Angxiu Ni's Website

Publications

Journal Publications

  1. “Divergence-Kernel method for linear responses and diffusion models”,
    Angxiu Ni, 2025, https://arxiv.org/abs/2509.03992
  2. “Backpropagation in unstable diffusions”,
    Angxiu Ni, 2025, https://arxiv.org/abs/2507.21497
  3. “Divergence-Kernel method for scores of random systems”,
    Angxiu Ni, 2025, https://arxiv.org/abs/2507.04035
  4. “Differentiating unstable diffusion”,
    Angxiu Ni, 2025, https://arxiv.org/abs/2503.00718
  5. “Optimal response for hyperbolic systems by the fast adjoint response method”,
    Stefano Galatolo, Angxiu Ni, Nonlinearity, 38:115002, 11 2025. Journal link, Arxiv link.
  6. “Ergodic and Foliated Kernel-Differentiation Method for Linear Responses of Random Systems”,
    Angxiu Ni, Journal of Nonlinear Science, 35:90, 10 2025. Journal link, Arxiv link.
  7. “Equivariant Divergence Formula for Hyperbolic Chaotic Flows”,
    Angxiu Ni, Yao Tong, J Stat Phys 191, 118 (2024). Journal link, Arxiv link.
  8. “Backpropagation in hyperbolic chaos via adjoint shadowing”,
    Angxiu Ni, 2024 Nonlinearity 37 035009. Journal link, Arxiv link.
  9. “Recursive Divergence Formulas for Perturbing Unstable Transfer Operators and Physical Measures”,
    Angxiu Ni, Yao Tong, J Stat Phys 190, 126 (2023). Journal link, Arxiv link.
  10. “Fast adjoint algorithm for linear responses of hyperbolic chaos”,
    Angxiu Ni, SIAM Journal on Applied Dynamical Systems, 22:2792–2824, 12 2023. Journal link, Arxiv link, GitHub code link.
  11. “Fast differentiation of chaos”,
    Angxiu Ni, Arxiv link, GitHub code link.
  12. “Approximating Linear Response by Nonintrusive Shadowing Algorithms”,
    Angxiu Ni, SIAM J. Numer. Anal., 59(6), Pages 2843-2865, 2021. Journal link, Arxiv link.
  13. “Adjoint sensitivity analysis on chaotic dynamical systems by non-intrusive least squares adjoint shadowing (NILSAS)”,
    Angxiu Ni*, Chaitanya Talnikar, Journal of Computational Physics, Volume 395, Pages 690-709, 2019. Journal link, Arxiv link, GitHub code link.
  14. “Hyperbolicity, shadowing directions, and sensitivity analysis of a turbulent 3-D flow”,
    Angxiu Ni, Journal of Fluid Mechanics, Volume 863, Page 644-669, 2019. Journal link, Arxiv link, YouTube videos of the CLVs and shadowing directions computed in this paper.
  15. “Sensitivity analysis on chaotic dynamical systems by finite difference non-intrusive least squares shadowing (FD-NILSS)”,
    Angxiu Ni*, Qiqi Wang, Pablo Fernandez, Chaitanya Talnikar, Journal of Computational Physics, Volume 394, Pages 615-631, 2019. Journal link, Arxiv link.
  16. “Sensitivity analysis on chaotic dynamical systems by non-intrusive least squares shadowing (NILSS)”,
    Angxiu Ni*, Qiqi Wang, Journal of Computational Physics, Volume 347, Page 56-77, 2017. Journal link, Arxiv link, GitHub code link.
  17. “Simplified least squares shadowing sensitivity analysis for chaotic ODEs and PDEs”,
    Mario Chater, Angxiu Ni, Qiqi Wang, Journal of Computational Physics 329, 126-140, 2017.
  18. “Least squares shadowing method for sensitivity analysis of differential equations”,
    Mario Chater, Angxiu Ni, Patrick Blonigan, Qiqi Wang, SIAM J. Numer. Anal., 55(6), 3030–3046.
  19. “Sensitivity analysis on chaotic dynamical system by non-intrusive least square shadowing (NI-LSS)”,
    Angxiu Ni, Patrick J. Blonigan, Mario Chater, Qiqi Wang, and Zhichao Zhang, 46th AIAA fluid dynamics conference, (AIAA 2016-4399), Journal link.
  20. “An improvement to NSGA-II algorithm and its application in optimization design of multi-element airfoil”,
    Angxiu Ni, Yufei Zhang, Haixin Chen, Acta Aerodynamica Sinica 32 (2), 252-257, 2014.

Misc. Publications

  1. “No-propagate algorithm for linear responses of random chaotic systems”,
    Angxiu Ni, Arxiv link.
    This unpublished draft is superseded by the above paper “ergodic and foliated … sytems”.
  2. “Adjoint shadowing directions in hyperbolic systems for sensitivity analysis”,
    Angxiu Ni, Arxiv link.
    This unpublished draft is superseded by the above paper “Adjoint shadowing … chaos”.
  3. “Linear range in gradient descent”,
    Angxiu Ni, Chaitanya Talnikar, Arxiv link.

The corresponding author(s) are marked by * when applicable.
My Google Scholar Page.