检索结果-内蒙古大学图书馆

Algorithmic Differentiation of a Complex C++ Code with Underlying Libraries

Procedia Computer Science 2013年 18卷 208-217页

作者： Max Sagebaum Nicolas R. Gauger Uwe Naumann Johannes Lotz Klaus Leppkes Computational Mathematics Group Department of Mathematics and Center for Computational Engineering Science (CCES) RWTH Aachen University Schinkelstr. 2 52062 Aachen Germany Software and Tools for Computational Engineering (STCE) RWTH Aachen University Süsterfeldstr. 65 52072 Aachen Germany

Algorithmic differentiation (AD) is a mathematical concept which evolved over the last decades to a very robust and well understood tool for computation of derivatives. It can be applied to mathematical algorithms, codes for numerical simulation, and whenever derivatives are needed. In this paper we report on the algorithmic differentiation of the discontinuous Galerkin solver padge , a large and complex code written in C++ with underlying external libraries. The reports on successful application of AD to large scale codes are rare in literature and up to now this is not state of the art. Most of the codes, which are differentiated nowadays, are written in C or Fortran. The padge code was differentiated with the operator overloading tool dco / c ++ in forward as well as reverse mode. The differentiated code is validated and runs in the expected time margins of AD.

关键词： Automatic differentiation Algorithmic differentiation AD dco deal.II Sacado PETSc external functions

来源：评论

学校读者我要写书评

暂无评论

A wish list for efficient adjoints of one-sided MPI communication

A wish list for efficient adjoints of one-sided MPI communic...

引用

19th European MPI Users' Group Meeting on Recent Advances in the Message Passing Interface, EuroMPI 2012

作者： Schanen, Michel Naumann, Uwe LuFG Informatik 12: Software and Tools for Computational Engineering RWTH Aachen University Germany

ISBN: (纸本)9783642335174

We present a generic approach to transforming one-sided MPI communication in the context of adjoint code. The adjoint allows us to compute gradients of multivariate function implementations at a computational cost that is independent of the size of these gradients. In this paper, we apply the adjoint model to codes containing one-side MPI communication. The Partitioned Global Address Space notation is used to derive the corresponding adjoint code. Our adjoint solutions rely on certain workarounds due to limited adjoint support in the current MPI standard. To avoid these, we provide a wish list for future MPI standards that potentially lead to a more efficient adjoint communication. © 2012 Springer-Verlag.

关键词： Codes (symbols)

来源：评论

学校读者我要写书评

暂无评论

Adjoining hybrid parallel code

Adjoining hybrid parallel code

引用

8th International Conference on engineering computational Technology, ECT 2012

作者： Schanen, M. Foerster, M. Lotz, J. Leppkes, K. Naumann, U. Software and Tools for Computational Engineering Dept. LuFG Informatik 12 RWTH Aachen University Germany

ISBN: (纸本)9781905088553

OpenMP and MPI are typically used in combination to implement distributed shared memory parallelization schemes for numerical simulations on hybrid systems. The performance of said numerical simulations is frequently linked to the efficient and accurate computation of derivatives. One method of acquiring this derivative information for a given code is algorithmic differentiation (AD). AD implementations are subdivided into either source transformation or overloading tools. We investigate a generic approach of applying AD tools on hybrid parallel codes. A dense matrixmatrix multiplication serves as a case study. © Civil-Comp Press, 2012.

