*Jacek A. Jankowski. *Parallel streamline tracking for Telemac, 15th Telemac User Club, Chatou, 9-10 October 2008.

The Telemac adaptation of the parallel streamline tracking algorithm for the domain decomposition method, originally developed for the MPI version of UnTRIM, is described in detail. The streamline tracking is the integral part of the semi-Lagrangian method of characteristics, being one of the most robust methods for the non-linear momentum advection, working also for larger Courant numbers. The method is however awkward to parallelise in the framework of the point-to-point communication typical for the domain decomposition method. A two-stage algorithm is applied for treatment of tracebacks followed through neighbouring partitions, whereby the final results of tracking and value interpolation at the end of tracebacks (the feet of characteristic curves) are delivered by global communication. The verification of the developments revealed some weaknesses of the given (serial) tracking methodology with difficulties in the reproducibility of the results.

Transparencies are available.