Welcome to the TROPICS team public web site

TROPICS is a research team of INRIA in Sophia-Antipolis, France

Latest version of our A.D. tool:
TAPENADE, version 3
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Our research themes and objectives :

We study Automatic Differentiation (A.D.) of algorithms and programs, from the point of view of Software analysis and transformation on one hand, and from the point of view of applications in Scientific Computing on the other hand. Our name is an acronym for "TRansformations et Outils Informatiques Pour le Calcul Scientifique", which means just that! We take into account the specific requirements of real large-scale scientific programs. Our team is composed of numerical analysis specialists, who bring their knowledge of scientific computing, and of software engineering specialists, who bring their knowledge of program analysis, transformation, and compilation.

We work at the junction of two research domains:

A.D. theory: On the one hand, we study A.D. as a software engineering techniques, to analyze and transform programs semi-automatically. A.D. transforms a program P that computes a function F, into a program P' that computes some derivatives of F, analytically. See our discussion about "What is A.D.?". We put a particular emphasis on the reverse mode of A.D. (sometimes called adjoint mode), which yields gradients for optimization at a remarkably low cost. The reverse mode of A.D. requires carefully crafted algorithms. There are computer science problems such as complexity of the computation of derivatives, memory usage for the reverse mode, or variable aliasing.
A.D. application to Scientific Computing: On the other hand, we study the application of A.D., and particularly of the adjoint mode, to e.g. Computational Fluid Dynamics. This involves adapting the strategies used in Scientific Computing, in order to take full advantage of A.D.. There are mathematical questions such as the behavior of A.D. in a neighborhood of program discontinuities (tests...), the convergence of derivatives compared to convergence of initial results, or the complexity of various A.D. strategies. This research is applied to several real-size applications.

A.D. is a relatively young and very interesting domain, as can be seen in the proceedings of conferences AD2000, AD04 Link to a different Web site

, AD08

, or from the www.autodiff.org

site for the Automatic Differentiation community, managed by our colleagues in Aachen and Argonne

Our ideas need to be validated in some testbench. Moreover, we want our research to be applicable to real-life programs. To this end, we develop the A.D. tool TAPENADE. See the TAPENADE links on the left for more information on the tool.

Links, collaborations :

The NODESIM European project, in which we contribute research on sensitivity analysis using second-order derivatives.
The European Workshops on Automatic Differentiation, that we co-organize twice a year together with Bruce Christianson (Univ. of Hetfordshire, UK), Shaun Forth (Cranfield University, Shrivenham, UK), and Martin Buecker (RWTH Aachen, Germany).
The 42nd "Colloque d'Aérodynamique Appliquée, Couplages et optimisation Multidisciplinaires" Sophia-Antipolis, March 2007.
The national research program "COS" on supersonic planes. See pages on sonic boom and on turbulence.
The European program HISAC on shape optimisation in CFD

Some recent news :

At least these news were recent upon last update!!

September 2010: Alain Dervieux presents a paper on "Application of hybrid and VMS-LES turbulent models to aerodynamic simulations" at the ICAS 2010 congress in Nice, France, September 19-24.
June 2010: Anca Belme presents a paper on Fully anisotropic goal-oriented mesh adaptation for unsteady flows at the ECCOMAS-CFD 2010 conference in Lisbon, Portugal, June 14-17.
June 2010: The 10th European Workshop on Automatic Differentiation takes place on June 3-4 in Paderborn, Germany.
May 2010: Michel Schanen, from RWTH Aachen, presents a common paper on "Interpretative Adjoints for Numerical Simulation Codes using MPI" at ICCS 2010, Amsterdam, The Netherlands.
May 2010: The teams involved in the ANR project EVA-Flo meet in Perpignan, France.
April 2010: We co-organize a scientific meeting on the occasion of Andreas Griewank's 60th birthday. 40 participants from all over the world, reflecting the carrier and achievements of Andreas. Fun is also part of the programme, with three new songs created as a tribute to AD.
April 2010: We organize a one-day meeting at Sophia-Antipolis, on matters related to AD, taking advantage of the presence of four distinguished professors: Jorge More (ANL, Illinois, USA), Ralph Baker Kearfott (University of Louisiana, USA), Trond Steihaug (Universty of Bergen, Norway), and Andreas Griewank (Humboldt University, Berlin, Germany).
... previous news

Last modified: Mon Sep 5 10:19:05 CEST 2011 by the Tropics team Mail to ...