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Reactant Coordinate Based State-to-State Reactive Scattering Dynamics Implemented on Graphical Processing Units

JOURNAL OF PHYSICAL CHEMISTRY A 2014年第39期118卷 8929-8935页

作者： Zhang, Pei-Yu Han, Ke-Li Chinese Acad Sci Dalian Inst Chem Phys State Key Lab Mol React Dynam Dalian 116023 Peoples R China

A parallel code for state-to-state quantum dynamics with propagation of time-dependent wavepacket in reactant coordinates has been developed on graphical processing units (GPUs). The propagation of wavepacket and the transformation of wavepacket from reactant to product Jacobi coordinates are entirey calculated on GPUs. A new interpolation procedure is introduced for coordinate transformation to decrease the five loop computation to two four loop computations. This procedure has a neglible consumption of extra GPU memory in comparison with that of the wavepacket and produces a considerable acceleration of the computational speed of the transformation. The code is tested to get differential cross sections of H+HD reaction and state-resolved reaction probabilities of O+HD reaction and state resolved reaction probabilities of O+HD for total angular momenta J = 0, 10, 20, and 30. The average speedups are 57.0 and 83.5 for the parallel computations on two c2070 and K20m GPUs relative to serial computation on Intel E5620 CPU, respectively.

关键词： SCATTERING (Physics) QUANTUM theory GRAPHICS processing units (Computers) PARALLEL computers WAVE packets interpolation algorithms

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Numerical Solution of Two-Point Boundary Value Problems by Interpolating Subdivision Schemes

ABSTRACT AND APPLIED ANALYSIS

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ABSTRACT AND APPLIED ANALYSIS 2014年第none期2014卷 1-13页

作者： Mustafa, Ghulam Ejaz, Syeda Tehmina Islamia Univ Bahawalpur Dept Math Bahawalpur 63100 Punjab India

A numerical interpolating algorithm of collocation is formulated, based on 8-point binary interpolating subdivision schemes for the generation of curves, to solve the two-point third order boundary value problems. It is observed that the algorithm produces smooth continuous solutions of the problems. Numerical examples are given to illustrate the algorithm and its convergence. Moreover, the approximation properties of the collocation algorithm have also been discussed.

关键词： NUMERICAL solutions to differential equations interpolation algorithms MATHEMATICAL programming APPROXIMATION algorithms STOCHASTIC convergence

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Model-independent constraints on the cosmological anisotropic stress

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Physical Review D 2014年第6期89卷 063538-063538页

作者： Luca Amendola Simone Fogli Alejandro Guarnizo Martin Kunz Adrian Vollmer Institut Für Theoretische Physik Ruprecht-Karls-Universität Heidelberg Philosophenweg 16 69120 Heidelberg Germany Dipartimento di Fisica e Astronomia Università di Bologna Via Irnerio 46 40126 Bologna Italy Département de Physique Théorique and Center for Astroparticle Physics Université de Genève Quai E. Ansermet 24 CH-1211 Genève 4 Switzerland African Institute for Mathematical Sciences 6 Melrose Road Muizenberg 7945 South Africa

The effective anisotropic stress or gravitational slip η=−Φ/Ψ is a key variable in the characterization of the physical origin of the dark energy, as it allows us to test for a nonminimal coupling of the dark sector to gravity in the Jordan frame. It is however important to use a fully model-independent approach when measuring η to avoid introducing a theoretical bias into the results. In this paper we forecast the precision with which future large surveys can determine η in a way that only relies on directly observable quantities. In particular, we do not assume anything concerning the initial spectrum of perturbations, nor on its evolution outside the observed redshift range, nor on the galaxy bias. We first leave η free to vary in space and time and then we model it as suggested in Horndeski models of dark energy. Among our results, we find that a future large scale lensing and clustering survey can constrain η to within 10% if k-independent, and to within 60% or better at k=0.1 h/Mpc if it is restricted to follow the Horndeski model.

