177 research outputs found
High-performance generalized tensor operations: A compiler-oriented approach
The efficiency of tensor contraction is of great importance. Compilers cannot optimize it well enough to come close to the performance of expert-tuned implementations. All existing approaches that provide competitive performance require optimized external code. We introduce a compiler optimization that reaches the performance of optimized BLAS libraries without the need for an external implementation or automatic tuning. Our approach provides competitive performance across hardware architectures and can be generalized to deliver the same benefits for algebraic path problems. By making fast linear algebra kernels available to everyone, we expect productivity increases when optimized libraries are not available. © 2018 Association for Computing Machinery
Socio – cultural existence of modern East Mary subethnos
The article deals with the history, traditions and way of life of sub-ethnic group of the Finno-Ugric tribes –the Eastern Maris, who are considered the "last pagans of Europe". Using specific ethnographic material, scientific and popular-scientific works, the authors showed the unique culture of the Eastern Maris sub-ethnos, pagan beliefs, preserved to date and reflecting people’s social existence, beauty of the traditions and essential national characteristics. The authors draw a conclusion that the Eastern Maris present an independent sub-ethnos tending to self-reproduction. Being amidst the powerful Slavic and Turkic civilizations, the Eastern Marian sub ethnos managed to maintain its national self-identity with some borrowings from neighboring cultures
Nuclear Scissors Mode with Pairing
The coupled dynamics of the scissors mode and the isovector giant quadrupole
resonance are studied using a generalized Wigner function moments method taking
into account pair correlations. Equations of motion for angular momentum,
quadrupole moment and other relevant collective variables are derived on the
basis of the time dependent Hartree-Fock-Bogoliubov equations. Analytical
expressions for energy centroids and transitions probabilities are found for
the harmonic oscillator model with the quadrupole-quadrupole residual
interaction and monopole pairing force. Deformation dependences of energies and
values are correctly reproduced. The inclusion of pair correlations
leads to a drastic improvement in the description of qualitative and
quantitative characteristics of the scissors mode.Comment: 36 pages, 5 figures, the results of calculation by another method and
the section concerning currents are adde
Gross shell structure at high spin in heavy nuclei
Experimental nuclear moments of inertia at high spins along the yrast line
have been determined systematically and found to differ from the rigid-body
values. The difference is attributed to shell effects and these have been
calculated microscopically. The data and quantal calculations are interpreted
by means of the semiclassical Periodic Orbit Theory. From this new perspective,
features in the moments of inertia as a function of neutron number and spin, as
well as their relation to the shell energies can be understood. Gross shell
effects persist up to the highest angular momenta observed.Comment: 40 pages total; 22 pages text, 19 figures sent as 27 .png file
Continued fraction representation of the Coulomb Green's operator and unified description of bound, resonant and scattering states
If a quantum mechanical Hamiltonian has an infinite symmetric tridiagonal
(Jacobi) matrix form in some discrete Hilbert-space basis representation, then
its Green's operator can be constructed in terms of a continued fraction. As an
illustrative example we discuss the Coulomb Green's operator in
Coulomb-Sturmian basis representation. Based on this representation, a quantum
mechanical approximation method for solving Lippmann-Schwinger integral
equations can be established, which is equally applicable for bound-, resonant-
and scattering-state problems with free and Coulombic asymptotics as well. The
performance of this technique is illustrated with a detailed investigation of a
nuclear potential describing the interaction of two particles.Comment: 7 pages, 4 ps figures, revised versio
Current status of the ecosystems in the territory of Tatneft OAO industrial activity
The brief analysis of a current status of an environment in the territory of Tatneft OAO activity is carried out. A species diversity of flora and fauna representatives is estimated. Efforts for the environmental conditions determination are performed. The parameter of stability of region ecosystems development is computed
Calculation of the properties of the rotational bands of Gd
We reexamine the long-standing problem of the microscopic derivation of a
particle-core coupling model. We base our research on the Klein-Kerman
approach, as amended by D\"onau and Frauendorf. We describe the formalism to
calculate energy spectra and transition strengths in some detail. We apply our
formalism to the rotational nuclei Gd, where recent experimental
data requires an explanation. We find no clear evidence of a need for Coriolis
attenuation.Comment: 27 pages, 13 uuencoded postscript figures. Uses epsf.st
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