74 research outputs found
Performance of SSE and AVX Instruction Sets
SSE (streaming SIMD extensions) and AVX (advanced vector extensions) are SIMD
(single instruction multiple data streams) instruction sets supported by recent
CPUs manufactured in Intel and AMD. This SIMD programming allows parallel
processing by multiple cores in a single CPU. Basic arithmetic and data
transfer operations such as sum, multiplication and square root can be
processed simultaneously. Although popular compilers such as GNU compilers and
Intel compilers provide automatic SIMD optimization options, one can obtain
better performance by a manual SIMD programming with proper optimization: data
packing, data reuse and asynchronous data transfer. In particular, linear
algebraic operations of vectors and matrices can be easily optimized by the
SIMD programming. Typical calculations in lattice gauge theory are composed of
linear algebraic operations of gauge link matrices and fermion vectors, and so
can adopt the manual SIMD programming to improve the performance.Comment: 7 pages, 5 figures, 4 tables, Contribution to proceedings of the 30th
International Symposium on Lattice Field Theory (Lattice 2012), June 24-29,
201
Update on form factor at zero-recoil using the Oktay-Kronfeld action
We present an update on the calculation of
semileptonic form factor at zero recoil using the Oktay-Kronfeld bottom and
charm quarks on flavor HISQ ensembles generated by the MILC
collaboration. Preliminary results are given for two ensembles with and fm and MeV. Calculations have been done
with a number of valence quark masses, and the dependence of the form factor on
them is investigated on the fm ensemble. The excited state is
controlled by using multistate fits to the three-point correlators measured at
4--6 source-sink separations.Comment: 7 pages and 4 figures. Talk at The 36th Annual International
Symposium on Lattice Field Theory - LATTICE201
Beyond the Standard Model B-parameters with improved staggered fermions in QCD
We calculate the kaon mixing B-parameters for operators arising generically
in theories of physics beyond the standard model. We use HYP-smeared improved
staggered fermions on the MILC asqtad lattices. Operator matching
is done perturbatively at one-loop order. Chiral extrapolations are done using
"golden combinations" in which one-loop chiral logarithms are absent. For the
combined sea-quark mass and continuum extrapolation, we use three lattice
spacings: and . Our results have a
total error of 5-6%, which is dominated by the systematic error from matching
and continuum extrapolation. For two of the BSM -parameters, we agree with
results obtained using domain-wall and twisted-mass dynamical fermions, but we
disagree by for the other two.Comment: 7 pages, 5 figures, Lattice 2013 Proceedin
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