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9,200 | Harmonic analysis of random number generators and multiplicative groups of residue class rings | physics.comp-ph | The spectral test of random number generators (R.R. Coveyou and R.D.
McPherson, 1967) is generalized. The sequence of random numbers is analyzed
explicitly not just via their n-tupel distributions. The generalized analysis
of many generators becomes possible due to a theorem on the harmonic analysis
of multiplicative g... | physics |
9,201 | Harmonic analysis of random number generators | physics.comp-ph | The spectral test of random number generators (R.R. Coveyou and R.D.
McPherson, 1967) is generalized. The sequence of random numbers is analyzed
explicitly, not just via their n-tupel distributions. We find that the mixed
multiplicative generator with power of two modulus does not pass the extended
test with an ideal r... | physics |
9,202 | A Fast Algorithm for High-Dimensional Markov Processes with Finite Sets of Transition Rates | physics.comp-ph | The discrete class algorithm presented in this paper is an efficient
simulation tool for stochastic processes governed by a reasonably small set of
transition rates. The algorithm is presented, its performance compared to
prevailing methods and applications to epitaxial growth and neuronal models are
sketched.
Source... | physics |
9,203 | Simultaneously Dissipative Operators And The Infinitesimal Moore Effect In Interval Spaces | physics.comp-ph | One of shortcomings of stepwise interval methods is the following. The
intervals determining the solution of a system are often expanded in the course
of time irrespective of the method and step used (the {\em Moore effect}). We
introduce the notion of general {\em interval spaces} and study the
infinitesimal Moore eff... | physics |
9,204 | K-system generator of pseudorandom numbers on Galois field | physics.comp-ph | We analyze the structure of the periodic trajectories of the K-system
generator of pseudorandom numbers on rational sublattice which coincides with
the Galois field. The period of the trajectories increases as a function of
lattice size and the dimension of the K-matrix. We emphasize the connection of
this approach wit... | physics |
9,205 | Modeling Metallic Microstructure Using Moving Finite Elements | physics.comp-ph | We present an efficient method for anealing 3d metallic grains using Gradient
Weighted Moving Finite Elements (GWMFE). The initial grain microstructure is
generated from Monte-Carlo evolution of a an effective discrete model on the
initial (frozen) unstructured grid generated for the external geometry of the
GWMFE calc... | physics |
9,206 | Hurst's Rescaled Range Statistical Analysis for Pseudorandom Number Generators used in Physical Simulations | physics.comp-ph | The rescaled range statistical analysis (R/S) is proposed as a new method to
detect correlations in pseudorandom number generators used in Monte Carlo
simulations. In an extensive test it is demonstrated that the RS analysis
provides a very sensitive method to reveal hidden long run and short run
correlations. Several ... | physics |
9,207 | Monte Carlo Simulation of Comptonization in Inhomogeneous Media | physics.comp-ph | Comptonization is the process in which photon spectrum changes due to
multiple Compton scatterings in the electronic plasma. It plays an important
role in the spectral formation of astrophysical X-ray and gamma-ray sources.
There are several intrinsic limitations for the analytical method in dealing
with the Comptoniza... | physics |
9,208 | Parallelization of adaptive MC Integrators | physics.comp-ph | Monte Carlo (MC) methods for numerical integration seem to be embarassingly
parallel on first sight. When adaptive schemes are applied in order to enhance
convergence however, the seemingly most natural way of replicating the whole
job on each processor can potentially ruin the adaptive behaviour. Using the
popular VEG... | physics |
9,209 | The 3-dimensional Fourier grid Hamiltonian method | physics.comp-ph | A method to compute the bound state eigenvalues and eigenfunctions of a
Schr\"{o}dinger equation or a spinless Salpeter equation with central
interaction is presented. This method is the generalization to the
three-dimensional case of the Fourier grid Hamiltonian method for
one-dimensional Schr\"{o}dinger equation. It ... | physics |
9,210 | The Anderson model of localization: a challenge for modern eigenvalue methods | physics.comp-ph | We present a comparative study of the application of modern eigenvalue
algorithms to an eigenvalue problem arising in quantum physics, namely, the
computation of a few interior eigenvalues and their associated eigenvectors for
the large, sparse, real, symmetric, and indefinite matrices of the Anderson
model of localiza... | physics |
9,211 | A Lanczos algorithm for linear response | physics.comp-ph | An iterative algorithm is presented for solving the RPA equations of linear
response. The method optimally computes the energy-weighted moments of the
strength function, allowing one to match the computational effort to the
intrinsic accuracy of the basic mean-field approximation, avoiding the problem
of solving very l... | physics |
9,212 | The solution of multi-scale partial differential equations using wavelets | physics.comp-ph | Wavelets are a powerful new mathematical tool which offers the possibility to
treat in a natural way quantities characterized by several length scales. In
this article we will show how wavelets can be used to solve partial
differential equations which exhibit widely varying length scales and which are
therefore hardly ... | physics |
9,213 | Encryption with Delayed Dynamics | physics.comp-ph | We propose here a new model of encryption of binary data taking advantage of
the complexity associated with delayed dynamics. In this scheme, the encryption
process is a coupling dynamics with various time delays between different bits
in the original data. It is shown that decoding of the encrypted data is
extremely d... | physics |
9,214 | Partial level densities for nuclear data calculations | physics.comp-ph | The main formalisms of partial level densities (PLD) used in preequilibrium
nuclear reaction models, based on the equidistant spacing model (ESM), are
considered. A collection of FORTRAN77 functions for PLD calculation by using 14
formalisms for the related partial-state densities is provided and 28 sample
cases (73 ve... | physics |
9,215 | A natural orbital functional for the many-electron problem | physics.comp-ph | The exchange-correlation energy in Kohn-Sham density functional theory is
expressed as a functional of the electronic density and the Kohn-Sham orbitals.
