Deepanshu Verma, Lars Ruthotto, Nicholas Au Yong

In this setting, control policies aim to optimize therapeutic outcomes by tailoring the parameters of a DBS system, typically via electrical stimulation, in real time based on the patient's ongoing neuronal activity.

Efficient Neural Network Approaches for Conditional Optimal Transport with Applications in Bayesian Inference

2 code implementations25 Oct 2023 Zheyu Oliver Wang, Ricardo Baptista, Youssef Marzouk, Lars Ruthotto, Deepanshu Verma

PCP-Map models conditional transport maps as the gradient of a partially input convex neural network (PICNN) and uses a novel numerical implementation to increase computational efficiency compared to state-of-the-art alternatives.

Bayesian Inference Computational Efficiency +2

Alternating Minimization for Regression with Tropical Rational Functions

1 code implementation31 May 2023 Alex Dunbar, Lars Ruthotto

We propose an alternating minimization heuristic for regression over the space of tropical rational functions with fixed exponents.

regression

Multilevel Diffusion: Infinite Dimensional Score-Based Diffusion Models for Image Generation

1 code implementation8 Mar 2023 Paul Hagemann, Sophie Mildenberger, Lars Ruthotto, Gabriele Steidl, Nicole Tianjiao Yang

We thereby intend to obtain diffusion models that generalize across different resolution levels and improve the efficiency of the training process.

Image Generation

Multivariate Quantile Function Forecaster

no code implementations23 Feb 2022 Kelvin Kan, François-Xavier Aubet, Tim Januschowski, Youngsuk Park, Konstantinos Benidis, Lars Ruthotto, Jan Gasthaus

We propose Multivariate Quantile Function Forecaster (MQF$^2$), a global probabilistic forecasting method constructed using a multivariate quantile function and investigate its application to multi-horizon forecasting.

slimTrain -- A Stochastic Approximation Method for Training Separable Deep Neural Networks

1 code implementation28 Sep 2021 Elizabeth Newman, Julianne Chung, Matthias Chung, Lars Ruthotto

In the absence of theoretical guidelines or prior experience on similar tasks, this requires solving many training problems, which can be time-consuming and demanding on computational resources.

Stochastic Optimization

An Introduction to Deep Generative Modeling

1 code implementation9 Mar 2021 Lars Ruthotto, Eldad Haber

Developing DGMs has become one of the most hotly researched fields in artificial intelligence in recent years.

Avoiding The Double Descent Phenomenon of Random Feature Models Using Hybrid Regularization

1 code implementation11 Dec 2020 Kelvin Kan, James G Nagy, Lars Ruthotto

To close this gap, the hybrid method considered in our paper combines the respective strengths of the two most common forms of regularization: early stopping and weight decay.

Image Classification

MGIC: Multigrid-in-Channels Neural Network Architectures

1 code implementation NeurIPS Workshop DLDE 2021 Moshe Eliasof, Jonathan Ephrath, Lars Ruthotto, Eran Treister

We present a multigrid-in-channels (MGIC) approach that tackles the quadratic growth of the number of parameters with respect to the number of channels in standard convolutional neural networks (CNNs).

Image Classification Point Cloud Classification

A Neural Network Approach Applied to Multi-Agent Optimal Control

1 code implementation9 Nov 2020 Derek Onken, Levon Nurbekyan, Xingjian Li, Samy Wu Fung, Stanley Osher, Lars Ruthotto

Our approach is grid-free and scales efficiently to dimensions where grids become impractical or infeasible.

Optimization and Control

Train Like a (Var)Pro: Efficient Training of Neural Networks with Variable Projection

1 code implementation26 Jul 2020 Elizabeth Newman, Lars Ruthotto, Joseph Hart, Bart van Bloemen Waanders

To solve the optimization problem more efficiently, we propose the use of variable projection (VarPro), a method originally designed for separable nonlinear least-squares problems.

Image Classification speech-recognition +1

Multigrid-in-Channels Architectures for Wide Convolutional Neural Networks

no code implementations11 Jun 2020 Jonathan Ephrath, Lars Ruthotto, Eran Treister

We present a multigrid approach that combats the quadratic growth of the number of parameters with respect to the number of channels in standard convolutional neural networks (CNNs).

Image Classification

OT-Flow: Fast and Accurate Continuous Normalizing Flows via Optimal Transport

3 code implementations29 May 2020 Derek Onken, Samy Wu Fung, Xingjian Li, Lars Ruthotto

On five high-dimensional density estimation and generative modeling tasks, OT-Flow performs competitively to state-of-the-art CNFs while on average requiring one-fourth of the number of weights with an 8x speedup in training time and 24x speedup in inference.

