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Physical Sciences and Mathematics Commons

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Applied Mathematics

Portland State University

Mathematics

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Full-Text Articles in Physical Sciences and Mathematics

Error Propagation And Algorithmic Design Of Contour Integral Eigensolvers With Applications To Fiber Optics, Benjamin Quanah Parker Dec 2021

Error Propagation And Algorithmic Design Of Contour Integral Eigensolvers With Applications To Fiber Optics, Benjamin Quanah Parker

Dissertations and Theses

In this work, the finite element method and the FEAST eigensolver are used to explore applications in fiber optics. The present interest is in computing eigenfunctions u and propagation constants β satisfing [sic] the Helmholtz equation Δu + k2n2u = β2u. Here, k is the freespace wavenumber and n is a spatially varying coefficient function representing the refractive index of the underlying medium. Such a problem arises when attempting to compute confinement losses in optical fibers that guide laser light. In practice, this requires the computation of functions u referred to as …


Conditional Tests On Basins Of Attraction With Finite Fields, Ian H. Dinwoodie Mar 2014

Conditional Tests On Basins Of Attraction With Finite Fields, Ian H. Dinwoodie

Mathematics and Statistics Faculty Publications and Presentations

An iterative method is given for computing the polynomials that vanish on the basin of attraction of a steady state in discrete polynomial dynamics with finite field coefficients. The algorithm is applied to dynamics of a T cell survival network where it is used to compare transition maps conditional on a basin of attraction.