An alternative to Kohn-Sham theory is to express the energy as a functional of
the reduced first-order density matrix or equivalently the natural orbitals. In
the for... | physics |
9,216 | Growth Models And The Question Of Universality Classes | physics.comp-ph | In the past many papers have appeared which simulated surface growth with
different growth models. The results showed that, if models differed only
slightly in their `growth' rules, the resulting surfaces may belong to
different universality classes, i.e. they are described by different
differential equations. In the p... | physics |
9,217 | Numerical Evidence for Divergent Burnett Coefficients | physics.comp-ph | In previous papers [Phys. Rev. A {\bf 41}, 4501 (1990), Phys. Rev. E {\bf
18}, 3178 (1993)], simple equilibrium expressions were obtained for nonlinear
Burnett coefficients. A preliminary calculation of a 32 particle Lennard-Jones
fluid was presented in the previous paper. Now, sufficient resources have
become availabl... | physics |
9,218 | The lid method for exhaustive exploration of metastable states of complex systems | physics.comp-ph | The `lid' algorithm performs an exhaustive exploration of neighborhoods of
local energy minima of energy landscapes. This paper describes an
implementation of the algorithm, including issues of parallel performance and
scalability. To illustrate the versatility of the approach and to stress the
common features present ... | physics |
9,219 | Novel Reconstruction mechanisms: A comparison between group-III-nitrides and "traditional" III-V-semiconductors | physics.comp-ph | We have studied the driving forces governing reconstructions on polar GaN
surfaces employing first-principles total-energy calculations. Our results
reveal properties not observed for other semiconductors, as for example a
strong tendency to stabilize Ga-rich surfaces. This mechanism is shown to have
important conseque... | physics |
9,220 | Regular order reductions of ordinary and delay-differential equations | physics.comp-ph | We present a C program to compute by successive approximations the regular
order reduction of a large class of ordinary differential equations, which
includes evolution equations in electrodynamics and gravitation. The code may
also find the regular order reduction of delay-differential equations. | physics |
9,221 | One class of integrals evaluation in magnet solitons theory | physics.comp-ph | An analytical-numeric calculation method of extremely complicated integrals
is presented. These integrals appear often in magnet soliton theory. The
appropriate analytical continuation and a corresponding integration contour
allow to reduce the calculation of wide class of integrals to a numeric search
of integrand den... | physics |
9,222 | Algorithm for numerical integration of the rigid-body equations of motion | physics.comp-ph | A new algorithm for numerical integration of the rigid-body equations of
motion is proposed. The algorithm uses the leapfrog scheme and the quantities
involved are angular velocities and orientational variables which can be
expressed in terms of either principal axes or quaternions. Due to specific
features of the algo... | physics |
9,223 | X-Ray Diffraction by Time-Dependent Deformed Crystals: Theoretical Model and Numerical Analysis | physics.comp-ph | The objective of this article is to study the behavior of electromagnetic
field under X-ray diffraction by time-dependent deformed crystals. Derived
system of differential equations looks like the Takagi equations in the case of
non-stationary crystals. This is a system of multidimensional first-order
hyperbolic equati... | physics |
9,224 | A Stochastic Tunneling Approach for Global Minimization of Complex Potential Energy Landscapes | physics.comp-ph | We investigate a novel stochastic technique for the global optimization of
complex potential energy surfaces (PES) that avoids the freezing problem of
simulated annealing by allowing the dynamical process to tunnel energetically
inaccessible regions of the PES by way of a dynamically adjusted nonlinear
transformation o... | physics |
9,225 | A New Technique for Sampling Multi-Modal Distributions | physics.comp-ph | In this paper we demonstrate that multi-modal Probability Distribution
Functions (PDFs) may be efficiently sampled using an algorithm originally
developed for numerical integrations by Monte-Carlo methods. This algorithm can
