Publications associées à Calcul formel

Lattice packings through division algebras

In this text, we will show the existence of lattice packings in a family of dimensions by employing division algebras. This construction is a generalization of Venkatesh's lattice packing result Venkatesh (Int Math Res Notices 2013(7): 1628-1642, 2013). In ...

SPRINGER HEIDELBERG2023

Spectral Hypergraph Sparsifiers of Nearly Linear Size

Mikhail Kapralov, Jakab Tardos

Graph sparsification has been studied extensively over the past two decades, culminating in spectral sparsifiers of optimal size (up to constant factors). Spectral hypergraph sparsification is a natural analogue of this problem, for which optimal bounds on ...

IEEE COMPUTER SOC2022

An analytical solution of the isentropic vortex problem in the special relativistic magnetohydrodynamics

Junming Duan

The isentropic vortex problem is frequently solved to test the accuracy of numerical methods and verify corresponding code. Unfortunately, its existing solution was derived in the relativistic magnetohydrodynamics by numerically solving an ordinary differe ...

ACADEMIC PRESS INC ELSEVIER SCIENCE2022

cRacklet: a spectral boundary integral method library for interfacial rupture simulation

Jean-François Molinari, Thibault Didier Roch, Fabian Barras

The study of dynamically propagating rupture along interfaces is of prime importance in various fields and system sizes, including tribology (nm to m), engineering (mm to m) and geophysics (m to km) (Armstrong-Hélouvry et al., 1994; Ben-Zion, 2008; Vanossi ...

2022

Admissibility of Uncertain Injections in Quadratic Algebraic Systems

Jean-Yves Le Boudec, Cong Wang, Eleni Stai

We study the admissibility problem in multivariate algebraic systems, such as ac electrical networks, where the power injection is quadratic in the state. The goal of such systems is to ensure that the state stays in some security set (e.g., magnitudes of ...

2021

A numerical approach to characterize the viscoelastic behaviour of fibre beds and to evaluate the influence of strain deviations on viscoelastic parameter extraction

Véronique Michaud, Vincent Werlen, Christian Rytka

The development of a robust material model able to accurately describe fibre bed compaction at different strain and strain rates is highly desirable because it is essential for the simulation of many composite manufacturing processes. In this study, we inv ...

2021

A new Euler-Lagrangian cavitation model for tip-vortex cavitation with the effect of non-condensable gas

Mohamed Farhat, Huaiyu Cheng

Numerical simulation of tip vortex cavitation (TVC) remains a challenging task in a variety of applica-tions, such as axial turbines and pumps as well as marine propellers. Although it is well known that TVC is highly sensitive to gas content, be it dissol ...

PERGAMON-ELSEVIER SCIENCE LTD2021

An Optimizing Multi-platform Source-to-source Compiler Framework for the NEURON MODeling Language

Felix Schürmann, James Gonzalo King, Michael Lee Hines, Pramod Shivaji Kumbhar, Omar Awile, Jorge Blanco Alonso, Liam Roger George Keegan

Domain-specific languages (DSLs) play an increasingly important role in the generation of high performing software. They allow the user to exploit domain knowledge for the generation of more efficient code on target architectures. Here, we describe a new c ...

Springer2020

Hierarchically refined isogeometric analysis of trimmed shells

Luca Coradello, Alessandro Reali, Davide D'Angella

This work focuses on the study of several computational challenges arising when trimmed surfaces are directly employed for the isogeometric analysis of Kirchhoff-Love shells. To cope with these issues and to resolve mechanical and/or geometrical features o ...

SPRINGER2020

High Performance Computing for gravitational lens modeling: Single vs double precision on GPUs and CPUs

Jean-Paul Richard Kneib, Markus Rexroth, Christoph Ernst René Schäfer

Strong gravitational lensing is a powerful probe of cosmology and the dark matter distribution. Efficient lensing software is already a necessity to fully use its potential and the performance demands will only increase with the upcoming generation of tele ...

ELSEVIER2020

Activity-Based Screening of Homogeneous Catalysts through the Rapid Assessment of Theoretically Derived Turnover Frequencies

Matthew Wodrich, Anne-Clémence Corminboeuf, Boodsarin Sawatlon

In homogeneous catalysis, the turnover frequency (TOF) and turnover number (TON) are the most commonly used quantities that experimentally describe catalytic activity. Computational studies, on the other hand, generally yield the ubiquitous free energy pro ...

AMER CHEMICAL SOC2019

Prism-based path set restriction for solving Markovian traffic assignment problem

Yuki Oyama

This paper deals with a main limitation of Markovian traffic assignment (MTA) models: when the network includes cyclic structures and the link costs are small enough, the fact that the MTA models assign traffic flows to all feasible paths causes computatio ...

Elsevier2019

Efficient Multi-dimensional Diracs Estimation with Linear Sample Complexity

Martin Vetterli, Thierry Blu, Hanjie Pan

Estimating Diracs in continuous two or higher dimensions is a fundamental problem in imaging. Previous approaches extended one dimensional methods, like the ones based on finite rate of innovation (FRI) sampling, in a separable manner, e.g., along the hori ...

2018

Multi space reduced basis preconditioners for parametrized partial differential equations

Niccolò Dal Santo

The multiquery solution of parametric partial differential equations (PDEs), that is, PDEs depending on a vector of parameters, is computationally challenging and appears in several engineering contexts, such as PDE-constrained optimization, uncertainty qu ...

EPFL2018

Fast hierarchical solvers for symmetric eigenvalue problems

Ana Susnjara

In this thesis we address the computation of a spectral decomposition for symmetric banded matrices. In light of dealing with large-scale matrices, where classical dense linear algebra routines are not applicable, it is essential to design alternative tech ...

EPFL2018

Numerical Modelling of Two-Phase Flow with Moving Boundary Fitted Meshes

Erik Gros

In this thesis, a computational approach is used to study two-phase flow including phase change by direct numerical simulation. This approach follows the interface with an adaptive moving mesh. The incompressible Navier-Stokes equations are solved, in tw ...

EPFL2018

Non-linear simulations of the TCV Scrape-Off Layer

Ivo Furno, Paolo Ricci, Benoît Labit, Joaquim Loizu Cisquella, Federico Nespoli, Federico David Halpern, Fabio Riva

To investigate the mechanisms leading to the heat deposition onto the first wall in the Scrape-Off Layer (SOL), we perform dedicated numerical non-linear simulations of the SOL plasma dynamics of a TCV discharge using the GBS code. The simulated parallel h ...

Elsevier Science Bv2017

Incremental Kinetic Modeling of Spectroscopic Data using a Reduced Calibration Model

Dominique Bonvin, Julien Léo Billeter

The identification of kinetic models is an important step for the monitoring, control and optimization of chemical processes. Kinetic models are often based on first principles that describe the evolution of concentrations by means of conservation and cons ...

2017

Efficient computation of Sommerfeld integral tails - methods and algorithms

Juan Ramon Mosig, Krzysztof Michalski

A review is presented of the most effective methods for the computation of Sommerfeld integral tails. Such integrals, which are often oscillatory, singular and divergent, commonly arise in layered media Green functions. The mathematical foundations of vari ...

Taylor & Francis Ltd2016

Efficient Hardware Design Of Iterative Stencil Loops

David Atienza Alonso, Ivan Beretta, Alessandro Antonio Nacci

A large number of algorithms for multidimensional signals processing and scientific computation come in the form of iterative stencil loops (ISLs), whose data dependencies span across multiple iterations. Because of their complex inner structure, automatic ...

Ieee-Inst Electrical Electronics Engineers Inc2016