Institute for Advanced Simulation (IAS)
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Institute for Advanced Simulation (IAS)
Speck, Robert (Ed.) (2009)
Technical Report IB200904, 2009
Jonathan Groß, Universität Leipzig
Adviser: Thomas Neuhaus, Marcus Richter, Binh Trieu
A simple model of a condensed polymer was simulated using the parallel tempering algorithm. The implementation makes use of multiple cores in modern workstations utilizing POSIX threads. Also there is an outlook to porting the parallel tempering algorithm to GPGPUs using NVIDIA's CUDA.
Ricardo Kennedy, Universität zu Köln
Adviser: Stefan Dürr
The controlledNOT (CNOT) gate is implemented faulttolerantly using the Juelich Massively Parallel Ideal Quantum Computer Simulator (JUMPIQCS) and its performance is tested under the influence of two different error sources: For decoherence errors, we find that the threshold for effective error correction (10^{6} < pthr< 10^{5}) is comparable to the single qubit threshold found in [1]. In the case of operational errors, we find that the threshold is of the same order of magnitude as in the single qubit case, but dependent on the initial state. It is determined to be σ_{thr1}=(5.5±0.3)*10^{2} for a separable initial state 11> and σ_{thr2}=(2.0±0.3)*10^{2} for the maximally entangled state 1/√2*(01>10>)
Malik Kirchner, Humboldt University Berlin
Adviser: Stefan Dürr
Calculations in lattice are very time consuming and need an enormous amount of memory and computing power. Inverting the Diracoperator is very costly. Many architectures compute faster in single than double precision. It is possible to speed up the inversion of the Diracoperator by iterative ``mixed precision'' solvers by a factor of almost two. The MonteCarlo integration is done by a multihit Metropolis algorithm based on random uniformly distributed (N)
Lukasz Kucharski, Adam Mickiewicz University Poznan
Adviser: Jan Meinke, Sandipan Mohanty, Wolfgang Frings
Recently ProFASi application has encountered the problem of excessive file usage on massively parallel systems. This became a real concern in terms of performance degradation and the file number quota limits. This work focuses on integrating SIONlib into ProFASi by introducing a new middle layer library called SFFS. SFFS aims to extend SIONlib capabilities to make it a general parallel I/O replacement for standard C/C++ paradigms. This paper introduces SFFS concepts and discusses ProFASi performance gains and the integration process.
Stilianos Louca, Friedrich Schiller Universität Jena
Adviser: Paul Gibbon, Benjamin Berberich
In particle codes for fusion plasma simulations, an upper bound for the integration timestep is set by the high frequency gyromotions (∼ THz) of electrons. A method for replacing the exact electron positions by their guiding centers is discussed and tested on single particle simulations. It is shown, that for typical electromagnetic fields found in fusion experiments as the TOKAMAK, the timestep can be increased by a factor of up to 100, while still maintaining deviations of the guiding centers in the order of 10^{2} gyroradii.
Moreover, a divergencefree interpolation method is introduced for cylindersymmetric magnetic fields defined on triangular meshes, which results in an almost everywhere smooth field. The interpolation is reduced to 1dimensional interpolations and can include an arbitrary number of basepoints.
Stefan Maintz, RWTH Aachen University
Adviser: Thomas Müller
Density functional theory (DFT) calculations have become an elemental tool for various natural sciences over the past decades. In this work calculations on 3dtransition metal complexes with Phthalocyanine ligands have been carried out using the B3LYP hybrid functional, in order to evaluate the performance of DFT applied to openshell complexes that contain many electronic excited states in the vincinity of the ground state. The results have been compared with predictions and expectations arising from ligand field theory (LFT). It was found that DFT apparently has inherent errors as not even expected trends within
Hannah Rittich, Bergische Universität Wuppertal
Adviser: Bernhard Steffen
In this report we will analyse the quality and performance of the library Hypre, a library wich provides highly parallel preconditioners and solvers for large sparse systems of linear equations. First we will give a short introduction into a certain class of iterative methods and preconditioners. Afterwards we will present results from different experiments analysing different parts of Hypre.
Martin Rückl, JuliusMaximiliansUniversität Würzburg
Adviser: Walter Nadler
Constrictions of heart arteries called stenosis can be detected by analysing the configuration of capillaries in myocardium using nuclear magnetic resonance (NMR). In this work a simulation model for the NMR signal formation was developed to check influence of capillary configuration on transversal relaxation processes. It has been found that faster diffusion strongly reinforces geometric influence.
Theodros Zelleke, RuhrUniversität Bochum
Adviser: Godehard Sutmann
A new parallel algorithm for classical Molecular Dynamics is presented. The algorithm is an extension to a common domain decomposition algorithm and is suitable for simulation systems with short range forces and an inhomogenous distribution of the particles and for low density systems. The implementation is presented in the context of the combined Molecular Dynamics/ Multiparticle Collision Dynamics program MP2C.