Using the OASIS3-MCT coupling library, the user has full flexibility to reproduce different coupling algorithms. In the components, the sending and receiving routines, respectively oasis_put and oasis_get, can be called at each component 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, or in any other time units as long as the same are used in all components and in the namcouple (see section 2.2.7). This date argument is automatically analysed by the coupling library and depending on the coupling period and the lag chosen by the user for the coupling field in the namcouple (LAG), different coupling algorithms can be reproduced without modifying the component codes themselves.
With OASIS3-MCT, a sequence index specified for a coupling field in the namcouple (SEQ), provides the coupling layer with an ability to detect a deadlock before it happens and exit.
The LAG and SEQ concept are explained in more detail below and some examples are provided.