Automatic first- and second-order adjoints for truncated Newton

Uwe Naumann, M. Maier, Jan Riehme, B. Christianson

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Abstract

    The analysis and modification of numerical programs in the context of
    generating and optimizing adjoint code automatically probably ranges among the
    technically and theoretically most challenging source transformation problems
    known today. A complete compiler for the target language (Fortran in our case)
    is needed to cover the technical side. This amounts to a mathematically motivated
    semantic transformation of the source code that involves the reversal of the flow
    of data through the program. Both the arithmetic complexity and the memory
    requirement can be substantial for large-scale numerical simulations. Finding the
    optimal data-flow reversal schedule turns out to be an NP-complete problem. The same complexity result applies to other domain-specific peephole optimizations.
    In this paper we present a first research prototype of the NAGWare Fortran compiler with the ability to generate adjoint code automatically.Moreover, we discuss an approach to generating second-order adjoint code for use in Newton-type algorithms for unconstrained nonlinear optimization. While the focus of this paper is mostly on the compiler issues some information on the mathematical background will be found helpful for motivational purposes
    Original languageEnglish
    Title of host publicationProcs of the Int Multiconference on Computer Science and Information Technology (IMCSIT)
    Subtitle of host publicationWorkshop on Computer Aspects of Numerical Algorithms (CANA'07)
    EditorsM. Ganzha, M. Paprzycki, T. Pelech-Pilichowski
    PublisherPolskie Towarzystwo Informatyczne
    Pages541-555
    Volume2
    Publication statusPublished - 2007

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