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Quantum ring-polymer contraction method: Including nuclear quantum effects at no additional computational cost in comparison to ab initio molecular dynamics

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Physical Review E 2016年第4期93卷 043305-043305页

作者： Christopher John Thomas Spura Scott Habershon Thomas D. Kühne Dynamics of Condensed Matter Department of Chemistry University of Paderborn Warburger Strasse 100 D-33098 Paderborn Germany and Paderborn Center for Parallel Computing and Institute for Lightweight Design Department of Chemistry University of Paderborn Warburger Strasse 100 D-33098 Paderborn Germany

We present a simple and accurate computational method which facilitates ab initio path-integral molecular dynamics simulations, where the quantum-mechanical nature of the nuclei is explicitly taken into account, at essentially no additional computational cost in comparison to the corresponding calculation using classical nuclei. The predictive power of the proposed quantum ring-polymer contraction method is demonstrated by computing various static and dynamic properties of liquid water at ambient conditions using density functional theory. This development will enable routine inclusion of nuclear quantum effects in ab initio molecular dynamics simulations of condensed-phase systems.

关键词： Electronic structure Quantum computation Density functional theory Molecular dynamics

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A Submatrix-Based Method for Approximate Matrix Function Evaluation in the Quantum Chemistry Code CP2K 20

A Submatrix-Based Method for Approximate Matrix Function Eva...

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Supercomputing Conference

作者： Michael Lass Robert Schade Thomas D. Kühne Christian Plessl Paderborn Center for Parallel Computing Paderborn University Warburger Str. 100 Paderborn Germany Paderborn University Warburger Str. 100 Paderborn Germany

ISBN: (数字)9781728199986

ISBN: (纸本)9781728199993

Electronic structure calculations based on density-functional theory (DFT) represent a significant part of today's HPC workloads and pose high demands on high-performance computing resources. To perform these quantum-mechanical DFT calculations on complex large-scale systems, so-called linear scaling methods instead of conventional cubic scaling methods are required. In this work, we take up the idea of the submatrix method and apply it to the DFT computations in the software package CP2K. For that purpose, we transform the underlying numeric operations on distributed, large, sparse matrices into computations on local, much smaller and nearly dense matrices. This allows us to exploit the full floating-point performance of modern CPUs and to make use of dedicated accelerator hardware, where performance has been limited by memory bandwidth before. We demonstrate both functionality and performance of our implementation and show how it can be accelerated with GPUs and FPGAs.

关键词： Tensors Temperature Discrete Fourier transforms Transforms Computational efficiency Sparse matrices Field programmable gate arrays

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Solving systems of equations on antichains for the computation of the ninth Dedekind Number

arXiv

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arXiv 2024年

作者： De Causmaecker, Patrick Van Hirtum, Lennart KU Leuven Department of Computer Science KULAK CODeS Belgium Paderborn Center for Parallel Computing Paderborn University Germany

We study four systems of equations, together with a way to count the number of solutions. One of the results was used in the recent computation of D(9), the others have potential to speed up existing techniques in the... 详细信息

关键词： Number theory

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Network-based resource allocation for Grid computing within an SLA context

Network-based resource allocation for Grid Computing within ...

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International Conference on Grid and Cooperative computing (GCC)

作者： Dang Minh Quan D. Frank Hsu Paderborn Center for Parallel Computing University of Paderborn Paderborn Germany Department of Computer and Information Science Fordham University New York NY USA

Service level agreements (SLAs) are currently one of the major research topics in grid computing. Among many system components for supporting of SLA-aware grid jobs, the SLA mapping mechanism receives important positions. It is responsible for assigning sub-jobs of the workflow to grid resource in a way that meet the user's deadline and as cheap as possible. With the distinguished workload and resource characteristics, mapping a heavy communication workflow within SLA context defines an unfamiliar problem and need a specific method to be solved. This paper presents the mapping algorithm, which can cope with the problem. Performance measurements deliver evaluation results on the quality and efficiency of the method

关键词： Resource management Grid computing High performance computing Runtime Context-aware services Quality of service parallel processing Context Measurement Information science

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Solving a media mapping problem in a hierarchical server network with parallel simulated annealing

Solving a media mapping problem in a hierarchical server net...

