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Abstract: Exploring Performance data with Boxfish

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Abstract: Exploring Performance Data with Boxfish

High Performance Computing, Networking, Storage and Analysis (SCC), SC Companion:

作者： Katherine E. Isaacs Aaditya G. Landge Todd Gamblin Peer-Timo Bremer Valerio Pascucci Bernd Hamann Institute for Data Analysis and Visualization Department of Computer Science University of California Davis CA USA Scientific Computing and Imaging Institute University of Utah Salt Lake UT USA Center for Applied Scientific Computing Lawrence Livermore National Laboratories Livermore CA USA

The growth in size and complexity of scaling applications and the systems on which they run pose challenges in analyzing and improving their overall performance. With metrics coming from thousands or millions of processes, visualization techniques are necessary to make sense of the increasing amount of data. To aid the process of exploration and understanding, we announce the initial release of Boxfish, an extensible tool for manipulating and visualizing data pertaining to application behavior. Combining and visually presenting data and knowledge from multiple domains, such as the application's communication patterns and the hardware's network configuration and routing policies, can yield the insight necessary to discover the underlying causes of observed behavior. Boxfish allows users to query, filter and project data across these domains to create interactive, linked visualizations.

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A scalable weakly-synchronous algorithm for solving partial differential equations

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arXiv 2019年

作者： Aditya, Konduri Gysi, Tobias Kwasniewski, Grzegorz Hoefler, Torsten Donzis, Diego A. Chen, Jacqueline H. Combustion Research Facility Sandia National Laboratories LivermoreCA94550 United States Department of Computer Science ETH Zurich Zuirch8092 Switzerland Department of Aerospace Engineering Texas A&M University College StationTX77843 United States Department of Computational and Data Sciences Indian Institute of Science Bangalore India

Synchronization overheads pose a major challenge as applications advance towards extreme scales. In current large-scale algorithms, synchronization as well as data communication delay the parallel computations at each time step in a time-dependent partial differential equation (PDE) solver. This creates a new scaling wall when moving towards exascale. We present a weakly-synchronous algorithm based on novel asynchrony-tolerant (AT) finite-difference schemes that relax synchronization at a mathematical level. We utilize remote memory access programming schemes that have been shown to provide significant speedup on modern supercomputers, to efficiently implement communications suitable for AT schemes, and compare to two-sided communications that are state-of-practice. We present results from simulations of Burgers' equation as a model of multi-scale strongly non-linear dynamical systems. Our algorithm demonstrate excellent scalability of the new AT schemes for large-scale computing, with a speedup of up to 3.3x in communication time and 2.19x in total runtime. We expect that such schemes can form the basis for exascale PDE algorithms. Copyright © 2019, The Authors. All rights reserved.

关键词： Synchronization

Gaussian-wave-packet model for single-photon generation based on cavity quantum electrodynamics under adiabatic and nonadiabatic conditions

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arXiv 2021年

作者： Utsugi, Takeru Goban, Akihisa Tokunaga, Yuuki Goto, Hayato Aoki, Takao Department of Applied Physics Waseda University 3-4-1 Okubo Shinjuku Tokyo169-8555 Japan Computer & Data Science Laboratories NTT Corporation Musashino180-8585 Japan Corporate Research & Development Center Toshiba Corporation Kanagawa Kawasaki212-8582 Japan

For single-photon generation based on cavity quantum electrodynamics, we investigate a practical model assuming a Gaussian wavepacket. This model makes it possible to comprehensively analyze the temporal dynamics of an atom-cavity system with both adiabatic and nonadiabatic conditions using analytical expressions. These results enable us to clarify the relationship between pulse width and maximum success probability, over the full range of coupling regimes. We demonstrate how to achieve a high success probability while keeping a short pulse width by optimizing the cavity transmittance parameter and the time-controlled exexternal field. Our formulations provide a practical tool for efficient single-photon generation in a wide variety of experimental platforms. Copyright © 2021, The Authors. All rights reserved.

关键词： Electron beams

Experimental demonstration of a high-fidelity virtual two-qubit gate

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Physical Review Research 2024年第1期6卷 013235-013235页

作者： Akhil Pratap Singh Kosuke Mitarai Yasunari Suzuki Kentaro Heya Yutaka Tabuchi Keisuke Fujii Yasunobu Nakamura Department of Applied Physics Graduate School of Engineering The University of Tokyo Bunkyo-ku Tokyo 113-8656 Japan Graduate School of Engineering Science Osaka University 1-3 Machikaneyama Toyonaka Osaka 560-8531 Japan NTT Computer and Data Science Laboratories NTT Corporation Musashino 180-8585 Japan RIKEN Center for Quantum Computing (RQC) Wako Saitama 351-0198 Japan

We experimentally demonstrate a virtual two-qubit gate and characterize it using quantum process tomography (QPT). The virtual two-qubit gate decomposes an actual two-qubit gate into single-qubit unitary gates and projection gates in quantum circuits for expectation-value estimation. We implement projection gates via midcircuit measurements. The deterministic sampling scheme reduces the number of experimental circuit evaluations required for decomposing a virtual two-qubit gate. We also apply quantum error mitigation to suppress the effect of measurement errors and improve the average gate fidelity of a virtual controlled-Z (CZ) gate to fav=0.9938±0.0002. Our results highlight a practical approach to implement virtual two-qubit gates with high fidelities, which are useful for simulating quantum circuits using fewer qubits and implementing two-qubit gates on a distant pair of qubits.