be used to generate an input PDF which can be used as an independence sampler
in a Metropolis-H... | physics |
9,226 | The recursive adaptive quadrature in MS Fortran-77 | physics.comp-ph | It is shown that MS Fortran-77 compilers allow to construct recursive
subroutines. The recursive one-dimensional adaptive quadrature subroutine is
considered in particular. Despite its extremely short body (only eleven
executable statements) the subroutine proved to be very effective and
competitive. It was tested on v... | physics |
9,227 | An Explicit Space-time Adaptive Method for Simulating Complex Cardiac Dynamics | physics.comp-ph | For plane-wave and many-spiral states of the experimentally based Luo-Rudy 1
model of heart tissue in large (8 cm square) domains, we show that an explicit
space-time-adaptive time-integration algorithm can achieve an order of
magnitude reduction in computational effort and memory - but without a
reduction in accuracy ... | physics |
9,228 | The Reason for the Efficiency of the Pian-Sumihara Basis | physics.comp-ph | A logical explanation as to why the choice of the Pian-Sumihara basis (as a
linear basis to approximate stress) leads to greater efficiency in enhanced
strain problems, is presented. An Airy stress function and the consequent
selective simplification resulting from the differentiation of an implied,
single, parent appr... | physics |
9,229 | Two-Particle Schroedinger Equation Animations of Wavepacket-Wavepacket Scattering (revised) | physics.comp-ph | A simple and explicit technique for the numerical solution of the
two-particle, time-dependent Schr\"{o}dinger equation is assembled and tested.
The technique can handle interparticle potentials that are arbitrary functions
of the coordinates of each particle, arbitrary initial and boundary conditions,
and multi-dimens... | physics |
9,230 | An improved Rosenbluth Monte Carlo scheme for cluster counting and lattice animal enumeration | physics.comp-ph | We describe an algorithm for the Rosenbluth Monte Carlo enumeration of
clusters and lattice animals. The method may also be used to calculate
associated properties such as moments or perimeter multiplicities of the
clusters. The new scheme is an extension of the Rosenbluth method for growing
polymer chains and is a sim... | physics |
9,231 | A Monte Carlo code for full simulation of a transition radiation detector | physics.comp-ph | A full simulation of a transition radiation detector (TRD) based on the
GEANT, GARFIELD, MAGBOLTZ and HEED codes has been developed. This simulation
can be used to study and develop TRD for high energy particle identification
using either the cluster counting or the total charge measurement method. In
this article it w... | physics |
9,232 | A Second-Order Stochastic Leap-Frog Algorithm for Multiplicative Noise Brownian Motion | physics.comp-ph | A stochastic leap-frog algorithm for the numerical integration of Brownian
motion stochastic differential equations with multiplicative noise is proposed
and tested. The algorithm has a second-order convergence of moments in a finite
time interval and requires the sampling of only one uniformly distributed
random varia... | physics |
9,233 | Comparision of direct and Fourier space techniques in time-dependent density functional theory | physics.comp-ph | Several techniques have appeared in the literatuare to solve the equations of
time-dependent density functional theory. We compare the efficiency of
different methods based on mesh representations of the wave function (direct
and Fourier space), taking as a test case the calculation of the surface
plasmon in the cluste... | physics |
9,234 | Efficient Methods for Handling Long-Range Forces in Particle-Particle Simulations | physics.comp-ph | A number of problems arise when long-range forces, such as those governed by
Bessel functions, are used in particle-particle simulations. If a simple
cut-off for the interaction is used, the system may find an equilibrium
configuration at zero temperature that is not a regular lattice yet has an
energy lower than the t... | physics |
9,235 | A unified approach for the solution of the Fokker-Planck equation | physics.comp-ph | This paper explores the use of a discrete singular convolution algorithm as a
unified approach for numerical integration of the Fokker-Planck equation. The
unified features of the discrete singular convolution algorithm are discussed.