关键词： Hybrid systems

来源：评论

学校读者我要写书评

暂无评论

Hierarchical algorithmic differentiation a case study 1

引用

6th International Conference on Automatic Differentiation, AD 2012

作者： Lotz, Johannes Naumann, Uwe Ungermann, Jörn Lehr- und Forschungsgebiet Informatik 12: Software and Tools for Computational Engineering RWTH Aachen University Aachen 52056 Germany Research Center Jülich GmbH Jülich 52425 Germany

ISBN: (数字)9783642300233

ISBN: (纸本)9783642300226

This case study in Algorithmic Differentiation (AD) discusses the semi-automatic generation of an adjoint simulation code in the context of an inverse atmospheric remote sensing problem. In-depth structural and performance analyses allow for the run time factor between the adjoint generated by overloading in C++ and the original forward simulation to be reduced to 3. 5. The dense Jacobian matrix of the underlying problem is computed at the same cost. This is achieved by a hierarchical AD using adjoint mode locally for preaccumulation and by exploiting interface contraction. For the given application this approach yields a speed-up over black-box tangent-linear and adjoint mode of more than 170. Furthermore, the memory consumption is reduced by a factor of 1,000 compared to applying black-box adjoint mode. © 2012 Springer-Verlag.

关键词： Jacobian matrices

来源：评论

学校读者我要写书评

暂无评论

Towards the Application of Algorithmic Differentiation on the NAG Library

Towards the Application of Algorithmic Differentiation on th...

引用

2012 4th International Conference on Computer engineering and Technology(ICCET 2012)

作者： Bui Ngoc Linh Johannes Lotz Jan Riehme Uwe Naumann The Sirindhorn International Thai-German Graduate School of Engineering (TGGS) King Mongkut's University of Technology North Bangkok (KMUTNB) Bangkok Thailand LuFG Informatik 12: Software and Tools for Computational Engineering RWTH Aachen UniversityAachen Germany

Algorithmic differentiation is a growing area of research that is concerned with the accuracy and efficient evaluation of derivatives for numerical functions defined by computer programs. In this paper, algorithmic differentiation by overloading is introduced and applied to the linear solver F07AEF of the NAG library. As a case study and for the verification purpose, its result is used to compute the sensitivity of the Newton method in solving a nonlinear system of equation generated by a minimum problem. The function chosen for the case study is Extended Rosenbrock function.

关键词： Algorithmic differentiation, Tangent-linear model, Algorithmic differentiation by overloading, Linear solver, Newton method.

来源：评论

学校读者我要写书评

暂无评论

Interpretative adjoints for numerical simulation codes using MPI

引用

Procedia Computer Science 2010年第1期1卷 1825-1833页

作者： Michel Schanen Uwe Naumann Laurent Hascoët Jean Utke LuFG Informatik 12: Software and Tools for Computational Engineering RWTH Aachen University Projet TROPICS INRIA Sophia-Antipolis Mathematics and Computer Science Division Argonne National Laboratory Argonne

An essential performance and correctness factor in numerical simulation and optimization is access to exact derivative information. Adjoint derivative models are particularly useful if a function’s number of inputs far exceeds the number of outputs. The propagation of adjoints requires the data flow to be reversed, implying the reversal of all communication in programs that use message-passing. This paper presents recent advances made in developing the adjoint MPI library AMPI. The described proof of concept aims to serve as the basis for coupling other overloading AD tools with AMPI. We illustrate its use in the context of a specific overloading tool for algorithmic differentiation (AD) for C++ programs. A simplified but representative application problem is discussed as a case study.

关键词： Adjoint MPI Automatic differentiation Source transformation

来源：评论

学校读者我要写书评

暂无评论

On the use of discrete adjoints in goal error estimation for shallow water equations

引用

Procedia Computer Science 2010年第1期1卷 107-115页

作者： Florian Rauser Jan Riehme Klaus Leppkes Peter Korn Uwe Naumann Max-Planck-Institut für Meteorologie Bundesstr. 53 20146 Hamburg Germany Department of Computer Science University of Hertfordshire Hatfield AL10 9AB UK LuFG Informatik 12: Software Tools for Computational Engineering RWTH Aachen University 52056 Aachen Germany

Goal oriented dual weight error estimation has been used in context of computational fluid dynamics for several years. The adaptation of this method to geophysical models is the subject of this paper. A differentiation-enabled prototype of the NAG Fortran compiler is used to generate a discrete adjoint version of such a geophysical model and allows to compute the required goal sensitivities. Numerical results are presented for a shallow water configuration of the Icosahedral Non-hydrostatic General Circulation Model (ICON). A special treatment of the underlying linear solver is discussed yielding improved scalability of this approach and a significant reduction in memory consumption and runtime.

