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From the Classical Sherman–Morrison Formula to Iterative Refinement and a Self-Correcting Modification for Improved Stability

Date
, 14:00
Category

Owing to its simplicity and efficiency, the Sherman-Morrison (SM) formula has seen widespread use across various scientific and engineering applications for solving rank-one perturbed linear systems of the form (A + uv')x = b. Although the formula dates back at least to 1944, its numerical stability properties have remained an open question and continue to be a...

Computing Accurate Eigenvalues and Singular Values Using a Mixed-Precision (One-Sided) Jacobi Algorithm

Date
, 14:00
Category

We studied mixed-precision preconditioned Jacobi algorithms for computing eigenvalues and singular values. The main idea was to construct a preconditioner in low precision and apply it in higher precision to improve the accuracy and convergence of the Jacobi algorithm. We presented a relative forward error analysis showing that the proposed approaches can achieve significantly smaller...

CoPiT: Conditional Position-induced Transformer for High-Fidelity Airfoil Flow Prediction

Date
, 13:00
Category

Airfoil aerodynamic optimization is critical for improving lift-to-drag performance, reducing fuel consumption, and mitigating environmental impact in aerospace engineering. Recent advances in data-driven surrogate modeling offer efficient alternatives to costly CFD simulations. In this work, we introduce CoPiT (Conditional Position-induced Transformer), a novel neural operator that augments the Position-induced Transformer (PiT) with Feature-wise Linear Modulation...

A Mathematical Introduction to the Material Point in a Finite Element Framework: Observations, Theory and Experiments

Date
, 14:00
Category

In its 30 or so years existence the Material Point Method (MPM) has proved to be outstanding in solving challenging modeling problems in engineering and in animation. The method models objects as a collection of particles that move on a fixed background grid. The method is used in a range of applications from modeling snow,...

Using Curved Meshes for a Diffusion Problem with a Surface Laplacian

Date
, 14:00
Category

This presentation focuses on the numerical analysis of a diffusion problem with a boundary condition involving a surface Laplacian using a high-order finite element method. In order to define this surface operator on the boundary, the domain is assumed to be smooth: hence, the meshed domain does not coincide with the initial physical domain, resulting...

Backward Error Analysis Framework for GMRES and Application to Mixed Precision Preconditioned GMRES

Date
, 14:00
Category

The Generalized Minimal Residual methods (GMRES) for the solution of general square linear systems  is often combined with a preconditioner to improve the convergence speed and the overall computing performance of the method. Successful mixed precision implementations for the application of the preconditioner inside GMRES have been previously proposed: certain strategy prescribes to apply the...

Mixed-Precision Iterative Refinement for Low-Rank Lyapunov Equations

Date
, 14:00
Category

We develop a mixed-precision iterative refinement framework for solving low-rank Lyapunov matrix equations , where  or *. Via rounding error analysis of the algorithms we derive sufficient conditions for the attainable normwise residuals in different precision settings and show how the algorithmic parameters should be chosen. Using the sign function Newton iteration as the solver, we show...

Decomposition of Polynomial Matrices: Algorithms and Applications

Date
, 14:00
Category

Polynomial matrices arise naturally in a variety of signal processing, control, communication, and MIMO system applications. Similar to conventional matrices, they require structured decompositions—such as eigenvalue decomposition (EVD), singular value decomposition (SVD), and QR decomposition—to enable optimal solutions in many practical problems. These factorizations play a critical role in broadband data compaction, MIMO-OFDM system design,...

Overview of New Floating-Point Standards: IEEE P3109 (May 2024 interim report) and Open Compute Project OCP8/MX 1.0

Date
, 14:00
Category

1985 saw a release of one of the most important standards in computing, the IEEE 754-1985 floating-point standard, which is at the foundation of most modern computing systems in use today. Two revisions of the standard, IEEE 754-2008 and IEEE 754-2019, have since been released. A working group for the IEEE 754-2029 is already assembled...