It is demonstrated that different implementations of the present algorithm,
such as g... | physics |
9,236 | Resampling Method For Unsupervised Estimation Of Cluster Validity | physics.comp-ph | We introduce a method for validation of results obtained by clustering
analysis of data. The method is based on resampling the available data. A
figure of merit that measures the stability of clustering solutions against
resampling is introduced. Clusters which are stable against resampling give
rise to local maxima of... | physics |
9,237 | Improved efficiency with variational Monte Carlo using two level sampling | physics.comp-ph | A two level sampling method is applied to variational Monte Carlo (VMC) that
samples the one and two body parts of the wave function separately. The method
is demonstrated on a single Li_2 molecule in free space and 32 H_2 molecules in
a periodic box. This simple modification increases the efficiency of a VMC
simulatio... | physics |
9,238 | Suggestion for a Fast Heuristic for the Hamiltonian Cycle Problem | physics.comp-ph | Some years ago I demonstrated a simulated annealing heuristic for the
Hamiltonian cycle problem (Science 273, 413 (1996)). Here I propose an improved
version of this heuristic. | physics |
9,239 | A Generator of Protein Folding Kinetics States for the Diffusion-Collision Model | physics.comp-ph | Two separate algorithms for calculating the intermediate states, using
cellular automata and the initial conditions in the rate matrix for the
diffusion-collision model are introduced. They enable easy and fast
calculations of the folding probabilities of the intermediate states, even for
a very large number of microdo... | physics |
9,240 | Complex Scaling of the Faddeev Equations | physics.comp-ph | In this work we compare two different approaches to calculation of the
three-body resonances on the basis of Faddeev differential equations. The first
one is the complex scaling approach. The second method is based on an immediate
calculation of resonances as zeros of the three-body scattering matrix
continued to the p... | physics |
9,241 | Solution of Poisson's equation for finite systems using plane wave methods | physics.comp-ph | Reciprocal space methods for solving Poisson's equation for finite charge
distributions are investigated. Improvements to previous proposals are
presented, and their performance is compared in the context of a real-space
density functional theory code. Two basic methodologies are followed:
calculation of correction ter... | physics |
9,242 | Quasilinearization Approach to Nonlinear Problems in Physics with Application to Nonlinear ODEs | physics.comp-ph | The general conditions under which the quadratic, uniform and monotonic
convergence in the quasilinearization method of solving nonlinear ordinary
differential equations could be proved are formulated and elaborated. The
generalization of the proof to partial differential equations is straight
forward. The method, whos... | physics |
9,243 | Implementation of analytical Hartree-Fock gradients for periodic systems | physics.comp-ph | We describe the implementation of analytical Hartree-Fock gradients for
periodic systems in the code CRYSTAL, emphasizing the technical aspects of this
task. The code is now capable of calculating analytical derivatives with
respect to nuclear coordinates for systems periodic in 0, 1, 2 and 3 dimensions
(i.e. molecules... | physics |
9,244 | Molecular dynamics simulation for pressure-induced structural transition from C$_{60}$ fullerene into amorphous diamond | physics.comp-ph | The pressure-induced structural transition in fcc C$_{60}$ fullerene by shock
compression and rapid quenching is investigated by a semi-empirical
tight-binding molecular dynamics simulation, adopting a constant-pressure
scheme and a method of the order N electronic structure calculation. At first,
the process of the am... | physics |
9,245 | A Note on Symplectic Algorithms | physics.comp-ph | We present the symplectic algorithm in the Lagrangian formalism for the
Hamiltonian systems by virtue of the noncommutative differential calculus with
respect to the discrete time and the Euler--Lagrange cohomological concepts. We
also show that the trapezoidal integrator is symplectic in certain sense. | physics |
9,246 | Topologically Modulated Signals and Predicate Gates For Their Processing | physics.comp-ph | In the paper electromagnetic signals distinguished by their discrete
modulation of spatial distributions of fields and amplitudes are considered.