关键词： Goal error estimation Discrete adjoint Derivative code compiler

来源：评论

学校读者我要写书评

暂无评论

Probabilistic Risk Assessment: Impact of Human Factors on Nondestructive Evaluation and Sensor Degradation on Structural Health Monitoring

引用

AIP Conference Proceedings 2007年第1期894卷

作者： John C. Aldrin Enrique A. Medina Daniel A. Allwine Mohammed QadeerAhmed Joseph Fisher Jeremy S. Knopp Eric A. Lindgren Computational Tools Gurnee IL 60031 Enrique Medina & Associates P.O. Box 340646 Dayton OH 45430 Austral Engineering & Software Inc. Dayton OH 45430 Air Force Research Laboratory AFRL/MLLP Wright‐Patterson AFB OH 45433

Managing human factors in nondestructive evaluation is critical for maintaining inspection reliability. Reliability of structural health monitoring systems is particularly sensitive to sensor degradation over time. To investigate the impact of these issues, probabilistic models for risk assessment and cost‐benefit analysis tools have been developed. Quantitative studies are presented evaluating the effects of variations in probability of detection associated with human factors, plus in‐situ sensor degradation effects on life cycle measures such as cost and probability of failure.

关键词：

来源：评论

学校读者我要写书评

暂无评论

Computing Adjoints with the NAGWare Fortran 95 Compiler

Lecture Notes in Computational Science and Engineering

引用

Lecture Notes in computational Science and engineering 2006年 50卷 159-169页

作者： Naumann, Uwe Riehme, Jan Software and Tools for Computational Engineering RWTH Aachen University Aachen Germany Department of Mathematics Humboldt University Berlin Berlin Germany

ISBN: (纸本)9783540284031

We present a new experimental version of the differentiation-enabled NAGWare Fortran 95 compiler (from now on referred to as "the AD compiler") that provides support for the computation of adjoints in the reverse mode of automatic differentiation (AD) [42, 136, 227]. Our implementation uses split program reversal [225, Chapter 10] in conjunction with a stack of gradients of all assignments executed inside the active section. Two papers describe the modifications of the compiler infrastructure that were required to provide forward-mode AD capabilities [126, 401]. The reverse mode presented in this paper makes extensive use of these features. Special emphasis is put on the presentation of the new user interface that provides a very easy and intuitive way for initiating derivative computations as well as for addressing the results. Various language extensions are introduced for this purpose. The compiler front-end is modified to accept these new constructs syntactically and semantically. The use of the language extensions triggers the automatic generation of derivative codes of various kinds by the compiler.

关键词： User interfaces

来源：评论

学校读者我要写书评

暂无评论

Cost Benefit Analysis Tool Incorporating Probabilistic Risk Assessment for Structural Health Monitoring

引用

AIP Conference Proceedings 2006年第1期820卷 1910-1918页

作者： John C. Aldrin Enrique A. Medina Jeremy Knopp 1Computational Tools Gurnee IL 60031 2Austral Engineering & Software Inc. Dayton OH 45430 3Air Force Research Laboratory (AFRL/MLLP) Wright‐Patterson AFB OH 45433

Prior work presented the development of a software platform for integrating NDI design and product life management tools to perform design tradeoffs in terms of cost and reliability. This work explores the development of probabilistic model components representing structural health monitoring systems, addressing the use of secondary NDE inspections and SHM system degradation. A discussion is presented concerning opportunities and pitfalls of SHM applications through both a qualitative survey and quantitative studies.

关键词：

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：