An efficient MPI/OpenMP parallelization of the Hartree-Fock method for the second generation of Intel Xeon Phi processor

Modern OpenMP threading techniques are used to convert the MPI-only Hartree-Fock code in the GAMESS program to a hybrid MPI/OpenMP algorithm. Two separate implementations that differ by the sharing or replication of key data structures among threads are considered, density and Fock matrices. All implementations are benchmarked on a super-computer of 3,000 Intel Xeon Phi processors. With 64 cores per processor, scaling numbers are reported on up to 192,000 cores. The hybrid MPI/OpenMP implementation reduces the memory footprint by approximately 200 times compared to the legacy code. The MPI/OpenMP code was shown to run up to six times faster than the original for a range of molecular system sizes.Comment: SC17 conference paper, 12 pages, 7 figure

Rate of steady-state reconnection in an incompressible plasma

The reconnection rate is obtained for the simplest case of 2D symmetric reconnection in an incompressible plasma. In the short note (Erkaev et al., Phys. Rev. Lett.,84, 1455 (2000)), the reconnection rate is found by matching the outer Petschek solution and the inner diffusion region solution. Here the details of the numerical simulation of the diffusion region are presented and the asymptotic procedure which is used for deriving the reconnection rate is described. The reconnection rate is obtained as a decreasing function of the diffusion region length. For a sufficiently large diffusion region scale, the reconnection rate becomes close to that obtained in the Sweet-Parker solution with the inverse square root dependence on the magnetic Reynolds number, determined for the global size of the current sheet. On the other hand, for a small diffusion region length scale, the reconnection rate turns out to be very similar to that obtained in the Petschek model with a logarithmic dependence on the magnetic Reynolds number. This means that the Petschek regime seems to be possible only in the case of a strongly localized conductivity corresponding to a small scale of the diffusion region.Comment: 11 pages, 3 figure

The structure of Atlantic Water at Eurasian continental slope in summer 2007

Intensive field campaigns during the IPY (2007-2009) allowed unprecedented coverage of Eurasian continental slope by CTD measurements. These data allowed detailed mapping of the warm Atlantic water on its way from Fram Strait to the East Siberian Sea. Fourteen cross-slope sections, carried out by Russian, US and German scientists in August-September 2007 were used to determine position and properties of the warm Atlantic water core. Temperature and salinity data were examined against traditional concept of warm intermediate layer in the Arctic Ocean and in the view of recently introduced new ideas (e.g. seasonal oscillations in AW layer far from Fram Strait). Joined analysis of CTD data with long-term mooring observations demonstrated complex nature of warming-cooling pulses, which enter Arctic Ocean through Fram Strait and effect thermal conditions in Eurasian sector of the Arctic Ocean

Studienführer

... Mit fast 35.000 Studierenden, darunter rund 7.000 AusländerInnen aus 129 Nationen, zählt die Johann Wolfgang Goethe-Universität zu den zehn größten Hochschulen Deutschlands. Unsere Universität bietet eine besonders rege Studienatmosphäre, die nicht nur durch die große Breite wissenschaftlicher Disziplinen, sondern auch durch das Ambiente einer der europäischen Metropolen geprägt ist. ..