Amplitudes of the impulses play a role of predicates and discrete spatial
distributions of fields serve as predicate variables. Designed electronic gates
are different by par... | physics |
9,247 | A guided Monte Carlo method for optimization problems | physics.comp-ph | We introduce a new Monte Carlo method by incorporating a guided distribution
function to the conventional Monte Carlo method. In this way, the efficiency of
Monte Carlo methods is drastically improved. To further speed up the algorithm,
we include two more ingredients into the algorithm. First, we freeze the
sub-patter... | physics |
9,248 | An efficient k.p method for calculation of total energy and electronic density of states | physics.comp-ph | An efficient method for calculating the electronic structure in large systems
with a fully converged BZ sampling is presented. The method is based on a
k.p-like approximation developed in the framework of the density functional
perturbation theory. The reliability and efficiency of the method are
demostrated in test ca... | physics |
9,249 | Quasilinearization approach to quantum mechanics | physics.comp-ph | The quasilinearization method (QLM) of solving nonlinear differential
equations is applied to the quantum mechanics by casting the Schr\"{o}dinger
equation in the nonlinear Riccati form. The method, whose mathematical basis in
physics was discussed recently by one of the present authors (VBM), approaches
the solution o... | physics |
9,250 | Quantization of energy and writhe in self-repelling knots | physics.comp-ph | Probably the most natural energy functional to be considered for knotted
strings is the one given by the electrostatic repulsion. In the absence of
counter-charges, a charged, knotted string evolving along the energy gradient
of electrostatic repulsion would progressively tighten its knotted domain into
a point on a pe... | physics |
9,251 | Implementation of the Hough Transform for 3D Track Reconstruction in Drift Chambers | physics.comp-ph | The paper is devoted to the method for 3D reconstruction of the straight
tracks in the tracking system consisting of the drift-chamber stereo layers.
The method is based on the Hough-transform approach - the discrete case of more
general Radon transform - and takes into account both coordinates of the hit
wires and dri... | physics |
9,252 | Foam: A General-Purpose Cellular Monte Carlo Event Generator | physics.comp-ph | A general purpose, self-adapting, Monte Carlo (MC) event generator
(simulator) is described. The high efficiency of the MC, that is small maximum
weight or variance of the MC weight is achieved by means of dividing the
integration domain into small cells. The cells can be $n$-dimensional
simplices, hyperrectangles or C... | physics |
9,253 | The Heterogeneous Multi-Scale Method | physics.comp-ph | The heterogeneous multi-scale method (HMM) is a general strategy for dealing
with problems involving multi-scales, with multi-physics, using multi-grids. It
not only unifies several existing multi-scale methods, but also provide a
methodology for designing new algorithms for new applications. In this paper,
we review t... | physics |
9,254 | KANGA(ROO): Handling the micro-DST of the BaBar Experiment with ROOT | physics.comp-ph | A system based on ROOT for handling the micro-DST of the BaBar experiment is
described. The purpose of the Kanga system is to have micro-DST data available
in a format well suited for data distribution within a world-wide collaboration
with many small sites. The design requirements, implementation and experience
in pra... | physics |
9,255 | Implementation of Liu's procedure in Mathematica for use in Relativistic Constitutive Theory | physics.comp-ph | The aim of this article is to show, how computer algebra can be used when
applying Liu's procedure. Although Mathematica (a commercial product by Wolfram
Research Inc.) is used, it is possible to use other computer algebra systems as
well. | physics |
9,256 | Solving the Maxwell equations by the Chebyshev method: A one-step finite-difference time-domain algorithm | physics.comp-ph | We present a one-step algorithm that solves the Maxwell equations for systems
with spatially varying permittivity and permeability by the Chebyshev method.
We demonstrate that this algorithm may be orders of magnitude more efficient
than current finite-difference time-domain algorithms. | physics |
9,257 | Methods for parallel simulations of surface reactions | physics.comp-ph | We study the opportunities for parallelism for the simulation of surface
reactions. We introduce the concept of a partition and we give new simulation
methods based on Cellular Automaton using partitions. We elaborate on the
advantages and disadvantages of the derived algorithms comparing with Dynamic
Monte Carlo algor... | physics |
9,258 | Geometric Random Inner Products: A New Family of Tests for Random Number Generators | physics.comp-ph | We present a new computational scheme, GRIP (Geometric Random Inner
Products), for testing the quality of random number generators. The GRIP
formalism utilizes geometric probability techniques to calculate the average
scalar products of random vectors generated in geometric objects, such as
circles and spheres. We show... | physics |
9,259 | Combining multigrid and wavelet ideas to construct more efficient multiscale algorithms for the solution of Poisson's equation | physics.comp-ph | It is shown how various ideas that are well established for the solution of
Poisson's equation using plane wave and multigrid methods can be combined with
wavelet concepts. The combination of wavelet concepts and multigrid techniques
turns out to be particularly fruitful. We propose a modified multigrid V cycle
scheme ... | physics |
