The Specific Coupling Configuration (SCC)

The Specific Coupling Configuration (SCC) contains the general characteristics and process management information of one coupled model simulation. There must be one SCC per coupled model (or per stand-alone application), named scc.xml, and written by the coupled model user either by hand or with the graphical user interface oasis-gui.tcl available in oasis4/util/gui.

The SCC Schema is given in oasis4/util/xmlfiles/scc.xsd.

After the call to prism_init in the application code, some of the SCC information is accessible directly by the model, with specific PSMILe calls (see section 5.2). In many cases, coherence with the compiling and running environment and scripts has to be ensured.

The SCC contains:

• some general information on the experiment defined by the user (element `experiment'):
  • the experiment name (attribute `local_name');

  • a description of the experiment (attribute `long_name');

  • the mode into which all applications of the coupled model will be started (attribute `start_mode': either spawn or not_spawn, see section 4.1); this user's choice, restricted by the possibilities given in the ADs, determines the way the applications should be started in the run script.

  • the number of processes used for the OASIS4 Driver/Transformer (element `nbr_procs' of element `driver') (this number must be equal to zero for a stand alone application)

  • the start date of the experiment (element `start_date')

  • the end date of the experiment (element `end_date')

• some general information on the current run, which therefore must be updated for each run of the experiment (element `run'):
  • the start date of the run (element `start_date'); the start date has to correspond to the lower bound of the time interval which is represented by the first time step of the run.

  • the end date of the run (element `end_date'); the end date has to correspond to the upper bound of the time interval which is represented by the last time step of the run. Note that the end date of the current run has to be used as start date for the subsequent run.

• the list of applications chosen by the user (elements `application'). For each chosen application:
  • the application name (as given in the corresponding AD) (attribute `local_name') which must match argument appl_name of the PSMILe call prism_init ;

  • the application executable name, defined by the compiling environment (attribute `executable_name') (used only in spawn mode as argument of the MPI_Comm_Spawn_Multiple ).

  • whether the application stdout shall be redirected or not (user's choice) (attribute `redirect', either true or false)

  • a list of launching arguments (that should be chosen in the list given in the corresponding AD; used only in spawn mode as argument of the MPI_Comm_Spawn_Multiple ) (elements `argument');

  • a list of hosts (elements `host'); for each host:
    • the host name (attribute `local_name') (used only in spawn mode as argument of the MPI_Comm_Spawn_Multiple ).

    • the number of processes to run this host (element `nbr_procs') (used in the not_spawn method to split the global communicator; for the spawn method, used as argument in MPI_Comm_Spawn_Multiple ).

  • the list of components activated (elements `component', that should be chosen in the list given in the corresponding AD); for each component:
    • the component name (as given in the corresponding AD) (attribute `local_name'), which must match the argument comp_name of PSMILe call prism_init_comp (see 5.1.2);

    • the lists of ranks in the total number of processes for the application (elements `ranks'): The ranks are the numbers of the application processes (starting with zero) used to run the component model. They are given as lists of 3 numbers giving, in each list, a minimum value, a maximum value, and an increment value. For example, if processes numbered 0 to 31 are used to run a component model, this can be describe with one rank list (0, 31, 1); if processes 0 to 2 and 5 to 7 are used, this can be described with two rank lists (0, 2, 1) and (5, 7, 1).