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Code coupling using CWIPI

  Monday 3 April 2023


Cerfacs is Qualiopi certified for its training activities

Duration : 1 day / 7 hours

Satisfaction index

In April 2023, 100% of participants were very satisfied

(results collected from 9 respondents out of 9 participants, a response rate of 100%)


A coupler is a software that allows the simultaneous execution and communication between several programs that were not specifically designed for this purpose. In addition to the exchange of information, the coupler can handle many tasks, for example intermediate calculations on the exchanged data, interpolation on different meshes, redistribution of data during parallel computing. The CWIPI coupler developed at ONERA, widely used by Cerfacs which also develops under the governance of ONERA, has many features and has very good parallel performance. Once taken in hand, the implementation of coupling cases is easy. The current application cases with this coupler are very broad, especially in the multi-physics domains where several solvers of different physics are coupled.

Objective of the training

The goal of the CWIPI training is to understand the concepts around the coupler and to learn how to use the interface of the CWIPI routines to quickly become autonomous on the instrumentation of the codes to be coupled and the use of the various features of the coupler. This training is very pragmatic with practical works. The CWIPI training is given by Cerfacs researchers who participate in its development.

Learning outcomes

Learn the main functionalities of CWIPI and how to use them.

At the end of the training, you will be able to:

– use autonomously the coupler to set up a coupling between calculation codes,

– find the relevant information in the manual to solve future problems you will encounter.

Teaching methods

The training is an alternation of theoretical presentations and practical work. A multiple choice question allows the final evaluation. The training room is equipped with computers, the work can be done in sub-groups of two people.

Referent teacher: Florent Duchaine

Target participants

This course is for engineers, physicists, computer scientists and numerical scientists who wish to develop or use coupled applications.


In order to follow this course, you must:

  • know how to use basic Linux commands,
  • be familiar with one of the following two programming languages: Fortran or C,
  • the training can take place in French or English depending on the audience, level B2 of the CEFR is required.

In order to verify that the prerequisites are satisfied, the following questionnaires must be completed. You need to get at least 75% of correct answers in order to be authorized to follow this training session. If you don’t succeed it, your subscription will not be validated. You only have two chances to complete it.

Questionnaire 1 : https://goo.gl/forms/nvxqmtG2odTJcflW2

Questionnaire 2 : https://goo.gl/forms/4D0iXqZLSpCoO0tw1


After completing the pre-requisite test and obtaining at least 75% correct answers, you can register here

Deadline for registration: 15 days before the starting date of each training

Before signing up, you may wish to report us any particular constraints (schedules, health, unavailability…) at the following e-mail address : training@cerfacs.fr


  • Trainees/PhDs/PostDocs : 112 € excl. tax
  • CERFACS shareholders/CNRS/INRIA : 280 € excl. tax
  • Public : 560 € excl. tax


The training takes place from 9:30 am to 5:30 pm:
– Presentation of the CWIPI library,
– First handling through a simplified exercise,
– Implementation of a coupling on a case with mobile geometry.
– Discussion of the results.

Evaluation of learning

A final exam will be conducted during the training.






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