Tim Warburton
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An Adaptive Mixed Precision and Dynamically Scaled Preconditioned Conjugate Gradient Algorithm Open
We propose an adaptive mixed precision and dynamically scaled preconditioned conjugate gradient algorithm (AMP-PCG). It dynamically adjusts the precision for storing vectors and computing, exploiting low precision when appropriate, while m…
Exascale Simulations of Fusion and Fission Systems Open
We discuss pioneering heat and fluid flow simulations of fusion and fission energy systems with NekRS on exascale computing facilities, including Frontier and Aurora. The Argonne-based code, NekRS, is a highly-performant open-source code f…
A stable decoupled perfectly matched layer for the 3D wave equation using the nodal discontinuous Galerkin method Open
In outdoor acoustics, the calculations of sound propagating in air can be computationally heavy if the domain is chosen large enough to fulfil the Sommerfeld radiation condition. By strategically truncating the computational domain with a …
Massively parallel nodal discontinous Galerkin finite element method simulator for room acoustics Open
We present a massively parallel and scalable nodal discontinuous Galerkin finite element method (DGFEM) solver for the time-domain linearized acoustic wave equations. The solver is implemented using the libParanumal finite element framewor…
Exascale Multiphysics Nuclear Reactor Simulations for Advanced Designs Open
ENRICO is a coupled application developed under the U.S. Department of Energy's Exascale Computing Project (ECP) targeting the modeling of advanced nuclear reactors. It couples radiation transport with heat and fluid simulation, including …
Stopping Criteria for the Conjugate Gradient Algorithm in High-Order Finite Element Methods Open
We consider stopping criteria that balance algebraic and discretization errors for the conjugate gradient algorithm applied to high-order finite element discretizations of Poisson problems. Firstly, we introduce a new stopping criterion th…
CEED ECP Milestone Report: Support ECP applications in their exascale challenge problem runs Open
ECP Milestone Report Support ECP applications in their exascale challenge problem runs WBS 2.2.6.06, Milestone CEED-MS40
View article: CEED ECP Milestone Report: Improve performance and capabilities of CEED-enabled ECP applications on Frontier/Aurora EA
CEED ECP Milestone Report: Improve performance and capabilities of CEED-enabled ECP applications on Frontier/Aurora EA Open
ECP Milestone Report Improve performance and capabilities of CEED-enabled ECP applications on Frontier/Aurora EA WBS 2.2.6.06, Milestone CEED-MS39
View article: CEED ECP Milestone Report: Improve performance and capabilities of CEED-enabled ECP applications on Frontier/Aurora EA
CEED ECP Milestone Report: Improve performance and capabilities of CEED-enabled ECP applications on Frontier/Aurora EA Open
ECP Milestone Report Improve performance and capabilities of CEED-enabled ECP applications on Frontier/Aurora EA WBS 2.2.6.06, Milestone CEED-MS39
On the Entropy Projection and the Robustness of High Order Entropy Stable Discontinuous Galerkin Schemes for Under-Resolved Flows Open
High order entropy stable schemes provide improved robustness for computational simulations of fluid flows. However, additional stabilization and positivity preserving limiting can still be required for variable-density flows with under-re…
CEED ECP Milestone Report: High-order algorithmic developments and optimizations for more robust exascale applications Open
ECP Milestone Report High-order algorithmic developments and optimizations for more robust exascale applications WBS 2.2.6.06, Milestone CEED-MS38
CEED ECP Milestone Report: High-order algorithmic developments and optimizations for more robust exascale applications Open
ECP Milestone Report High-order algorithmic developments and optimizations for more robust exascale applications WBS 2.2.6.06, Milestone CEED-MS38
On the entropy projection and the robustness of high order entropy stable discontinuous Galerkin schemes for under-resolved flows Open
High order entropy stable schemes provide improved robustness for computational simulations of fluid flows. However, additional stabilization and positivity preserving limiting can still be required for variable-density flows with under-re…
HipBone: A performance-portable GPU-accelerated C++ version of the NekBone benchmark Open
We present hipBone, an open source performance-portable proxy application for the Nek5000 (and NekRS) CFD applications. HipBone is a fully GPU-accelerated C++ implementation of the original NekBone CPU proxy application with several novel …
Highly Optimized Full-Core Reactor Simulations on Summit Open
Nek5000/RS is a highly-performant open-source spectral element code for simulation of incompressible and low-Mach fluid flow, heat transfer, and combustion with a particular focus on turbulent flows in complex domains. It is based on high-…
Port and optimize the CEED software stack to Aurora/Frontier EA (ECP Milestone Report) Open
The goal of this milestone was to port the CEED software stack, including Nek, MFEM and libCEED to the Frontier and Aurora early access hardware, work on optimizing the performance on AMD and Intel GPUs, and demonstrate impact in CEED-enab…
A Local Discontinuous Galerkin Level Set Reinitialization with Subcell Stabilization on Unstructured Meshes Open
In this paper we consider a level set reinitialization technique based on a high-order, local discontinuous Galerkin method on unstructured triangular meshes. A finite volume based subcell stabilization is used to improve the nonlinear sta…
Efficient exascale discretizations: High-order finite element methods Open
Efficient exploitation of exascale architectures requires rethinking of the numerical algorithms used in many large-scale applications. These architectures favor algorithms that expose ultra fine-grain parallelism and maximize the ratio of…
NekRS, a GPU-Accelerated Spectral Element Navier-Stokes Solver Open
The development of NekRS, a GPU-oriented thermal-fluids simulation code based on the spectral element method (SEM) is described. For performance portability, the code is based on the open concurrent compute abstraction and leverages scalab…
High-order algorithmic developments and optimizations for large-scale GPU-accelerated simulations (Milestone CEED-MS36) Open
The goal of this milestone was to improve the high-order software ecosystem for CEED-enabled ECP applications by making progress on efficient matrix-free kernels targeting forthcoming ECP architectures. These kernels included matrix-free p…
Initial Guesses for Sequences of Linear Systems in a GPU-Accelerated Incompressible Flow Solver Open
We consider several methods for generating initial guesses when iteratively solving sequences of linear systems, showing that they can be implemented efficiently in GPU-accelerated PDE solvers, specifically solvers for incompressible flow.…
Entropy stable modal discontinuous Galerkin schemes and wall boundary conditions for the compressible Navier-Stokes equations Open
Entropy stable schemes ensure that physically meaningful numerical solutions also satisfy a semi-discrete entropy inequality under appropriate boundary conditions. In this work, we describe a discretization of viscous terms in the compress…
CEED ECP Milestone Report: Support CEED-enabled ECP applications in their preparation for Aurora/Frontier Open
ECP Milestone Report Support CEED-enabled ECP applications in their preparation for Aurora/Frontier WBS 2.2.6.06, Milestone CEED-MS35
Support CEED-enabled ECP applications in their preparation for Aurora/Frontier Open
The goal of this milestone was to help CEED-enabled ECP applications (particularly ExaSMR, MARBL, ExaAM, ExaWind and E3SM) in their preparations for the Aurora and Frontier architectures. This work included collaboration with ECP vendors a…
Portable high-order finite element kernels I: Streaming Operations Open
This paper is devoted to the development of highly efficient kernels performing vector operations relevant in linear system solvers. In particular, we focus on the low arithmetic intensity operations (i.e., streaming operations) performed …