Gradient-free optimization of chaotic acoustics with reservoir computing

F Huhn, L Magri - Physical Review Fluids, 2022 - APS
Gradient-based optimization of chaotic acoustics is challenging for a threefold reason:(i) first-
order perturbations grow exponentially in time;(ii) the statistics of the solution may have a …

Periodic shadowing sensitivity analysis of chaotic systems

D Lasagna, A Sharma, J Meyers - Journal of Computational Physics, 2019 - Elsevier
The sensitivity of long-time averages of a hyperbolic chaotic system to parameter
perturbations can be determined using the shadowing direction, the uniformly-bounded-in …

Decomposing the dynamics of the Lorenz 1963 model using unstable periodic orbits: Averages, transitions, and quasi-invariant sets

CC Maiocchi, V Lucarini, A Gritsun - Chaos: An Interdisciplinary …, 2022 - pubs.aip.org
Unstable periodic orbits (UPOs) are a valuable tool for studying chaotic dynamical systems,
as they allow one to distill their dynamical structure. We consider here the Lorenz 1963 …

Efficient computation of linear response of chaotic attractors with one-dimensional unstable manifolds

N Chandramoorthy, Q Wang - SIAM Journal on Applied Dynamical Systems, 2022 - SIAM
The sensitivity of time averages in a chaotic system to an infinitesimal parameter
perturbation grows exponentially with the averaging time. However, long-term averages or …

[HTML][HTML] Sensitivity analysis of chaotic systems using a frequency-domain shadowing approach

KD Kantarakias, G Papadakis - Journal of Computational Physics, 2023 - Elsevier
We present a frequency-domain method for computing the sensitivities of time-averaged
quantities of chaotic systems with respect to input parameters. Such sensitivities cannot be …

A method to regularize optimization problems governed by chaotic dynamical systems

J Hicken, V Ramakrishnan - Chaos, Solitons & Fractals, 2024 - Elsevier
Long-time averages of outputs from chaotic dynamical systems exhibit high-frequency
oscillations in parameter space, which makes gradient-based optimization impractical. We …

A computable realization of Ruelle's formula for linear response of statistics in chaotic systems

N Chandramoorthy, Q Wang - arXiv preprint arXiv:2002.04117, 2020 - arxiv.org
We present a computable reformulation of Ruelle's linear response formula for chaotic
systems. The new formula, called Space-Split Sensitivity or S3, achieves an error …

Computational assessment of smooth and rough parameter dependence of statistics in chaotic dynamical systems

AA Śliwiak, N Chandramoorthy, Q Wang - Communications in Nonlinear …, 2021 - Elsevier
An assumption of smooth response to small parameter changes, of statistics or long-time
averages of a chaotic system, is generally made in the field of sensitivity analysis, and the …

Adjoint-based limit cycle oscillation instability sensitivity and suppression

S He, E Jonsson, JRRA Martins - Nonlinear Dynamics, 2023 - Springer
Dynamical systems often exhibit limit cycle oscillations (LCOs), self-sustaining oscillations of
limited amplitude. LCOs can be supercritical or subcritical. The supercritical response is …

A preconditioned multiple shooting shadowing algorithm for the sensitivity analysis of chaotic systems

K Shawki, G Papadakis - Journal of Computational Physics, 2019 - Elsevier
We propose a preconditioner that can accelerate the rate of convergence of the Multiple
Shooting Shadowing (MSS) method [1]. This recently proposed method can be used to …