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International Conference on parallel Processing (ICPP)

作者： Xiaobo Zhou R. Luling Li Xie Paderborn Center for Parallel Computing (PC2) University of Paderborn Paderborn Germany Department of Computer Science Nanjing University Nanjing China

Advances in storage and high-speed broadband communication network technologies are making it feasible to design and implement distributed scalable video-on-demand server networks. In this paper a hierarchical structure for a server network is proposed to support a metropolitan TV-Anytime service. A key issue, how to map the media assets onto such a hierarchical server network, is addressed in this paper. The definition and heuristic methods for the solution of this new combinatorial optimization problem are presented. The mapping problem studied here addresses the management of media assets taking the storage capacity, communication bandwidth limitation and access pattern into account. The methods presented in this paper are based on parallel simulated annealing and are verified by the use of a set of benchmark instances. The results show that the methods provide a near to optimal performance in terms of the Quality of Service (QoS).

关键词： Intelligent networks Network servers Simulated annealing Streaming media Bandwidth Quality of service Computational modeling parallel processing Multimedia systems Large-scale systems

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The NRW-Metacomputer - building blocks for a worldwide computational grid

The NRW-Metacomputer - building blocks for a worldwide compu...

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Heterogeneous computing Workshop

作者： C. Bitten J. Gehring U. Schwiegelshohn R. Yahyapour Regional Computing Centre University of Cologne Cologne Germany Paderborn Center for Parallel Computing University of Paderborn Paderborn Germany Computer Engineering Institute University of Dortmund Dortmund Germany

Presents the results of the NRW-Metacomputing Taskforce, which has been working on the development of a (German) country-wide metacomputer since 1996. The resulting installation is among the very few that are already operational, have full support for heterogeneous resources, contain a decent security model and feature an advanced scheduling subsystem for the metacomputing environment. The NRW-Metacomputer has been implemented using a modular software architecture. Hence, its concepts and components can be re-used by others without the need to obtain the metacomputing software as a whole. Furthermore, the NRW-Metacomputer already provides well-defined interfaces for linking the system with other metacomputing environments to form a truly global computational grid. Distinctive features of this system are its highly scalable and fault-tolerant software architecture, its advanced resource planning mechanisms, as well as an integration into a DCE (Distributed computing Environment)/DFS (Distributed File System) environment.

关键词： Grid computing Metacomputing Concurrent computing Security Joining processes Software systems Supercomputers Power grids parallel processing Power system planning

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parallel quantum chemistry on noisy intermediate-scale quantum computers

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Physical Review Research 2022年第3期4卷 033160-033160页

作者： Robert Schade Carsten Bauer Konstantin Tamoev Lukas Mazur Christian Plessl Thomas D. Kühne Paderborn Center for Parallel Computing Paderborn University 33098 Paderborn Germany Dynamics of Condensed Matter and Institute for Sustainable Systems Design Chair of Theoretical Chemistry Paderborn University 33098 Paderborn Germany Department for Computer Science Paderborn University 33098 Paderborn Germany

A parallel hybrid quantum-classical algorithm for the solution of the quantum-chemical ground-state energy problem on gate-based quantum computers is presented. This approach is based on the reduced density-matrix functional theory (RDMFT) formulation of the electronic structure problem. For that purpose, the density-matrix functional of the full system is decomposed into an indirectly coupled sum of density-matrix functionals for all its subsystems using the adaptive cluster approximation to RDMFT. The approximations involved in the decomposition and the adaptive cluster approximation itself can be systematically converged to the exact result. The solutions for the density-matrix functionals of the effective subsystems involves a constrained minimization over many-particle states that are approximated by parametrized trial states on the quantum computer similarly to the variational quantum eigensolver. The independence of the density-matrix functionals of the effective subsystems introduces a new level of parallelization and allows for the computational treatment of much larger molecules on a quantum computer with a given qubit count. In addition, for the proposed algorithm techniques are presented to reduce the qubit count, the number of quantum programs, as well as its depth. The evaluation of a density-matrix functional as the essential part of our approach is demonstrated for Hubbard-like systems on IBM quantum computers based on superconducting transmon qubits.

