Search Results for author: Akil Narayan

Found 16 papers, 5 papers with code

TGPT-PINN: Nonlinear model reduction with transformed GPT-PINNs

1 code implementation6 Mar 2024 Yanlai Chen, Yajie Ji, Akil Narayan, Zhenli Xu

We introduce the Transformed Generative Pre-Trained Physics-Informed Neural Networks (TGPT-PINN) for accomplishing nonlinear model order reduction (MOR) of transport-dominated partial differential equations in an MOR-integrating PINNs framework.

Influence of Material Parameter Variability on the Predicted Coronary Artery Biomechanical Environment via Uncertainty Quantification

no code implementations26 Jan 2024 Caleb C. Berggren, David Jiang, Y. F. Jack Wang, Jake A. Bergquist, Lindsay C. Rupp, Zexin Liu, Rob S. MacLeod, Akil Narayan, Lucas H. Timmins

Unary and binary interactions within the adventitial layer were the main contributors to stress variance, and the leading factor in stress variability was uncertainty in the stress-like material parameter summarizing contribution of the embedded fibers to the overall artery stiffness.

Uncertainty Quantification

Multi-Resolution Active Learning of Fourier Neural Operators

1 code implementation29 Sep 2023 Shibo Li, Xin Yu, Wei Xing, Mike Kirby, Akil Narayan, Shandian Zhe

To overcome this problem, we propose Multi-Resolution Active learning of FNO (MRA-FNO), which can dynamically select the input functions and resolutions to lower the data cost as much as possible while optimizing the learning efficiency.

Active Learning LEMMA +2

Proximal Implicit ODE Solvers for Accelerating Learning Neural ODEs

no code implementations19 Apr 2022 Justin Baker, Hedi Xia, Yiwei Wang, Elena Cherkaev, Akil Narayan, Long Chen, Jack Xin, Andrea L. Bertozzi, Stanley J. Osher, Bao Wang

Learning neural ODEs often requires solving very stiff ODE systems, primarily using explicit adaptive step size ODE solvers.

Computational Efficiency

Learning POD of Complex Dynamics Using Heavy-ball Neural ODEs

1 code implementation24 Feb 2022 Justin Baker, Elena Cherkaev, Akil Narayan, Bao Wang

We compare HBNODE with other popular ROMs on several complex dynamical systems, including the von K\'{a}rm\'{a}n Street flow, the Kurganov-Petrova-Popov equation, and the one-dimensional Euler equations for fluids modeling.

Model Reduction of Linear Dynamical Systems via Balancing for Bayesian Inference

1 code implementation25 Nov 2021 Elizabeth Qian, Jemima M. Tabeart, Christopher Beattie, Serkan Gugercin, Jiahua Jiang, Peter R. Kramer, Akil Narayan

We introduce Gramian definitions relevant to the inference setting and propose a balanced truncation approach based on these inference Gramians that yield a reduced dynamical system that can be used to cheaply approximate the posterior mean and covariance.

Bayesian Inference Dimensionality Reduction

A Metalearning Approach for Physics-Informed Neural Networks (PINNs): Application to Parameterized PDEs

no code implementations26 Oct 2021 Michael Penwarden, Shandian Zhe, Akil Narayan, Robert M. Kirby

Physics-informed neural networks (PINNs) as a means of discretizing partial differential equations (PDEs) are garnering much attention in the Computational Science and Engineering (CS&E) world.

BIG-bench Machine Learning Physics-informed machine learning +1

Meta-Learning with Adjoint Methods

no code implementations16 Oct 2021 Shibo Li, Zheng Wang, Akil Narayan, Robert Kirby, Shandian Zhe

the initialization, we only need to run the standard ODE solver twice -- one is forward in time that evolves a long trajectory of gradient flow for the sampled task; the other is backward and solves the adjoint ODE.

Meta-Learning

Multifidelity Modeling for Physics-Informed Neural Networks (PINNs)

no code implementations25 Jun 2021 Michael Penwarden, Shandian Zhe, Akil Narayan, Robert M. Kirby

Candidates for this approach are simulation methodologies for which there are fidelity differences connected with significant computational cost differences.

A bandit-learning approach to multifidelity approximation

no code implementations29 Mar 2021 Yiming Xu, Vahid Keshavarzzadeh, Robert M. Kirby, Akil Narayan

Multifidelity approximation is an important technique in scientific computation and simulation.

On the computation of recurrence coefficients for univariate orthogonal polynomials

no code implementations28 Jan 2021 Zexin Liu, Akil Narayan

Associated to a finite measure on the real line with finite moments are recurrence coefficients in a three-term formula for orthogonal polynomials with respect to this measure.

Numerical Analysis Numerical Analysis 33D45, 42C10, 65D15

Randomized weakly admissible meshes

no code implementations11 Jan 2021 Yiming Xu, Akil Narayan

A weakly admissible mesh (WAM) on a continuum real-valued domain is a sequence of discrete grids such that the discrete maximum norm of polynomials on the grid is comparable to the supremum norm of polynomials on the domain.

Numerical Analysis Numerical Analysis Probability Computation

Analysis of The Ratio of $\ell_1$ and $\ell_2$ Norms in Compressed Sensing

no code implementations13 Apr 2020 Yiming Xu, Akil Narayan, Hoang Tran, Clayton G. Webster

We first propose a novel criterion that guarantees that an $s$-sparse signal is the local minimizer of the $\ell_1/\ell_2$ objective; our criterion is interpretable and useful in practice.

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