Coupling algorithms - SEQ and LAG concepts

Using PSMILe library, the user has full flexibility to reproduce different coupling algorithms, without modifying the component model codes themselves. In the component codes, the sending and receiving routines, respectively prism_put_proto and prism_get_proto, can be called at each model timestep, with the appropriate date argument giving the actual time (at the beginning of the timestep), expressed in ``number of seconds since the start of the run''. This date argument is automatically analysed by the PSMILe and depending on the coupling period, the lag and sequencing indices (LAG and SEQ), chosen by the user for each coupling field in the configuration file namcouple, different coupling algorithms can be reproduced without modifying anything in the component model codes themselves. The lag and sequence concepts and indices are explained in more details here below. These mechanisms are valid for fields exchanged through OASIS3 main process and for fields exchanged directly between the component models.

• The lag concept
• The sequence concept
• A mix of lag and sequence: the sequential coupled model
• Mixing sequential and parallel runs using prism_put_restart_proto