关键词： Quantum algorithms Quantum software Molecules Superconducting qubits Ab initio molecular dynamics Density matrix methods Electron-correlation calculations Hubbard model Quantum chemistry methods Trial wave functions Variational approach Variational wave functional methods

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Virtual Execution Environments for ensuring SLA-compliant Job Migration in Grids

Virtual Execution Environments for ensuring SLA-compliant Jo...

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IEEE International Conference on Services computing (SCC)

作者： Dominic Battre Matthias Hovestadt Odej Kao Axel Keller Kerstin Voss Technische Universität Berlin Germany Paderborn Center for Parallel Computing (PC2) Universität Paderborn Germany

OpenCCS is an SLA-aware resource management system which uses transparent checkpointing of applications and migration of checkpoint datasets for ensuring SLA-compliance also in case of resource outages. Migration of checkpoints presumes a high grade of compatibility between source and target resource. Hence, even in large Grid systems only a small number of resources are eligible migration targets. This short paper describes the concept of virtual execution environments and how they increase the number of potential migration targets. It will also outline an implementation within OpenCCS.

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On Advantages of Grid computing for parallel Job Scheduling 02

On Advantages of Grid Computing for Parallel Job Scheduling

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IEEE/ACM International Symposium on Cluster computing and the Grid (CCGRID)

作者： C. Ernemann V. Hamscher U. Schwiegelshohn R. Yahyapour A. Streit Computer Engineering Institute University of Dortmund Dortmund Germany PC2-Paderborn Center for Parallel Computing Paderborn Germany

ISBN: (纸本)9780769515823

This paper addresses the potential benefit of sharing jobs between independent sites in a grid computing environment. Also the aspect of parallel multi-site job execution on different sites is discussed. To this end, various scheduling algorithms have been simulated for several machine configurations with different workloads which have been derived from real traces. The results showed that a significant improvement in terms of a smaller average response time is achievable. The usage of multi-site applications can additionally improve the results as long as the increase of the execution time due to communication overhead is limited to about 25%.

关键词： Grid computing Processor scheduling Delay Distributed computing Concurrent computing Electronic switching systems Computational modeling Application software Metacomputing parallel processing

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On the comparison of CPLEX-computed job schedules with the self-tuning dynP job scheduler

On the comparison of CPLEX-computed job schedules with the s...

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International Symposium on parallel and Distributed Processing (IPDPS)

作者： S. Grothklags A. Streit Faculty of Computer Science Electrical Engineering and Mathematics Institute of Computer Science Paderborn University Germany Paderborn Center for Parallel Computing Paderborn University Germany

Summary form only given. We present a comparison of CPLEX-computed job schedules with the self-tuning dynP scheduler. This scheduler switches the active scheduling policy dynamically during run time, in order to reject changing characteristics of waiting jobs. Each times the self-tuning dynP scheduler checks for a new policy a quasi offline scheduling is done as the numbers of jobs are fixed. Two questions arise from this fact: what is the optimal schedule in each self-tuning step? And what is the performance difference between the optimal schedule and the best schedule generated with one of the scheduling policies? For that we model the scheduling problem as an integer problem, which is then solved with the well-known CPLEX library. Due to the size of the problem, we apply time-scaling, i.e. the schedule is computed on a larger than one second precise scale. We use the CTC job trace as input for a discrete event simulation and evaluate the performance difference between the CPLEX-computed schedules and the schedules generated by the self-tuning dynP scheduler. The results show, that the performance of the self-tuning dynP scheduler is close to solutions computed by CPLEX. However, the self-tuning dynP scheduler needs much less time for generating the schedules than CPLEX.

关键词： Optimal scheduling Processor scheduling Dynamic scheduling Resource management Delay Computer science High performance computing Mathematics parallel processing Switches

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