9,260 | Equation-Free Multiscale Computation: enabling microscopic simulators to perform system-level tasks | physics.comp-ph | We present and discuss a framework for computer-aided multiscale analysis,
which enables models at a "fine" (microscopic/stochastic) level of description
to perform modeling tasks at a "coarse" (macroscopic, systems) level. These
macroscopic modeling tasks, yielding information over long time and large space
scales, ar... | physics |
9,261 | Foam: A General purpose Monte Carlo Cellular Algorithm | physics.comp-ph | A general-purpose, self-adapting Monte Carlo (MC) algorithm implemented in
the program {\tt Foam} is described. The high efficiency of the MC, that is
small maximum weight or variance of the MC weight is achieved by means of
dividing the integration domain into small cells. The cells can be
$n$-dimensional simplices, h... | physics |
9,262 | XrdML, a new way to store (and exchange) X-ray powder diffraction measurement data | physics.comp-ph | Recently PANalytical introduced the XrdML file format as a new data platform
for powder diffraction experiments. We will explain why an industrial standard
(XML) was chosen and show the XML schema used to precisely describe the
instrumental and experimental conditions. This schema is used to validate the
contents of th... | physics |
9,263 | A Novel Scaled Boundary Finite Element Method in Computational Electromagnetics | physics.comp-ph | A Novel Scaled boundary finite element method, initially developed in Civil
Engineering, is reformulated for solving boundary value problems in
computational electromagnetics. | physics |
9,264 | Divergence Condition for the novel Scaled Boundary Finite Element Method in Computational Electromagnetics | physics.comp-ph | The divergence condition is reformulated in the scaled boundary coordinates
so as to prevent the spurious solutions in the finite element formulation. | physics |
9,265 | Application of the Covariant projection finite elements in the E field formulation for wave guide analysis | physics.comp-ph | The use of covariant projection finite elements in the efficient 3-D vector
finite element analysis of wave guide is presented. | physics |
9,266 | SINGINT: Automatic numerical integration of singular integrands | physics.comp-ph | We explore the combination of deterministic and Monte Carlo methods to
facilitate efficient automatic numerical computation of multidimensional
integrals with singular integrands. Two adaptive algorithms are presented that
employ recursion and are runtime and memory optimised, respectively. SINGINT, a
C implementation ... | physics |
9,267 | Boundary processing for Monte Carlo Simulations in the Gap-Tooth Scheme | physics.comp-ph | This note reports on a scheme for interpolating the boundary conditions be-
tween non-adjacent modeling regions when the model is based on Monte-Carlo
computations of a collection of particles. The scheme conserves particles in a
natural way, and thereby can be made to conserve other quantities. | physics |
9,268 | Deciding the Nature of the "Coarse Equation" through Microscopic Simulations: the Baby-Bathwater Scheme | physics.comp-ph | Recent developments in multiscale computation allow the solution of ``coarse
equations'' for the expected macroscopic behavior of
microscopically/stochastically evolving particle distributions without ever
obtaining these coarse equations in closed form. The closure is obtained ``on
demand'' through appropriately initi... | physics |
9,269 | Two-dimensional projections of an hypercube | physics.comp-ph | We present a method to project a hypercube of arbitrary dimension on the
plane, in such a way as to preserve, as well as possible, the distribution of
distances between vertices. The method relies on a Montecarlo optimization
procedure that minimizes the squared difference between distances in the plane
and in the hype... | physics |
9,270 | Morphology of the universal function for the critical circle map | physics.comp-ph | We describe the morphology of the universal function for the critical (cubic)
circle map at the golden mean, paying particular attention to the birth of
inflection points and their reproduction. In this way one can fully understand
its intricacies. | physics |
9,271 | Dynamics and Topological Aspects of a Reconstructed Two-Dimensional Foam Time Series Using Potts Model on a Pinned Lattice | physics.comp-ph | We discuss a method to reconstruct an approximate two-dimensional foam
structure from an incomplete image using the extended Potts mode with a pinned
lattice we introduced in a previous paper. The initial information consists of
the positions of the vertices only. We locate the centers of the bubbles using
the Euclidea... | physics |
9,272 | Lyapunov exponents in constrained and unconstrained ordinary differential equations | physics.comp-ph | We discuss several numerical methods for calculating Lyapunov exponents (a
quantitative measure of chaos) in systems of ordinary differential equations.
We pay particular attention to constrained systems, and we introduce a variety
of techniques to address the complications introduced by constraints. For all
cases cons... | physics |
9,273 | Energy minimization using Sobolev gradients: application to phase separation and ordering | physics.comp-ph | A common problem in physics and engineering is the calculation of the minima
of energy functionals. The theory of Sobolev gradients provides an efficient
method for seeking the critical points of such a functional. We apply the
method to functionals describing coarse-grained Ginzburg-Landau models commonly
used in patt... | physics |
9,274 | Global Stationary Phase and the Sign Problem | physics.comp-ph | We present a computational strategy for reducing the sign problem in the
evaluation of high dimensional integrals with non-positive definite weights.
