@inproceedings {INPROC-2015-63, author = {Nehzat Emamy and Martin Karcher and Roozbeh Mousavi and Martin Oberlack}, title = {{A high-order fully coupled electro-fluid-dynamics solver for multiphase flow simulations}}, booktitle = {VI International Conference on Computational Methods for Coupled Problems in Science and Engineering}, address = {San Servolo Island, Venice, Greece}, publisher = {ECCOMAS}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, pages = {753--759}, type = {Conference Paper}, month = {May}, year = {2015}, language = {English}, cr-category = {I.6.0 Simulation and Modeling General}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-63&engl=1} } @inproceedings {INPROC-2015-61, author = {Stefan Wagner and Dirk Pfl{\"u}ger and Miriam Mehl}, title = {{Simulation Software Engineering: Experiences and Challenges}}, booktitle = {Proceedings of the 3rd International Workshop on Software Engineering for High Performance Computing in Computational Science and Engineering}, publisher = {ACM}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, series = {SE-HPCCSE '15}, pages = {1--4}, type = {Conference Paper}, month = {January}, year = {2015}, doi = {10.1145/2830168.2830171}, isbn = {978-1-4503-4012-0}, keywords = {simulation software, software engineering}, language = {German}, cr-category = {D.2.0 Software Engineering General}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems; University of Stuttgart, Institute of Software Technology, Software Engineering}, abstract = {Using software for large-scale simulations has become an important research method in many disciplines. With increasingly complex simulations, simulation software becomes a valuable assest. Yet, the quality of many simulation codes is worrying. In this paper, we want to collect and structure the challenges for a systematic simulation software engineering as a reference and the basis for further research. We describe our own experiences with developing simulation software and collaborating with non-computer-scientists. We complement our experienced challenges with a brief literature review. We structured the challenges for simulation software engineering into six areas: motivation and recognition; education and training; developer turnover; software length of life; verification, validation and debugging; and efficiency vs. maintainability. Overcoming these challenges needs efforts from research agencies, scientific computing researchers as well as software engineering researchers.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-61&engl=1} } @inproceedings {INPROC-2015-58, author = {Mario Heene and Dirk Pfl{\"u}ger}, title = {{Efficient and scalable distributed-memory hierarchization algorithms for the sparse grid combination technique}}, booktitle = {Parallel Computing: On the Road to Exascale}, publisher = {IOS Press}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, series = {Advances in Parallel Computing}, volume = {27}, pages = {339--348}, type = {Conference Paper}, month = {April}, year = {2015}, doi = {10.3233/978-1-61499-621-7-339}, keywords = {high-performance computing; sparse grids; plasma physics; gyrokinetics}, language = {English}, cr-category = {G.4 Mathematical Software}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {Finding solutions to higher dimensional problems, such as the simulation of plasma turbulence in a fusion device as described by the five-dimensional gyrokinetic equations, is a grand challenge facing current and future high performance computing (HPC). The sparse grid combination technique is a promising approach to the solution of these problems on large scale distributed memory systems. The combination technique numerically decomposes a single large problem into multiple moderately sized partial problems that can be computed in parallel, independently and asynchronously of each other. The ability to efficiently combine the individual partial solutions to a common sparse grid solution is a key consideration to the overall performance of large scale computations with the combination technique. This requires a transfer of each partial solution from the nodal basis representation into the hierarchical basis representation by hierarchization. In this work we will present a new, efficient and scalable algorithm for the hierarchization of partial solutions that are distributed over multiple process groups of an HPC system.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-58&engl=1} } @inproceedings {INPROC-2015-32, author = {Alfredo Parra Hinojosa and Christoph Kowitz and Mario Heene and Dirk Pfl{\"u}ger and Hans-Joachim Bungartz}, title = {{Towards a fault-tolerant, scalable implementation of GENE}}, booktitle = {Proceedings of ICCE 2014}, publisher = {Springer-Verlag}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, series = {Lecture Notes in Computational Science and Engineering}, type = {Conference Paper}, month = {January}, year = {2015}, language = {German}, cr-category = {I.6 Simulation and Modeling}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {leer}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-32&engl=1} } @inproceedings {INPROC-2015-29, author = {Florian Lindner and Miriam