关键词： Quantum algorithms Quantum algorithms & computation Quantum benchmarking Quantum circuits Quantum computation Quantum gates Quantum nondemolition measurement Quantum simulation

Efficient and high-performance routing of lattice-surgery paths on three-dimensional lattice

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arXiv 2024年

作者： Hamada, Kou Suzuki, Yasunari Tokunaga, Yuuki Department of Mathematical Informatics Graduate School of Information Science and Technology The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo113-0033 Japan NTT Computer and Data Science Laboratories NTT Corporation Musashino180-8585 Japan JST PRESTO 4-1-8 Honcho Saitama Kawaguchi332-0012 Japan

Encoding logical qubits with surface codes and performing multi-qubit logical operations with lattice surgery is one of the most promising approaches to demonstrate fault-tolerant quantum computing. Thus, a method to efficiently schedule a sequence of lattice-surgery operations is vital for high-performance fault-tolerant quantum computing. A possible strategy to improve the throughput of lattice-surgery operations is splitting a large instruction into several small instructions such as Bell state preparation and measurements and executing a part of them in advance. However, scheduling methods to fully utilize this idea have yet to be explored. In this paper, we propose a fast and high-performance scheduling algorithm for lattice-surgery instructions leveraging this strategy. We achieved this by converting the scheduling problem of lattice-surgery instructions to a graph problem of embedding 3D paths into a 3D lattice, which enables us to explore efficient scheduling by solving path search problems in the 3D lattice. Based on this reduction, we propose a method to solve the path-finding problems, Dijkstra projection. We numerically show that this method reduced the execution time of benchmark programs generated from quantum phase estimation algorithms by 2.7 times compared with a naive method based on greedy algorithms. Our study establishes the relation between the lattice-surgery scheduling and graph search problems, which leads to further theoretical analysis on compiler optimization of fault-tolerant quantum computing. Copyright © 2024, The Authors. All rights reserved.

关键词： Qubits

Virtual entanglement purification via noisy entanglement

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arXiv 2024年

作者： Yamamoto, Kaoru Matsuzaki, Yuichiro Suzuki, Yasunari Tokunaga, Yuuki Endo, Suguru NTT Computer and Data Science Laboratories NTT Corporation Musashino180-8585 Japan Department of Electrical Electronic and Communication Engineering Faculty of Science and Engineering Chuo University 1-13-27 Kasuga Bunkyo-ku Tokyo112-8551 Japan JST PRESTO 4-1-8 Honcho Kawaguchi Saitama332-0012 Japan

Distributed quantum computation (DQC) is a promising approach for scalable quantum computing, where high-fidelity non-local operations among remote devices are required for universal quantum computation. These operations are typically implemented through state and gate teleportation with the consumption of high-fidelity entanglement prepared via entanglement purification. However, noisy local operations and classical communication (LOCC) limit the fidelity of purified entanglement, thereby degrading the quality of non-local operations. Meanwhile, circuit knitting and cutting, which simulate non-local operations by preparing separable states along with LOCC, has been considered for DQC as an alternative. Although this approach needs no entanglement among remote devices, it requires excessive circuit runs. Here, we present a protocol utilizing virtual operations that purifies noisy entanglement at the level of expectation values. Our protocol offers the following advantages over conventional methods: surpasses the fidelity limit of entanglement purification in the presence of noise in LOCC, requires fewer sampling shots than circuit knitting, and exhibits robustness against infidelity fluctuations in shared noisy Bell states, unlike probabilistic error cancellation. Our protocol bridges the gap between the entanglement-based and circuit-knitting DQC methods, offering a flexible approach to achieve further scalability despite hardware limitations. Copyright © 2024, The Authors. All rights reserved.

关键词： Quantum computers

Streaming-Aware Cellular Resource Allocation for UHD Video Streaming over Ultra Dense Network

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Streaming-Aware Cellular Resource Allocation for UHD Video S...

