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Code Coupling and User Interface


CERFACS has a strong expertise in the development and use of generic code coupling libraries.The couplers developed at CERFACS are daily used to address complex scientific problems such as:

Chemistry-Atmosphere coupling with OASIS

Chemistry-Atmosphere coupling with OASIS

  • earth system modelisation for climate science
  • multiphysics coupling (heat transfer, fluid/structure interaction …)
  • multi-composant coupling
  • data assimilation
  • multidisciplinary optimization

All these applications rely on the integration of different solvers that interact at different levels between each others following coupling algorithms.


OASIS and OpenPALM couplers are used to make modular and evolutive coupled applications in a user friendly way. The domains of applications go from many types of research fields to industrial uses.

Any type of code can be coupled with different languages (Fortran, C, C++, Python, Perl, R, …) and type of parallelization (from mono-processor to massively parallel). Coupling of commercial solvers is performed thanks to TCP/IP protocols through user defined functions.

Both coupling libraries provide interpolation functionalities when quantities to exchanges are discretized on different meshes. In OASIS, the interpolation is dedicated to geophysical applications while OpenPALM provide a more generic interpolation framework based on an unstructured mesh formalism thanks to the CWIPI library developed by ONERA.

Both OASIS and OpenPALM runs on high performance computers where computation times as well as parallel data exchanges are optimized in order to not penalize the speed up of massively parallel codes.

ESCAPADE project with OpenPALM

ESCAPADE project with OpenPALM

Associated with the Graphical User Interface generator OpenTea, OASIS and OpenPALM are daily used by Cerfacs and its partners involving academic laboratories as well as industrial companies. OASIS and OpenPALM are distributed under the OpenSource license LGPL.

About two training per year are proposed for Oasis and OpenPalm. OASIS and OpenPALM are still under development following users’ requests as well as optimizations and bug corrections. The funding of these actions rely on different collaborations through industrial, national or european projects.



Tribute to Françoise Chatelin

Brigitte Yzel |  23 July 2021

  Tribute to Françoise CHATELIN   Virtual & Face to Face event @ Cerfacs 14 October 2021, CERFACS, Toulouse (France) 2 pm - 6.30 pm   Cerfacs is organizing a half scientific day on Thursday October 14, 2021 in tribute to Françoise Chatelin who left us prematurely on May 14, 2020   After graduating from the Ecole Normale Supérieure in Paris (1960-63), and her PhD in Mathematics at Grenoble University (1971) , Françoise Chatelin led with worldwide recognition her research in many areas, from spectral theory for linear operators in Banach spaces and finite precision to Dickson algebras. Professor Chatelin taught at the Universities Grenoble 2 - Pierre Mendès-France and Paris 9 - Dauphine before moving to Toulouse in 1996. She became Emeritus Professor in 2015. She was a visiting researcher at Berkeley and Stanford Universities, IBM San Jose (Ca) and Yorktown Heights (NY). For almost a decade, she was a scientific manager in Industry (in charge of intensive computing) first at the Centre Scientifique IBM France in Paris (1985 -1992) and then in the Central Research Lab of Thales (known as Thomson-CSF at that time) near Paris (1992-95). Françoise Chatelin was Head of the Qualitative Computing group at the Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (Cerfacs) in Toulouse, France. Professor Chatelin has authored four books; the first three are now classic references available from SIAM. Her second book Valeurs Propres de Matrices (Masson, Paris, 1988) has received the IBM - France prize for « Best Scientific and technical publication 1988 ». Beyond her scientific contribution, Françoise Chatelin played a structuring role on research at CERFACS through multiple thesis on innovative topics. This event is devoted to the human and scientific tribute of her life. As a faithful image of the active and passionate woman that...Read more

CERFACS is involved in the NextSim project

CERFACS |  19 July 2021

The primary objective is to increase the capabilities of Computational Fluid Dynamics tools on extreme-scale parallel computing platforms for aeronautical design. The Kick-Off Meeting took place on 12 March 2021. This project has received funding from the European High-Performance Computing Joint Undertaking (JU) under grant agreement N° 956104. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and Spain, France, Germany. For more information, please visit  EuroHPC website : Project webpage :Read more