Mehl and Klaudius Scheufele and Benjamin Uekermann}, title = {{A Comparison of various Quasi-Newton Schemes for Partitioned Fluid-Structure Interaction}}, booktitle = {Coupled Problems}, publisher = {ECCOMAS}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, type = {Conference Paper}, month = {January}, year = {2015}, language = {German}, cr-category = {I.6 Simulation and Modeling}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {leer}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2015-29&engl=1} } @article {ART-2015-14, author = {Benjamin Peherstorfer and Stefan Zimmer and Christoph Zenger and Hans-Joachim Bungartz}, title = {{A Multigrid Method for Adaptive Sparse Grids}}, journal = {SIAM Journal on Scientific Computing}, publisher = {SIAM}, volume = {37}, number = {5}, pages = {51--70}, type = {Article in Journal}, month = {October}, year = {2015}, doi = {10.1137/140974985}, language = {English}, cr-category = {G.1.3 Numerical Linear Algebra}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2015-14&engl=1} } @article {ART-2015-08, author = {Hans-Joachim Bungartz and Florian Lindner and Miriam Mehl and Benjamin Uekermann}, title = {{A plug-and-play coupling approach for parallel multi-field simulations}}, journal = {Computational Mechanics}, address = {Berlin, Heidelberg, New York}, publisher = {Springer}, volume = {55}, number = {6}, pages = {1119--1129}, type = {Article in Journal}, month = {January}, year = {2015}, isbn = {0178-7675 (ISSN print)}, isbn = {1432-0924 (ISSN online)}, isbn = {10.1007/s00466-014-1113-2 (DOI)}, language = {English}, cr-category = {J.2 Physical Sciences and Engineering}, ee = {ftp://ftp.informatik.uni-stuttgart.de/pub/library/ncstrl.ustuttgart_fi/ART-2015-08/ART-2015-08.pdf, http://link.springer.com/article/10.1007/s00466-014-1113-2}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {For multi-field simulations involving a larger number of different physical fields and in cases where the involved fields or simulation codes change due to new modelling insigts, e.g., flexible and robust partitioned coupling schemes are an important prerequisite to keep time-to-solution within reasonable limits. They allow for a fast, almost plug-and-play combination of existing established codes to the respective multi-field simulation environment. In this paper, we study a class of coupling approaches that we originally introduced in order to improve the parallel scalability of partitioned simulations. Due to the symmetric structure of these coupling methods and the use of 'long' vectors of coupling data comprising the input and output of all involved codes at a time, they turn out to be particularly suited also for simulations involving more than two coupled fields. As standard two-field coupling schemes are not suited for such cases as shown in our numerical results, this allows the simulation of a new range of applications in a partitioned way.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2015-08&engl=1} } @article {ART-2015-06, author = {Benjamin Peherstorfer and Christoph Kowitz and Dirk Pfl{\"u}ger and Hans-Joachim Bungartz}, title = {{Selected Recent Applications of Sparse Grids}}, journal = {Numerical Mathematics: Theory, Methods and Applications}, publisher = {Cambridge Journals}, volume = {8}, number = {01}, pages = {47--77}, type = {Article in Journal}, month = {February}, year = {2015}, language = {German}, cr-category = {I.6 Simulation and Modeling}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {leer}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2015-06&engl=1} } @inbook {INBOOK-2015-07, author = {David Blom and Florian Lindner and Miriam Mehl and Klaudius Scheufele and Alexander van Zuijlen}, title = {{A Review on Fast Quasi-Newton and Accelerated Fixed Point Iterations for Partitioned Fluid-Structure Interaction Simulation}}, series = {Advances in Computational Fluid-Structure Interaction}, publisher = {Springer International Publishing}, series = {Modeling and Simulation in Science, Engineering and Technology}, pages = {1--12}, type = {Article in Book}, month = {January}, year = {2015}, isbn = {978-3-319-40827-9}, isbn = {978-3-319-40825-5}, language = {English}, cr-category = {I.6 Simulation and Modeling}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {The partitioned simulation of fluid{\^a}€“structure interactions offers great flexibility in terms of exchanging flow and structure solver and using existing established codes. However, it often suffers from slow convergence and limited parallel scalability. Quasi-Newton or accelerated fixed-point iterations are a very efficient way to solve the convergence issue. At the same time, they stabilize and speed up not only the standard staggered fluid{\^a}€“structure coupling iterations, but also the variant with simultaneous execution of flow and structure solver that is fairly inefficient if no acceleration methods for the underlying fixed-point iteration are used. In this chapter, we present a review on combinations of iteration patterns (parallel and staggered) and of quasi-Newton methods and compare their suitability in terms of convergence speed, robustness, and parallel scalability. Some of these variants use the so-called manifold mapping that yields an additional speedup by using an approach that can be interpreted as a generalization of the multi-level idea.