IEEE Conference on Wireless Communications and Networking

作者： Xinjing Yuan Lingjun Pu Xiaohang Xu Yuwei Xu Jingdong Xu Institute of Systems and Networks College of Computer Science Nankai University Tianjin China Tianjin Key Laboratory of Network and Data Security Technology Tianjin China State Key Laboratory of Integrated Services Networks (Xidian University) Xi’an China Purple Mountain Laboratories for Network and Communication Security China

Ultra-High-Definition (UHD) videos have absorbed great attention in recent years. However, as they are of significant size, streaming them require an extremely high bandwidth to achieve a good quality of experience, which poses a great challenge on the current cellular networks. Realizing the great potentials of coordinated multi-point joint transmission (JT-CoMP) in 5G Ultra Dense Network, we propose a novel Tuner framework for the UHD video streaming service. In this framework, we strive to design an efficient algorithm for VBS sleeping and VBS grouping to maximize the data rates of overall video users while reducing the overhead of cellular networks. To this end, we provide a comprehensive framework model and formulate a single-timescale VBS sleeping & grouping problem. We design a novel master-slave based algorithm to solve the formulated mixed-integer programming problem optimally with low complexity. In addition, we extend it to facilitate the more practical setting, i.e., two-timescale VBS sleeping & grouping. Extensive simulations validate the superior performance of our framework in various system settings.

关键词： Cellular networks Tuners 5G mobile communication Streaming media Programming Master-slave Complexity theory

Measurement optimization of variational quantum simulation by classical shadow and derandomization

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arXiv 2022年

作者： Nakaji, Kouhei Endo, Suguru Matsuzaki, Yuichiro Hakoshima, Hideaki 1-1-1 Umezono Ibaraki Tsukuba305-8568 Japan NTT Computer and Data Science laboratories NTT corporation Musashino Tokyo180-8585 Japan Center for Quantum Information and Quantum Biology Osaka University 1-2 Machikaneyama Osaka Toyonaka560-0043 Japan

Simulating large quantum systems is the ultimate goal of quantum computing. Variational quantum simulation (VQS) gives us a tool to achieve the goal in near-term devices by distributing the computation load to both classical and quantum computers. However, as the size of the quantum system becomes large, the execution of VQS becomes more and more challenging. One of the most severe challenges is the drastic increase in the number of measurements;for example, the number of measurements tends to increase by the fourth power of the number of qubits in a quantum simulation with a chemical Hamiltonian. This work aims to optimize measurements in VQS by recently proposed measurement optimization techniques such as classical shadow and derandomization. Even though previous literature shows that the measurement optimization techniques successfully reduce measurements in the variational quantum optimization (VQO), how to apply them to VQS was unclear due to the gap between VQO and VQS in measuring observables. In this paper, we bridge the gap by changing the way of measuring observables in VQS and propose an algorithm to optimize measurements in VQS. Our numerical experiment shows the validity of using our algorithm with quantum chemical systems. Importantly, we theoretically reveal the advantage of using shadow-based strategies, e.g., classical shadow and derandomization, not only in VQS but also in VQO by calculating the variance of an observable. To the best of our knowledge, the advantage of using shadow-based strategies in VQO was given only numerically in previous research;therefore, this paper also gives significant implications for measurement optimization in general variational quantum algorithms. © 2022, CC BY.

关键词： Quantum chemistry

Perturbative Quantum Simulation

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Physical Review Letters 2022年第12期129卷 120505-120505页

作者： Jinzhao Sun Suguru Endo Huiping Lin Patrick Hayden Vlatko Vedral Xiao Yuan Center on Frontiers of Computing Studies Peking University Beijing 100871 China Clarendon Laboratory University of Oxford Parks Road Oxford OX1 3PU United Kingdom Quantum Advantage Research Beijing 100080 China NTT Computer & Data Science Laboratories NTT corporation Musashino Tokyo 180-8585 Japan School of Computer Science Peking University Beijing 100871 China Stanford Institute for Theoretical Physics Stanford University Stanford California 94305 USA Centre for Quantum Technologies National University of Singapore Singapore 117543 Singapore

Approximation based on perturbation theory is the foundation for most of the quantitative predictions of quantum mechanics, whether in quantum many-body physics, chemistry, quantum field theory, or other domains. Quantum computing provides an alternative to the perturbation paradigm, yet state-of-the-art quantum processors with tens of noisy qubits are of limited practical utility. Here, we introduce perturbative quantum simulation, which combines the complementary strengths of the two approaches, enabling the solution of large practical quantum problems using limited noisy intermediate-scale quantum hardware. The use of a quantum processor eliminates the need to identify a solvable unperturbed Hamiltonian, while the introduction of perturbative coupling permits the quantum processor to simulate systems larger than the available number of physical qubits. We present an explicit perturbative expansion that mimics the Dyson series expansion and involves only local unitary operations, and show its optimality over other expansions under certain conditions. We numerically benchmark the method for interacting bosons, fermions, and quantum spins in different topologies, and study different physical phenomena, such as information propagation, charge-spin separation, and magnetism, on systems of up to 48 qubits only using an 8+1 qubit quantum hardware. We demonstrate our scheme on the IBM quantum cloud, verifying its noise robustness and illustrating its potential for benchmarking large quantum processors with smaller ones.

关键词： Quantum algorithms Quantum computation Quantum simulation