Publications

Results 101–150 of 165

Search results

Jump to search filters

Efficient expression templates for operator overloading-based automatic differentiation

Lecture Notes in Computational Science and Engineering

Phipps, Eric T.; Pawlowski, Roger

Expression templates are a well-known set of techniques for improving the efficiency of operator overloading-based forward mode automatic differentiation schemes in the C++ programming language by translating the differentiation from individual operators to whole expressions. However standard expression template approaches result in a large amount of duplicate computation, particularly for large expression trees, degrading their performance. In this paper we describe several techniques for improving the efficiency of expression templates and their implementation in the automatic differentiation package Sacado (Phipps et al., Advances in automatic differentiation, Lecture notes in computational science and engineering, Springer, Berlin, 2008; Phipps and Gay, Sacado automatic differentiation package. http://trilinos.sandia.gov/packages/sacado/, 2011). We demonstrate their improved efficiency through test functions as well as their application to differentiation of a large-scale fluid dynamics simulation code. © 2012 Springer-Verlag.

More Details
TYPE Conference YEAR 2012
OSTIScopus

Automating embedded analysis capabilities and managing software complexity in multiphysics simulation, Part I: Template-based generic programming

Scientific Programming

Pawlowski, Roger; Phipps, Eric T.; Salinger, Andrew G.

An approach for incorporating embedded simulation and analysis capabilities in complex simulation codes through template-based generic programming is presented. This approach relies on templating and operator overloading within the C++ language to transform a given calculation into one that can compute a variety of additional quantities that are necessary for many state-of-the-art simulation and analysis algorithms. An approach for incorporating these ideas into complex simulation codes through general graph-based assembly is also presented. These ideas have been implemented within a set of packages in the Trilinos framework and are demonstrated on a simple problem from chemical engineering. © 2012 - IOS Press and the authors. All rights reserved.

More Details
TYPE Journal Article YEAR 2012
ScopusOSTIDOI

Capabilities for Uncertainty in Predictive Science (LDRD Final Report)

Phipps, Eric T.; Eldred, Michael; Salinger, Andrew G.

Predictive simulation of systems comprised of numerous interconnected, tightly coupled components promises to help solve many problems of scientific and national interest. However predictive simulation of such systems is extremely challenging due to the coupling of a diverse set of physical and biological length and time scales. This report investigates un-certainty quantification methods for such systems that attempt to exploit their structure to gain computational efficiency. The traditional layering of uncertainty quantification around nonlinear solution processes is inverted to allow for heterogeneous uncertainty quantification methods to be applied to each component in a coupled system. Moreover this approach allows stochastic dimension reduction techniques to be applied at each coupling interface. The mathematical feasibility of these ideas is investigated in this report, and mathematical formulations for the resulting stochastically coupled nonlinear systems are developed.

More Details
TYPE SAND Report YEAR 2008
DOIOSTI
Results 101–150 of 165
Results 101–150 of 165