TY - JOUR AB - N-body methods are one of the essential algorithmic building blocks of high-performance and parallel computing. Previous research has shown promising performance for implementing n-body simulations with pairwise force calculations on FPGAs. However, to avoid challenges with accumulation and memory access patterns, the presented designs calculate each pair of forces twice, along with both force sums of the involved particles. Also, they require large problem instances with hundreds of thousands of particles to reach their respective peak performance, limiting the applicability for strong scaling scenarios. This work addresses both issues by presenting a novel FPGA design that uses each calculated force twice and overlaps data transfers and computations in a way that allows to reach peak performance even for small problem instances, outperforming previous single precision results even in double precision, and scaling linearly over multiple interconnected FPGAs. For a comparison across architectures, we provide an equally optimized CPU reference, which for large problems actually achieves higher peak performance per device, however, given the strong scaling advantages of the FPGA design, in parallel setups with few thousand particles per device, the FPGA platform achieves highest performance and power efficiency. AU - Menzel, Johannes AU - Plessl, Christian AU - Kenter, Tobias ID - 28099 IS - 1 JF - ACM Transactions on Reconfigurable Technology and Systems SN - 1936-7406 TI - The Strong Scaling Advantage of FPGAs in HPC for N-body Simulations VL - 15 ER - TY - JOUR AB -

State-of-the-art methods in materials science such as artificial intelligence and data-driven techniques advance the investigation of photovoltaic materials.

AU - Mirhosseini, Hossein AU - Kormath Madam Raghupathy, Ramya AU - Sahoo, Sudhir K. AU - Wiebeler, Hendrik AU - Chugh, Manjusha AU - Kühne, Thomas D. ID - 32246 IS - 46 JF - Physical Chemistry Chemical Physics KW - Physical and Theoretical Chemistry KW - General Physics and Astronomy SN - 1463-9076 TI - In silico investigation of Cu(In,Ga)Se2-based solar cells VL - 22 ER - TY - JOUR AB - In scientific computing, the acceleration of atomistic computer simulations by means of custom hardware is finding ever-growing application. A major limitation, however, is that the high efficiency in terms of performance and low power consumption entails the massive usage of low precision computing units. Here, based on the approximate computing paradigm, we present an algorithmic method to compensate for numerical inaccuracies due to low accuracy arithmetic operations rigorously, yet still obtaining exact expectation values using a properly modified Langevin-type equation. AU - Rengaraj, Varadarajan AU - Lass, Michael AU - Plessl, Christian AU - Kühne, Thomas ID - 12878 IS - 2 JF - Computation TI - Accurate Sampling with Noisy Forces from Approximate Computing VL - 8 ER - TY - JOUR AB - CP2K is an open source electronic structure and molecular dynamics software package to perform atomistic simulations of solid-state, liquid, molecular, and biological systems. It is especially aimed at massively parallel and linear-scaling electronic structure methods and state-of-theart ab initio molecular dynamics simulations. Excellent performance for electronic structure calculations is achieved using novel algorithms implemented for modern high-performance computing systems. This review revisits the main capabilities of CP2K to perform efficient and accurate electronic structure simulations. The emphasis is put on density functional theory and multiple post–Hartree–Fock methods using the Gaussian and plane wave approach and its augmented all-electron extension. AU - Kühne, Thomas AU - Iannuzzi, Marcella AU - Ben, Mauro Del AU - Rybkin, Vladimir V. AU - Seewald, Patrick AU - Stein, Frederick AU - Laino, Teodoro AU - Khaliullin, Rustam