Capacités actuelles de la Différentiation Automatique: l'adjoint d'OPA par TAPENADE

Bruno Ferron (IFREMER, Laboratoire de Physique des Océans, 29280 PLOUZANE, France) Laurent Hascoët (INRIA, BP93, 06902 Sophia-Antipolis, France)

Proceedings of the Colloque National sur l'Assimilation de Données, May 9-10, 2006, Toulouse, France (6 pages, in French)

Abstract: Variational Data Assimilation relies on Adjoint Codes, which can either be written by hand, or generated through Automatic Differentiation (AD) of the program that solves the initial direct equations. AD tools have been around for about twenty years. They now have reached a sufficient maturity to produce adjoint codes automatically in a few minutes, with a quality that is comparable to hand written adjoints. After a brief summary of the principles of adjoint or reverse AD, we describe the state of the art for this field of AD. We put a particular emphasis on the advancement of the AD tool "TAPENADE", developed by the TROPICS team of INRIA. We illustrate the capacities of AD and of TAPENADE with the generation of the adjoint of the oceanography code OPA 9.0.

Keywords: Automatic Differentiation, Adjoint code, TAPENADE, Reverse mode AD, 4D-Var Variational Data Assimilation, Oceanography, OPA

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@inproceedings{FerronHascoet06,
  author = {Ferron, B. and Hasco\"et, L.},
  title = {Capacit\'es actuelles de la Diff\'erentiation Automatique: l'adjoint d'OPA par TAPENADE},
  booktitle = {Colloque National sur l'Assimilation de Donn\'ees, Toulouse, France},
  year = 2006
}