Дерево горит

To relax the local authorities and to receive the guests of high rank «with no tie» the so-called «Fisherman's House» was built at the source of Angara-river, near Lake Baikal. Vladimir Ivanov, a young architect, was noticed by his skillful performa nee of exclusive orders and became the author of this house. At the time of ferroconcrete boom the proposal to build a wooden guest house turned out to be unexpectedly to the point and was graciously approved. The economic department was entrusted to select the men good for carpenter's work, and the forestry department was entrusted to provide thick round timber. And the work started. But, as it usually happens, the workers did not take the trouble and made the first eight rims of the current timber with an inappropriate diameter.And when Pavlov insisted on demolishing the construction and replacing the logs by the logs with the necessary diameter, the building work obeyed to his will and was finished suecessfully.The architecture of the house is not the derived action of the saw and the fret-saw. It is a technology of the axe. It is natural, convincing and original. It is no use to look for the local sources in it. It grew up in the area of timber and cold winter. And this clear and efficient action kept the construction from the annoying vulgarity and provided Siberian exotics easily penetrating into one's soul, refined as it may be.One of the eminent guests said with admiration: «Even if Pavlov had created nothing more, he would have justified his professional choice with this single house.» Why not to say it as a good toast. However, this is a suitable case to add: style is an absence of style. It is a taste.After the Fisherman's House Irkutsk architects were attracted by wood. They followed the strictness in wood and, as much as they could, created a couple of successful remakes, until the cylinder logs and ... new Russian architects appeared. With their own aesthetics.After Pavlov had left Irkutsk, near his house appeared another one, it was not a log house, and its style was glaringly unfriendly. And soon the Fisherman's House burnt down. Not with vexation, but naturally, with smoke and fire. The author of the building next door considers the rebuilding of the lost house unpractical

Propagation of tsunami-induced acoustic-gravity waves in the atmosphere

A dynamical core of an atmospheric GCM is utilized for assessing the qualitative picture of propagation of atmospheric acoustic-gravity waves in response to perturbations generated by tsunami waves at the surface. Both resting isothermal atmosphere and model- generated atmosphere with realistic stratification and circulation features were considered. Shallow water tsunami model was run in two different configurations: ocean of equal depth of 4 km and ocean with realistic continents and bottom topography. Amplitude and timing of atmospheric response is analyzed as a function of vertical stratification and configuration of atmospheric jets. This approach has a potential for early tsunami detection by measuring changes in electric properties of the upper atmosphere in response to acoustic-gravity waves generated by tsunami.DJN was supported in part by Cooperative Institute for Alaska Research with funds from NOAA under cooperative agreement NA08OAR4320751 with the University of Alaska

Uncertainties in Arctic Precipitation

We acknowledge the generous support of the National Science Foundation under grant ARC-0909525,as well as the JAMSTEC- IARC cooperative agreement.It is crucial to measure precipitation accurately to predict future water budget with confidence. In our study, we aim to understand and compare precipitation datasets and discrepancies associated with them. We divide our datasets into three classes-raw data (data that have only been preprocessed to minimum quality control);corrected products (data that have been adjusted by their respective authors); finally, a reanalysis dataset (a combination of observed data and model output)

Nanocomposition of PEDOT:PSS with metal phthalocyanines as promising hole transport layers for organic photovoltaics

PEDOT:PSS is one of the most widely used materials as a hole selective layer in organic photovoltaics due to its easy processing and high reproducibility. Unfortunately, the material is limited when testing new donor:acceptor systems due to its intrinsic frontier energy levels which typically leads to energy losses due to inadequate energy level alignment and presence of resistive losses. In this work, PEDOT:PSS:metal phthalocyanines nanocomposite thin films are formulated and used as hole transport layer for organic solar cells (OSCs). PEDOT:PSS is formulated with H2Pc, CuPc, CoPc and ZnPc metal phthalocyanines (MPc) with nanobelt morphology which confers the compatibility with the active layer. Atomic force microscopy (AFM) and x-ray diffraction (XRD) were used to study the morphology and structure of nanocomposite films, respectively. OSCs based on PEDOT:PSS:MPc nanocomposite films were fabricated and the effect of hybrid hole transport layer with various phthalocyanines on photovoltaics properties was studied. Overall, nanocomposition of PEDOT:PSS with metal phthalocyanines improves the final power conversion efficiency of solar cells by 20% by a reduction of the resistive losses due to inadequate energy level alignment. The addition of metal phthalocyanines to PEDOT:PSS is a promising method for tailor-made hole transport materials for new donor:acceptor systems to improve their efficiencies.Funding for open access charge: CRUE-Universitat Jaume