The method involves stochastic sampling with a positive semidefinite weight
that is adaptively and optimally determined during the course of a simulation.
The optimal cri... | physics |
9,275 | Quantum signatures in laser-driven relativistic multiple-scattering | physics.comp-ph | The dynamics of an electronic Dirac wave packet evolving under the influence
of an ultra-intense laser pulse and an ensemble of highly charged ions is
investigated numerically. Special emphasis is placed on the evolution of
quantum signatures from single to multiple scattering events. We quantify the
occurrence of quan... | physics |
9,276 | Software Scalability Issues in Large Clusters | physics.comp-ph | The rapid development of large clusters built with commodity hardware has
highlighted scalability issues with deploying and effectively running system
software in large clusters. We describe here our experiences with monitoring,
image distribution, batch and other system administration software tools within
the 1000+ n... | physics |
9,277 | The GRID and the Linux Farm at the RCF | physics.comp-ph | The emergence of the GRID architecture and related tools will have a large
impact in the operation and design of present and future large clusters. We
present here the ongoing efforts to equip the Linux Farm at the RHIC Computing
Facility with Grid-like capabilities. | physics |
9,278 | HEP Applications on the Grid Canada Testbed | physics.comp-ph | A Grid testbed has been established using resources at 12 sites across Canada
involving researchers from particle physics as well as other fields of science.
We describe our use of the testbed with the BaBar Monte Carlo production and
the ATLAS data challenge software. In each case the remote sites have no
application-... | physics |
9,279 | Computational Techniques for Simulating Light Propagation in High-Energy Neutrino Telescopes | physics.comp-ph | To maximize the accuracy of background simulation and event reconstruction,
high-energy neutrino telescopes require detailed knowledge of light propagation
over a large volume of detection medium. If light scattering and absorption
leng ths in the medium are of the same scale as the detector size, this problem
can only... | physics |
9,280 | New vertex reconstruction algorithms for CMS | physics.comp-ph | The reconstruction of interaction vertices can be decomposed into a pattern
recognition problem (``vertex finding'') and a statistical problem (``vertex
fitting''). We briefly review classical methods. We introduce novel approaches
and motivate them in the framework of high-luminosity experiments like at the
LHC. We th... | physics |
9,281 | Atlas Data-Challenge 1 on NorduGrid | physics.comp-ph | The first LHC application ever to be executed in a computational Grid
environment is the so-called ATLAS Data-Challenge 1, more specifically, the
part assigned to the Scandinavian members of the ATLAS Collaboration. Taking
advantage of the NorduGrid testbed and tools, physicists from Denmark, Norway
and Sweden were abl... | physics |
9,282 | Java Physics Generator and Analysis Modules | physics.comp-ph | A Java software framework allows modules written in different languages to be
used in a high level Object-Oriented (OO) environment. Java Native Interfaces
(JNI) for Linear Collider (LC) physics event generators are used in defining a
common generator interface package. Portable-JNI for TESLA and Asian JLC
detector sim... | physics |
9,283 | Running CMS software on GRID Testbeds | physics.comp-ph | Starting in the middle of November 2002, the CMS experiment undertook an
evaluation of the European DataGrid Project (EDG) middleware using its event
simulation programs. A joint CMS-EDG task force performed a "stress test" by
submitting a large number of jobs to many distributed sites. The EDG testbed
was complemented... | physics |
9,284 | FAMOS: A Dynamically Configurable System for Fast Simulation and Reconstruction for CMS | physics.comp-ph | Detailed detector simulation and reconstruction of physics objects at the LHC
are very CPU intensive and hence time consuming due to the high energy and
multiplicity of the Monte-Carlo events and the complexity of the detectors. We
present a dynamically configurable system for fast Monte-Carlo simulation and
reconstruc... | physics |
9,285 | The CDF Data Handling System | physics.comp-ph | The Collider Detector at Fermilab (CDF) records proton-antiproton collisions
at center of mass energy of 2.0 TeV at the Tevatron collider. A new collider
run, Run II, of the Tevatron started in April 2001. Increased luminosity will
result in about 1~PB of data recorded on tapes in the next two years. Currently
the CDF ... | physics |
9,286 | Development of an Interface for Using EGS4 Physics Processes in Geant4 | physics.comp-ph | As simulation system, the variety of physics processes implemented is one of
the most important functionalities. In that sense, Geant4 is one of the most
powerful simulation toolkits. Its flexibility and expansibility brought by
object-oriented approach make it possible for us to easily assimilate external
simulation p... | physics |
9,287 | Use of the European Data Grid software in the framework of the BaBar distributed computing model | physics.comp-ph | We present an evaluation of the European Data Grid software in the framework
