Achieving accurate and context‐sensitive timing for code optimization

Key computational kernels must run near their peak efficiency for most high‐performance computing (HPC) applications. Getting this level of efficiency has always required extensive tuning of the kernel on a particular platform of interest. The success or failure of an optimization is usually measured by invoking a timer. Understanding how to build reliable and context‐sensitive timers is one of the most neglected areas in HPC, and this results in a host of HPC software that looks good when reported in the papers, but delivers only a fraction of the reported performance when used by actual HPC applications. In this paper, we motivate the importance of timer design and then discuss the techniques and methodologies we have developed in order to accurately time HPC kernel routines for our well‐known empirical tuning framework, ATLAS. Copyright © 2008 John Wiley & Sons, Ltd.     

High-Energy Physics on the Grid: the ATLAS and CMS Experience

In this paper we present the experience of the ATLAS and CMS High-Energy Physics (HEP) experiments at the Large Hadron Collider (LHC) with the LCG/EGEE Grid infrastructure. The activity developed around the following two main lines: large-scale physics and detector simulations and end-user analysis. The LCG/EGEE Grid infrastructure offers a large amount of computing and storage resources and is growing very rapidly. It provides the natural environment for large-scale physics and detector simulations. Also, the analysis of these detector simulation data (and in the near future of the reconstructed data from physics collisions) requires efficient end-users access to Grid resources. In this paper, the main findings and lessons learned in terms of performance, robustness and scalability of the whole system are discussed in detail.     

用有向图实现的ATLAS编译系统中的设备分配

ATLAS是测试领域的流行语言，用其编写的测试程序可在任一个具体的自动化测试平台上工作。设备分配是每个ATLAS编译系统都要面临的任务之一。该文提出了将被测设备与自动化测试平台组成的系统看成是有向图，利用图的遍历算法来实现设备分配过程。     

Minimizing development and maintenance costs in supporting persistently optimized BLAS

The Basic Linear Algebra Subprograms (BLAS) define one of the most heavily used performance‐critical APIs in scientific computing today. It has long been understood that the most important of these routines, the dense Level 3 BLAS, may be written efficiently given a highly optimized general matrix multiply routine. In this paper, however, we show that an even larger set of operations can be efficiently maintained using a much simpler matrix multiply kernel. Indeed, this is how our own project, ATLAS (which provides one of the most widely used BLAS implementations in use today), supports a large variety of performance‐critical routines. Copyright © 2004 John Wiley & Sons, Ltd.     

Code assessment of ATLAS integral effect test simulating main steam-line break accident of an advanced pressurized water reactor

KAERI has been operating an integral effect test facility, Advanced Thermal–Hydraulic Test Loop for Accident Simulation (ATLAS), for accident simulations of advanced pressurized water reactors. As an integral effect test database for major design basis accidents has been accumulated, a domestic standard problem (DSP) exercise using ATLAS was proposed in order to transfer the database to domestic nuclear industries and to contribute to improving the safety analysis technology for pressurized water reactors (PWRs). As the third DSP exercise, a double-ended guillotine break of the main steam-line at an 8% power without loss of off-site power was decided as a target scenario. Seventeen domestic organizations joined this DSP exercise. They include universities, government, and nuclear industries. The participants of DSP-03 were classified into three groups and each group has focused on the specific subject related to the enhancement of the code assessment; (1) scaling capability of the ATLAS test data by comparing with the code analysis for a prototype, (2) multi-dimensional thermal–hydraulic phenomena anticipated during the steam-line break transient, (3) effect of various models in the one-dimensional safety analysis codes.     

基于ATLAS语言的某指示器自动测试程序设计

ATLAS语言的广泛应用在于其以信号为基础,面向测试对象,独立于测试设备等特点,是测试领域通用的用于编写测试程序和描述测试需求的语言.详细介绍了系统的设计过程,利用VC+ +6.0软件编写某指示器的自动测试程序,对该指示器磁航向系统航向精度进行测试并通过ATLAS语言来实现,最后通过GPTS3.0通用自动测试平台和ATLAS语言来实现测试环境搭建及测试结果输出.测试结果表明,基于ATLAS语言的某指示器自动测试程序可以成功得到预期的测试结果.     

LHC and the dark matter search: A review

The restart of the Large Hadron Collider (LHC) at CERN, foreseen in November 2009 after the incident of 2008, will finally open a new window on the physics at the TeV scale and will allow the discovery of the Standard Model Higgs boson, if it exists, or of possible alternative schemes for the spontaneous symmetry-breaking mechanism. Moreover the LHC Collider will hopefully provide an answer to one of the most compelling questions of today coming from astronomical observations, astrophysics and cosmic ray experiments: which is the particle physics candidate for the Dark Matter component of the Universe? Supersymmetry (SUSY) is a theoretically attractive scenario for physics beyond the Standard Model which can provide a suitable Dark Matter candidate in case R-parity is conserved. If SUSY is manifesting at the TeV scale, as favored by several arguments, it will be accessible at the LHC Collider within the first few years of data taking. In this paper search strategies for a generic SUSY models with R-parity conservation with the ATLAS detector are described. These inclusive search strategies are based on signatures with missing transverse momentum from undetected neutralinos, in addition to multiple hard jets and leptons. The corresponding discovery reach for the first fb⁻¹ of integrated luminosity of ATLAS data will be presented together with a discussion of possible measurements needed to extract the masses of SUSY particles including the Lightest Supersymmetric Particle (LSP), which in various supersymmetric (SUSY) symmetry breaking scenarios, is the lightest neutralino .     

基于ATLAS语言的航空自动测试系统的设计与实现

在简要介绍ATLAS语言的基础上,结合某型航空自动测试系统的研制,详细介绍了基于ATLAS语言的航空自动测试系统的组成及特点.     

基于IVI的ATLAS驱动程序开发技术

本文首先介绍了IVI规范以及ATLAS语言。针对ATLAS中信号语句的实现问题。介绍了一种基于IVI的ATLAS驱动程序开发方法．即采用COM技术。在ATLAS上层程序和IVI驱动程序间建立一个信号接口,从而实现测试程序与底层仪器设备之间的交互通信。实践表明,这种方法在充分利用现有技术的基础上,很好地保证了仪器的可互换性和TPS的可移植性。     

A separate effect test on the cooling behavior in a pressurized water reactor core under a low reflooding rate condition by using ATLAS and RELAP5/MOD3.3 code assessment

A separate effect test was performed on the cooling behavior in a PWR core under a low reflooding rate condition by using the ATLAS (Advanced Thermal–Hydraulic Test Loop for Accident Simulation) which is a thermal–hydraulic integral effect test facility for the pressurized water reactors APR1400 and OPR1000. Although several integral tests for the reflood phase of a large break loss of coolant accident (LBLOCA) of APR1400 have been performed with the ATLAS, the previous integral effect tests for the reflood phase of a LBLOCA are not easily simulated by existing codes, such as the RELAP5/MOD3, due to a unique phenomena in ATLAS, that resulted from an injection of large amount of subcooled water onto the heated wall of which temperature was higher than the target value.