no code implementations • 30 Jan 2024 • Dimitris G. Giovanis, Dimitrios Loukrezis, Ioannis G. Kevrekidis, Michael D. Shields
To this end, we employ Principal Geodesic Analysis on the Grassmann manifold of the response to identify a set of disjoint principal geodesic submanifolds, of possibly different dimension, that captures the variation in the data.
no code implementations • 17 Nov 2022 • Eric Diehl, Moritz von Tresckow, Lou Scholtissek, Dimitrios Loukrezis, Nicolas Marsic, Wolfgang F. O. Müller, Herbert De Gersem
This work suggests to optimize the geometry of a quadrupole magnet by means of a genetic algorithm adapted to solve multi-objective optimization problems.
no code implementations • 9 Feb 2022 • Katiana Kontolati, Dimitrios Loukrezis, Dimitris G. Giovanis, Lohit Vandanapu, Michael D. Shields
Constructing surrogate models for uncertainty quantification (UQ) on complex partial differential equations (PDEs) having inherently high-dimensional $\mathcal{O}(10^{\ge 2})$ stochastic inputs (e. g., forcing terms, boundary conditions, initial conditions) poses tremendous challenges.
no code implementations • 28 Sep 2021 • Ketson R. M. dos Santos, Dimitrios G. Giovanis, Katiana Kontolati, Dimitrios Loukrezis, Michael D. Shields
Using this representation, geometric harmonics, an out-of-sample function extension technique, is employed to create a global map from the space of input parameters to a Grassmannian diffusion manifold.
2 code implementations • 21 Jul 2021 • Katiana Kontolati, Dimitrios Loukrezis, Ketson R. M. dos Santos, Dimitrios G. Giovanis, Michael D. Shields
For this purpose, we employ Grassmannian diffusion maps, a two-step nonlinear dimension reduction technique which allows us to reduce the dimensionality of the data and identify meaningful geometric descriptions in a parsimonious and inexpensive manner.
1 code implementation • 16 Dec 2019 • Dimitrios Loukrezis, Armin Galetzka, Herbert De Gersem
We present an algorithm for computing sparse, least squares-based polynomial chaos expansions, incorporating both adaptive polynomial bases and sequential experimental designs.
Computational Engineering, Finance, and Science
no code implementations • 19 Jul 2018 • Niklas Georg, Dimitrios Loukrezis, Ulrich Römer, Sebastian Schöps
By combining the Leja adaptive algorithm with an adjoint-based error indicator, an even smaller complexity is obtained.
Computational Engineering, Finance, and Science Numerical Analysis Computational Physics Optics 60H15, 60H35, 65N30, 78A40, 78M10 I.6.3; J.2; G.1.8
1 code implementation • 19 Dec 2017 • Dimitrios Loukrezis, Ulrich Römer, Herbert De Gersem
We consider the problem of quantifying uncertainty regarding the output of an electromagnetic field problem in the presence of a large number of uncertain input parameters.
Computational Engineering, Finance, and Science Numerical Analysis Numerical Analysis Computation 78Axx, 65D30, 65D32, 65D15, 65D05, 68U20, 65C20