关键词： JORDAN matrix DARK energy (Astronomy) PERTURBATION (Astronomy) GALAXIES -- Clusters KRONECKER delta interpolation spaces interpolation algorithms

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Selection of interpolation parameters depending on the location of measurement points

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GISCIENCE & REMOTE SENSING 2013年第5期50卷 515-526页

作者： Gosciewski, Dariusz Univ Warmia & Mazury Fac Geodesy & Land Management Inst Geodesy PL-10957 Olsztyn Poland

Digital terrain models (DTM) are created increasingly often on the basis of data recorded automatically. In the processing of such sets, there is often a need to organize the measured values and present them in the form of a specific GRID (a regular grid of nodes: the points forming the DTM are located in the corners of squares with a specified side length) or TIN (triangulated irregular network) structure. The correct setting of processing criteria and the proper selection of the structural parameters of a given structure are important factors influencing terrain model accuracy. The GRID structure not only allows data to be organized, but also increases the efficiency of data processing in LIS/GIS (land information systems/geographical information systems). If a large volume of measurement data is acquired, using the GRID structure reduces its volume and eliminates redundancies. To maintain proper DTM quality, it is necessary to set correct processing parameters during the construction of the network forming the GRID structure. This paper analyzes the effect of measurement point distribution on the selection of the structural parameters of a regular square grid used to create the digital bottom model.

关键词： GIS interpolation algorithms digital terrain model regular GRID structure large observation sets data reduction

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The effect of the distribution of measurement points around the node on the accuracy of interpolation of the digital terrain model

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JOURNAL OF GEOGRAPHICAL SYSTEMS 2013年第4期15卷 513-535页

作者： Gosciewski, Dariusz Univ Warmia & Mazury Inst Geodesy Fac Geodesy & Land Management PL-10957 Olsztyn Poland

Contemporary land information systems allow the generation of models of numerical surfaces by applying a number of interpolation algorithms. The appropriate selection of measurement points included in the calculations is one of the key factors influencing the quality and accuracy of interpolation. Properly selected points contribute to improving the accuracy of the generated surface models and to shortening the computation process. This paper analyzes the effect of the location and density of measurement points on the accuracy of interpolation surfaces in view of the morphological differentiation of the generated models.

关键词： Digital terrain model GRID structure interpolation algorithms

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Numerical research on lid-driven cavity flows using a three-dimensional lattice Boltzmann model on non-uniform meshes

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Science China(Technological Sciences) 2013年第9期56卷 2178-2187页

作者： TANG XueLin SU YanWen WANG FuJun LI LinWei College of Water Resources and Civil Engineering China Agricultural University

A lattice Boltzmann model combined with curvilinear coordinate is proposed for lid-driven cavity three-dimensional (3D) flows. For particle velocity distribution, the particle collision process is performed in physical domain, and the particle streaming process is carried out in the corresponding computational domain, which is transferred from the physical domain using interpolation method. For the interpolation calculation, a second-order upwind interpolation method is adopted on internal lattice nodes in flow fields while a second-order central interpolation algorithm is employed at neighbor-boundary lattice nodes. Then the above-mentioned model and algorithms are used to numerically simulate the 3D flows in the lid-driven cavity at Reynolds numbers of 100, 400 and 1000 on non-uniform meshes. Various vortices on the x-y, y-z and x-z symmetrical planes are successfully predicted, and their changes in position with the Reynolds number increasing are obtained. The velocity profiles of u component along the vertical centerline and w component along the horizontal centerline are both in good agreement with the data in literature and the calculated results on uniform meshes. Besides, the velocity vector distributions on various cross sections in lid-driven cavity predicted on non-uniform meshes are compared with those simulated on uniform meshes and those in the literature. All the comparisons and validations show that the 3D lattice Boltzmann model and all the numerical algorithms on non-uniform meshes are accurate and reliable to predict effectively flow fields.

关键词： lattice Boltzmann model interpolation algorithms body-fitted meshes lid-driven cavity flows

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Drag of Tandem Spheroids in Power-Law Fluids at Moderate Reynolds Numbers

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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 2013年第33期52卷 11773-11778页

作者： Rathore, A. S. Chaitanya, P. Kishore, Nanda Indian Inst Technol Guwahati Dept Chem Engn Gauhati 781039 Assam India

The relative motion between a power-law fluid and two tandem spheroid particles was investigated numerically. The field equations that govern this problem were solved using a commercial computational-fluid-dynamics-based solver. The semi-implicit method for pressure-linked equations (SIMPLE) algorithm and the quadratic upstream interpolation for convective kinematics (QUICK) scheme for convective terms were used. The solver was thoroughly benchmarked through domain and grid studies. Further, extensive new results are presented for the following ranges of conditions: Reynolds number (Re), 1-200;particle aspect ratio (e), 0.5-2;power-law index (n), 0.4-1.6;and interparticle distance (S), 2-5. The main focus of this work was to report the effects of these parameters on the streamlines, surface viscosity, and drag coefficients of the tandem particles. The dependence of the average drag coefficient on the power-law index and Reynolds number had a crossover Reynolds number that was found to be a strong function of the particle aspect ratio and the interparticle distance. Below this crossover Reynolds number, the average drag coefficient increased with decreasing power-law index, whereas for Reynolds numbers greater than the crossover Reynolds number, the average drag coefficient decreased with decreasing power-law index.

