A differentiation-enabled Fortran 95 compiler

Naumann, Uwe; Riehme, Jan

doi:10.1145/1114268.1114270

Cited by 24 publications

(13 citation statements)

References 12 publications

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“…This method is applied to a large number of transformation rules currently being implemented in OpenAD [21] and the differentiation-enabled NAGWare Fortran compiler [18]. It is based on analyzing the data dependences in the PGAS versions of the original message-passing program.…”

Section: Discussionmentioning

confidence: 99%

A Framework for Proving Correctness of Adjoint Message-Passing Programs

Naumann

Hascoët

Hill

et al. 2008

Recent Advances in Parallel Virtual Machine and Message Passing Interface

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Section: Discussionmentioning

confidence: 99%

A Framework for Proving Correctness of Adjoint Message-Passing Programs

Naumann

Hascoët

Hill

et al. 2008

Recent Advances in Parallel Virtual Machine and Message Passing Interface

Self Cite

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“…To generate the routine adjoint timestep, we apply the AD-enabled NAGWare Fortran compiler that was developed by the University of Hertfordshire and RWTH Aachen University in collaboration with NAG Ltd. The compiler provides forward [12] and reverse modes [11] of AD by operator overloading as well as by source transformation [9].…”

Section: Optimal Flow Controlmentioning

confidence: 99%

MultiStage Approaches for Optimal Offline Checkpointing

Stumm¹,

Walther²

2009

SIAM J. Sci. Comput.

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The computation of derivatives for optimizing time-dependent flow problems is often based on the integration of the adjoint differential equation. For this purpose, the knowledge of the complete forward solution is required. In the area of flow control, especially for three-dimensional problems, it may be impossible to keep track of the full forward solution due to the lack of storage capacities. One usual method to overcome this problem is checkpointing. Using a checkpointing strategy, only parts of the forward solution are kept in the main memory and additional time steps have to be performed. If one extends this approach such that some checkpoints can be stored on disc too, one can reduce the number of additional time steps. On the other hand, one has to take the access cost to one checkpoint into account. On parallel machines, one may use parallel I/O facilities to store and retrieve checkpoints. In these cases, the access cost of the checkpoints is also no longer negligible. Therefore, in this paper, the write and read counts for each checkpoint in a binomial checkpointing approach are examined. This way, the overall access cost to checkpoints is minimized. Numerical results illustrate the derived checkpointing approaches. They also show that checkpointing techniques may reduce the overall computing time despite the required recalculations.

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“…In detail, we compare adjoint codes generated by Transformation of Algorithms in Fortran (TAF) [18] and Open_AD [19] and TAPENADE [20] as the AD tools representing SCT approach. As for the OO based AD tool, we choose NAGWare [21]. All these AD tools have the tangent linear and adjoint mode for differentiation.…”

Section: Introductionmentioning

confidence: 99%

The efficiency of geophysical adjoint codes generated by automatic differentiation tools

Vlasenko

Köhl

Stammer

2016

Computer Physics Communications

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The accuracy of numerical models that describe complex physical or chemical processes depends on the choice of model parameters. Estimating an optimal set of parameters by optimization algorithms requires knowledge of the sensitivity of the process of interest to model parameters. Typically the sensitivity computation involves differentiation of the model, which can be performed by applying algorithmic differentiation (AD) tools to the underlying numerical code. However, existing AD tools differ substantially in design, legibility and computational efficiency. In this study we show that, for geophysical data assimilation problems of varying complexity, the performance of adjoint codes generated by the existing AD tools (i) Open_AD, (ii) Tapenade, (iii) NAGWare and (iv) Transformation of Algorithms in Fortran (TAF) can be vastly different. Based on simple test problems, we evaluate the efficiency of each AD tool with respect to computational speed, accuracy of the adjoint, the efficiency of memory usage, and the capability of each AD tool to handle modern FORTRAN 90-95 elements such as structures and pointers, which are new elements that either combine groups of variables or provide aliases to memory addresses, respectively. We show that, while operator overloading tools are the only ones suitable for modern codes written in object-oriented programming languages, their computational efficiency lags behind source transformation by orders of magnitude, rendering the application of these modern tools to practical assimilation problems prohibitive. In contrast, the application of source transformation tools appears to be the most efficient choice, allowing handling even large geophysical data assimilation problems. However, they can only be applied to numerical models written in earlier generations of programming languages. Our study indicates that applying existing AD tools to realistic geophysical problems faces limitations that urgently need to be solved to allow the continuous use of AD tools for solving geophysical problems on modern computer architectures. (C) 2015 Elsevier B.V. All rights reserved

show abstract

A differentiation-enabled Fortran 95 compiler

Cited by 24 publications

References 12 publications

A Framework for Proving Correctness of Adjoint Message-Passing Programs

A Framework for Proving Correctness of Adjoint Message-Passing Programs

MultiStage Approaches for Optimal Offline Checkpointing

The efficiency of geophysical adjoint codes generated by automatic differentiation tools

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