881,179 research outputs found
High Energy Physics Forum for Computational Excellence: Working Group Reports (I. Applications Software II. Software Libraries and Tools III. Systems)
Computing plays an essential role in all aspects of high energy physics. As
computational technology evolves rapidly in new directions, and data throughput
and volume continue to follow a steep trend-line, it is important for the HEP
community to develop an effective response to a series of expected challenges.
In order to help shape the desired response, the HEP Forum for Computational
Excellence (HEP-FCE) initiated a roadmap planning activity with two key
overlapping drivers -- 1) software effectiveness, and 2) infrastructure and
expertise advancement. The HEP-FCE formed three working groups, 1) Applications
Software, 2) Software Libraries and Tools, and 3) Systems (including systems
software), to provide an overview of the current status of HEP computing and to
present findings and opportunities for the desired HEP computational roadmap.
The final versions of the reports are combined in this document, and are
presented along with introductory material.Comment: 72 page
A conjectured scenario for order-parameter fluctuations in spin glasses
We study order-parameter fluctuations (OPF) in disordered systems by
considering the behavior of some recently introduced paramaters which
have proven very useful to locate phase transitions. We prove that both
parameters G (for disconnected overlap disorder averages) and (for
connected disorder averages) take the respective universal values 1/3 and 13/31
in the limit for any {\em finite} volume provided the ground state is
{\em unique} and there is no gap in the ground state local-field distributions,
conditions which are met in generic spin-glass models with continuous couplings
and no gap at zero coupling. This makes ideal parameters to locate
phase transitions in disordered systems much alike the Binder cumulant is for
ordered systems. We check our results by exactly computing OPF in a simple
example of uncoupled spins in the presence of random fields and the
one-dimensional Ising spin glass. At finite temperatures, we discuss in which
conditions the value 1/3 for G may be recovered by conjecturing different
scenarios depending on whether OPF are finite or vanish in the infinite-volume
limit. In particular, we discuss replica equivalence and its natural
consequence when OPF are finite. As an example of
a model where OPF vanish and replica equivalence does not give information
about G we study the Sherrington-Kirkpatrick spherical spin-glass model by
doing numerical simulations for small sizes. Again we find results compatible
with G=1/3 in the spin-glass phase.Comment: 18 pages, 9 postscript figure
Distributed-memory large deformation diffeomorphic 3D image registration
We present a parallel distributed-memory algorithm for large deformation
diffeomorphic registration of volumetric images that produces large isochoric
deformations (locally volume preserving). Image registration is a key
technology in medical image analysis. Our algorithm uses a partial differential
equation constrained optimal control formulation. Finding the optimal
deformation map requires the solution of a highly nonlinear problem that
involves pseudo-differential operators, biharmonic operators, and pure
advection operators both forward and back- ward in time. A key issue is the
time to solution, which poses the demand for efficient optimization methods as
well as an effective utilization of high performance computing resources. To
address this problem we use a preconditioned, inexact, Gauss-Newton- Krylov
solver. Our algorithm integrates several components: a spectral discretization
in space, a semi-Lagrangian formulation in time, analytic adjoints, different
regularization functionals (including volume-preserving ones), a spectral
preconditioner, a highly optimized distributed Fast Fourier Transform, and a
cubic interpolation scheme for the semi-Lagrangian time-stepping. We
demonstrate the scalability of our algorithm on images with resolution of up to
on the "Maverick" and "Stampede" systems at the Texas Advanced
Computing Center (TACC). The critical problem in the medical imaging
application domain is strong scaling, that is, solving registration problems of
a moderate size of ---a typical resolution for medical images. We are
able to solve the registration problem for images of this size in less than
five seconds on 64 x86 nodes of TACC's "Maverick" system.Comment: accepted for publication at SC16 in Salt Lake City, Utah, USA;
November 201
On the Move to Meaningful Internet Systems: OTM 2015 Workshops: Confederated International Workshops: OTM Academy, OTM Industry Case Studies Program, EI2N, FBM, INBAST, ISDE, META4eS, and MSC 2015, Rhodes, Greece, October 26-30, 2015. Proceedings
International audienceThis volume constitutes the refereed proceedings of the following 8 International Workshops: OTM Academy; OTM Industry Case Studies Program; Enterprise Integration, Interoperability, and Networking, EI2N; International Workshop on Fact Based Modeling 2015, FBM; Industrial and Business Applications of Semantic Web Technologies, INBAST; Information Systems, om Distributed Environment, ISDE; Methods, Evaluation, Tools and Applications for the Creation and Consumption of Structured Data for the e-Society, META4eS; and Mobile and Social Computing for collaborative interactions, MSC 2015. These workshops were held as associated events at OTM 2015, the federated conferences "On The Move Towards Meaningful Internet Systems and Ubiquitous Computing", in Rhodes, Greece, in October 2015.The 55 full papers presented together with 3 short papers and 2 popsters were carefully reviewed and selected from a total of 100 submissions. The workshops share the distributed aspects of modern computing systems, they experience the application pull created by the Internet and by the so-called Semantic Web, in particular developments of Big Data, increased importance of security issues, and the globalization of mobile-based technologies
Application-motivated, holistic benchmarking of a full quantum computing stack
Quantum computing systems need to be benchmarked in terms of practical tasks they would be expected to do. Here, we propose 3 "application-motivated" circuit classes for benchmarking: deep (relevant for state preparation in the variational quantum eigensolver algorithm), shallow (inspired by IQP-type circuits that might be useful for near-term quantum machine learning), and square (inspired by the quantum volume benchmark). We quantify the performance of a quantum computing system in running circuits from these classes using several figures of merit, all of which require exponential classical computing resources and a polynomial number of classical samples (bitstrings) from the system. We study how performance varies with the compilation strategy used and the device on which the circuit is run. Using systems made available by IBM Quantum, we examine their performance, showing that noise-aware compilation strategies may be beneficial, and that device connectivity and noise levels play a crucial role in the performance of the system according to our benchmarks
WebFlow - A Visual Programming Paradigm for Web/Java Based Coarse Grain Distributed Computing
We present here the recent work at NPAC aimed at developing WebFlow---a general purpose Web based visual interactive programming environment for coarse grain distributed computing. We follow the 3-tier architecture with the central control and integration WebVM layer in tier-2, interacting with the visual graph editor applets in tier-1 (front-end) and the legacy systems in tier-3. WebVM is given by a mesh of Java Web servers such as Jeeves from JavaSoft or Jigsaw from MIT/W3C. All system control structures are implemented as URL-addressable servlets which enable Web browser-based authoring, monitoring, publication, documentation and software distribution tools for distributed computing. We view WebFlow/WEbVM as a promising programming paradigm and coordination model for the exploding volume of Web/Java software, and we illustrate it in a set of ongoing application development activities
High-performance computing: the essential tool and the essential challenge
[EN] Prolog to the Journal of Supercomputing, volume 73, issue 1.We would also like to acknowledge to the “Ministerio de Educación y Ciencia” of Spain, for its support to the Spanish CAPAP-H5 network (HPC in Heterogeneous Systems, TIN2014-53522-REDT), and to the “Ministerio de Economía y Competitividad” from Spain/FEDER for supporting Grants TEC2015-67387-C4-1-R and TEC2015-67387-C4-3-R.Alonso-Jordá, P.; Ranilla, J.; Vigo-Aguiar, J. (2017). High-performance computing: the essential tool and the essential challenge. The Journal of Supercomputing. 73(1):1-3. https://doi.org/10.1007/s11227-016-1922-5S1373
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