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2015-07&engl=1} } @inbook {INBOOK-2015-05, author = {David Blom and Benjamin Uekermann and Miriam Mehl and Alexander van Zuijlen and Hester Bijl}, title = {{Multi-Level Acceleration of Parallel Coupled Partitioned Fluid-Structure Interaction with Manifold Mapping}}, series = {Recent Trends in Computational Engineering}, address = {Berlin, Heidelberg, New York}, publisher = {Springer}, series = {Lecture Notes in Computational Science and Engineering}, volume = {105}, pages = {135--150}, type = {Article in Book}, month = {January}, year = {2015}, isbn = {ISBN 978-3-319-22996-6}, language = {English}, cr-category = {J.2 Physical Sciences and Engineering}, ee = {http://www.springer.com/us/book/9783319229966}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {Strongly coupled fluid-structure interaction simulations often suffer from slow convergence, limited parallel scalability or difficulties in using black-box solvers. As partitioned simulations still play an important role in cases where new combinations of models, discretizations and codes have to be tested in an easy and fast way, we propose a combination of a parallel black-box coupling with a manifold mapping algorithm as an acceleration method. In this approach, we combine a com- putationally inexpensive low-fidelity FSI model with a high-fidelity FSI model to reduce the number of coupling iterations of the high fidelity FSI model. Information from previous time steps is taken into account with a secant update step similar to the Broyden update. The used black-box approach is applied for an incompressible laminar flow over a fixed cylinder with an attached flexible flap and a wave prop- agation in a three-dimensional elastic tube problem. A reduction of approximately 55 \% in terms of high fidelity iterations is achieved compared to the Anderson mix- ing method if the fluid and the structure solvers are executed in parallel.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2015-05&engl=1} } @inbook {INBOOK-2015-04, author = {Hans-Joachim Bungartz and Harald Klimach and Verena Krupp and Florian Lindner and Miriam Mehl and Sabine Roller and Benjamin Uekermann}, title = {{Fluid-Acoustics Interaction on Massively Parallel Systems}}, series = {Recent Trends in Computational Engineering}, address = {Berlin, Heidelberg, New York}, publisher = {Springer}, series = {Lecture Notes in Computational Science and Engineering}, volume = {105}, pages = {151--165}, type = {Article in Book}, month = {January}, year = {2015}, isbn = {ISBN 978-3-319-22996-6}, language = {English}, cr-category = {J.2 Physical Sciences and Engineering}, ee = {http://www.springer.com/us/book/9783319229966}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems}, abstract = {To simulate fluid-acoustic interaction, we couple inviscid Euler equations in the near-field, which is relevant for noise generation, to linearized Euler equations in the far-field. This allows us to separate the critical scales and treat each domain with an individual discretization. Both fields are computed by the high-order discontinuous Galerkin solver Ateles, while we couple the solvers at the interface by the library preCICE. We discuss a detailed performance analysis of the coupled simulation on massively parallel systems. Furthermore, to show the full potential of our approach, we simulate a flow around a sphere.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INBOOK-2015-04&engl=1} } @book {BOOK-2015-01, editor = {Miriam Mehl and Manfred Bischoff and Michael Sch{\"a}fer}, title = {{Recent Trends in Computational Engineering}}, address = {Berlin, Heidelberg, New York}, publisher = {Springer}, series = {Lecture Notes in Computational Science and Engineering}, volume = {105}, pages = {317}, type = {Book}, month = {January}, year = {2015}, isbn = {ISBN 978-3-319-22996-6}, language = {English}, cr-category = {J.2 Physical Sciences and Engineering}, ee = {http://www.springer.com/us/book/9783319229966}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Simulation of Large Systems; University of Stuttgart, Institute of Parallel and Distributed Systems}, abstract = {This book presents selected papers from the 3rd International Workshop on Computational Engineering held in Stuttgart from October 6 to 10, 2014, bringing together innovative contributions from related fields with computer science and mathematics as an important technical basis among others. The workshop discussed the state of the art and the further evolution of numerical techniques for simulation in engineering and science. We focus on current trends in numerical simulation in science and engineering, new requirements arising from rapidly increasing parallelism in computer architectures, and novel mathematical approaches. Accordingly, the chapters of the book particularly focus on parallel algorithms and performance optimization, coupled systems, and complex applications and optimization.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=BOOK-2015-01&engl=1} }