关键词： REYNOLDS number RELATIVE motion EINSTEIN field equations COMPUTATIONAL fluid dynamics interpolation algorithms DRAG coefficient

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Switching-based variable step-size approach for partial update LMS algorithms

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ELECTRONICS LETTERS 2013年第17期49卷 1081-1082页

作者： Chien, Y. -R. Tseng, W. -J. Natl Ilan Univ Dept Elect Engn Ilan City 26041 Taiwan

A switching-based variable step-size approach for partial update least-mean-square (LMS) algorithms is proposed. During the initial stage, the errors are dominated by the mismatch between the tap weights of the adaptive filter and its ideal weights. In this reported work, the error signals are correlated with the linear interpolated error signals to gain a large step-size;on the other hand, during the steady state, the errors mainly come from the additive noise. Therefore, the correlation is switched to the other mode so that the effect of noise can be eliminated. This can be done by correlating the error signals with a delayed version of the error signals, hence a small step-size is obtained during the late stages. Simulation results show that when only a half of all taps are updated in one iteration, the proposed method significantly enhances the convergence rate, especially for the 'data independent' partial update LMS algorithms.

关键词： ADAPTIVE filters ADDITIVE functions LEAST squares interpolation algorithms ANALOG integrated circuits

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A global method of data reduction applied to seven-hole probes

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EXPERIMENTS IN FLUIDS 2013年第6期54卷 1535-1535页

作者： Benay, R. Off Natl Etud & Rech Aerosp F-92190 Meudon France

A novel calibration method of multi-hole pressure probes is presented. The case of a particular in-house seven-hole probe is treated explicitly. The three components of the velocity vector are recovered by minimising the difference between the pressures measured at the ports and those interpolated in the calibration data set. A Levenberg algorithm is used for the minimisation procedure while interpolation is carried out by exponential splines. A local least square polynomial-fitting technique is also implemented as an auxiliary module. The method is efficient in determining the velocity vector in the largest part of the domain spanned by the Mach number and the orientation of the probe. An important point is that no zoning of the data is necessary. Uncertainties are found that are due to mechanical limitations of the experimental facility. An overall objective of the method is to reduce the size of the calibration data set needed for multi-hole pressure probe.

关键词： DATA reduction CALIBRATION PRESSURE interpolation algorithms MACH number POLYNOMIALS LEAST squares MODULES (Algebra)

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Local regression models for spatial interpolation of urban heat island-an example from Wrocaw, SW Poland

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THEORETICAL AND APPLIED CLIMATOLOGY 2012年第1-2期108卷 53-71页

作者： Szymanowski, Mariusz Kryza, Maciej Univ Wroclaw Inst Geog & Reg Dev PL-50137 Wroclaw Poland

Geographically weighted regression algorithm (GWR) has been applied to derive the spatial structure of urban heat island (UHI) in the city of Wrocaw, SW Poland. Seven UHI cases, measured during various meteorological conditions and characteristic of different seasons, were selected for analysis. GWR results were compared with global regression models (MLR), using various statistical procedures including corrected Akaike Information Criterion, determination coefficient, analysis of variance, and Moran's I index. It was found that GWR is better suited for spatial modeling of UHI than MLR models, as it takes into account non-stationarity of the spatial process. However, Monte Carlo and F3 tests for spatial stationarity of the independent variables suggest that for several spatial predictors a mixed GWR-MLR approach is recommended. Both local and global models were extended by the interpolation of regression residuals and used for spatial interpolation of the UHI structure. The interpolation results were evaluated with the cross-validation approach. It was found that the incorporation of the spatially interpolated residuals leads to significant improvement of the interpolation results for both GWR and MLR approaches. Because GWR is better justified in terms of statistical specification, the combined GWR + interpolated regression residuals (GWR residual kriging;GWRK) approach is recommended for spatial modeling of UHI, instead of widely applied MLR models.

关键词： URBAN heat islands SPATIAL data structures REGRESSION analysis interpolation algorithms

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