Section: New Results

Differentiation of third-party codes

Participants : Valérie Pascual, Laurent Hascoet, Alain Dervieux.

This year, we have differentiated two applications brought to us by academic colleagues. This is an important activity as it points us to problems that should be solved or interfaces that should be improved in tapenade .

• Striation simulates ionospheric plasma. It was developed in the University of Lille, then Toulouse. The Fortran90 source is relatively compact (10,000 lines). We obtained and validated the tangent and adjoint derivatives that were needed to solve an inverse problem i.e., identify the initial condition that causes an observed instability in plasma density. This work uncovered important AD issues when dynamic memory is used intensively, cf  6.2 .

• Mascaret is a hydrodynamic simulation code developed and used by EDF to study river flows. Mascaret consists of 120,000 lines of Fortran90. In this first experiment, we differentiated only one of the three kernel solvers. We obtained validated tangent and adjoint derivatives. A further collaboration with EDF and CERFACS is planned next year.

In addition, Automatic Differentiation of the CFD code aironum (cf  5.1 ) will continue in cooperation with the partners of the FP7 project UMRIDA.