16 research outputs found
Extending the QUDA library for Domain Wall and Twisted Mass fermions
We extend the QUDA library, an open source library for performing calculations in lattice QCD on Graphics
Processing Units (GPUs) using NVIDIA's CUDA platform, to include kernels for non-degenerate twisted mass and
multi-gpu Domain Wall fermion operators. Performance analysis is provided for both cases
A QUDA-branch to compute disconnected diagrams in GPUs
Although QUDA allows for an efficient computation of many QCD quantities, it
is surprinsingly lacking tools to evaluate disconnected diagrams, for which
GPUs are specially well suited. We aim to fill this gap by creating our own
branch of QUDA, which includes new kernels and functions required to calculate
fermion loops using several methods and fermionic regularizations.Comment: 7 pages, 4 figures. Proceedings of the talk given during the code
session of the 31st International Symposium on Lattice Field Theory, July 29
- August 3, 2013, Mainz, Germany. Added a missing reference (number [4]
Heat kernel of non-minimal gauge field kinetic operators on Moyal plane
We generalize the Endo formula originally developed for the computation of
the heat kernel asymptotic expansion for non-minimal operators in commutative
gauge theories to the noncommutative case. In this way, the first three
non-zero heat trace coefficients of the non-minimal U(N) gauge field kinetic
operator on the Moyal plane taken in an arbitrary background are calculated. We
show that the non-planar part of the heat trace asymptotics is determined by
U(1) sector of the gauge model. The non-planar or mixed heat kernel
coefficients are shown to be gauge-fixing dependent in any dimension of
space-time. In the case of the degenerate deformation parameter the lowest
mixed coefficients in the heat expansion produce non-local gauge-fixing
dependent singularities of the one-loop effective action that destroy the
renormalizability of the U(N) model at one-loop level. The twisted-gauge
transformation approach is discussed.Comment: 21 pages, misprints correcte
Nucleon Mass with Highly Improved Staggered Quarks
We present the first computation in a program of lattice-QCD baryon physics
using staggered fermions for sea and valence quarks. For this initial study, we
present a calculation of the nucleon mass, obtaining MeV with all
sources of statistical and systematic errors controlled and accounted for. This
result is the most precise determination to date of the nucleon mass from first
principles. We use the highly-improved staggered quark action, which is
computationally efficient. Three gluon ensembles are employed, which have
approximate lattice spacings fm, fm, and fm, each with
equal-mass /, , and quarks in the sea. Further, all ensembles have
the light valence and sea / quarks tuned to reproduce the physical pion
mass, avoiding complications from chiral extrapolations or nonunitarity. Our
work opens a new avenue for precise calculations of baryon properties, which
are both feasible and relevant to experiments in particle and nuclear physics.Comment: 33 pages, 19 figures; published in Physical Review
Evaluating Portable Parallelization Strategies for Heterogeneous Architectures in High Energy Physics
High-energy physics (HEP) experiments have developed millions of lines of
code over decades that are optimized to run on traditional x86 CPU systems.
However, we are seeing a rapidly increasing fraction of floating point
computing power in leadership-class computing facilities and traditional data
centers coming from new accelerator architectures, such as GPUs. HEP
experiments are now faced with the untenable prospect of rewriting millions of
lines of x86 CPU code, for the increasingly dominant architectures found in
these computational accelerators. This task is made more challenging by the
architecture-specific languages and APIs promoted by manufacturers such as
NVIDIA, Intel and AMD. Producing multiple, architecture-specific
implementations is not a viable scenario, given the available person power and
code maintenance issues.
The Portable Parallelization Strategies team of the HEP Center for
Computational Excellence is investigating the use of Kokkos, SYCL, OpenMP,
std::execution::parallel and alpaka as potential portability solutions that
promise to execute on multiple architectures from the same source code, using
representative use cases from major HEP experiments, including the DUNE
experiment of the Long Baseline Neutrino Facility, and the ATLAS and CMS
experiments of the Large Hadron Collider. This cross-cutting evaluation of
portability solutions using real applications will help inform and guide the
HEP community when choosing their software and hardware suites for the next
generation of experimental frameworks. We present the outcomes of our studies,
including performance metrics, porting challenges, API evaluations, and build
system integration.Comment: 18 pages, 9 Figures, 2 Table