HYDROCODE SENSITIVITIES BY MEANS OF AUTOMATIC DIFFERENTIATION Metadata

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Title

  • Main Title HYDROCODE SENSITIVITIES BY MEANS OF AUTOMATIC DIFFERENTIATION

Creator

  • Author: HENNINGER, R.
    Creator Type: Personal
  • Author: CARLE, A.
    Creator Type: Personal
  • Author: MAUDLIN, P.
    Creator Type: Personal

Contributor

  • Sponsor: United States. Department of Energy.
    Contributor Type: Organization
    Contributor Info: US Department of Energy (United States)

Publisher

  • Name: Los Alamos National Laboratory
    Place of Publication: New Mexico
    Additional Info: Los Alamos National Lab., NM (United States)

Date

  • Creation: 2001-01-01

Language

  • English

Description

  • Content Description: The purpose of this project has been to provide sensitivities of results from an Eulerian hydrodynamics computer code (hydrocode) for use in design-optimization and uncertainty analyses. We began by applying an equation-based sensitivity technique used successfully in the early eighties that was applied to reactor-safety thermal-hydraulics problems, which is called Differential Sensitivity Theory (DST). The methodology is as follows: the system of partial differential equations (the forward or physical PDEs) is assembled, and differentiated with respect to the model parameters of interest; the adjoint equations are then determined using the inner-product rules of Hilbert spaces; and finally, the resulting adjoint PDEs are solved using straightforward numerical operators. The forward-variable solutions when needed for the adjoint solutions are provided by the original computer code that solves the physical (or forward) problem. In the present hydrocode application, acceptable results were obtained for one-material, one-dimensional problems. The DST results were then improved by means of ''compatible'' finite difference operators. We have seen, however, that DST techniques do not produce accurate values for sensitivities to all of the parameters of interest and for problems with discontinuities such as a multi-material problem. To obtain accurate sensitivities for arbitrary numerical resolution a more code-based approach was then tried. We attempted to apply automatic differentiation (AD) in the forward mode using Automatic Differentiation of Fortran (ADIFOR, version 2.0) and the Tangent-linear and Adjoint Model Compiler (TAMC) in the forward and adjoint modes. We were successful for one-dimensional problems in both modes but failed to obtain accurate sensitivities in the adjoint mode for two-dimensional problem. Here we present the successful results for two-dimensional problems in both the forward and adjoint modes using ADIFOR, version 3.0. In what follows, we describe AD methods in the context of their use for a hydrocode. We then examine setup time, results, accuracy, and computer run times for three test problems obtained by ADIFOR. Finally, we outline our plans for future work.
  • Physical Description: 124 Kilobytes pages

Subject

  • Keyword: Computer Codes
  • STI Subject Categories: 99 General And Miscellaneous//Mathematics, Computing, And Information Science
  • Keyword: Two-Dimensional Calculations
  • Keyword: Sensitivity
  • Keyword: Partial Differential Equations
  • Keyword: Hilbert Space
  • Keyword: Hydrodynamics
  • Keyword: Accuracy

Source

  • Conference: Conference title not supplied, Conference location not supplied, Conference dates not supplied

Collection

  • Name: Office of Scientific & Technical Information Technical Reports
    Code: OSTI

Institution

  • Name: UNT Libraries Government Documents Department
    Code: UNTGD

Resource Type

  • Article

Format

  • Text

Identifier

  • Report No.: LA-UR-01-514
  • Grant Number: W-7405-ENG-36
  • Office of Scientific & Technical Information Report Number: 774349
  • Archival Resource Key: ark:/67531/metadc723976
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