of the BaBar experiment. Two kinds of applications have been considered: first,
a typical data analysis on real data producing physics n-tuples, and second, a
distributed Monte-Carlo production on a computational grid. Both applications
will b... | physics |
9,288 | The POOL Data Storage, Cache and Conversion Mechanism | physics.comp-ph | The POOL data storage mechanism is intended to satisfy the needs of the LHC
experiments to store and analyze the data from the detector response of
particle collisions at the LHC proton-proton collider. Both the data rate and
the data volumes will largely differ from the past experience. The POOL data
storage mechanism... | physics |
9,289 | Lattice QCD Calculations on Commodity Clusters at DESY | physics.comp-ph | Lattice Gauge Theory is an integral part of particle physics that requires
high performance computing in the multi-Tflops regime. These requirements are
motivated by the rich research program and the physics milestones to be reached
by the lattice community. Over the last years the enormous gains in processor
performan... | physics |
9,290 | Simulation in ALICE | physics.comp-ph | ALICE, the experiment dedicated to the study of heavy ion collisions at the
LHC, uses an object-oriented framework for simulation, reconstruction and
analysis (AliRoot) based on ROOT. Here, we describe the general ALICE
simulation strategy and those components of the framework related to
simulation. Two main requiremen... | physics |
9,291 | A New Implementation of the Region of Interest Strategy for the ATLAS Second Level Trigger | physics.comp-ph | Among the many challenges presented by the future ATLAS detector at the LHC
are the high data taking rate and volume and the derivation of a rapid trigger
decision with limited resources. To address this challenge within the ATLAS
second level trigger system, a Region-of-Interest mechanism has been adopted
which dramat... | physics |
9,292 | AliEn - EDG Interoperability in ALICE | physics.comp-ph | AliEn (ALICE Environment) is a GRID-like system for large scale job
submission and distributed data management developed and used in the context of
ALICE, the CERN LHC heavy-ion experiment. With the aim of exploiting upcoming
Grid resources to run AliEn-managed jobs and store the produced data, the
problem of AliEn-EDG... | physics |
9,293 | Event Data Definition in LHCb | physics.comp-ph | We present the approach used for defining the event object model for the LHCb
experiment. This approach is based on a high level modelling language, which is
independent of the programming language used in the current implementation of
the event data processing software. The different possibilities of object
modelling ... | physics |
9,294 | Magda - Manager for grid-based data | physics.comp-ph | Magda is a distributed data manager prototype for grid-resident data. It
makes use of the MySQL open source relational database, Perl, Java and C++ to
provide file cataloging, retrieval and replication services. For data movement,
gridFTP, bbftp and scp can be chosen depending on available protocols. Third
party transf... | physics |
9,295 | The BTeV Software Tutorial Suite | physics.comp-ph | The BTeV Collaboration is starting to develop its C++ based offline software
suite, an integral part of which is a series of tutorials. These tutorials are
targeted at a diverse audience, including new graduate students, experienced
physicists with little or no C++ experience, those with just enough C++ to be
dangerous... | physics |
9,296 | Securing a HENP Computing Facility | physics.comp-ph | Traditionally, HENP computing facilities have been open facilities that are
accessed in many different ways by users that are both internal and external to
the facility. However, the need to protect the facility from cybersecurity
threats has made it difficult to maintain the openness of the facility to
off-site and on... | physics |
9,297 | Interfacing the JQMD and JAM Nuclear Reaction Codes to Geant4 | physics.comp-ph | Geant4 is a toolkit for the simulation of the passage of particles through
matter. It provides a comprehensive set of tools for geometry, tracking,
detector response, run, event and track management, visualization and user
interfaces. Geant4 also has an abundant set of physics models that handle the
diverse interaction... | physics |
9,298 | Grid Based Monitoring on the Rutgers CDF Analysis Farm | physics.comp-ph | Run II at the Fermilab Tevatron Collider started in March 2001, and it will
continue probing the high energy frontier in particle physics until the start
of the LHC at CERN. The CDF collaboration at Fermilab has already stored 260 TB
of data and expects to store 1PB of data in the next two years. The HEXCAF
computing f... | physics |
9,299 | Use of a Generic Identification Scheme Connecting Events and Detector Description in the ATLAS Experiment | physics.comp-ph | High energy physics detectors can be described hierarchically from the
different subsystems to their divisions in r, phi, theta and to the individual
readout channels. An identification schema that follows the logical
decomposition of the ATLAS detector has been introduced allowing identification
of individual readout ... | physics |
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