Density Estimation

PNKH-B: A Projected Newton-Krylov Method for Large-Scale Bound-Constrained Optimization

1 code implementation27 May 2020 Kelvin Kan, Samy Wu Fung, Lars Ruthotto

We present an interior point method to solve the quadratic projection problem efficiently.

Numerical Analysis Numerical Analysis

A Machine Learning Framework for Solving High-Dimensional Mean Field Game and Mean Field Control Problems

1 code implementation4 Dec 2019 Lars Ruthotto, Stanley Osher, Wuchen Li, Levon Nurbekyan, Samy Wu Fung

State-of-the-art numerical methods for solving such problems utilize spatial discretization that leads to a curse-of-dimensionality.

BIG-bench Machine Learning

LeanConvNets: Low-cost Yet Effective Convolutional Neural Networks

no code implementations29 Oct 2019 Jonathan Ephrath, Moshe Eliasof, Lars Ruthotto, Eldad Haber, Eran Treister

In practice, the input data and the hidden features consist of a large number of channels, which in most CNNs are fully coupled by the convolution operators.

Image Classification Semantic Segmentation +2

LeanResNet: A Low-cost Yet Effective Convolutional Residual Networks

no code implementations15 Apr 2019 Jonathan Ephrath, Lars Ruthotto, Eldad Haber, Eran Treister

Convolutional Neural Networks (CNNs) filter the input data using spatial convolution operators with compact stencils.

General Classification Image Classification

IMEXnet: A Forward Stable Deep Neural Network

1 code implementation6 Mar 2019 Eldad Haber, Keegan Lensink, Eran Treister, Lars Ruthotto

Deep convolutional neural networks have revolutionized many machine learning and computer vision tasks, however, some remaining key challenges limit their wider use.

Semantic Segmentation

ADMM-SOFTMAX : An ADMM Approach for Multinomial Logistic Regression

1 code implementation27 Jan 2019 Samy Wu Fung, Sanna Tyrväinen, Lars Ruthotto, Eldad Haber

Solution of the least-squares problem can be be accelerated by pre-computing a factorization or preconditioner, and the separability in the smooth, convex problem can be easily parallelized across examples.

General Classification Image Classification +2

Never look back - A modified EnKF method and its application to the training of neural networks without back propagation

no code implementations21 May 2018 Eldad Haber, Felix Lucka, Lars Ruthotto

Further, we provide numerical examples that demonstrate the potential of our method for training deep neural networks.

Deep Neural Networks Motivated by Partial Differential Equations

1 code implementation12 Apr 2018 Lars Ruthotto, Eldad Haber

In the latter area, PDE-based approaches interpret image data as discretizations of multivariate functions and the output of image processing algorithms as solutions to certain PDEs.

Denoising Image Classification +2

Reversible Architectures for Arbitrarily Deep Residual Neural Networks

2 code implementations12 Sep 2017 Bo Chang, Lili Meng, Eldad Haber, Lars Ruthotto, David Begert, Elliot Holtham

In this work, we interpret deep residual networks as ordinary differential equations (ODEs), which have long been studied in mathematics and physics with rich theoretical and empirical success.

Image Classification

LAP: a Linearize and Project Method for Solving Inverse Problems with Coupled Variables

1 code implementation28 May 2017 James Herring, James Nagy, Lars Ruthotto

LAP is most promising for cases when the subproblem corresponding to one of the variables is considerably easier to solve than the other.

Image Super-Resolution

Stable Architectures for Deep Neural Networks

4 code implementations9 May 2017 Eldad Haber, Lars Ruthotto

While our new architectures restrict the solution space, several numerical experiments show their competitiveness with state-of-the-art networks.

A Lagrangian Gauss-Newton-Krylov Solver for Mass- and Intensity-Preserving Diffeomorphic Image Registration

no code implementations13 Mar 2017 Andreas Mang, Lars Ruthotto

We use an optimal control formulation, in which the velocity field of a hyperbolic PDE needs to be found such that the distance between the final state of the system (the transformed/transported template image) and the observation (the reference image) is minimized.

Image Registration

Learning across scales - A multiscale method for Convolution Neural Networks

1 code implementation6 Mar 2017 Eldad Haber, Lars Ruthotto, Elliot Holtham, Seong-Hwan Jun

In this work we establish the relation between optimal control and training deep Convolution Neural Networks (CNNs).

Relation

jInv -- a flexible Julia package for PDE parameter estimation

3 code implementations23 Jun 2016 Lars Ruthotto, Eran Treister, Eldad Haber

Estimating parameters of Partial Differential Equations (PDEs) from noisy and indirect measurements often requires solving ill-posed inverse problems.

Mathematical Software

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