Applied and Computational Mathematics Seminar
Department of Mathematics and Statistics
Applied and Computational Mathematics Seminar
Department of Mathematics and Statistics
Fall 2026 Schedule
Friday 2:00 pm - 3:15 pm (CST)
Location: 2122 STEM-AG
For any questions or requests, please contact Zezhong Zhang (zez0002@auburn.edu)
Week 1:
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Week 2:
Date and time: Aug 28 (Friday) 2:00 pm - 3:15 pm @ 2122 STEM-AG
Speaker: Shu Liu (Florida State University)
Title: A Natural Primal-Dual Gradient Method for Adversarial Neural Network Training for Solving Partial Differential Equations
Abstract: Computing high-dimensional PDEs remains an important yet challenging problem in computational mathematics. We propose a scalable deep learning–based algorithm for solving PDEs that integrates preconditioned gradient methods with adversarial training. We reformulate the problem as an inf–sup saddle-point problem and apply the Primal–Dual Hybrid Gradient algorithm. To enhance efficiency and stability, we introduce suitable preconditioning operators into the proximal steps of the PDHG algorithm, which leads to a natural gradient ascent–descent scheme for updating neural network parameters. The resulting natural gradients are evaluated using the Krylov subspace method (MINRES), allowing the inversion of preconditioning matrices to be handled through matrix–vector products. Convergence guarantees are established for time-continuous formulation of the algorithm when applied to linear equations, particularly elliptic PDEs in divergence form. We further validate the proposed method on a broad range of linear and nonlinear PDEs across varying dimensions. Numerical results demonstrate that our approach is both efficient and robust, exhibiting more stable convergence and higher accuracy than benchmark deep learning–based solvers.
Week 3
Date and time: Sep 4 (Friday) 2:00 pm - 3:15 pm @ 2122 STEM-AG
Speaker: Xuenan Li (Purdue University)
Title: Pseudo-magnetism in a strained discrete honeycomb lattice
Abstract: Slowly-varying nonuniform strain in honeycomb media can generate an effective pseudo-magnetic field, even though the underlying medium is non-magnetic. This phenomenon was first discovered in graphene and later in photonic crystals, and other physical settings. In this talk, I will start from a discrete nearest-neighbor tight-binding model for a nonuniformly strained honeycomb medium. I will then show how this model leads to a continuum magnetic Dirac Hamiltonian that describes wave packets concentrated near a Dirac point of the undeformed structure. I will focus on unidirectional deformations with bounded gradients that preserve translation invariance along the armchair direction. In this setting, we prove the existence of eigenmodes that behave like plane waves along the armchair direction and are strongly localized in the transverse direction, together with quantitative correction estimates. These results apply to deformations that produce an approximately constant pseudo-magnetic field perpendicular to the plane. They also lead to nearly flat bands and, as a consequence, a very high density of states. These analytical results are also supported by numerical simulations of the corresponding deformations. This is joint work with Michael I. Weinstein.
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Week 5:
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Week 6:
Date and time: Sep 25 (Friday) 2:00 pm - 3:15 pm @ 2122 STEM-AG
Speaker: Ruoyu Hu (Auburn University)
Title: Advanced Filtering and Data Assimilation for Partially Observed Dynamical Systems: From State Estimation to Control
Abstract: Data assimilation combines model predictions with noisy or partial observations to estimate the evolving state of a dynamical system. In this talk, I will discuss the Ensemble Score Filter (EnSF), a training-free score-based method for nonlinear and high-dimensional data assimilation. Applications include two-phase flow in porous media under uncertain permeability and real-data energy-consumption forecasting with a pretrained black-box forward model. I will then turn to a recent extension from state estimation to control in power-grid applications. Using a customized transmission-network simulator, we study how load uncertainty affects heuristic and reinforcement-learning controllers, and whether EnSF-based load correction can improve downstream grid operation. Together, these examples illustrate how modern data assimilation methods can connect state estimation, forecast correction, and sequential decision-making in partially observed dynamical systems.
Week 7: (Cancelled)
Date and time: Oct 2 (Friday) 2:00 pm - 3:15 pm @ 2122 STEM-AG
Speaker: Chunmei Wang (University of Florida)
Title: TBD
Abstract: TBD
Week 8:
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Week 9:
Date and time: Oct 16 (Friday) 2:00 pm - 3:15 pm @ 2122 STEM-AG
Speaker: Yiran Wang (University of Alabama)
Title: TBD
Abstract: TBD
Week 10:
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Week 11:
Date and time: Oct 30 (Friday) 2:00 pm - 3:15 pm @ 2122 STEM-AG
Speaker: Xiaoliang Wan (Louisiana State University)
Title: TBD
Abstract: TBD
Week 12:
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Week 13:
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Week 14:
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Week 15:
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Week 16:
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