Z. AU - Schütt, Ole AU - Schiffmann, Florian AU - Golze, Dorothea AU - Wilhelm, Jan AU - Chulkov, Sergey AU - Mohammad Hossein Bani-Hashemian, Mohammad Hossein Bani-Hashemian AU - Weber, Valéry AU - Borstnik, Urban AU - Taillefumier, Mathieu AU - Jakobovits, Alice Shoshana AU - Lazzaro, Alfio AU - Pabst, Hans AU - Müller, Tiziano AU - Schade, Robert AU - Guidon, Manuel AU - Andermatt, Samuel AU - Holmberg, Nico AU - Schenter, Gregory K. AU - Hehn, Anna AU - Bussy, Augustin AU - Belleflamme, Fabian AU - Tabacchi, Gloria AU - Glöß, Andreas AU - Lass, Michael AU - Bethune, Iain AU - Mundy, Christopher J. AU - Plessl, Christian AU - Watkins, Matt AU - VandeVondele, Joost AU - Krack, Matthias AU - Hutter, Jürg ID - 16277 IS - 19 JF - The Journal of Chemical Physics TI - CP2K: An electronic structure and molecular dynamics software package - Quickstep: Efficient and accurate electronic structure calculations VL - 152 ER - TY - JOUR AB - We address the general mathematical problem of computing the inverse p-th root of a given matrix in an efficient way. A new method to construct iteration functions that allow calculating arbitrary p-th roots and their inverses of symmetric positive definite matrices is presented. We show that the order of convergence is at least quadratic and that adaptively adjusting a parameter q always leads to an even faster convergence. In this way, a better performance than with previously known iteration schemes is achieved. The efficiency of the iterative functions is demonstrated for various matrices with different densities, condition numbers and spectral radii. AU - Richters, Dorothee AU - Lass, Michael AU - Walther, Andrea AU - Plessl, Christian AU - Kühne, Thomas ID - 21 IS - 2 JF - Communications in Computational Physics TI - A General Algorithm to Calculate the Inverse Principal p-th Root of Symmetric Positive Definite Matrices VL - 25 ER - TY - JOUR AU - Platzner, Marco AU - Plessl, Christian ID - 12871 JF - Informatik Spektrum SN - 0170-6012 TI - FPGAs im Rechenzentrum ER - TY - JOUR AU - Riebler, Heinrich AU - Vaz, Gavin Francis AU - Kenter, Tobias AU - Plessl, Christian ID - 7689 IS - 2 JF - ACM Trans. Archit. Code Optim. (TACO) KW - htrop TI - Transparent Acceleration for Heterogeneous Platforms with Compilation to OpenCL VL - 16 ER - TY - JOUR AU - Mertens, Jan Cedric AU - Boschmann, Alexander AU - Schmidt, M. AU - Plessl, Christian ID - 6516 IS - 4 JF - Sports Engineering SN - 1369-7072 TI - Sprint diagnostic with GPS and inertial sensor fusion VL - 21 ER - TY - JOUR AU - Luk, Samuel M. H. AU - Lewandowski, P. AU - Kwong, N. H. AU - Baudin, E. AU - Lafont, O. AU - Tignon, J. AU - Leung, P. T. AU - Chan, Ch. K. P. AU - Babilon, M. AU - Schumacher, Stefan AU - Binder, R. ID - 13348 IS - 1 JF - Journal of the Optical Society of America B SN - 0740-3224 TI - Theory of optically controlled anisotropic polariton transport in semiconductor double microcavities VL - 35 ER - TY - JOUR AB - Approximate computing has shown to provide new ways to improve performance and power consumption of error-resilient applications. While many of these applications can be found in image processing, data classification or machine learning, we demonstrate its suitability to a problem from scientific computing. Utilizing the self-correcting behavior of iterative algorithms, we show that approximate computing can be applied to the calculation of inverse matrix p-th roots which are required in many applications in scientific computing. Results show great opportunities to reduce the computational effort and bandwidth required for the execution of the discussed algorithm, especially when targeting special accelerator hardware. AU - Lass, Michael AU - Kühne, Thomas AU - Plessl, Christian ID - 20 IS - 2 JF - Embedded Systems Letters SN - 1943-0663 TI - Using Approximate Computing for the Calculation of Inverse Matrix p-th Roots VL - 10 ER -