Publications - Daniel Tameling

Journal Article

  1. Multilevel Summation for Dispersion: A Linear-Time Algorithm for 1/r^6 Potentials
    Journal of Chemical Physics, Volume 140, pp. 024105, January 2014.
    @article{Tameling2014:590,
        author  = "Daniel Tameling and Paul Springer and Paolo Bientinesi and {Ahmed E.} Ismail",
        title   = "Multilevel Summation for Dispersion: A Linear-Time Algorithm for 1/r^6 Potentials",
        journal = "Journal of Chemical Physics",
        year    = 2014,
        volume  = 140,
        pages   = 24105,
        month   = jan,
        url     = "http://arxiv.org/abs/1308.4005"
    }
    The multilevel summation (MLS) method was developed to evaluate long-range interactions in molecular dynamics (MD) simulations. MLS was initially introduced for Coulombic potentials; we have extended this method to dispersion interactions. While formally short-ranged, for an accurate calculation of forces and energies in cases such as in interfacial systems, dispersion potentials require long-range methods. Since long-range solvers tend to dominate the time needed to perform MD calculations, increasing their performance is of vital importance. The MLS method offers some significant advantages when compared to mesh-based Ewald methods like the particle-particle particle-mesh and particle mesh Ewald methods. Unlike mesh-based Ewald methods, MLS does not use fast Fourier transforms and is thus not limited by communication and bandwidth concerns. In addition, it scales linearly in the number of particles, as compared to the O(N log N) complexity of the mesh-based Ewald methods. While the structure of the MLS method is invariant for different potentials, every algorithmic step had to be adapted to accommodate the 1/r^6 form of the dispersion interactions. In addition, we have derived error bounds, similar to those obtained by Hardy for the electrostatic MLS. Using a prototype implementation, we can already demonstrate the linear scaling of the MLS method for dispersion, and present results establishing the accuracy and efficiency of the method.
    abstractwebPDFbibtexhide

Theses

  1. Algorithmen fuer nichtlokale Materialgesetze in der Gradienten-Einkristall-Plastizitaet
    Diplomarbeit, Karlsruhe Institute of Technology (KIT), 2011.
    @mastersthesis{Tameling2011:458,
        author = "Daniel Tameling",
        title  = "Algorithmen fuer nichtlokale Materialgesetze in der Gradienten-Einkristall-Plastizitaet",
        school = "Karlsruhe Institute of Technology (KIT)",
        year   = 2011,
        type   = "Diplomarbeit",
        url    = "/~tameling/sources/Diplomarbeit.pdf"
    }
    The scope of this work is the comparison of different algorithms for single crystal plasticity with consideration of the Nye-tensor in a implementation within the Finite-Element- Method. Therefore, the plastic variables are included in the solution vector of the system of linear equations. For this purpose the kinematics of a single crystal are revised. Subsequently the free energy of the crystal is established, where the Nye-tensor is incorporated. Then the principle of virtual power is exploited to find a formulation, which is solved with the Finite-Element-Method. There are different ways to incorporate the constraints into the resultant equations. In this work it is done with the Active Set Search. But there are different variants where this Search is committed during the Newton-iteration. Subsequently it is tested whether these different methods lead to equivalent solutions and they are compared regarding their computational costs. For the simulation only one active slip system is used. Finally these methods are rated.
    abstractPDFbibtexhide
  2. Modellierung und Simulation muskelgesteuerter Bewegungen eines menschlichen Skelettmodells
    Studienarbeit, Karlsruhe Institute of Technology (KIT), 2009.
    @mastersthesis{Tameling2009:930,
        author = "Daniel Tameling",
        title  = "Modellierung und Simulation muskelgesteuerter Bewegungen eines menschlichen Skelettmodells",
        school = "Karlsruhe Institute of Technology (KIT)",
        year   = 2009,
        type   = "Studienarbeit",
        url    = "/~tameling/sources/Studienarbeit.pdf"
    }
    PDFbibtexhide

Technical Report

  1. A Note on Time Measurements in LAMMPS
    Aachen Institute for Computational Engineering Science, RWTH Aachen, February 2016.
    Technical Report AICES-2016/02-1.
    @techreport{Tameling2016:140,
        author      = "Daniel Tameling and Paolo Bientinesi and {Ahmed E.} Ismail",
        title       = "A Note on Time Measurements in LAMMPS",
        institution = "Aachen Institute for Computational Engineering Science, RWTH Aachen",
        year        = 2016,
        month       = feb,
        note        = "Technical Report AICES-2016/02-1",
        url         = "http://arxiv.org/abs/1602.05566"
    }
    We examine the issue of assessing the efficiency of components of a parallel program at the example of the MD package LAMMPS. In particular, we look at how LAMMPS deals with the issue and explain why the approach adopted might lead to inaccurate conclusions. The misleading nature of this approach is subsequently verified experimentally with a case study. Afterwards, we demonstrate how one should correctly determine the efficiency of the components and show what changes to the code base of LAMMPS are necessary in order to get the correct behavior.
    abstractPDFbibtexhide