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math.NA2026

A Structure-Preserving Scheme for Computing the Gradient of the Eikonal Equation

Ka Lun Leung, Shingyu Leung

We propose a first-order, structure-preserving method for directly computing the normalized traveltime gradient of the eikonal equation in smooth first-arrival regions. The method…

math.NA2026

Geodesic Interpolation on the Grassmann Manifold: GLERP and Recursive GIDER Interpolants

Shingyu Leung

This article develops a geodesic interpolation framework for data on the Grassmann manifold. The motivation is that many matrix-valued data sets represent subspaces rather than fix…

math.NA2026

Analytic First Derivatives of SIDER Interpolation

Shingyu Leung

Spherical interpolation is required in numerical and geometric applications in which the unknowns are constrained to remain on the unit sphere. Spherical Interpolation of orDER …

math.NA2026

A Quaternion--BCH Framework for the Local Accuracy of SIDER Interpolation

Shingyu Leung

Spherical Interpolation of orDER (SIDER-) is a recursive high-order interpolation method for data on the unit sphere , built from repeated spherical linear int…

math.NA2026

Local Consistency and Higher-Order Structure of Spherical Interpolation

Shingyu Leung

Spherical Interpolation of orDER (SIDER-) is a recursive high-order interpolation construction for data on the unit sphere , built from repeated spherical line…

math.NA2026

A Semi-Lagrangian Spherical Essentially Non-Oscillatory (SENO) Scheme for Advection Equations of S2-valued Functions

Shingyu Leung

We develop a numerical scheme for solving the advection equation of -valued functions of real variables, which models the time-evolution of a -valued ma…

math.NA2025

A multilayer level-set method for eikonal-based traveltime tomography

Wenbin Li, Ken K. T. Hung, Shingyu Leung

We present a novel multilayer level-set method (MLSM) for eikonal-based first-arrival traveltime tomography. Unlike classical level-set approaches that rely solely on the zero-leve…

math.NA2025

The Closest Point Heat Method for Solving Eikonal Equations on Implicit Surfaces

Tony Wong, Shingyu Leung, Byungjoon Lee

We introduce the Closest Point Heat Method (CPHM), a novel approach for solving the surface Eikonal equation on general smooth surfaces. Building on the strengths of the classical…

math.NA2025

A Spherical Crank-Nicolson Integrator Based on the Exponential Map and the Spherical Linear Interpolation

Shingyu Leung

We propose implicit integrators for solving stiff differential equations on unit spheres. Our approach extends the standard backward Euler and Crank-Nicolson methods in Cartesian s…

math.NA2024

Solving Partial Differential Equations on Evolving Surfaces via the Constrained Least-Squares and Grid-Based Particle Method

Ningchen Ying, Shingyu Leung

We present a framework for solving partial different equations on evolving surfaces. Based on the grid-based particle method (GBPM) [18], the method can naturally resample the surf…

math.NA2024

A Constrained Least-Squares Ghost Sample Points (CLS-GSP) Method for Differential Operators on Point Clouds

Ningchen Ying, Kwunlun Chu, Shingyu Leung

We introduce a novel meshless method called the Constrained Least-Squares Ghost Sample Points (CLS-GSP) method for solving partial differential equations on irregular domains or ma…